docs/MESA_packed_depth_stencil.spec

   1 Name
   2
   3     MESA_packed_depth_stencil
   4
   5 Name Strings
   6
   7     GL_MESA_packed_depth_stencil
   8
   9 Contact
  10
  11     Keith Whitwell, VA Linux Systems Inc. (keithw 'at' valinux.com)
  12     Brian Paul, VA Linux Systems Inc. (brianp 'at' valinux.com)
  13
  14 Status
  15
  16     Obsolete.
  17
  18 Version
  19
  20     $Id: MESA_packed_depth_stencil.spec,v 1.2 2003/09/19 14:58:21 brianp Exp $
  21
  22 Number
  23
  24     ???
  25
  26 Dependencies
  27
  28     EXT_abgr affects the definition of this extension
  29     SGIS_texture4D affects the definition of this extension
  30     EXT_cmyka affects the definition of this extension
  31     ARB_packed_pixels affects the definition of this extension
  32
  33 Overview
  34
  35     Provides a mechanism for DrawPixels and ReadPixels to efficiently
  36     transfer depth and stencil image data.  Specifically, we defined new
  37     packed pixel formats and types which pack both stencil and depth
  38     into one value.
  39
  40 Issues:
  41
  42     1. Is this the right way to distinguish between 24/8 and 8/24
  43        pixel formats?  Should we instead provide both:
  44
  45        GL_DEPTH_STENCIL_MESA
  46        GL_STENCIL_DEPTH_MESA
  47
  48        And perhaps just use GL_UNSIGNED_INT, GL_UNSIGNED_SHORT ?
  49
  50     2. If not, is it correct to use _REV to indicate that stencil
  51        preceeds depth in the 1_15 and 8_24 formats?
  52
  53     3. Do we really want the GL_UNSIGNED_SHORT formats?
  54
  55
  56 New Procedures and Functions
  57
  58     None.
  59
  60 New Tokens
  61
  62     Accepted by the <format> parameter of ReadPixels and DrawPixels:
  63
  64         GL_DEPTH_STENCIL_MESA           0x8750
  65
  66     Accepted by the <type> parameter of ReadPixels and DrawPixels:
  67
  68         GL_UNSIGNED_INT_24_8_MESA       0x8751
  69         GL_UNSIGNED_INT_8_24_REV_MESA   0x8752
  70         GL_UNSIGNED_SHORT_15_1_MESA     0x8753
  71         GL_UNSIGNED_SHORT_1_15_REV_MESA 0x8754
  72
  73 Additions to Chapter 2 of the 1.1 Specification (OpenGL Operation)
  74
  75     None
  76
  77 Additions to Chapter 3 of the 1.1 Specification (Rasterization)
  78
  79     One entry is added to table 3.5 (DrawPixels and ReadPixels formats).
  80     The new table is:
  81
  82                         Target
  83         Format Name     Buffer  Element Meaning and Order
  84         -----------     ------  -------------------------
  85         COLOR_INDEX     Color   Color index
  86         STENCIL_INDEX   Stencil Stencil index
  87         DEPTH_COMPONENT Depth   Depth component
  88         RED             Color   R component
  89         GREEN           Color   G component
  90         BLUE            Color   B component
  91         ALPHA           Color   A component
  92         RGB             Color   R, G, B components
  93         RGBA            Color   R, G, B, A components
  94         BGRA            Color   B, G, R, A components
  95         ABGR_EXT        Color   A, B, G, R components
  96         CMYK_EXT        Color   Cyan, Magenta, Yellow, Black components
  97         CMYKA_EXT       Color   Cyan, Magenta, Yellow, Black, A components
  98         LUMINANCE       Color   Luminance component
  99         LUMINANCE_ALPHA Color   Luminance, A components
 100         DEPTH_STENCIL   Depth,  Depth component, stencil index.
 101                         Stencil
 102
 103         Table 3.5: DrawPixels and ReadPixels formats.  The third column
 104         gives a description of and the number and order of elements in a
 105         group.
 106
 107     Add to the description of packed pixel formats:
 108
 109         <type> Parameter                Data    of        Matching
 110         Token Name                      Type    Elements  Pixel Formats
 111         ----------------                ----    --------  -------------
 112
 113         UNSIGNED_BYTE_3_3_2           ubyte   3       RGB
 114         UNSIGNED_BYTE_2_3_3_REV       ubyte   3       RGB
 115         UNSIGNED_SHORT_5_6_5          ushort  3       RGB
 116         UNSIGNED_SHORT_5_6_5_REV      ushort  3       RGB
 117         UNSIGNED_SHORT_4_4_4_4        ushort  4       RGBA,BGRA,ABGR_EXT,CMYK_EXT
 118         UNSIGNED_SHORT_4_4_4_4_REV    ushort  4       RGBA,BGRA
 119         UNSIGNED_SHORT_5_5_5_1        ushort  4       RGBA,BGRA,ABGR_EXT,CMYK_EXT
 120         UNSIGNED_SHORT_1_5_5_5_REV    ushort  4       RGBA,BGRA
 121         UNSIGNED_INT_8_8_8_8          uint    4       RGBA,BGRA,ABGR_EXT,CMYK_EXT
 122         UNSIGNED_INT_8_8_8_8_REV      uint    4       RGBA,BGRA
 123         UNSIGNED_INT_10_10_10_2       uint    4       RGBA,BGRA,ABGR_EXT,CMYK_EXT
 124         UNSIGNED_INT_2_10_10_10_REV   uint    4       RGBA,BGRA
 125         UNSIGNED_SHORT_15_1_MESA      ushort  2       DEPTH_STENCIL_MESA
 126         UNSIGNED_SHORT_1_15_REV_MESA  ushort  2       DEPTH_STENCIL_MESA
 127         UNSIGNED_SHORT_24_8_MESA      ushort  2       DEPTH_STENCIL_MESA
 128         UNSIGNED_SHORT_8_24_REV_MESA  ushort  2       DEPTH_STENCIL_MESA
 129
 130         UNSIGNED_INT_8_24:
 131
 132              31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10  9  8  7  6  5  4  3  2  1  0
 133             +-----------------------+-----------------------------------------------------------------------+
 134             |                       |                                                                       |
 135             +-----------------------+-----------------------------------------------------------------------+
 136
 137                     first                                       second
 138                     element                                     element
 139
 140
 141         UNSIGNED_INT_24_8:
 142
 143              31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10  9  8  7  6  5  4  3  2  1  0
 144             +----------------------------------------------------------------------+------------------------+
 145             |                                                                      |                        |
 146             +----------------------------------------------------------------------+------------------------+
 147
 148                     first                                                                 second
 149                     element                                                               element
 150
 151         UNSIGNED_SHORT_15_1:
 152
 153               15  14  13  12  11  10  9   8   7   6   5   4   3   2   1   0
 154             +-----------------------------------------------------------+---+
 155             |                                                           |   |
 156             +-----------------------------------------------------------+---+
 157
 158                         first                                           second
 159                         element                                         element
 160
 161
 162         UNSIGNED_SHORT_1_15_REV:
 163
 164               15  14  13  12  11  10  9   8   7   6   5   4   3   2   1   0
 165             +---+-----------------------------------------------------------+
 166             |   |                                                           |
 167             +---+-----------------------------------------------------------+
 168
 169             second                  first
 170             element                 element
 171
 172     The assignment of elements to fields in the packed pixel is as
 173     described in the table below:
 174
 175                            First       Second   Third       Fourth
 176         Format             Element     Element  Element     Element
 177         ------             -------     -------  -------     -------
 178         RGB                red         green    blue
 179         RGBA               red         green    blue        alpha
 180         BGRA               blue        green    red         alpha
 181         ABGR_EXT           alpha       blue     green       red
 182         CMYK_EXT           cyan        magenta  yellow      black
 183         DEPTH_STENCIL_MESA depth       stencil
 184
 185 Additions to Chapter 4 of the 1.1 Specification (Per-Fragment Operations
 186 and the Frame Buffer)
 187
 188     The new format is added to the discussion of Obtaining Pixels from the
 189     Framebuffer.  It should read " If the <format> is one of RED, GREEN,
 190     BLUE, ALPHA, RGB, RGBA, ABGR_EXT, LUMINANCE, or LUMINANCE_ALPHA, and
 191     the GL is in color index mode, then the color index is obtained."
 192
 193     The new format is added to the discussion of Index Lookup.  It should
 194     read "If <format> is one of RED, GREEN, BLUE, ALPHA, RGB, RGBA,
 195     ABGR_EXT, LUMINANCE, or LUMINANCE_ALPHA, then the index is used to
 196     reference 4 tables of color components: PIXEL_MAP_I_TO_R,
 197     PIXEL_MAP_I_TO_G, PIXEL_MAP_I_TO_B, and PIXEL_MAP_I_TO_A."
 198
 199
 200 Additions to Chapter 5 of the 1.1 Specification (Special Functions)
 201
 202     None
 203
 204 Additions to Chapter 6 of the 1.1 Specification (State and State Requests)
 205
 206     None
 207
 208 Additions to the GLX Specification
 209
 210     None
 211
 212 GLX Protocol
 213
 214     TBD
 215
 216 Errors
 217
 218     None
 219
 220 New State
 221
 222     None
 223
 224 Revision History
 225
 226     Version 1.0 - 23 Sep 2000
 227         Keith's original version.
 228
 229     Version 1.1 - 3 Nov 2000
 230         Brian's edits, assigned values to new enums.
 231