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comparison: gfx/angle/extensions/ANGLE_depth_texture.txt
gfx/angle/extensions/ANGLE_depth_texture.txt
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| -1:000000000000 | 0:258d3972cce4 |
|---|---|
| 1 Name | |
| 2 | |
| 3 ANGLE_depth_texture | |
| 4 | |
| 5 Name Strings | |
| 6 | |
| 7 GL_ANGLE_depth_texture | |
| 8 | |
| 9 Contributors | |
| 10 | |
| 11 Nicolas Capens, TransGaming | |
| 12 Daniel Koch, TransGaming | |
| 13 Shannon Woods, TransGaming | |
| 14 Kenneth Russell, Google | |
| 15 Vangelis Kokkevis, Google | |
| 16 Gregg Tavares, Google | |
| 17 Contributors to OES_depth_texture | |
| 18 Contributors to OES_packed_depth_stencil | |
| 19 | |
| 20 Contact | |
| 21 | |
| 22 Shannon Woods, TransGaming (shannon 'dot' woods 'at' transgaming.com) | |
| 23 | |
| 24 Status | |
| 25 | |
| 26 Implemented in ANGLE. | |
| 27 | |
| 28 Version | |
| 29 | |
| 30 Last Modified Date: February 25, 2013 | |
| 31 Revision: #4 | |
| 32 | |
| 33 Number | |
| 34 | |
| 35 TBD | |
| 36 | |
| 37 Dependencies | |
| 38 | |
| 39 OpenGL ES 2.0 is required. | |
| 40 This extension is written against the OpenGL ES 2.0.25 specification | |
| 41 | |
| 42 OES_packed_depth_stencil affects the definition of this extension. | |
| 43 | |
| 44 EXT_texture_storage affects the definition of this extension. | |
| 45 | |
| 46 Overview | |
| 47 | |
| 48 This extension defines support for 2D depth and depth-stencil | |
| 49 textures in an OpenGL ES implementation. | |
| 50 | |
| 51 This extension incorporates the depth texturing functionality of | |
| 52 OES_depth_texture and OES_packed_depth_stencil, but does not | |
| 53 provide the ability to load existing data via TexImage2D or | |
| 54 TexSubImage2D. This extension also allows implementation | |
| 55 variability in which components from a sampled depth texture | |
| 56 contain the depth data. Depth textures created with this | |
| 57 extension only support 1 level. | |
| 58 | |
| 59 New Procedures and Functions | |
| 60 | |
| 61 None | |
| 62 | |
| 63 New Tokens | |
| 64 | |
| 65 Accepted by the <format> parameter of TexImage2D and TexSubImage2D and | |
| 66 <internalformat> parameter of TexImage2D: | |
| 67 | |
| 68 DEPTH_COMPONENT 0x1902 | |
| 69 DEPTH_STENCIL_OES 0x84F9 | |
| 70 | |
| 71 Accepted by the <type> parameter of TexImage2D, TexSubImage2D: | |
| 72 | |
| 73 UNSIGNED_SHORT 0x1403 | |
| 74 UNSIGNED_INT 0x1405 | |
| 75 UNSIGNED_INT_24_8_OES 0x84FA | |
| 76 | |
| 77 Accepted by the <internalformat> parameter of TexStorage2DEXT: | |
| 78 | |
| 79 DEPTH_COMPONENT16 0x81A5 | |
| 80 DEPTH_COMPONENT32_OES 0x81A7 | |
| 81 DEPTH24_STENCIL8_OES 0x88F0 | |
| 82 | |
| 83 Additions to Chapter 2 of the OpenGL ES 2.0 Specification (OpenGL Operation) | |
| 84 | |
| 85 Update Section 2.10.5 "Shader Execution" in the subsection titled | |
| 86 "Texture Access" add a new paragraph before the last paragraph add | |
| 87 this line: | |
| 88 | |
| 89 "The stencil index texture internal component is ignored if the base | |
| 90 internal format is DEPTH_STENCIL_OES. | |
| 91 | |
| 92 If a vertex shader uses..." | |
| 93 | |
| 94 Additions to Chapter 3 of the OpenGL ES 2.0 specification (Rasterization) | |
| 95 | |
| 96 Add the following rows to Table 3.2 (page 62): | |
| 97 | |
| 98 type Parameter GL Data Type Special | |
| 99 ------------------------------------------------ | |
| 100 ... ... ... | |
| 101 UNSIGNED_SHORT ushort No | |
| 102 UNSIGNED_INT uint No | |
| 103 UNSIGNED_INT_24_8_OES uint Yes | |
| 104 | |
| 105 Add the following rows to Table 3.3 (page 62): | |
| 106 | |
| 107 Format Name Element Meaning and Order Target Buffer | |
| 108 ------------------------------------------------------------------ | |
| 109 ... ... ... | |
| 110 DEPTH_COMPONENT Depth Depth | |
| 111 DEPTH_STENCIL_OES Depth and Stencil Index Depth and Stencil | |
| 112 ... ... ... | |
| 113 | |
| 114 Add a row to Table 3.5 "Packed pixel formats" (page 64): | |
| 115 | |
| 116 type Parameter GL Type Components Pixel Formats | |
| 117 ------------------------------------------------------------------ | |
| 118 ... ... ... ... | |
| 119 UNSIGNED_INT_24_8_OES uint 2 DEPTH_STENCIL_OES | |
| 120 | |
| 121 Add a new table after Table 3.6 (page 64): | |
| 122 | |
| 123 UNSIGNED_INT_24_8_OES | |
| 124 | |
| 125 31 30 29 28 27 26 ... 12 11 10 9 8 7 6 5 4 3 2 1 0 | |
| 126 +----------------------------------+---------------+ | |
| 127 | 1st Component | 2nd Component | | |
| 128 +----------------------------------+---------------+ | |
| 129 | |
| 130 Table 3.6.B: UNSIGNED_INT formats | |
| 131 | |
| 132 Add a row to Table 3.7 "Packed pixel field assignments" (page 65): | |
| 133 | |
| 134 Format | 1st 2nd 3rd 4th | |
| 135 ------------------+------------------------------- | |
| 136 ... | ... ... ... ... | |
| 137 DEPTH_STENCIL_OES | depth stencil N/A N/A | |
| 138 | |
| 139 Add the following paragraph to the end of the section "Conversion to | |
| 140 floating-point" (page 65): | |
| 141 | |
| 142 "For groups of components that contain both standard components and index | |
| 143 elements, such as DEPTH_STENCIL_OES, the index elements are not converted." | |
| 144 | |
| 145 In section 3.7.1 "Texture Image Specification", update page 67 to | |
| 146 say: | |
| 147 | |
| 148 "The selected groups are processed as described in section 3.6.2, stopping | |
| 149 just before final conversion. Each R, G, B, A, or depth value so generated | |
| 150 is clamped to [0, 1], while the stencil index values are masked by 2^n-1, | |
| 151 where n is the number of stencil bits in the internal format resolution | |
| 152 (see below). | |
| 153 | |
| 154 Components are then selected from the resulting R, G, B, A, depth, or | |
| 155 stencil index values to obtain a texture with the base internal format | |
| 156 specified by <internalformat>. Table 3.8 summarizes the mapping of R, G, | |
| 157 B, A, depth, or stencil values to texture components, as a function of the | |
| 158 base internal format of the texture image. <internalformat> may be | |
| 159 specified as one of the internal format symbolic constants listed in | |
| 160 table 3.8. Specifying a value for <internalformat> that is not one of the | |
| 161 above values generates the error INVALID_VALUE. If <internalformat> does | |
| 162 not match <format>, the error INVALID_OPERATION is generated. | |
| 163 | |
| 164 Textures with a base internal format of DEPTH_COMPONENT or | |
| 165 DEPTH_STENCIL_OES are supported by texture image specification commands | |
| 166 only if <target> is TEXTURE_2D. Using these formats in conjunction with | |
| 167 any other <target> will result in an INVALID_OPERATION error. | |
| 168 | |
| 169 Textures with a base internal format of DEPTH_COMPONENT or | |
| 170 DEPTH_STENCIL_OES only support one level of image data. Specifying a | |
| 171 non-zero value for <level> will result in an INVALID_OPERATION error. | |
| 172 | |
| 173 Textures with a base internal format of DEPTH_COMPONENT or DEPTH_STENCIL_OES | |
| 174 require either depth component data or depth/stencil component data. | |
| 175 Textures with other base internal formats require RGBA component data. The | |
| 176 error INVALID_OPERATION is generated if the base internal format is | |
| 177 DEPTH_COMPONENT or DEPTH_STENCIL_OES and <format> is not DEPTH_COMPONENT or | |
| 178 DEPTH_STENCIL_OES, or if the base internal format is not DEPTH_COMPONENT or | |
| 179 DEPTH_STENCIL_OES and <format> is DEPTH_COMPONENT or DEPTH_STENCIL_OES. | |
| 180 | |
| 181 Textures with a base internal format of DEPTH_COMPONENT or | |
| 182 DEPTH_STENCIL_OES do not support loading image data via the TexImage | |
| 183 commands. They can only have their contents specified by rendering | |
| 184 to them. The INVALID_OPERATION error is generated by the TexImage2D | |
| 185 command if <data> is not NULL for such textures." | |
| 186 | |
| 187 Add a row to table 3.8 (page 68), and update the title of the | |
| 188 second column: | |
| 189 | |
| 190 Base Internal Format RGBA, Depth and Stencil Values Internal Components | |
| 191 ------------------------------------------------------------------------- | |
| 192 ... ... ... | |
| 193 DEPTH_COMPONENT Depth D | |
| 194 DEPTH_STENCIL_OES Depth,Stencil D,S | |
| 195 ... ... ... | |
| 196 | |
| 197 Update the caption for table 3.8 (page 68) | |
| 198 | |
| 199 "Table 3.8: Conversion from RGBA, depth, and stencil pixel components to | |
| 200 internal texture components. Texture components R, G, B, A, and L are | |
| 201 converted back to RGBA colors during filtering as shown in table 3.12. | |
| 202 Texture components D are converted to RGBA colors as described in | |
| 203 section 3.7.8-1/2." | |
| 204 | |
| 205 Add the following to section 3.7.2 "Alternate Texture Image Specification | |
| 206 Commands": | |
| 207 | |
| 208 "CopyTexImage2D and CopyTexSubImage2D generate the INVALID_OPERATION | |
| 209 error if the base internal format of the destination texture is | |
| 210 DEPTH_COMPONENT or DEPTH_STENCIL_OES. | |
| 211 | |
| 212 TexSubImage2D generates the INVALID_OPERATION error if the base internal | |
| 213 format of the texture is DEPTH_COMPONENT or DEPTH_STENCIL_OES." | |
| 214 | |
| 215 Add a new section between sections 3.7.8 and 3.7.9: | |
| 216 | |
| 217 "3.7.8-1/2 Depth/Stencil Textures | |
| 218 | |
| 219 If the currently bound texture's base internal format is DEPTH_COMPONENT or | |
| 220 DEPTH_STENCIL_OES, then the output of the texture unit is as described | |
| 221 below. Otherwise, the texture unit operates in the normal manner. | |
| 222 | |
| 223 Let <D_t> be the depth texture value, provided by the shader's texture lookup | |
| 224 function. Then the effective texture value is computed as follows: | |
| 225 <Tau> = <D_t> | |
| 226 | |
| 227 If the texture image has a base internal format of DEPTH_STENCIL_OES, then | |
| 228 the stencil index texture component is ignored. The texture value <Tau> does | |
| 229 not include a stencil index component, but includes only the depth | |
| 230 component. | |
| 231 | |
| 232 The resulting <Tau> is assigned to <R_t>. In some implementations, <Tau> is | |
| 233 also assigned to <G_t>, <B_t>, or <A_t>. Thus in table 3.12, textures with | |
| 234 depth component data behave as if their base internal format is RGBA, with | |
| 235 values in <G_t>, <B_t>, and <A_t> being implementation dependent." | |
| 236 | |
| 237 Add the following to section 3.7.11 "Mipmap Generation": | |
| 238 | |
| 239 "If the level zero array contains depth or depth-stencil data, the | |
| 240 error INVALID_OPERATION is generated." | |
| 241 | |
| 242 Insert a new paragraph after the first paragraph of the "Texture Access" | |
| 243 subsection of section 3.8.2 on page 87, which says: | |
| 244 | |
| 245 "Texture lookups involving textures with depth component data generate | |
| 246 a texture source color by using depth data directly, as described in | |
| 247 section 3.7.8-1/2. The stencil texture internal component is ignored | |
| 248 if the base internal format is DEPTH_STENCIL_OES." | |
| 249 | |
| 250 Additions to Chapter 4 of the OpenGL ES 2.0 specification (Per-Fragment | |
| 251 Operations and the Framebuffer) | |
| 252 | |
| 253 In section 4.4.5 "Framebuffer Completeness", replace the the 3rd | |
| 254 paragraph with the following text: | |
| 255 | |
| 256 "* An internal format is color-renderable if it is one of the formats | |
| 257 from table 4.5 noted as color-renderable or if it is unsized format | |
| 258 RGBA or RGB. No other formats, including compressed internal formats, | |
| 259 are color-renderable. | |
| 260 | |
| 261 * An internal format is depth-renderable if it is one of the sized | |
| 262 internal formats from table 4.5 noted as depth-renderable, if it | |
| 263 is the unsized format DEPTH_COMPONENT or if it is the internal | |
| 264 format value of DEPTH24_STENCIL8_OES. No other formats are | |
| 265 depth-renderable. | |
| 266 | |
| 267 * An internal format is stencil-renderable if it is one of the sized | |
| 268 internal formats from table 4.5 noted as stencil-renderable or if it | |
| 269 is DEPTH24_STENCIL8_OES. No other formats are stencil-renderable." | |
| 270 | |
| 271 Additions to Chapter 5 of the OpenGL ES 2.0 Specification (Special | |
| 272 Functions) | |
| 273 | |
| 274 None. | |
| 275 | |
| 276 Additions to Chapter 6 of the OpenGL ES 2.0 Specification (State and State | |
| 277 Requests) | |
| 278 | |
| 279 None. | |
| 280 | |
| 281 Interactions with OES_packed_depth_stencil | |
| 282 | |
| 283 If OES_packed_depth_stencil is not supported, mentions of | |
| 284 DEPTH_STENCIL_OES and UNSIGNED_INT_24_8_OES as a format/type combinations | |
| 285 for TexImage2D and TexSubImage2D are omitted. Mentions of | |
| 286 the internal format DEPTH24_STENCIL8_OES are also omitted. | |
| 287 | |
| 288 Interactions with EXT_texture_storage | |
| 289 | |
| 290 If EXT_texture_storage is supported the following internalformat | |
| 291 to format/type mappings are used: | |
| 292 | |
| 293 <internalformat> <format> <type> | |
| 294 ---------------- -------- ------ | |
| 295 DEPTH_COMPONENT16 DEPTH_COMPONENT UNSIGNED_SHORT | |
| 296 DEPTH_COMPONENT32_OES DEPTH_COMPONENT UNSIGNED_INT | |
| 297 DEPTH24_STENCIL8_OES DEPTH_STENCIL_OES UNSIGNED_INT | |
| 298 | |
| 299 Textures with the above <internalformats> only support one level of | |
| 300 image data. Specifying a value other than one for the <levels> parameter | |
| 301 to TexStorage2DEXT will result in an INVALID_OPERATION error. | |
| 302 | |
| 303 If EXT_texture_storage is not supported, ignore any references | |
| 304 to TexStorage2DEXT. | |
| 305 | |
| 306 Errors | |
| 307 | |
| 308 The error INVALID_OPERATION is generated by TexImage2D if <format> and | |
| 309 <internalformat> are DEPTH_COMPONENT and <type> is not UNSIGNED_SHORT, | |
| 310 or UNSIGNED_INT. | |
| 311 | |
| 312 The error INVALID_OPERATION is generated by TexSubImage2D if <format> is | |
| 313 DEPTH_COMPONENT and <type> is not UNSIGNED_SHORT, or UNSIGNED_INT. | |
| 314 | |
| 315 The error INVALID_OPERATION is generated by TexImage2D if <format> and | |
| 316 <internalformat> are not DEPTH_COMPONENT and <type> is UNSIGNED_SHORT, | |
| 317 or UNSIGNED_INT. | |
| 318 | |
| 319 The error INVALID_OPERATION is generated by TexSubImage2D if <format> is | |
| 320 not DEPTH_COMPONENT and <type> is UNSIGNED_SHORT, or UNSIGNED_INT. | |
| 321 | |
| 322 The error INVALID_OPERATION is generated by TexImage2D if <format> and | |
| 323 <internalformat> are DEPTH_STENCIL_OES and <type> is not | |
| 324 UNSIGNED_INT_24_8_OES. | |
| 325 | |
| 326 The error INVALID_OPERATION is generated by TexSubImage2D if <format> | |
| 327 is DEPTH_STENCIL_OES and <type> is not UNSIGNED_INT_24_8_OES. | |
| 328 | |
| 329 The error INVALID_OPERATION is generated by TexImage2D if <format> and | |
| 330 <internalformat> is not DEPTH_STENCIL_OES and <type> is | |
| 331 UNSIGNED_INT_24_8_OES. | |
| 332 | |
| 333 The error INVALID_OPERATION is generated by TexSubImage2D if <format> | |
| 334 is not DEPTH_STENCIL_OES and <type> is UNSIGNED_INT_24_8_OES. | |
| 335 | |
| 336 The error INVALID_OPERATION is generated in the following situations: | |
| 337 - TexImage2D is called with <format> and <internalformat> of | |
| 338 DEPTH_COMPONENT or DEPTH_STENCIL_OES and | |
| 339 - <target> is not TEXTURE_2D, | |
| 340 - <data> is not NULL, or | |
| 341 - <level> is not zero. | |
| 342 - TexSubImage2D is called with <format> of DEPTH_COMPONENT or | |
| 343 DEPTH_STENCIL_OES. | |
| 344 - TexStorage2DEXT is called with <internalformat> of DEPTH_COMPONENT16, | |
| 345 DEPTH_COMPONENT32_OES, or DEPTH24_STENCIL8_OES, and | |
| 346 - <target> is not TEXTURE_2D, or | |
| 347 - <levels> is not one. | |
| 348 - CopyTexImage2D is called with an <internalformat> that has a base | |
| 349 internal format of DEPTH_COMPONENT or DEPTH_STENCIL_OES. | |
| 350 - CopyTexSubImage2D is called with a target texture that has a base | |
| 351 internal format of DEPTH_COMPONENT or DEPTH_STENCIL_OES. | |
| 352 - GenerateMipmap is called on a texture that has a base internal format | |
| 353 of DEPTH_COMPONENT or DEPTH_STENCIL_OES. | |
| 354 | |
| 355 New State | |
| 356 | |
| 357 None. | |
| 358 | |
| 359 Issues | |
| 360 | |
| 361 1) What are the differences between this extension and OES_depth_texture | |
| 362 and OES_packed_depth_stencil? | |
| 363 | |
| 364 RESOLVED: This extension: | |
| 365 - does not support loading pre-baked depth stencil data via | |
| 366 TexImage2D or TexSubImage2D. | |
| 367 - allows variability in the y-, z-, and w-components of the sample | |
| 368 results from depth textures. | |
| 369 - only supports one level textures. | |
| 370 - explicitly lists the errors for unsupported functionality. | |
| 371 Since these were not clearly specified in the OES_depth_texture | |
| 372 extension there may be differences in error values between | |
| 373 implementations of OES_depth_texture and ANGLE_depth_texture. | |
| 374 This specification was also rebased to apply against the OpenGL ES 2.0 | |
| 375 specification instead of the OpenGL specification, making it more | |
| 376 obvious what all the functionality changes are. | |
| 377 | |
| 378 2) Why does TexSubImage2D accept the new format/type combinations even | |
| 379 though it does not actually support loading data? | |
| 380 | |
| 381 RESOLVED: This was done to be more consistent with the OES_depth_texture | |
| 382 extension and to make it easier to add support for loading texture | |
| 383 data if it is possible to support in the future. | |
| 384 | |
| 385 3) Why are only 1-level depth textures supported? | |
| 386 | |
| 387 RESOLVED: The only use for multiple levels of depth textures would | |
| 388 be for fitlered texturing. However since it is not possible to | |
| 389 render to non-zero-level texture levels in OpenGL ES 2.0, and since | |
| 390 this extension forbids loading existing data and GenerateMipmap on | |
| 391 depth textures, it is impossible to initialize or specify contents | |
| 392 for non-zero levels of depth textures. | |
| 393 | |
| 394 Revision History | |
| 395 | |
| 396 02/25/2013 swoods revise to allow texture lookup to guarantee depth values | |
| 397 only in red channel of sample result. | |
| 398 06/04/2012 dgkoch fix errors, disallow multi-level depth textures. | |
| 399 05/30/2012 dgkoch minor updates and add issues. | |
| 400 05/23/2012 dgkoch intial revision based on OES_depth_texture and | |
| 401 OES_packed_depth_stencil and rebased against the ES 2.0 spec | |
| 402 |
