tests/general/drawpix-z.c

   1 /*
   2  * Copyright 2012 VMware, Inc.
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21  * DEALINGS IN THE SOFTWARE.
  22  */
  23
  24 /**
  25  * Test glDrawPixels(GL_DEPTH_COMPONENT)
  26  * Brian Paul
  27  * June 2012
  28  *
  29  * We don't rely on glReadPixels(GL_DEPTH_COMPONENT) in case it's not
  30  * working.  Instead we test by drawing an image into the depth buffer
  31  * while setting the color buffer to white.  Next, we draw quads just
  32  * in front and behind where we expect the Z values to be.  The quad
  33  * behind should be invisible while the quad in front should be totally
  34  * visible.
  35  */
  36
  37 #include "piglit-util-gl.h"
  38
  39 PIGLIT_GL_TEST_CONFIG_BEGIN
  40
  41         config.supports_gl_compat_version = 10;
  42
  43         config.window_width = 200;
  44         config.window_height = 200;
  45         config.window_visual = PIGLIT_GL_VISUAL_RGB | PIGLIT_GL_VISUAL_DOUBLE | PIGLIT_GL_VISUAL_DEPTH;
  46         config.khr_no_error_support = PIGLIT_NO_ERRORS;
  47
  48 PIGLIT_GL_TEST_CONFIG_END
  49
  50 static void
  51 draw_z_gradient(GLfloat zLeft, GLfloat zRight)
  52 {
  53         GLfloat verts[4][3];
  54
  55         verts[0][0] = -1.0;  verts[0][1] = -1.0;  verts[0][2] = zLeft;
  56         verts[1][0] =  1.0;  verts[1][1] = -1.0;  verts[1][2] = zRight;
  57         verts[2][0] =  1.0;  verts[2][1] =  1.0;  verts[2][2] = zRight;
  58         verts[3][0] = -1.0;  verts[3][1] =  1.0;  verts[3][2] = zLeft;
  59
  60         glEnableClientState(GL_VERTEX_ARRAY);
  61         glVertexPointer(3, GL_FLOAT, 0, verts);
  62         glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
  63 }
  64
  65
  66 enum piglit_result
  67 piglit_display(void)
  68 {
  69         /* a tight epsilon isn't important for this test */
  70         const GLfloat epsilon = 4.0 / piglit_width;
  71         static const GLfloat white[4] = { 1, 1, 1, 1 };
  72         static const GLfloat green[4] = { 0, 1, 0, 1 };
  73         static const GLfloat red[4] = { 1, 0, 0, 1 };
  74         GLfloat *buf;
  75         bool pass = true;
  76         int i, j;
  77         float zLeft, zRight;
  78
  79         /* For both glDrawPixels and the polygon rendering below we
  80          * use a range of Z values in [0, 1] where 0=near and 1=far.
  81          * So object Z coords are the same as normalized depth coords.
  82          */
  83
  84         zLeft = epsilon;
  85         zRight = 1.0 - epsilon;
  86
  87         /* create image of Z values increasing from left to right */
  88         buf = (GLfloat *)
  89                 malloc(piglit_width * piglit_height * sizeof(GLfloat));
  90         for (j = 0; j < piglit_height; j++) {
  91                 for (i = 0; i < piglit_width; i++) {
  92                         float z = i / (float) (piglit_width - 1);
  93                         z = zLeft + z * (zRight - zLeft);
  94                         buf[j * piglit_width + i] = z;
  95                 }
  96         }
  97
  98         glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  99
 100         /* glDrawPixels the Z gradient image */
 101         glColor4fv(white);
 102         glWindowPos2i(0, 0);
 103         glDrawPixels(piglit_width, piglit_height,
 104                      GL_DEPTH_COMPONENT, GL_FLOAT, buf);
 105
 106         free(buf);
 107
 108         /* draw a red quad behind the Z gradient - it should not be visible */
 109         glColor4fv(red);
 110         draw_z_gradient(zLeft + epsilon, zRight + epsilon);
 111         if (!piglit_probe_rect_rgb(0, 0, piglit_width, piglit_height, white)) {
 112                 printf("Quad behind test failed\n");
 113                 pass = false;
 114         }
 115
 116         /* draw green quad in front of the Z gradient - it should be visible */
 117         glColor4fv(green);
 118         draw_z_gradient(zLeft - epsilon, zRight - epsilon);
 119         if (!piglit_probe_rect_rgb(0, 0, piglit_width, piglit_height, green)) {
 120                 printf("Quad in front test failed\n");
 121                 pass = false;
 122         }
 123
 124         piglit_present_results();
 125
 126         return pass ? PIGLIT_PASS : PIGLIT_FAIL;
 127 }
 128
 129
 130 void
 131 piglit_init(int argc, char **argv)
 132 {
 133         /* Setup projection matrix such that zObj=0 becomes zBuffer=0
 134          * and zObj=1 becomes zBuffer=1 (identity transform).
 135          * So, glOrtho maps zObj=0 to zNDC=-1 and maps zObj=1 to zNDC=1.
 136          * Then, zNDC=-1 maps to zBuffer=0 and zNDC=1 maps to zBuffer=1.
 137          */
 138         glMatrixMode(GL_PROJECTION);
 139         glLoadIdentity();
 140         glOrtho(-1.0, 1.0, -1.0, 1.0, 0.0, -1.0);
 141
 142         glEnable(GL_DEPTH_TEST);
 143 }