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2 <html>
3 <head>
5 </head>
6 <body>
9 <h1>
11 </h1>
12 <h2>
13 <center>
16 </h3>
17 </center>
18 </h2>
20 Cedar Park, Texas. All Rights Reserved. <br>
21 <br>
22 Permission is granted to make and distribute verbatim copies of this
23 document provided the copyright notice and this permission notice are
24 preserved on all copies.<br>
25 </p>
29 This document describes a subset of the Mesa implemented by Tungsten
30 Graphics, Inc. for embedded devices. Prior to reading this
31 document the reader should be familiar with the OpenGL 1.2.1
33 href="http://www.opengl.org/developers/documentation/specs.html">http://www.opengl.org/developers/documentation/specs.html</a>.)
36 </a><br>
37 Tungsten Graphics, Inc. is working with industry standards
38 organizations +in an attempt to standardize this Mesa subset and any
39 other possible subsets +as a result of this work. <br>
40 <br>
41 Appendix A contains a list of issues of which some may not be resolved.<br>
42 <br>
43 To summarize, the following major features of Mesa are omitted from the
44 subset:<br>
45 <ul>
62 </li>
63 </ul>
65 </p>
69 </p>
70 <p>The Tungsten Graphics, Inc. Mesa subset library is hereafter
72 <br>
73 </p>
76 The basic rendering primitives are points, lines and triangles.
77 Quadrilaterals and polygons are composed of triangles.
81 <br>
85 <br>
97 </div>
98 <br>
101 <br>
103 points<br>
104 GL_LINES - a series of disjoint line segments<br>
105 GL_LINE_STRIP - series of connected line segments<br>
106 GL_LINE_LOOP - a closed loop of line segments<br>
107 GL_TRIANGLES - a series of individual triangles<br>
108 GL_TRIANGLE_STRIP - a connected strip of triangles<br>
109 GL_TRIANGLE_FAN - a sequence of triangles all sharing a common vertex<br>
110 GL_QUADS - a sequence of individual quadrilaterals<br>
111 GL_QUAD_STRIP - a connected strip of quadrilaterals<br>
112 GL_POLYGON - a closed, convex polygon<br>
113 <br>
114 </div>
115 <br>
117 or three floating point coordinates, or a pointer to an array of two or
119 homogeneous coordinates. The fourth component, unspecified by the
121 one.<br>
122 <br>
125 </h2>
128 specify colors and texture coordinates for each vertex:<br>
129 <br>
130 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glColor3f</span>(GLfloat<span
148 <br>
149 </div>
151 the color and optionally, the alpha value, for subsequent vertices.
153 alpha is set to one.<br>
154 <br>
156 specify the texture coordinate for subsequent vertices. Texture
157 coordinates are actually four-component coordinates: (s, t, r, q).
159 set s and t explicitly. The r and q components are zero and one,
160 respectively.<br>
161 <br>
169 GL_INVALID_OPERATION.<br>
170 <br>
172 None of the following commands related to primitive specification are
173 supported by the subset:<br>
174 <br>
176 </div>
179 glVertex2i, glVertex2s, glVertex3d, glVertex3i, glVertex3s, glVertex4d,
180 glVertex4i, glVertex4s, glVertex2dv, glVertex2iv, glVertex2sv,
181 glVertex3dv, glVertex3iv, glVertex3sv, glVertex4dv, glVertex4iv,
182 glVertex4sv,<br>
183 glNormal3b, glNormal3d, glNormal3f, glNormal3i, glNormal3s, </span><span
185 glNormal3iv, glNormal3sv,<br>
186 glIndexd, glIndexf, glIndexi, glIndexs, glIndexub, glIndexdv,
187 glIndexfv, glIndexiv, glIndexsv, glIndexubv,<br>
188 glColor3b, glColor3d, glColor3i, glColor3s, glColor3ub, glColor3ui,
190 glColor3dv, glColor3iv, glColor3sv, glColor3ubv, glColor3uiv,
192 glColor4d, glColor4i, glColor4s, glColor4ub, glColor4ui, glColor4us, </span><span
194 glColor4sv, glColor4ubv, glColor4uiv, glColor4usv,<br>
196 glTexCoord1i, glTexCoord1s, glTexCoord2d, glTexCoord2i, glTexCoord2s,
197 glTexCoord3d, glTexCoord3f, glTexCoord3i, glTexCoord3s, glTexCoord4d,
198 glTexCoord4f, glTexCoord4i, glTexCoord4s, glTexCoord1dv, glTexCoord1fv,
199 glTexCoord1iv, glTexCoord1sv, glTexCoord2dv, glTexCoord2iv,
200 glTexCoord2sv, glTexCoord3dv, glTexCoord3fv, glTexCoord3iv,
201 glTexCoord3sv, glTexCoord4dv, glTexCoord4fv, glTexCoord4iv,
202 glTexCoord4sv,<br>
204 <br>
205 </div>
206 Vertex array commands:<br>
208 glColorPointer, glIndexPointer, glTexCoordPointer, glEdgeFlagPointer,
209 glNormalPointer, glInterleavedArrays, glArrayElement, glDrawArrays,
210 glDrawElements, glDrawRangeElements, glEnableClientState,
211 glDisableClientState</span><br>
212 </div>
213 </div>
215 Rectangle commands:<br>
217 glRecti, glRectf, glRectd, glRectsv, glRectiv, glRectfv, glRectdv,<br>
218 <br>
219 </span></div>
220 </div>
222 </div>
224 glMateriali, glMaterialfv, glMaterialiv<br>
225 </span><br>
226 </div>
231 glEvalCoord2dv, glEvalCoord2fv,<br>
233 <br>
234 </div>
235 </div>
238 Vertex coordinates are transformed by the current modelview and
239 projection matrices then mapped to window coordinates as specified by
240 the viewport. The following coordinate transformation commands are
241 supported by the subset<br>
242 <br>
272 <span style="font-weight: normal;"><span style="font-weight: bold;">glOrtho(</span>GLdouble<span
284 </div>
285 <br>
288 The mode parameter may be GL_MODELVIEW or GL_PROJECTION to specify
289 the modelview matrix or projection matrix. Subsequent matrix
290 commands will effect the current matrix. Also associated with the
291 modelview and projection matrices are a modelview matrix stack and
292 projection matrix stack.<br>
293 <br>
295 replaces the current matrix with the identity matrix. The matrix
296 elements are specified in column-major order.<br>
297 <br>
299 a copy of the current matrix onto either the modelview matrix stack or
301 command replaces the current matrix with a copy of the top matrix off
302 the modelview matrix stack or projection matrix stack, the pops the
303 stack. Matrix stacks are useful for traversing and rendering
304 hierarchical models.<br>
305 <br>
307 post-multiplies the current matrix by the specified matrix. The
308 matrix elements are specified in column-major order.<br>
309 <br>
311 post-multiplies the current matrix by a rotation matrix defined by the
312 angle and rotation axis defined by x, y and z.<br>
313 <br>
315 post-multiplies the current matrix by a translation matrix defined by
321 post-multiplies the current matrix by a scaling matrix defined by the <span
327 post-multiplies the current matrix by a perspective projection matrix.
335 the projection matrix.<br>
336 <br>
338 post-multiplies the current matrix by an orthographic projection matrix.
345 is normally used to modify the projection matrix.<br>
346 <br>
348 specifies the mapping of coordinates from normalized device coordinates
351 viewport's lower-left corner in the window and the <span
355 does not effect the current matrix.<br>
356 <br>
359 <br>
361 View-volume clipping automatically discards or trims primitives which
362 lie completely or partially outside of the view volume specified by <span
366 clipping region.<br>
367 <br>
369 space - </span>the coordinates produced after applying the projection
370 matrix.<br>
371 <br>
373 The current raster position specifies the location for drawing images
375 raster position is set with the commands:<br>
376 <br>
377 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glRasterPos2f</span>(GLfloat<span
387 </div>
388 <br>
391 like a vertex; it is transformed by the modelview matrix, the projection
392 matrix and mapped to the viewport. The resulting window coordinate
393 is stored as the current raster position. The coordinate is
394 clipped-tested against the frustum like a vertex. If the
395 coordinate is clipped, then the current raster position becomes invalid
397 have no effect.<br>
398 <br>
400 current raster color and current raster texture coordinates. The
401 current raster color is updated (copied) from the current color (as
403 The current raster texture coordinate is updated (copied) from the
404 current texture coordinate (as specified by <span
406 <br>
408 The following commands related to vertex transformation are not
409 supported by the subset:<br>
410 <br>
413 </div>
415 <br>
420 glLighti, glLightfv, glLightiv, glColorMaterial</span><br>
421 </div>
422 <br>
424 commands:<br>
425 </div>
429 glTexGenfv, glTexGeniv, </span><br>
431 </div>
432 Double-valued commands:<br>
434 glMultMatrixd, glRotated, glTranslated, glScaled</span><br
436 </div>
437 <br>
438 Depth Range command:<br>
441 </div>
442 <br>
443 Extra RasterPos commands:<br>
445 glRasterPos2s, glRasterPos3d, glRasterPos3f, glRasterPos3i,
446 glRasterPos3s, glRasterPos4d, glRasterPos4f, glRasterPos4i,
447 glRasterPos4s, glRasterPos2dv, glRasterPos2sv, glRasterPos3dv,
448 glRasterPos3fv, glRasterPos3iv, glRasterPos3sv, glRasterPos4dv,
449 glRasterPos4fv, glRasterPos4iv, glRasterPos4sv</span><br>
450 </div>
451 <br>
452 <br>
453 </div>
455 This section describes the commands and options for drawing points,
457 is the term for the process which produces fragments from the geometric
458 description of a primitive (a point, line, polygon or bitmap). For
459 example, given the two coordinates for the end-points of a line segment,
460 rasterization determines which pixels in the frame buffer are modified
462 fragment is a tuple which consists of a window coordinate, colors and
463 texture coordinates. The fragments produced by rasterization are
464 subsequently processed by the per-fragment operations described later.<br>
465 <br>
467 Points are rendered with the command sequence <span
472 The truncated coordinate with its associated color and texture
473 coordinate is sent as a single fragment to the per-fragment processing
474 stages.<br>
475 <br>
478 <br>
479 Point smoothing (antialiasing) is also not supported.<br>
480 <br>
482 Lines are rendered with the command sequence <span
489 GL_LINE_STRIP or GL_LINE_LOOP. Lines are rasterized as described
492 lines: the last fragment in a line segment is omitted so that endpoint
493 pixels shared by two line segments will only be drawn once instead of
494 twice.<br>
495 <br>
497 The width of lines can be controlled by<br>
498 <br>
499 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glLineWidth</span>(GLfloat<span
501 </div>
502 <br>
505 width to a value less than or equal to zero will raise the error
506 GL_INVALID_VALUE.<br>
507 <br>
509 </h3>
510 Lines may be stippled (i.e. dashed) with the command<br>
511 <br>
512 <div style="margin-left: 40px;"><span style="font-weight: bold;">glLineStipple</span>(GLint<span
515 </div>
516 <br>
518 pattern for the fragments produced by rasterization and <span
520 fragments are kept or culled for each pattern bit. Line stippling
521 can be enabled or disabled by the commands <span
524 <br>
526 Lines may be antialiased. For antialiased lines, each fragment
527 produced by rasterization is assigned a <span
529 much of the fragment's area is considered to be <span
531 alpha value of each fragment is multiplied by the coverage value.
532 By blending the fragments into the frame buffer, the edges of
533 lines appear smoothed.<br>
534 <br>
535 Line antialiasing can be enabled or disabled with the commands <span
538 <br>
540 Polygons, quadrilaterals and triangles share the same polygon
541 rasterization options. <br>
542 <br>
543 Triangles are rendered by the command sequence <span
551 For GL_TRIANGLES mode, the number of vertices should be a multiple
552 of three - extra vertices will be ignored. For GL_TRIANGLE_STRIP
553 and GL_TRIANGLE_FAN, at least three vertices should be specified.
555 <br>
564 GL_QUADS, the number of vertices should be a multiple of four - extra
565 vertices will be ignored. For GL_QUAD_STRIP, the number of
566 vertices should be even and at least four. Extra vertices (one)
567 will be ignored.<br>
568 <br>
577 <br>
580 (clockwise or counter-clockwise) is significant. It is used to
583 By default, a front-facing polygon's vertices are in
586 front-facing triangles and quadrilaterals, respectively.<br>
587 <br>
588 The command<br>
589 <br>
590 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glFrontFace</span>(GLenum<span
592 </div>
593 <br>
594 specifies whether clockwise or counter-clockwise winding indicates a
598 counter-clockwise winding are front-facing. The default value is
600 GL_CCW or GL_CW then the error GL_INVALID_ENUM will be raised.<span
602 <br>
604 Polygons may be culled (discarded) depending on whether they are
606 <br>
609 </div>
610 <br>
611 specifies whether front-facing, back-facing or all polygons should be
616 is GL_FRONT_AND_BACK then all polygons will be culled. Any other
618 error GL_INVALID_ENUM.<br>
619 <br>
620 Polygon culling is enabled and disabled with the commands <span
623 respectively.<br>
624 <br>
626 Polygons may be antialiased in order to smooth their edges.
630 <br>
631 When polygon antialiasing is enabled each fragment produced by polygon,
632 triangle and quadrilateral rasterization will be given a <span
634 much of the fragment is covered by the polygon. Fragments
636 completely outside the polygon have zero coverage (in theory).
637 Fragments which intersect the polygon's edge have a coverage value
639 <br>
640 The fragment's alpha value is multiplied by the coverage value.
641 By enabling the appropriate blending mode, polygon edges will
642 appear smoothed.<br>
643 <br>
645 The command<br>
646 <br>
647 <div style="margin-left: 40px;"> void <span style="font-weight: bold;">glShadeModel</span>(GLenum<span
649 </div>
650 <br>
651 determines whether colors are interpolated between vertices during
653 GL_FLAT then vertex colors are not interpolated. The color used
654 for drawing lines, triangles and quadrilaterals is that of the last
655 vertex used to specify each primitive. For polygons, the color of
658 are linearly interpolated to produce the fragment colors.<br>
659 <br>
661 A bitmap is a monochromatic, binary image in which each image element
662 (or pixel) is represented by one bit. Fragments are only generated
663 for the bits (pixels) which are set. Bitmaps are commonly used to
664 draw text (glyphs) and markers.<br>
665 <br>
666 A bitmap is drawn with the command<br>
667 <br>
668 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glBitmap</span>(GLsizei<span
676 </div>
677 <br>
686 data.<br>
687 <br>
688 If the current raster position is not valid, <span
690 <br>
694 client memory subject to byte swapping, non-default row strides, etc.
696 <br>
699 </div>
701 The following unpacking parameters may be set:<br>
702 <br>
705 <tbody>
706 <tr>
709 </td>
712 </td>
714 </td>
715 </tr>
716 <tr>
718 </td>
720 pixels.<br>
721 </td>
723 </td>
724 </tr>
725 <tr>
727 </td>
729 significant bit is unpacked first from each byte. GL_TRUE
730 indicates that the least significant bit is unpacked first from each
731 byte. <br>
732 </td>
734 </td>
735 </tr>
736 </tbody>
737 </table>
738 <br>
739 <br>
740 The GL_UNPACK_ROW_LENGTH specifies the stride (in pixels) for advancing
744 image in memory.<br>
745 <br>
746 GL_UNPACK_LSB_FIRST determines whether the least significant or most
747 significant bit in each byte is unpacked first. Unpacking occurs
748 in left to right order (in image space).<br>
749 <br>
750 The value of bit (i, j) of the image (where i is the image row and j is
751 the image column) is found as follows:<br>
752 <br>
755 <br>
758 <br>
761 else<br>
763 <br>
766 else<br>
768 <br>
769 </div>
774 following algorithm:<br>
775 <br>
777 j++) {<br>
779 i++) {<br>
781 fragment.x =
783 + i;<br>
784 fragment.y =
786 + j;<br>
787 fragment.color
788 = GL_CURRENT_RASTER_COLOR;<br>
789
790 fragment.texture = GL_CURRENT_RASTER_TEXTURE_COORDS;<br>
791
792 ProcessFragment(fragment)<br>
795 }<br>
796 <br>
797 After the bitmap has been rendered the current raster position is
798 updated as follows:<br>
799 <br>
803 </div>
804 <br>
807 <br>
809 The following commands related to rasterization are not supported by
810 the subset.<br>
811 <br>
814 </div>
815 <br>
816 Polygon commands:<br>
818 glPolygonOffset<br>
819 glPolygonMode<br>
820 <br>
821 </div>
822 </div>
824 </div>
826 </div>
827 <br>
828 <br>
830 </h1>
831 There are four elements to texture mapping: texture coordinate
832 specification, texture image specification, texture sampling and texture
833 application.<br>
834 <br>
835 Texture mapping is enabled and disabled with the commands <span
838 <br>
840 A texture image is specified with the command:<br>
841 <br>
842 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glTexImage2D</span>(GLenum<span
852 </div>
853 <br>
857 is a hint to indicate the preferred internal storage format for the
864 points to the incoming texture image. These parameters are
865 described in more detail below.<br>
866 <br>
869 Texture images must have dimensions (width and height) that are powers
873 for some positive integers n and m.<br>
874 <br>
875 Mipmapping is a method of antialiasing or filtering textures to improve
876 their appearance. A mipmap is a set of images consisting of a base
877 image and a set of filtered, reduced-resolution images. If the
881 level is half the width and height of the previous level, or at least
883 <br>
884 The following is an example of a mipmap's image levels:<br>
885 <br>
888 <tbody>
889 <tr>
891 </td>
893 </td>
895 </td>
896 </tr>
897 <tr>
899 </td>
901 </td>
903 </td>
904 </tr>
905 <tr>
907 </td>
909 </td>
911 </td>
912 </tr>
913 <tr>
915 </td>
917 </td>
919 </td>
920 </tr>
921 <tr>
923 </td>
925 </td>
927 </td>
928 </tr>
929 <tr>
931 </td>
933 </td>
935 </td>
936 </tr>
937 <tr>
939 </td>
941 </td>
943 </td>
944 </tr>
945 <tr>
947 </td>
949 </td>
951 </td>
952 </tr>
953 <tr>
955 </td>
957 </td>
959 </td>
960 </tr>
961 <tr>
963 </td>
965 </td>
967 </td>
968 </tr>
969 </tbody>
970 </table>
971 <br>
974 two, the error GL_INVALID_VALUE is raised. If the image levels in
975 a mipmap do not satisfy the restrictions listed above the texture is
977 and the system will behave as if the texturing is disabled.<br>
978 <br>
987 parameter must be GL_UNSIGNED_BYTE. Pixel component values are
989 <br>
991 the image has one byte per pixel which specifies the pixel's red, green,
993 <br>
995 image has three bytes per pixel which specify the pixel's red, green and
997 <br>
999 image has four bytes per pixel which specify the pixel's red, green,
1000 blue and alpha values (in that order).<br>
1001 <br>
1002 The command<br>
1003 <br>
1007 </div>
1008 <br>
1011 indicate the stride, in pixels, between subsequent rows of the image in
1012 client memory. If GL_UNPACK_ROW_LENGTH is zero (the default) then
1016 <br>
1020 texture image to one of the supported internal texture formats.<br>
1021 <br>
1023 indicates the desired internal format for the texture and may be either
1024 GL_INTENSITY8, GL_RGB5 or GL_RGBA8.<br>
1025 <br>
1027 GL_INTENSITY8 then the texture has one byte per texel (texture element)
1028 which indicates the texel's intensity (or brightness). The
1029 intensity is obtained from the incoming image's red channel.<br>
1030 <br>
1034 <br>
1038 <br>
1039 The internal format is also significant to texture application (see
1041 <br>
1043 Texture coordinates control the mapping from local polygon space to
1044 texture image space. Texture coordinates are set for each vertex
1046 During line and polygon rasterization the vertex's texture
1047 coordinates are interpolated across the primitive to produce a texture
1048 coordinate for each fragment. The fragment texture coordinates are
1049 used to sample the current texture image.<br>
1050 <br>
1052 outside that range are processed according to the <span
1054 texture wrap mode is set with the command<br>
1055 <br>
1056 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glTexParameteri</span>(GLenum<span
1060 <br>
1061 </div>
1064 GL_TEXTURE_WRAP_S or GL_TEXTURE_WRAP_T then <span
1066 GL_CLAMP_TO_EDGE or GL_REPEAT.<br>
1067 <br>
1068 For GL_CLAMP_TO_EDGE, texture coordinates are effectively clamped to
1070 <br>
1071 For GL_REPEAT, the integer part of texture coordinates is ignored; only
1072 the fractional part of the texture coordinates is used. This
1073 allows texture images to repeated or tiled across an object.<br>
1074 <br>
1076 Texture sampling is the process of using texture coordinates to extract
1077 a color from the texture image. Multiple, weighted samples may be
1078 taken from the texture and combined during the filtering step.<br>
1079 <br>
1080 During texture coordinate interpolation a <span
1082 computed for each fragment. For a mipmapped texture, lambda
1083 determines which level (or levels) of the mipmap will be sampled to
1084 obtain the texture color.<br>
1085 <br>
1086 If lambda indicates that multiple texels map to a single screen pixel,
1088 filter will be used. Otherwise, if lambda indicates that a single
1089 texel maps to multiple screen pixels, then the texture <span
1094 The texture minification filter is set with the <span
1101 GL_LINEAR, GL_NEAREST_MIPMAP_NEAREST,
1102 GL_NEAREST_MIPMAP_LINEAR, GL_LINEAR_MIPMAP_NEAREST or
1103 GL_LINEAR_MIPMAP_LINEAR.<br>
1104 <br>
1105 GL_NEAREST samples the texel nearest the texture coordinate in the
1107 <br>
1108 GL_LINEAR samples the four texels around the texture coordinate in the
1110 compute the final texel value.<br>
1111 <br>
1112 GL_NEAREST_MIPMAP_NEAREST samples the texel nearest the texture
1113 coordinate in the level N texture image. N is the level of detail
1114 and is computed by the partial derivatives of the texture coordinates
1115 with respect to the window coordinates.<br>
1116 <br>
1117 GL_NEAREST_MIPMAP_LINEAR samples two texels nearest the texture
1119 are linearly weighted to compute the final texel value. N is the
1120 level of detail and is computed by the partial derivatives of the
1121 texture coordinates with respect to the window coordinates.<br>
1122 <br>
1123 GL_LINEAR_MIPMAP_NEAREST samples four texels around the texture
1124 coordinate in the level N texture image. The four texels are
1125 linearly weighted to compute the final texel value. N is the level
1126 of detail and is computed by the partial derivatives of the texture
1127 coordinates with respect to the window coordinates.<br>
1128 <br>
1129 GL_LINEAR_MIPMAP_LINEAR samples four texels around the texture
1130 coordinate in the level N texture image and four texels around the
1132 texels are linearly weighted to compute the final texel value. N
1133 is the level of detail and is computed by the partial derivatives of the
1134 texture coordinates with respect to the window coordinates.<br>
1135 <br>
1136 Filter modes other than GL_LINEAR and GL_NEAREST requires that the
1137 texture have a complete set of mipmaps. If the mipmap is
1138 incomplete, it is as if texturing is disabled.<br>
1141 The texture magnification filter is set with the <span
1147 to GL_NEAREST or GL_LINEAR.<br>
1148 <br>
1149 GL_NEAREST samples the texel nearest the texture coordinate in the
1151 <br>
1152 GL_LINEAR samples the four texels around the texture coordinate in the
1154 compute the final texel value.<br>
1155 <br>
1157 The sampled texture value is combined with the incoming fragment color
1158 to produce a new fragment color. The fragment and texture colors
1159 are combined according to the texture environment mode and the current
1160 texture's base internal format. The texture environment mode is
1161 set with the command<br>
1162 <br>
1167 </div>
1168 <br>
1172 must be one of GL_REPLACE, GL_MODULATE, GL_DECAL, or GL_BLEND.<br>
1173 <br>
1176 environment color can be set with the command<br>
1177 <br>
1182 </div>
1187 point to an array of four values which specify the red, green, blue,
1188 and alpha values of the texture environment color. The values are
1191 The following table describes the arithmetic used for each combination
1192 of environment mode and base internal format. (Rf, Gf, Bf, Af) is
1193 the incoming fragment color. (Rt, Gt, Bt, At) is the sampled
1196 intensity. (Rc, Gc, Bc, Ac) is the texture environment color.
1198 <br>
1199 <br>
1202 <tbody>
1203 <tr>
1205 </td>
1207 </td>
1209 </td>
1211 </td>
1213 </td>
1214 </tr>
1215 <tr>
1217 </td>
1219 Gv = It<br>
1220 Bv = It<br>
1221 Bf = It<br>
1222 </td>
1224 Gv = Gf * It<br>
1225 Bv = Bf * It<br>
1226 Av = Af * It</td>
1228 </td>
1233 </tr>
1234 <tr>
1236 </td>
1238 Gv = Gt<br>
1239 Bv = Bt<br>
1240 Av = Af<br>
1241 </td>
1243 Gv = Gf * Gt<br>
1244 Bv = Bf * Bt<br>
1245 Av = Af<br>
1246 </td>
1248 Gv = Gt<br>
1249 Bv = Bt<br>
1250 Av = Af</td>
1254 Av = Af</td>
1255 </tr>
1256 <tr>
1258 </td>
1260 Gv = Gt<br>
1261 Bv = Bt<br>
1262 Av = At<br>
1263 </td>
1265 Gv = Gf * Gt<br>
1266 Bv = Bf * Bt<br>
1267 Av = Af * At</td>
1271 Av = Af<br>
1272 </td>
1276 Av = Af*At</td>
1277 </tr>
1278 </tbody>
1279 </table>
1280 <br>
1281 <br>
1282 <br>
1284 Texture objects encapsulate a set of texture images (mipmap) and
1285 related state into a named object. This facilitates use of
1286 multiple textures in an application. Texture objects are named
1287 with GLuints (unsigned integers). There is a default texture
1288 object with the name/identifier zero which can never be deleted.<br>
1289 <br>
1291 A texture object is created by binding a new GLuint identifier to the
1292 GL_TEXTURE_2D target with the command:<br>
1293 <br>
1294 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glBindTexture</span>(GLenum<span
1297 </div>
1298 <br>
1302 does not name an existing texture object, a new texture object with that
1303 ID will be created, initialized to the default state. Whether the
1304 ID is new or existed previously, that named texture object is bound as
1309 current texture object.<br>
1313 One or more texture objects may be deleted with the command:<br>
1314 <br>
1315 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glDeleteTextures</span>(GLsizei<span
1318 </div>
1319 <br>
1322 texture objects will be deleted. If the current texture object is
1323 deleted the default texture object (number 0) will be bound as the
1324 current texture object.<br>
1325 <br>
1327 A list of new, unused texture IDs can be obtained by calling the command<br>
1328 <br>
1329 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glGenTextures</span>(GLsizei<span
1332 </div>
1333 <br>
1336 array.<br>
1337 <br>
1338 <br>
1340 The fragments produced by rasterization are subjected to a number of
1341 operations which either modify the fragment or test the fragment
1342 (discarding the fragment if the test fails.) This chapter
1343 describes the per-fragment operations. They are presented in the
1344 order in which they're performed. If a fragment fails a test it is
1345 discarded and not subjected to subsequent tests or modifications.<br>
1346 <br>
1348 The scissor test limits rendering to a 2-D rectangular region of the
1350 <br>
1351 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glScissor</span>(GLint<span
1356 </div>
1357 <br>
1358 defines a clipping region with the lower-left corner at (<span
1362 enabled and disabled with the command <span style="font-weight: bold;">glEnable</span>(GL_SCISSOR_TEST)
1364 <br>
1366 then the fragment will pass the test if <span
1373 fragment is discarded.<br>
1374 <br>
1377 GL_INVALID_VALUE is raised. The default scissor rectangle bounds
1380 <br>
1382 The alpha test compares the fragment's alpha value against a reference
1383 value and discards the fragment if the comparison fails. The test
1384 is specified by the command<br>
1385 <br>
1386 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glAlphaFunc</span>(GLenum<span
1389 </div>
1390 <br>
1393 to compare against. The following table lists all possible
1395 corresponding test:<br>
1396 <br>
1399 <tbody>
1400 <tr>
1402 </td>
1404 </td>
1405 </tr>
1406 <tr>
1408 </td>
1411 </td>
1412 </tr>
1413 <tr>
1415 </td>
1418 </tr>
1419 <tr>
1421 </td>
1424 </tr>
1425 <tr>
1427 </td>
1430 </tr>
1431 <tr>
1433 </td>
1436 </tr>
1437 <tr>
1439 </td>
1442 </tr>
1443 <tr>
1445 </td>
1447 </td>
1448 </tr>
1449 <tr>
1451 </td>
1453 </td>
1454 </tr>
1455 </tbody>
1456 </table>
1457 <br>
1460 <br>
1461 The alpha test is enabled and disabled with the commands <span
1464 <br>
1466 <br>
1468 The stencil buffer stores an N-bit integer value for each pixel in the
1469 frame buffer. The stencil test compares the stencil buffer value
1470 at the fragment's position to a reference value and possibly discards
1471 the fragment based on the outcome. Furthermore, the stencil buffer
1472 value may be updated or modified depending on the outcome. If
1473 there is no stencil buffer the stencil test is bypassed.<br>
1474 <br>
1475 Stenciling is controlled by the commands<br>
1476 <br>
1477 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glStencilFunc</span>(GLenum<span
1485 </div>
1486 <br>
1490 command controls the how the stencil buffer is updated/modified after
1491 the test.<br>
1492 <br>
1496 <br>
1497 The following table lists all possible values for the <span
1499 test will pass. Both the stencil buffer value and the stencil
1500 reference value are bit-wise ANDed with the <span
1502 <br>
1505 <table
1508 <tbody>
1509 <tr>
1512 </td>
1514 </td>
1515 </tr>
1516 <tr>
1518 </td>
1522 </td>
1523 </tr>
1524 <tr>
1526 </td>
1530 </tr>
1531 <tr>
1533 </td>
1537 </tr>
1538 <tr>
1540 </td>
1544 </tr>
1545 <tr>
1547 </td>
1551 </tr>
1552 <tr>
1554 </td>
1558 </tr>
1559 <tr>
1561 </td>
1563 </td>
1564 </tr>
1565 <tr>
1567 </td>
1569 </td>
1570 </tr>
1571 </tbody>
1572 </table>
1573 <br>
1575 If the stencil test passes, the fragment is passed to the next
1576 per-fragment operation. Otherwise, if the stencil test fails, the
1577 value in the stencil buffer is updated according to the value of the <span
1580 <br>
1583 <tbody>
1584 <tr>
1586 value<br>
1587 </td>
1589 </td>
1590 </tr>
1591 <tr>
1593 </td>
1595 </td>
1596 </tr>
1597 <tr>
1599 </td>
1601 </td>
1602 </tr>
1603 <tr>
1605 </td>
1607 i.e. ~originalValue<br>
1608 </td>
1609 </tr>
1610 <tr>
1612 </td>
1614 </td>
1615 </tr>
1616 <tr>
1618 </td>
1621 </tr>
1622 <tr>
1624 </td>
1627 </tr>
1628 </tbody>
1629 </table>
1632 <br>
1638 in the table will cause the error GL_INVALID_ENUM to be raised.<br>
1639 <br>
1640 The stencil test is enabled and disabled with the commands <span
1643 <br>
1644 The default stencil function is GL_ALWAYS. The default stencil
1646 default stencil fail operation is GL_KEEP.<br>
1647 <br>
1648 Values written into the stencil buffer are masked with the command<br>
1649 <br>
1650 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glStencilMask</span>(GLuint<span
1652 </div>
1653 <br>
1655 will be modified in the stencil buffer when written to. If each
1656 stencil buffer value has N bits, only the least significant N bits of <span
1659 <br>
1661 Blending or a logic operation combines the incoming fragment color with
1662 the destination frame buffer color according to a blending equation or
1663 bit-wise Boolean logical operation.<br>
1664 <br>
1665 Blending is enabled and disabled with the commands <span
1668 <br>
1669 The logic operation is enabled and disabled with the commands <span
1672 <br>
1673 If both blending and the logic operation are enabled, the logic
1674 operation has higher priority; blending is bypassed.<br>
1675 <br>
1677 The command<br>
1678 <br>
1679 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glLogicop</span>(GLenum<span
1681 <br>
1682 </div>
1683 Specifies the Boolean logic operation for combining the incoming
1684 fragment color with the destination frame buffer color. Both the
1685 incoming fragment color and destination frame buffer colors are
1686 interpreted as four-tuples of unsigned integer color components in the
1689 <br>
1690 The following table lists all values for <span
1692 to combine the incoming fragment color value (src)<span
1697 <br>
1700 <tbody>
1701 <tr>
1704 </td>
1706 </td>
1707 </tr>
1708 <tr>
1710 </td>
1712 </td>
1713 </tr>
1714 <tr>
1716 </td>
1718 </td>
1719 </tr>
1720 <tr>
1722 </td>
1724 </td>
1725 </tr>
1726 <tr>
1728 </td>
1730 </td>
1731 </tr>
1732 <tr>
1734 </td>
1736 </td>
1737 </tr>
1738 <tr>
1740 </td>
1742 </td>
1743 </tr>
1744 <tr>
1746 </td>
1748 </td>
1749 </tr>
1750 <tr>
1752 </td>
1754 </td>
1755 </tr>
1756 <tr>
1758 </td>
1760 </td>
1761 </tr>
1762 <tr>
1764 </td>
1766 </td>
1767 </tr>
1768 <tr>
1770 </td>
1772 </td>
1773 </tr>
1774 <tr>
1776 </td>
1778 </td>
1779 </tr>
1780 <tr>
1782 </td>
1784 </td>
1785 </tr>
1786 <tr>
1788 </td>
1790 </td>
1791 </tr>
1792 <tr>
1794 </td>
1796 </td>
1797 </tr>
1798 <tr>
1800 </td>
1802 </td>
1803 </tr>
1804 </tbody>
1805 </table>
1806 <br>
1807 The fragment's color is replaced by the result of the logic operation.<br>
1808 <br>
1810 other than those listed in the above table will cause the error
1811 GL_INVALID_ENUM to be raised.<br>
1812 <br>
1815 <br>
1817 The command<br>
1818 <br>
1819 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glBlendFunc</span>(GLenum<span
1822 </div>
1823 <br>
1824 specifies the terms of the blending equation. If Cf = (Rf, Gf,
1825 Bf, Af) is the incoming fragment color and Cb = (Rb, Gb, Bb, Ab) is the
1826 frame buffer color, then the resulting color Cv = (Rv, Gv, Bv, Av) is
1827 computed by:<br>
1828 <br>
1835 and the corresponding arithmetic term are listed in the following table:<br>
1836 <br>
1839 <tbody>
1840 <tr>
1842 </td>
1843 <td style="vertical-align: top;"><span style="font-style: italic;">srcTerm</span>Arithmetic<br>
1844 </td>
1845 </tr>
1846 <tr>
1848 </td>
1850 </td>
1851 </tr>
1852 <tr>
1854 </td>
1856 </td>
1857 </tr>
1858 <tr>
1860 </td>
1862 </td>
1863 </tr>
1864 <tr>
1866 </td>
1868 </td>
1869 </tr>
1870 <tr>
1872 </td>
1874 </td>
1875 </tr>
1876 <tr>
1878 </td>
1880 </td>
1881 </tr>
1882 <tr>
1884 </td>
1886 </td>
1887 </tr>
1888 <tr>
1890 </td>
1892 </td>
1893 </tr>
1894 <tr>
1896 </td>
1899 </td>
1900 </tr>
1901 </tbody>
1902 </table>
1903 <br>
1905 and the corresponding arithmetic term are listed in the following table:<br>
1906 <br>
1909 <tbody>
1910 <tr>
1912 </td>
1913 <td style="vertical-align: top;"><span style="font-style: italic;">dstTerm</span>Arithmetic<br>
1914 </td>
1915 </tr>
1916 <tr>
1918 </td>
1920 </td>
1921 </tr>
1922 <tr>
1924 </td>
1926 </td>
1927 </tr>
1928 <tr>
1930 </td>
1932 </td>
1933 </tr>
1934 <tr>
1936 </td>
1938 </td>
1939 </tr>
1940 <tr>
1942 </td>
1944 </td>
1945 </tr>
1946 <tr>
1948 </td>
1950 </td>
1951 </tr>
1952 <tr>
1954 </td>
1956 </td>
1957 </tr>
1958 <tr>
1960 </td>
1962 </td>
1963 </tr>
1964 </tbody>
1965 </table>
1966 <br>
1967 The fragment's color is replaced by the result of the blending equation.<br>
1968 <br>
1971 the table will cause the error GL_INVALID_ENUM to be raised.<br>
1972 <br>
1976 <br>
1978 The final fragment color is written into the current color buffer at
1979 the end of the per-fragment operations. Normally, all color
1980 channels in the frame buffer are replaced with the final fragment color.
1982 <br>
1983 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glColorMask</span>(GLboolean<span
1988 </div>
1989 <br>
1992 the red color channel is enabled, otherwise it's disabled.
1994 <br>
1995 Initially all four mask values are GL_TRUE.<br>
1996 <br>
1997 Color masking is not enabled/disabled with the <span
2000 <br>
2002 The frame buffer is considered to be a two-dimensional array of pixels.
2003 The frame buffer is also organized into layers or logical buffers.
2004 There may be a front color buffer, back color buffer and stencil
2005 buffer. A double-buffered frame buffer has both a front color
2006 buffer and back color buffer. A single-buffered framebuffer only
2007 has a front color buffer. Each pixel in a color buffer has a red,
2008 green and blue value and an optional alpha value.<br>
2009 <br>
2011 Buffers are cleared (set to uniform values) with the command<br>
2012 <br>
2013 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glClear</span>(GLbitfield<span
2015 </div>
2016 <br>
2018 the value may be the bitwise-OR of the values GL_COLOR_BUFFER_BIT and
2019 GL_STENCIL_BUFFER_BIT. If the GL_COLOR_BUFFER_BIT bit is
2020 specified, the current color buffer will be cleared. If the
2021 GL_STENCIL_BUFFER_BIT bit is specified, the stencil buffer will be
2022 cleared.<br>
2023 <br>
2024 The current color buffer is specified with the command<br>
2025 <br>
2026 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glDrawBuffer</span>(GLenum<span
2028 </div>
2029 <br>
2031 GL_BACK or GL_NONE. GL_FRONT indicates that the front color buffer
2033 any drawing command. GL_BACK indicates that the back color buffer
2035 any drawing command. GL_NONE indicates that neither color buffer
2037 any drawing command. GL_BACK is only valid for double-buffered
2038 frame buffers.<br>
2039 <br>
2040 The current scissor rectangle, set by the <span
2051 <br>
2052 The current clear color is set with the command<br>
2053 <br>
2054 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glClearColor</span>(GLclampf<span
2059 </div>
2060 <br>
2065 The current stencil clear value is set with the command<br>
2066 <br>
2067 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glClearStencil</span>(GLint<span
2069 </div>
2070 <br>
2071 If the stencil buffer is N bits deep, the least significant N bits of <span
2073 stencil buffer.<br>
2074 <br>
2075 <br>
2078 A rectangular region of pixels can be read from the frame buffer and
2079 placed in client memory with the command<br>
2080 <br>
2081 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glReadPixels</span>(GLint<span
2089 </div>
2090 <br>
2093 lower-left corner of the region to read and <span
2097 specifies the format of image data and must be either GL_RGB or
2099 data type of the image data and must be either GL_UNSIGNED_BYTE or
2102 GL_INVALID_ENUM to be raised.<br>
2103 <br>
2104 The framebuffer may contain 3-component colors (red, green, blue) or
2107 <br>
2108 The frame buffer color components (red, green, blue, alpha) are either
2113 green, blue, alpha) tuples are then stored as GL_RGB triplets (by
2114 dropping the alpha component) or GL_RGBA quadruples in client memory.<br>
2115 <br>
2117 client memory according to the pixel packing parameters which are set by
2118 the command<br>
2119 <br>
2120 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glPixelStorei</span>(GLenum<span
2123 </div>
2124 <br>
2127 indicates the stride (in pixels) between subsequent rows in the
2128 destination image. If GL_PACK_ROW_LENGTH is zero (the default)
2131 <br>
2132 Pixel readback takes place as follows:<br>
2133 <br>
2136 else<br>
2138 <br>
2141 i++) {<br>
2144 k = (i *
2161 }<br>
2162 else {<br>
2164 i++) {<br>
2167 k = (i *
2189 }<br>
2190 </div>
2191 <br>
2193 returns the pixel in the frame buffer at column <span
2197 GLubyte pointer or a GLfloat pointer, depending on the <span
2202 <br>
2203 Pixels may be read from either the front or back color buffer.
2205 <br>
2206 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glReadBuffer</span>(GLenum<span
2208 </div>
2209 <br>
2210 specifies the source for reading images with <span
2214 is GL_BACK then the back color buffer is the source. It is illegal
2215 to specify GL_BACK when the color buffer is not double buffered.
2217 will raise the error GL_INVALID_ENUM.<br>
2218 <br>
2219 The default read source is GL_BACK if the frame buffer is double
2221 <br>
2223 Selection mode is typically used to implement <span
2225 primitive(s) are present at particular window positions. The
2226 command<br>
2227 <br>
2228 <div style="margin-left: 40px;">GLint <span style="font-weight: bold;">glRenderMode</span>(GLenum<span
2230 </div>
2231 <br>
2238 GL_INVALID_ENUM.<br>
2239 <br>
2240 When in selection mode rendering commands will not effect the
2241 framebuffer. Instead, a record of the primitives that would have
2244 is specified with the command<br>
2245 <br>
2246 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glSelectionBuffer</span>(GLsizei<span
2249 </div>
2254 values will be placed in the buffer.<br>
2255 <br>
2257 (LIFO) of unsigned integer names. The following commands
2258 manipulate the name stack:<br>
2259 <br>
2260 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glInitNames</span>(void)<br>
2266 </div>
2267 <br>
2276 Stack underflow and overflow conditions cause the errors
2277 GL_STACK_OVERFLOW and GL_STACK_UNDERFLOW to be raised.<br>
2278 <br>
2279 While in selection mode, primitives (points, lines, polygons) are
2280 transformed and clip-tested normally. Primitives which aren't
2283 data consists of three pieces of information: a hit flag, a minimum Z
2284 value and a maximum Z value. First, the hit flag is set.
2285 Then, for each of the primitive's vertices, the vertex Z value is
2286 compared to the minimum and maximum Z values. The minimum Z value
2287 is updated if the vertex's Z value is less than the minimum Z value.
2288 The maximum Z value is updated if the vertex's Z value is greater
2289 than the maximum Z value.<br>
2290 <br>
2298 written to the selection buffer.<br>
2299 <br>
2300 A hit record consists of a sequence of unsigned integers. The
2301 first value is the size of the name stack. The second value is the
2304 values are the values in the name stack, in bottom to top order.
2305 The hit flag is cleared after a hit record is written to the
2306 selection buffer. Hit records are places sequentially into the
2307 selection buffer until it is full or selection mode is terminated.<br>
2308 <br>
2309 Selection mode is terminated by calling <span
2313 return value will indicate the number of values written into the
2314 selection buffer.<br>
2315 <br>
2317 The command<br>
2318 <br>
2320 </div>
2321 <br>
2322 makes the graphics library to flush all pending graphics commands.
2326 </div>
2327 <br>
2328 makes the graphics library flush the command queue and wait until those
2330 will not return until all previous graphics commands have been fully
2331 completed.<br>
2332 <br>
2333 These commands are typically used to force completion of rendering to
2334 the front color buffer. Otherwise, rendering to the front color
2336 command (part of the window system binding library) does an implicit
2339 implicit flush before reading pixel data from the frame buffer.<br>
2340 <br>
2342 The current value of nearly all library state variables can be queried.
2343 This chapter describes the commands used for querying the value of
2344 state variables.<br>
2345 <br>
2347 The command<br>
2348 <br>
2349 <div style="margin-left: 40px;">void <span style="font-weight: bold;">glGetFloatv</span>(GLenum<span
2352 </div>
2353 <br>
2354 returns the value(s) of the state variable specified by <span
2359 GL_INVALID_ENUM to be raised.<br>
2360 <br>
2363 <tbody>
2364 <tr>
2367 </td>
2369 </td>
2371 </td>
2372 </tr>
2373 <tr>
2375 </td>
2377 </td>
2379 in the frame buffer.<br>
2380 </td>
2381 </tr>
2382 <tr>
2384 </td>
2386 </td>
2388 disabled.<br>
2389 One if the alpha test is enabled.<br>
2390 </td>
2391 </tr>
2392 <tr>
2394 </td>
2396 </td>
2398 </td>
2399 </tr>
2400 <tr>
2402 </td>
2404 </td>
2406 One if blending is enabled.<br>
2407 </td>
2408 </tr>
2409 <tr>
2411 </td>
2413 </td>
2415 </td>
2416 </tr>
2417 <tr>
2419 </td>
2421 </td>
2423 </td>
2424 </tr>
2425 <tr>
2427 </td>
2429 </td>
2431 the frame buffer.<br>
2432 </td>
2433 </tr>
2434 <tr>
2436 </td>
2438 </td>
2440 alpha).<br>
2441 </td>
2442 </tr>
2443 <tr>
2445 </td>
2447 </td>
2449 green, blue, alpha).<br>
2450 Zero if writing is disabled.<br>
2451 One if writing is enabled.<br>
2452 </td>
2453 </tr>
2454 <tr>
2456 </td>
2458 </td>
2460 disabled.<br>
2461 One if polygon culling is enabled.<br>
2462 </td>
2463 </tr>
2464 <tr>
2466 </td>
2468 </td>
2470 GL_BACK or GL_FRONT_AND_BACK.<br>
2471 </td>
2472 </tr>
2473 <tr>
2475 </td>
2477 </td>
2479 alpha).<br>
2480 </td>
2481 </tr>
2482 <tr>
2484 </td>
2486 </td>
2488 (red, green, blue, alpha).<br>
2489 </td>
2490 </tr>
2491 <tr>
2493 </td>
2495 </td>
2497 coordinates (s, t, r, q).<br>
2498 </td>
2499 </tr>
2500 <tr>
2502 </td>
2504 </td>
2506 z, w).<br>
2507 </td>
2508 </tr>
2509 <tr>
2511 </td>
2513 </td>
2515 is invalid.<br>
2516 One if current raster position is valid.<br>
2517 </td>
2518 </tr>
2519 <tr>
2521 </td>
2523 </td>
2525 t, r, q)<br>
2526 </td>
2527 </tr>
2528 <tr>
2530 </td>
2532 </td>
2534 single-buffered.<br>
2535 One if color buffer is double-buffered.<br>
2536 </td>
2537 </tr>
2538 <tr>
2540 </td>
2542 </td>
2544 GL_FRONT or GL_BACK.<br>
2545 </td>
2546 </tr>
2547 <tr>
2550 </td>
2552 GL_CW or GL_CCW.<br>
2553 </td>
2554 </tr>
2555 <tr>
2557 </td>
2559 </td>
2561 in the frame buffer.<br>
2562 </td>
2563 </tr>
2564 <tr>
2566 </td>
2568 </td>
2570 disabled.<br>
2571 One if line smoothing is enabled.<br>
2572 </td>
2573 </tr>
2574 <tr>
2576 </td>
2578 </td>
2580 disabled.<br>
2581 One if line stippling is enabled.<br>
2582 </td>
2583 </tr>
2584 <tr>
2586 </td>
2588 </td>
2590 </td>
2591 </tr>
2592 <tr>
2594 </td>
2596 </td>
2598 </td>
2599 </tr>
2600 <tr>
2602 </td>
2604 </td>
2606 </td>
2607 </tr>
2608 <tr>
2610 </td>
2612 </td>
2614 </td>
2615 </tr>
2616 <tr>
2618 </td>
2620 </td>
2622 widths.<br>
2623 </td>
2624 </tr>
2625 <tr>
2627 </td>
2629 </td>
2631 line widths.</td>
2632 </tr>
2633 <tr>
2635 </td>
2637 </td>
2639 One if logicop is enabled.<br>
2640 </td>
2641 </tr>
2642 <tr>
2644 </td>
2646 </td>
2648 </td>
2649 </tr>
2650 <tr>
2652 </td>
2654 </td>
2656 GL_PROJECTION.<br>
2657 </td>
2658 </tr>
2659 <tr>
2661 </td>
2663 </td>
2665 matrix stack.<br>
2666 </td>
2667 </tr>
2668 <tr>
2670 </td>
2672 </td>
2674 name stack.<br>
2675 </td>
2676 </tr>
2677 <tr>
2679 </td>
2681 </td>
2683 matrix stack.<br>
2684 </td>
2685 </tr>
2686 <tr>
2688 </td>
2690 </td>
2692 and height.<br>
2693 </td>
2694 </tr>
2695 <tr>
2697 </td>
2700 height in pixels.<br>
2701 </td>
2702 </tr>
2703 <tr>
2705 </td>
2707 </td>
2709 values.<br>
2710 </td>
2711 </tr>
2712 <tr>
2714 </td>
2716 </td>
2718 matrix stack.<br>
2719 </td>
2720 </tr>
2721 <tr>
2723 </td>
2725 </td>
2727 name stack.<br>
2728 </td>
2729 </tr>
2730 <tr>
2732 </td>
2734 </td>
2736 </td>
2737 </tr>
2738 <tr>
2740 </td>
2742 </td>
2744 disabled.<br>
2745 One if polygon smoothing is enabled.<br>
2746 </td>
2747 </tr>
2748 <tr>
2750 </td>
2752 </td>
2754 values.<br>
2755 </td>
2756 </tr>
2757 <tr>
2759 </td>
2761 </td>
2763 matrix stack.<br>
2764 </td>
2765 </tr>
2766 <tr>
2768 </td>
2770 </td>
2772 GL_BACK.<br>
2773 </td>
2774 </tr>
2775 <tr>
2777 </td>
2779 </td>
2781 the frame buffer.<br>
2782 </td>
2783 </tr>
2784 <tr>
2786 </td>
2788 </td>
2790 GL_RENDER or GL_SELECTION.<br>
2791 </td>
2792 </tr>
2793 <tr>
2795 </td>
2797 </td>
2799 </td>
2800 </tr>
2801 <tr>
2803 </td>
2805 </td>
2807 height).<br>
2808 </td>
2809 </tr>
2810 <tr>
2812 </td>
2814 </td>
2816 One if scissor test is enabled.<br>
2817 </td>
2818 </tr>
2819 <tr>
2821 </td>
2823 </td>
2825 </td>
2826 </tr>
2827 <tr>
2829 </td>
2831 </td>
2833 GL_SMOOTH.<br>
2834 </td>
2835 </tr>
2836 <tr>
2838 </td>
2840 </td>
2842 in the frame buffer.<br>
2843 </td>
2844 </tr>
2845 <tr>
2847 </td>
2849 </td>
2851 </td>
2852 </tr>
2853 <tr>
2855 </td>
2857 </td>
2859 </td>
2860 </tr>
2861 <tr>
2863 </td>
2865 </td>
2867 </td>
2868 </tr>
2869 <tr>
2871 </td>
2873 </td>
2875 </td>
2876 </tr>
2877 <tr>
2879 </td>
2881 </td>
2883 One if stencil test is enabled.<br>
2884 </td>
2885 </tr>
2886 <tr>
2888 </td>
2890 </td>
2892 </td>
2893 </tr>
2894 <tr>
2896 </td>
2898 </td>
2900 </td>
2901 </tr>
2902 <tr>
2904 </td>
2906 </td>
2908 disabled.<br>
2910 </td>
2911 </tr>
2912 <tr>
2915 </td>
2917 texture object.<br>
2918 </td>
2919 </tr>
2920 <tr>
2922 </td>
2924 </td>
2926 green, blue, alpha).<br>
2927 </td>
2928 </tr>
2929 <tr>
2931 </td>
2933 </td>
2935 </td>
2936 </tr>
2937 <tr>
2939 </td>
2941 </td>
2943 </td>
2944 </tr>
2945 <tr>
2947 </td>
2949 </td>
2951 unpacked first for bitmaps.<br>
2952 One if least significant bit is unpacked first for bitmaps.<br>
2953 </td>
2954 </tr>
2955 <tr>
2957 </td>
2959 </td>
2961 height).<br>
2962 </td>
2963 </tr>
2964 </tbody>
2965 </table>
2966 <br>
2967 <br>
2969 The command<br>
2970 <br>
2974 </div>
2975 <br>
2978 table:<br>
2979 <br>
2982 <tbody>
2983 <tr>
2985 </td>
2987 </td>
2988 </tr>
2989 <tr>
2991 </td>
2994 </td>
2995 </tr>
2996 <tr>
2998 </td>
3001 </td>
3002 </tr>
3003 <tr>
3005 </td>
3008 </td>
3009 </tr>
3010 <tr>
3012 </td>
3014 the supported extensions. </td>
3015 </tr>
3016 </tbody>
3017 </table>
3018 <br>
3020 The command<br>
3021 <br>
3022 <div style="margin-left: 40px;">GLenum <span style="font-weight: bold;">glGetError</span>(void)<br>
3023 </div>
3024 <br>
3025 returns the current error code. The current error code will be
3026 set by a GL command when an error condition has been detected. If
3027 the current error code is already set, subsequent errors will not be
3030 following error codes are possible:<br>
3031 <br>
3034 <tbody>
3035 <tr>
3037 </td>
3039 </td>
3040 </tr>
3041 <tr>
3043 </td>
3045 </td>
3046 </tr>
3047 <tr>
3049 </td>
3051 value.<br>
3052 </td>
3053 </tr>
3054 <tr>
3056 </td>
3058 invalid value.<br>
3059 </td>
3060 </tr>
3061 <tr>
3063 </td>
3065 legal to do so.<br>
3066 </td>
3067 </tr>
3068 <tr>
3070 </td>
3072 matrix stack is full.<br>
3073 </td>
3074 </tr>
3075 <tr>
3077 </td>
3079 matrix stack is empty.<br>
3080 </td>
3081 </tr>
3082 <tr>
3084 </td>
3086 memory.<br>
3087 </td>
3088 </tr>
3089 </tbody>
3090 </table>
3091 <br>
3092 <br>
3094 This section lists other features and functions which are not supported
3095 and not previously discussed.<br>
3096 <br>
3098 Feedback mode and the following related functions are not supported.<br>
3099 <br>
3102 </div>
3103 <br>
3105 </h2>
3108 <br>
3122 </div>
3123 <br>
3125 </h2>
3126 Texture images may only be specified with <span
3128 alternate texture image commands are not supported:<br>
3129 <br>
3131 glCopyTexImage2D<br>
3132 glCopyTexSubImage2D<br>
3133 </div>
3134 <br>
3136 Proxy textures are not supported and the GL_PROXY_TEXTURE_2D token is
3137 not supported by any function.<br>
3138 <br>
3139 <br>
3141 The following commands related to texture mapping are not supported by
3142 the subset:<br>
3143 <br>
3145 glAreTexturesResident<br>
3146 glIsTexture<br>
3147 glTexEnviv<br>
3148 glTexEnvf<br>
3149 glTexParameterf<br>
3150 glTexParameteriv<br>
3151 glTexParameterfv<br>
3152 </div>
3153 <br>
3154 <br>
3156 </h2>
3157 The following commands are not supported:<br>
3158 <br>
3160 glCopyPixels<br>
3161 glPixelZoom<br>
3162 <br>
3163 </span></div>
3165 </h2>
3166 Color index mode and the following related commands are not supported:<br>
3167 <br>
3172 glIndexf<br>
3173 glIndexd<br>
3177 glIndexfv<br>
3179 glIndexMask<br>
3182 <br>
3183 </div>
3185 The pixel transfer operations (scale, bias, look-up table, etc) are not
3186 supported and the following commands are omitted:<br>
3203 </div>
3204 <br>
3206 Hints and the following related command is not supported:<br>
3207 <br>
3209 </span><br>
3210 </div>
3212 </h2>
3213 The following state query commands are not supported:<br>
3214 <br>
3216 glGetIntegerv<br>
3217 glGetDoublev<br>
3218 glGetPointerv<br>
3219 glGetTexEnvi<br>
3220 glGetTexEnvf<br>
3221 glGetTexParameteriv<br>
3222 glGetTexParameterfv<br>
3223 glGetTexLevelParameteriv<br>
3224 glGetTexLevelParameterfv<br>
3225 glGetTexImage<br>
3226 glGetClipPlane<br>
3227 </div>
3228 <br>
3230 State attribute stacks and the following related commands are not
3231 supported:<br>
3232 <br>
3237 </div>
3239 All functions which take double-precision floating point values, but
3240 for which there is an equivalent single-precision valued function, are
3242 <br>
3300 glRectd<br>
3301 glRectdv<br>
3303 </span> </div>
3305 Evaluators and the following related commands are not supported:<br>
3306 <br>
3351 </div>
3352 <br>
3354 Display lists and the following related commands are not supported:<br>
3355 <br>
3357 glDeleteLists<br>
3358 glGenLists<br>
3359 glNewList<br>
3360 glEndList<br>
3361 glCallList<br>
3362 glCallLists<br>
3363 glListBase<br>
3364 </div>
3365 <br>
3367 The accumulation buffer and the following related commands are not
3368 supported:<br>
3373 </div>
3374 <br>
3376 Fog and the following related commands are not supported:<br>
3377 <br>
3379 glFogf<br>
3380 glFogiv<br>
3381 glFogfv<br>
3382 </div>
3383 <br>
3385 Depth testing and the following related commands are not supported:<br>
3386 <br>
3394 </div>
3395 <br>
3397 The OpenGL imaging subset (which implements features such as
3398 convolution, histogram, min/max recording, color matrix and color
3399 tables) is not supported.<br>
3400 <br>
3401 <br>
3403 This appendix lists documentation and subset issues with their current
3404 status. For items which are still open, the documentation (above)
3405 follows the recommended solution.<br>
3406 <br>
3408 Should vertex arrays be supported? Is there a performance
3409 advantage?<br>
3410 <br>
3411 RESOLUTION: No, there isn't enough of a performance advantage to
3412 justify them.<br>
3413 <br>
3415 Should edge flags be supported for antialiasing?<br>
3416 <br>
3417 Edge flags don't effect antialiasing, at least not normally. A
3418 number of approaches to antialiasing have been summarized in email.<br>
3419 <br>
3420 RECOMMENDATION: don't support edge flags. They don't effect
3421 polygon antialiasing.<br>
3422 <br>
3424 <br>
3426 Should glRasterPos and/or glWindowPos commands be supported?<br>
3427 <br>
3428 RESOLUTION: Closed: implement glRasterPos commands, but not glWindowPos
3429 commands.<br>
3430 <br>
3432 Should the GL_IBM_rasterpos_clip extension be implemented?<br>
3433 <br>
3435 <br>
3437 Which image formats and types should be supported for <span
3440 <br>
3442 variety of image formats and data types. Only a few are commonly
3443 used.<br>
3444 <br>
3446 <br>
3451 to be GL_RGBA, GL_RGB or GL_INTENSITY as well. Basically, only
3452 support image formats/types that are directly supported by the Radeon
3455 copy texture images.<br>
3456 <br>
3460 GL_RGB or GL_RGBA. This is just enough to support the OpenGL
3461 conformance tests.<br>
3462 <br>
3463 RESOLUTION: open<br>
3464 <br>
3467 has GL_REPLACE, GL_MODULATE, GL_DECAL and GL_BLEND. GL_DECAL isn't
3468 defined for all base internal texture formats. GL_ADD is another
3470 <br>
3471 RECOMMENDATION: implement the standard modes GL_REPLACE, GL_MODULATE,
3472 GL_DECAL and GL_BLEND.<br>
3473 <br>
3474 RESOLUTION: open<br>
3475 <br>
3477 Should we support the GL_TEXTURE_BASE_LEVEL, GL_TEXTURE_MAX_LEVEL,
3478 GL_TEXTURE_MIN_LOD and GL_TEXTURE_MAX_LOD texture parameters?<br>
3479 <br>
3480 RECOMMENDATION: We propose omitting these features at this time,
3481 in the interest of simplifying the driver.<br>
3482 <br>
3483 RESOLUTION: open<br>
3484 <br>
3486 Should the subset support texture priorities via <span
3489 <br>
3490 RECOMMENDATION: Few applications use these features and
3492 <br>
3493 RESOLUTION: open<br>
3494 <br>
3496 Should we support the GL_PACK_ALIGNMENT and GL_UNPACK_ALIGNMENT options?<br>
3497 <br>
3502 aligned address and appropriate GL_PACK_ROW_LENGTH or
3503 GL_UNPACK_ROW_LENGTH values instead.<br>
3504 <br>
3506 <br>
3507 RESOLUTION: open<br>
3508 <br>
3510 Should we support the GL_UNPACK_SKIP_PIXELS, GL_UNPACK_SKIP_ROWS,
3511 GL_PACK_SKIP_PIXELS and GL_PACK_SKIP_ROWS options for pixel
3512 unpacking/packing?<br>
3513 <br>
3514 These options aren't really needed since the user can adjust the start
3515 address and GL_PACK/UNPACK_ROW_LENGTH parameters to achieve the same
3516 effect.<br>
3517 <br>
3519 <br>
3520 RESOLUTION: open<br>
3521 <br>
3524 glGetTexParameteri/fv</span> and <span style="font-weight: bold;">glGetTexLevelParameteri/fv</span>?<br>
3525 <br>
3527 implementation is several hundred lines of code in length.<br>
3528 <br>
3530 <br>
3535 <br>
3536 RECOMMENDATION: Omit the boolean, integer and double-valued
3537 functions. All state values which can be queried by these commands can
3538 be expressed as floating point values and queried with <span
3540 implementation of the other three commands involves many lines of code.<br>
3541 <br>
3543 <br>
3546 be subjected to the per-fragment operations?<br>
3547 <br>
3548 If bitmaps are implemented with points it will be easy to implement the
3550 <br>
3551 RECOMMENDATION: Implement glBitmap by drawing points/pixels with
3552 the hardware. This will make supporting the per-fragments
3553 trivially easy. Also, it makes portrait-mode display relatively
3554 easy.<br>
3555 <br>
3557 <br>
3559 Should we produce a reduced gl.h header file which only defines the
3560 tokens and functions which are implemented by the subset?<br>
3561 <br>
3562 RECOMMENDATION: yes. It would be a useful reference to
3563 programmers to quickly determine which functions and tokens are
3564 supported.<br>
3565 <br>
3566 RESOLUTION: open<br>
3567 <br>
3570 <br>
3572 <br>
3574 <br>
3575 <br>
3576 <p> </p>
3577 </body>
3578 </html>