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