11 Ian Romanick
, IBM
(idr 'at' us.ibm.com
)
23 $Date
: 2007/05/16$ $Revision
: 0.4$
31 OpenGL
1.2 or GL_EXT_texture3D is required.
33 Support
for ARB_fragment_program is assumed
, but not required.
35 Support
for ARB_fragment_program_shadow is assumed
, but not required.
37 Support
for EXT_framebuffer_object is assumed
, but not required.
39 Written based on the wording of the OpenGL
2.0 specification and
40 ARB_fragment_program_shadow but not dependent on them.
44 There are a number of circumstances where an application may wish to
45 blend two textures out of a larger
set of textures. Moreover
, in some
46 cases the selected textures may vary on a per
-fragment basis within
47 a polygon. Several examples include
:
49 1. High dynamic range textures. The application stores several
50 different "exposures" of an image as different textures. On a
51 per
-fragment basis
, the application selects which exposures are
54 2. A terrain engine where the altitude of a point determines the
55 texture applied to it. If the transition is from beach sand to
56 grass to rocks to snow
, the application will store each texture
57 in a different texture map
, and dynamically
select which two
58 textures to blend at run
-time.
60 3. Storing short video clips
in textures. Each depth slice is a
61 single frame of video.
63 Several solutions to this problem have been proposed
, but they either
64 involve using a separate texture unit
for each texture map or using
3D
65 textures without mipmaps. Both of these options have major drawbacks.
67 This extension provides a third alternative that eliminates the major
68 drawbacks of both previous methods. A new texture target
,
69 TEXTURE_2D_ARRAY
, is added that functions identically to TEXTURE_3D
in
70 all aspects except the sizes of the non
-base level images. In
71 traditional
3D texturing
, the size of the N
+1 LOD is half the size
72 of the N LOD
in all three dimensions. For the TEXTURE_2D_ARRAY target
,
73 the height and width of the N
+1 LOD is halved
, but the depth is the
74 same
for all levels of detail. The texture
then becomes an array of
75 2D textures. The per
-fragment texel is selected by the R texture
80 http
://www.opengl.org
/discussion_boards
/cgi_directory
/ultimatebb.cgi?ubb
=get_topic
;f
=3;t
=011557
81 http
://www.opengl.org
/discussion_boards
/cgi_directory
/ultimatebb.cgi?ubb
=get_topic
;f
=3;t
=000516
82 http
://www.opengl.org
/discussion_boards
/cgi_directory
/ultimatebb.cgi?ubb
=get_topic
;f
=3;t
=011903
83 http
://www.delphi3d.net
/articles
/viewarticle.php?article
=terraintex.htm
85 New Procedures and Functions
87 All functions come directly from EXT_texture_array.
89 void FramebufferTextureLayerEXT
(enum target
, enum attachment
,
90 uint texture
, int level
, int layer
);
94 All token names and values come directly from EXT_texture_array.
96 Accepted by the
<cap
> parameter of Enable
, Disable
, and IsEnabled
, by
97 the
<pname
> parameter of GetBooleanv
, GetIntegerv
, GetFloatv
, and
98 GetDoublev
, and by the
<target
> parameter of TexImage3D
, GetTexImage
,
99 GetTexLevelParameteriv
, GetTexLevelParameterfv
, GetTexParameteriv
, and
102 TEXTURE_1D_ARRAY_EXT
0x8C18
103 TEXTURE_2D_ARRAY_EXT
0x8C1A
105 Accepted by the
<target
> parameter of TexImage2D
, TexSubImage2D
,
106 CopyTexImage2D
, CopyTexSubImage2D
, CompressedTexImage2D
,
107 CompressedTexSubImage2D
, GetTexLevelParameteriv
, and
108 GetTexLevelParameterfv
:
111 PROXY_TEXTURE_1D_ARRAY_EXT
0x8C19
113 Accepted by the
<target
> parameter of TexImage3D
, TexSubImage3D
,
114 CopyTexSubImage3D
, CompressedTexImage3D
, CompressedTexSubImage3D
,
115 GetTexLevelParameteriv
, and GetTexLevelParameterfv
:
118 PROXY_TEXTURE_2D_ARRAY_EXT
0x8C1B
120 Accepted by the
<pname
> parameter of GetBooleanv
, GetIntegerv
,
121 GetFloatv
, and GetDoublev
123 TEXTURE_BINDING_1D_ARRAY_EXT
0x8C1C
124 TEXTURE_BINDING_2D_ARRAY_EXT
0x8C1D
125 MAX_ARRAY_TEXTURE_LAYERS_EXT
0x88FF
127 Accepted by the
<param
> parameter of TexParameterf
, TexParameteri
,
128 TexParameterfv
, and TexParameteriv when the
<pname
> parameter is
129 TEXTURE_COMPARE_MODE_ARB
:
131 COMPARE_REF_DEPTH_TO_TEXTURE_EXT
0x884E
133 (Note
: COMPARE_REF_DEPTH_TO_TEXTURE_EXT is simply an
alias for the
134 existing COMPARE_R_TO_TEXTURE token
in OpenGL
2.0; the alternate name
135 reflects the fact that the R coordinate is not always used.
)
137 Accepted by the
<internalformat
> parameter of TexImage3D and
138 CompressedTexImage3D
, and by the
<format
> parameter of
139 CompressedTexSubImage3D
:
141 COMPRESSED_RGB_S3TC_DXT1_EXT
142 COMPRESSED_RGBA_S3TC_DXT1_EXT
143 COMPRESSED_RGBA_S3TC_DXT3_EXT
144 COMPRESSED_RGBA_S3TC_DXT5_EXT
146 Accepted by the
<pname
> parameter of
147 GetFramebufferAttachmentParameterivEXT
:
149 FRAMEBUFFER_ATTACHMENT_TEXTURE_LAYER_EXT
0x8CD4
151 (Note
: FRAMEBUFFER_ATTACHMENT_TEXTURE_LAYER is simply an
alias for the
152 FRAMEBUFFER_ATTACHMENT_TEXTURE_3D_ZOFFSET_EXT token provided
in
153 EXT_framebuffer_object. This extension generalizes the notion of
154 "
<zoffset
>" to include layers of an array texture.
)
156 Additions to Chapter
2 of the OpenGL
2.0 Specification
(OpenGL Operation
)
160 Additions to Chapter
3 of the OpenGL
2.0 Specification
(Rasterization
)
162 -- Section
3.8.1 "Texture Image Specification"
164 Change the first paragraph
(page
150) to say
(spec changes identical to
169 void TexImage3D
(enum target
, int level
, int internalformat
,
170 sizei width
, sizei height
, sizei depth
, int border
,
171 enum format
, enum
type, void
*data
);
173 is used to specify a three
-dimensional texture image. target must be one
174 one of TEXTURE_3D
for a three
-dimensional texture or
175 TEXTURE_2D_ARRAY_EXT
for an two
-dimensional array texture.
176 Additionally
, target may be either PROXY_TEXTURE_3D
for a
177 three
-dimensional proxy texture
, or PROXY_TEXTURE_2D_ARRAY_EXT
for a
178 two
-dimensional proxy array texture."
180 Change the fourth paragraph on page
151 to say
(spec changes identical
181 to EXT_texture_array
):
183 "Textures with a base internal format of DEPTH_COMPONENT are supported
184 by texture image specification commands only
if target is TEXTURE_1D
,
185 TEXTURE_2D
, TEXTURE_1D_ARRAY_EXT
, TEXTURE_2D_ARRAY_EXT
,
186 PROXY_TEXTURE_1D
, PROXY_TEXTURE_2D
, PROXY_TEXTURE_1D_ARRAY_EXT
, or
187 PROXY_TEXTURE_2D_ARRAY_EXT. Using this format
in conjunction with any
188 other target will result
in an INVALID_OPERATION error."
191 Change the fourth paragraph on page
156 to say
(spec changes identical
192 to EXT_texture_array
):
196 void TexImage2D
(enum target
, int level
,
197 int internalformat
, sizei width
, sizei height
,
198 int border
, enum format
, enum
type, void
*data
);
200 is used to specify a two
-dimensional texture image. target must be one
201 of TEXTURE_2D
for a two
-dimensional texture
, TEXTURE_1D_ARRAY_EXT
for a
202 one
-dimensional array texture
, or one of TEXTURE_CUBE_MAP_POSITIVE_X
,
203 TEXTURE_CUBE_MAP_NEGATIVE_X
, TEXTURE_CUBE_MAP_POSITIVE_Y
,
204 TEXTURE_CUBE_MAP_NEGATIVE_Y
, TEXTURE_CUBE_MAP_POSITIVE_Z
, or
205 TEXTURE_CUBE_MAP_NEGATIVE_Z
for a cube map texture. Additionally
,
206 target may be either PROXY_TEXTURE_2D
for a two
-dimensional proxy
207 texture
, PROXY_TEXTURE_1D_ARRAY_EXT
for a one
-dimensional proxy array
208 texture
, or PROXY TEXTURE_CUBE_MAP
for a cube map proxy texture
in the
209 special
case discussed
in section
3.8.11. The other parameters match
210 the corresponding parameters of TexImage3D.
212 For the purposes of decoding the texture image
, TexImage2D is
213 equivalent to calling TexImage3D with corresponding arguments and depth
216 * The border depth
, d_b
, is zero
, and the depth of the image is
217 always
1 regardless of the value of border.
219 * The border height
, h_b
, is zero
if <target
> is
220 TEXTURE_1D_ARRAY_EXT
, and
<border
> otherwise.
222 * Convolution will be performed on the image
(possibly changing its
223 width and height
) if SEPARABLE
2D or CONVOLUTION
2D is enabled.
225 * UNPACK SKIP IMAGES is ignored."
227 -- Section
3.8.2 "Alternate Texture Image Specification Commands"
229 Change the second paragraph
(page
159) (spec changes identical
230 to EXT_texture_array
):
234 void CopyTexImage2D
(enum target
, int level
,
235 enum internalformat
, int x
, int y
, sizei width
,
236 sizei height
, int border
);
238 defines a two
-dimensional texture image
in exactly the manner of
239 TexImage2D
, except that the image data are taken from the framebuffer
240 rather than from client memory. Currently
, target must be one of
241 TEXTURE_2D
, TEXTURE_1D_ARRAY_EXT
, TEXTURE_CUBE_MAP_POSITIVE_X
,
242 TEXTURE_CUBE_MAP_NEGATIVE_X
, TEXTURE_CUBE MAP_POSITIVE_Y
,
243 TEXTURE_CUBE_MAP_NEGATIVE_Y
, TEXTURE_CUBE_MAP_POSITIVE_Z
, or
244 TEXTURE_CUBE_MAP_NEGATIVE_Z.
247 Change the last paragraph on page
160 to say
(spec changes identical
248 to EXT_texture_array
):
250 "Currently the target arguments of TexSubImage1D and CopyTexSubImage1D
251 must be TEXTURE_1D
, the target arguments of TexSubImage2D and
252 CopyTexSubImage2D must be one of TEXTURE_2D
, TEXTURE_1D_ARRAY_EXT
,
253 TEXTURE_CUBE_MAP_POSITIVE_X
, TEXTURE_CUBE_MAP_NEGATIVE_X
,
254 TEXTURE_CUBE_MAP_POSITIVE_Y
, TEXTURE_CUBE_MAP_NEGATIVE_Y
,
255 TEXTURE_CUBE_MAP_POSITIVE_Z
, or TEXTURE_CUBE_MAP_NEGATIVE_Z
, and the
256 target arguments of TexSubImage3D and CopyTexSubImage3D must be
257 TEXTURE_3D or TEXTURE_2D_ARRAY_EXT. ..."
260 -- Section
3.8.4 "Texture Parameters"
262 Change the first paragraph
(page
166) to say
:
264 "Various parameters control how the texel array is treated when
265 specified or changed
, and when applied to a fragment. Each parameter is
268 void TexParameter
{if}(enum target
, enum pname
, T param
);
269 void TexParameter
{if}v
(enum target
, enum pname
, T params
);
271 target is the target
, either TEXTURE_1D
, TEXTURE_2D
, TEXTURE_3D
,
272 TEXTURE_CUBE_MAP
, TEXTURE_1D_ARRAY_EXT
, or TEXTURE_2D_ARRAY_EXT."
275 -- Section
3.8.8 "Texture Minification"
in the section "Scale Factor and Level of Detail"
277 Change the first paragraph
(page
172) to say
:
279 "Let s
(x
,y
) be the
function that associates an s texture coordinate
280 with each
set of window coordinates
(x
,y
) that lie within a primitive
;
281 define t
(x
,y
) and r
(x
,y
) analogously. Let u
(x
,y
) = w_t
* s
(x
,y
),
282 v
(x
,y
) = h_t
* t
(x
,y
), and w
(x
,y
) = d_t
* r
(x
,y
), where w_t
, h_t
,
283 and d_t are as defined by equations
3.15, 3.16, and
3.17 with
284 w_s
, h_s
, and d_s equal to the width
, height
, and depth of the
285 image array whose level is level_base. For a one
-dimensional
286 texture or a one
-dimensional array texture
, define v
(x
,y
) = 0 and
287 w
(x
,y
) = 0; for a two
-dimensional texture or a two
-dimensional array
288 texture
, define w
(x
,y
) = 0..."
290 -- Section
3.8.8 "Texture Minification"
in the section "Mipmapping"
292 Change the third paragraph
(page
174) to say
:
294 "For a two
-dimensional texture
, two
-dimensional array texture
, or
297 Change the fourth paragraph
(page
174) to say
:
299 "And
for a one
-dimensional texture or a one
-dimensional array texture
,"
301 After the first paragraph
(page
175) add
:
303 "For one
-dimensional array textures
, h_b and d_b are treated as
1,
304 regardless of the actual values
, when performing mipmap calculations.
305 For two
-dimensional array textures
, d_b is always treated as one
,
306 regardless of the actual value
, when performing mipmap calculations."
308 -- Section
3.8.8 "Automatic Mipmap Generation"
in the section "Mipmapping"
310 Change the third paragraph
(page
176) to say
(spec changes identical
311 to EXT_texture_array
):
313 "The contents of the derived arrays are computed by repeated
, filtered
314 reduction of the level_base array. For one
- and two
-dimensional array
315 textures
, each layer is filtered independently. ..."
317 -- Section
3.8.8 "Manual Mipmap Generation"
in the section "Mipmapping"
319 Change first paragraph to say
(spec changes identical to
322 "Mipmaps can be generated manually with the
command
324 void GenerateMipmapEXT
(enum target
);
326 where
<target
> is one of TEXTURE_1D
, TEXTURE_2D
, TEXTURE_CUBE_MAP
,
327 TEXTURE_3D
, TEXTURE_1D_ARRAY
, or TEXTURE_2D_ARRAY. Mipmap generation
328 affects the texture image attached to
<target
>. ..."
330 -- Section
3.8.10 "Texture Completeness"
332 Change the second paragaph
(page
177) to say
(spec changes identical
333 to EXT_texture_array
):
335 "For one
-, two
-, or three
-dimensional textures and one
- or
336 two
-dimensional array textures
, a texture is complete
if the following
337 conditions all hold true
:"
339 -- Section
3.8.11 "Texture State and Proxy State"
341 Change the second and third paragraphs
(page
179) to say
(spec changes
342 identical to EXT_texture_array
):
344 "In addition to image arrays
for one
-, two
-, and three
-dimensional
345 textures
, one
- and two
-dimensional array textures
, and the six image
346 arrays
for the cube map texture
, partially instantiated image arrays
347 are maintained
for one
-, two
-, and three
-dimensional textures and one
-
348 and two
-dimensional array textures. Additionally
, a single proxy image
349 array is maintained
for the cube map texture. Each proxy image array
350 includes width
, height
, depth
, border width
, and internal format state
351 values
, as well as state
for the red
, green
, blue
, alpha
, luminance
,
352 and intensity component resolutions. Proxy image arrays
do not include
353 image data
, nor
do they include texture properties. When TexImage3D is
354 executed with target specified as PROXY_TEXTURE_3D
, the
355 three
-dimensional proxy state values of the specified level
-of
-detail
356 are recomputed and updated. If the image array would not be supported
357 by TexImage3D called with target
set to TEXTURE
3D
, no error is
358 generated
, but the proxy width
, height
, depth
, border width
, and
359 component resolutions are
set to zero. If the image array would be
360 supported by such a call to TexImage3D
, the proxy state values are
set
361 exactly as though the actual image array were being specified. No pixel
362 data are transferred or processed
in either
case.
364 Proxy arrays
for one
- and two
-dimensional textures and one
- and
365 two
-dimensional array textures are operated on
in the same way when
366 TexImage1D is executed with target specified as PROXY_TEXTURE_1D
,
367 TexImage2D is executed with target specified as PROXY_TEXTURE_2D or
368 PROXY_TEXTURE_1D_ARRAY_EXT
, or TexImage3D is executed with target
369 specified as PROXY_TETXURE_2D_ARRAY_EXT."
371 -- Section
3.8.12 "Texture Objects"
373 Change section
(page
180) to say
(spec changes identical to
376 "In addition to the default textures TEXTURE_1D
, TEXTURE_2D
,
377 TEXTURE_3D
, TEXTURE_CUBE_MAP
, TEXTURE_1D_ARRAY_EXT
, and TEXTURE_2D_EXT
,
378 named one
-, two
-, and three
-dimensional
, cube map
, and one
- and
379 two
-dimensional array texture objects can be created and operated upon.
380 The name space
for texture objects is the unsigned integers
, with zero
383 A texture object is created by binding an unused name to TEXTURE_1D
,
384 TEXTURE_2D
, TEXTURE_3D
, TEXTURE_CUBE_MAP
, TEXTURE_1D_ARRAY_EXT
, or
385 TEXTURE_2D_ARRAY_EXT. The binding is effected by calling
387 void BindTexture
(enum target
, uint texture
);
389 with
<target
> set to the desired texture target and
<texture
> set to
390 the unused name. The resulting texture object is a new state vector
,
391 comprising all the state values listed
in section
3.8.11, set to the
392 same initial values. If the new texture object is bound to TEXTURE_1D
,
393 TEXTURE_2D
, TEXTURE_3D
, TEXTURE_CUBE_MAP
, TEXTURE_1D_ARRAY_EXT
, or
394 TEXTURE_2D_ARRAY_EXT
, it is and remains a one
-, two
-,
395 three
-dimensional
, cube map
, one
- or two
-dimensional array texture
396 respectively
until it is deleted.
398 BindTexture may also be used to
bind an existing texture object to
399 either TEXTURE_1D
, TEXTURE_2D
, TEXTURE_3D
, TEXTURE_CUBE_MAP
,
400 TEXTURE_1D_ARRAY_EXT
, or TEXTURE_2D_ARRAY_EXT. The error
401 INVALID_OPERATION is generated
if an attempt is made to
bind a texture
402 object of different dimensionality than the specified target. If the
403 bind is successful no change is made to the state of the bound texture
404 object
, and any previous binding to target is broken.
406 While a texture object is bound
, GL operations on the target to which
407 it is bound affect the bound object
, and queries of the target to which
408 it is bound
return state from the bound object. If texture mapping of
409 the dimensionality of the target to which a texture object is bound is
410 enabled
, the state of the bound texture object directs the texturing
413 In the initial state
, TEXTURE_1D
, TEXTURE_2D
, TEXTURE_3D
,
414 TEXTURE_CUBE_MAP
, TEXTURE_1D_ARRAY_EXT
, and TEXTURE_2D_ARRAY_EXT have
415 one
-, two
-, three
-dimensional
, cube map
, and one
- and two
-dimensional
416 array texture state vectors respectively associated with them. In order
417 that access to these initial textures not be lost
, they are treated as
418 texture objects all of whose names are
0. The initial one
-, two
-,
419 three
-dimensional
, cube map
, one
- and two
-dimensional array textures
420 are therefore operated upon
, queried
, and applied as TEXTURE_1D
,
421 TEXTURE_2D
, TEXTURE_3D
, TEXTURE_CUBE_MAP
, TEXTURE_1D_ARRAY_EXT
, and
422 TEXTURE_2D_ARRAY_EXT respectively
while 0 is bound to the corresponding
425 Change second paragraph on page
181 to say
(spec changes identical to
428 "... If a texture that is currently bound to one of the targets
429 TEXTURE_1D
, TEXTURE_2D
, TEXTURE_3D
, TEXTURE_CUBE_MAP
,
430 TEXTURE_1D_ARRAY_EXT
, or TEXTURE_2D_ARRAY_EXT is deleted
, it is as
431 though BindTexture had been executed with the same target and texture
434 Change second paragraph on page
182 to say
(spec changes identical to
437 "The texture object name space
, including the initial one
-, two
-, and
438 three dimensional
, cube map
, and one
- and two
-dimensional array texture
439 objects
, is shared among all texture units. ..."
442 -- Section
3.8.14 "Depth Texture Comparison Modes"
in "Texture Comparison Modes"
444 Change second through fourth paragraphs
(page
188) to say
:
446 "Let D_t be the depth texture value
, in the range
[0, 1]. For
447 texture lookups from one
- and two
-dimesional
, rectangle
, and
448 one
-dimensional array targets
, let R be the interpolated
<r
>
449 texture coordinate
, clamped to the range
[0, 1]. For texture lookups
450 from two
-dimesional array texture targets
, let R be the interpolated
451 <q
> texture coordinate
, clamped to the range
[0, 1]. Then the
452 effective texture value L_t
, I_t
, or A_t is computed as follows
:
454 If the value of TEXTURE_COMPARE_MODE is NONE
, then
458 If the value of TEXTURE_COMPARE_MODE is
459 COMPARE_REF_DEPTH_TO_TEXTURE_EXT
), then r depends on the texture
460 comparison
function as shown
in table
3.27."
462 -- Section
3.8.15 "Texture Application"
464 Change the first paragraph
(page
189) to say
:
466 "Texturing is enabled or disabled using the generic Enable and Disable
467 commands
, respectively
, with the symbolic constants TEXTURE_1D
,
468 TEXTURE_2D
, TEXTURE_3D
, TEXTURE_CUBE_MAP
, TEXTURE_1D_ARRAY_EXT
, or
469 TEXTURE_2D_ARRAY_EXT to
enable one
-, two
-, three
-dimensional
, cube
470 map
, one
-dimensional array
, or two
-dimensional array texture
,
471 respectively. If both two
- and one
-dimensional textures are enabled
,
472 the two
-dimensional texture is used. If the three
-dimensional and
473 either of the two
- or one
-dimensional textures is enabled
, the
474 three
-dimensional texture is used. If the cube map texture and any of
475 the three
-, two
-, or one
-dimensional textures is enabled
, then cube map
476 texturing is used. If one
-dimensional array texture is enabled and any
477 of cube map
, three
-, two
-, or one
-dimensional textures is enabled
,
478 one
-dimensional array texturing is used. If two
-dimensional array
479 texture is enabled and any of cube map
, three
-, two
-, one
-dimensional
480 textures or one
-dimensional array texture is enabled
, two
-dimensional
481 array texturing is used..."
483 -- Section
3.11.2 of ARB_fragment_program
(Fragment Program Grammar and Restrictions
):
485 (mostly add to existing grammar rules
)
487 <optionName
> ::= "MESA_texture_array"
494 |
<arrayTarget
> (if program option is present
)
495 |
<shadowTarget
> (if program option is present
)
497 <arrayTarget
> ::= "ARRAY1D"
500 <shadowTarget
> ::= "SHADOW1D"
503 |
<shadowArrayTarget
> (if program option is present
)
505 <shadowArrayTarget
> ::= "SHADOWARRAY1D"
509 -- Add Section
3.11.4.5.4 "Texture Stack Option"
511 "If a fragment program specifies the "MESA_texture_array" program
512 option
, the
<texTarget
> rule is modified to add the texture targets
513 ARRAY1D and ARRAY2D
(See Section
3.11.2)."
515 -- Section
3.11.6 "Fragment Program Texture Instruction Set"
517 (replace
1st and
2nd paragraphs with the following paragraphs
)
519 "The first three texture instructions described below specify the
520 mapping of
4-tuple input vectors to
4-tuple output vectors.
521 The sampling of the texture works as described
in section
3.8,
522 except that texture environments and texture functions are not
523 applicable
, and the texture enables hierarchy is replaced by explicit
524 references to the desired texture target
(i.e.
, 1D
, 2D
, 3D
, cube map
,
525 rectangle
, ARRAY1D
, ARRAY2D
). These texture instructions specify
526 how the
4-tuple is mapped into the coordinates used
for sampling. The
527 following
function is used to describe the texture sampling
in the
530 vec4 TextureSample
(vec4 coord
, float lodBias
, int texImageUnit
,
533 Note that not all four components of the texture coordinates
<coord
>
534 are used by all texture targets. Component usage
for each
<texTarget
>
535 is defined
in table X.
538 texTarget Texture Type s t r layer shadow
539 ---------------- --------------------- ----- ----- ------
540 1D TEXTURE_1D x
- - - -
541 2D TEXTURE_2D x y
- - -
542 3D TEXTURE_3D x y z
- -
543 CUBE TEXTURE_CUBE_MAP x y z
- -
544 RECT TEXTURE_RECTANGLE_ARB x y
- - -
545 ARRAY1D TEXTURE_1D_ARRAY_EXT x
- - y
-
546 ARRAY2D TEXTURE_2D_ARRAY_EXT x y
- z
-
547 SHADOW1D TEXTURE_1D x
- - - z
548 SHADOW2D TEXTURE_2D x y
- - z
549 SHADOWRECT TEXTURE_RECTANGLE_ARB x y
- - z
550 SHADOWARRAY1D TEXTURE_1D_ARRAY_EXT x
- - y z
551 SHADOWARRAY2D TEXTURE_2D_ARRAY_EXT x y
- z w
553 Table X
: Texture types accessed
for each of the
<texTarget
>, and
554 coordinate mappings. The "coordinates used" column indicate the
555 input values used
for each coordinate of the texture lookup
, the
556 layer selector
for array textures
, and the reference value
for
557 texture comparisons."
559 -- Section
3.11.6.2 "TXP
: Project coordinate and map to color"
561 Add to the end of the section
:
563 "A program will fail to load
if the TXP instruction is used
in
564 conjunction with the SHADOWARRAY2D target."
566 Additions to Chapter
4 of the OpenGL
2.0 Specification
(Per
-Fragment Operations
)
568 -- Section
4.4.2.3 "Attaching Texture Images to a Framebuffer"
570 Add to the end of the section
(spec changes identical to
575 void FramebufferTextureLayerEXT
(enum target
, enum attachment
,
576 uint texture
, int level
, int layer
);
578 operates identically to FramebufferTexture3DEXT
, except that it
579 attaches a single layer of a three
-dimensional texture or a one
- or
580 two
-dimensional array texture.
<layer
> is an integer indicating the
581 layer number
, and is treated identically to the
<zoffset
> parameter
in
582 FramebufferTexture3DEXT. The error INVALID_VALUE is generated
if
583 <layer
> is negative. The error INVALID_OPERATION is generated
if
584 <texture
> is non
-zero and is not the name of a three dimensional
585 texture or one
- or two
-dimensional array texture. Unlike
586 FramebufferTexture3D
, no
<textarget
> parameter is accepted.
588 If
<texture
> is non
-zero and the
command does not result
in an error
,
589 the framebuffer attachment state corresponding to
<attachment
> is
590 updated as
in the other FramebufferTexture commands
, except that
591 FRAMEBUFFER_ATTACHMENT_TEXTURE_LAYER_EXT is
set to
<layer
>."
593 -- Section
4.4.4.1 "Framebuffer Attachment Completeness"
595 Add to the end of the list of completeness rules
(spec changes
596 identical to EXT_texture_array
):
598 "
* If FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE_EXT is TEXTURE and
599 FRAMEBUFFER_ATTACHMENT_OBJECT_NAME_EXT names a one
- or
600 two
-dimensional array texture
, then
601 FRAMEBUFFER_ATTACHMENT_TEXTURE_LAYER_EXT must be smaller than the
602 number of layers
in the texture."
604 Additions to Chapter
5 of the OpenGL
2.0 Specification
(Special Functions
)
606 -- Section
5.4 "Display Lists"
608 Change the first paragraphi on page
242 to say
(spec changes
609 identical to EXT_texture_array
):
611 "TexImage3D
, TexImage2D
, TexImage1D
, Histogram
, and ColorTable are
612 executed immediately when called with the corresponding proxy arguments
613 PROXY_TEXTURE_3D or PROXY_TEXTURE_2D_ARRAY_EXT
; PROXY_TEXTURE_2D
,
614 PROXY_TEXTURE_CUBE_MAP
, or PROXY_TEXTURE_1D_ARRAY_EXT
;
615 PROXY_TEXTURE_1D
; PROXY_HISTOGRAM
; and PROXY_COLOR_TABLE
,
616 PROXY_POST_CONVOLUTION_COLOR_TABLE
, or
617 PROXY_POST_COLOR_MATRIX_COLOR_TABLE."
619 Additions to Chapter
6 of the OpenGL
2.0 Specification
(State and State Requests
)
621 -- Section
6.1.3 "Enumerated Queries"
623 Add after the line beginning "If the value of
624 FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE_EXT is TEXTURE"
(spec changes
625 identical to EXT_texture_array
):
627 "If
<pname
> is FRAMEBUFFER_ATTACHMENT_TEXTURE_LAYER_EXT and the
628 texture object named FRAMEBUFFER_ATTACHMENT_OBJECT_NAME_EXT is a
629 three
-dimensional texture or a one
- or two
-dimensional array texture
,
630 then <params
> will contain the number of texture layer attached to the
631 attachment point. Otherwise
, <params
> will contain the value zero."
633 -- Section
6.1.4 "Texture Queries"
635 Change the first three paragraphs
(page
248) to say
(spec changes
636 identical to EXT_texture_array
):
640 void GetTexImage
(enum tex
, int lod
, enum format
,
641 enum
type, void
*img
);
643 is used to obtain texture images. It is somewhat different from the
644 other get commands
; tex is a symbolic value indicating which texture
645 (or texture face
in the
case of a cube map texture target name
) is to
646 be obtained. TEXTURE_1D
, TEXTURE_2D
, TEXTURE_3D
, TEXTURE_1D_ARRAY_EXT
,
647 and TEXTURE_2D_ARRAY_EXT indicate a one
-, two
-, or three
-dimensional
648 texture
, or one
- or two
-dimensional array texture
, respectively.
649 TEXTURE_CUBE_MAP_POSITIVE_X
, ...
651 GetTexImage obtains... from the first image to the last
for
652 three
-dimensional textures. One
- and two
-dimensional array textures
653 are treated as two
- and three
-dimensional images
, respectively
, where
654 the layers are treated as rows or images. These groups are
then...
656 For three
-dimensional and two
-dimensional array textures
, pixel storage
657 operations are applied as
if the image were two
-dimensional
, except
658 that the additional pixel storage state values PACK_IMAGE_HEIGHT and
659 PACK_SKIP_IMAGES are applied. ..."
661 Additions to Appendix A of the OpenGL
2.0 Specification
(Invariance
)
665 Additions to the AGL
/GLX
/WGL Specifications
673 Dependencies on ARB_fragment_program
675 If ARB_fragment_program is not supported
, the changes to section
3.11
678 Dependencies on EXT_framebuffer_object
680 If EXT_framebuffer_object is not supported
, the changes to section
681 3.8.8 ("Manual Mipmap Generation"
), 4.4.2.3, and
6.1.3 should be ignored.
683 Dependencies on EXT_texture_compression_s3tc and NV_texture_compression_vtc
685 (Identical dependency as EXT_texture_array.
)
687 S3TC texture compression is supported
for two
-dimensional array textures.
688 When
<target
> is TEXTURE_2D_ARRAY_EXT
, each layer is stored independently
689 as a compressed two
-dimensional textures. When specifying or querying
690 compressed images using one of the S3TC formats
, the images are provided
691 and
/or returned as a series of two
-dimensional textures stored
692 consecutively
in memory
, with the layer closest to zero specified first.
693 For array textures
, images are not arranged
in 4x4x4 or
4x4x2 blocks as
in
694 the three
-dimensional compression format provided
in the
695 EXT_texture_compression_vtc extension. Pixel store parameters
, including
696 those specific to three
-dimensional images
, are ignored when compressed
697 image data are provided or returned
, as
in the
698 EXT_texture_compression_s3tc extension.
700 S3TC compression is not supported
for one
-dimensional texture targets
in
701 EXT_texture_compression_s3tc
, and is not supported
for one
-dimensional
702 array textures
in this extension. If compressed one
-dimensional arrays
703 are needed
, use a two
-dimensional texture with a height of one.
705 This extension allows the use of the four S3TC internal format types
in
706 TexImage3D
, CompressedTexImage3D
, and CompressedTexSubImage3D calls.
714 (add to table
6.15, p.
276)
717 Get Value Type Get Command Value Description Sec. Attribute
718 ---------------------------- ----- ----------- ----- -------------------- ------ ---------
719 TEXTURE_BINDING_1D_ARRAY_EXT
2*xZ
+ GetIntegerv
0 texture object bound
3.8.12 texture
721 TEXTURE_BINDING_2D_ARRAY_EXT
2*xZ
+ GetIntegerv
0 texture object bound
3.8.12 texture
725 New Implementation Dependent State
727 (add to Table
6.32, p.
293)
730 Get Value Type Get Command Value Description Sec. Attribute
731 ---------------------------- ---- ----------- ------- ------------------ ----- ---------
732 MAX_TEXTURE_ARRAY_LAYERS_EXT Z
+ GetIntegerv
64 maximum number of
3.8.1 -
738 (1) Is "texture stack" a good name
for this functionality?
740 NO. The name is changed to "array texture" to match the
741 nomenclature used by GL_EXT_texture_array.
743 (2) Should the R texture coordinate be treated as normalized or
744 un
-normalized? If it were un
-normalized
, floor
(R
) could be thought
745 of as a direct index into the array texture. This may be more
746 convenient
for applications.
748 RESOLVED. All texture coordinates are normalized. The issue of
749 un
-normalized texture coordinates has been discussed
in the ARB
750 before and should be left
for a layered extension.
752 RE
-RESOLVED. The R coordinate is un
-normalized. Accessing an array
753 using
[0, layers
-1] coordinates is much more natural.
755 (3) How does LOD selection work
for stacked textures?
757 RESOLVED. For
2D array textures the R coordinate is ignored
, and
758 the LOD selection equations
for 2D textures are used. For
1D
759 array textures the T coordinate is ignored
, and the LOD selection
760 equations
for 1D textures are used. The expected usage is
in a
761 fragment program with an explicit LOD selection.
763 (4) What is the maximum size of a
2D array texture? Is it the same
764 as
for a
3D texture
, or should a new query be added? How about
for 1D
767 RESOLVED. A new query is added.
769 (5) How are array textures exposed
in GLSL?
771 RESOLVED. Use GL_EXT_texture_array.
773 (6) Should a
1D array texture also be exposed?
775 RESOLVED. For orthogonality
, yes.
777 (7) How are stacked textures attached to framebuffer objects?
779 RESOLVED. Layers of both one
- and two
-dimensional array textures
780 are attached using FreambufferTextureLayerEXT. Once attached
, the
781 array texture layer behaves exactly as either a one
- or
782 two
-dimensional texture.
784 (8) How is this extension related to GL_EXT_texture_array?
786 This extension adapats GL_MESAX_texture_stack to the notation
,
787 indexing
, and FBO access of GL_EXT_texture_array. This extension
788 replaces the GLSL support of GL_EXT_texture_array with
789 GL_ARB_fragment_program support.
791 Assembly program support is also provided by GL_NV_gpu_program4.
792 GL_NV_gpu_program4 also adds support
for other features that are
793 specific to Nvidia hardware
, while this extension adds only support
796 Much of text of this extension that has changed since
797 GL_MESAX_texture_stack comes directly from either
798 GL_EXT_texture_array or GL_NV_gpu_program4.
802 ||
2005/11/15||
0.1||idr||Initial draft MESAX version.||
803 ||
2005/12/07||
0.2||idr||Added framebuffer object interactions.||
804 ||
2005/12/12||
0.3||idr||Updated fragment program interactions.||
805 ||
2007/05/16||
0.4||idr||Converted to MESA_texture_array. Brought
in line with EXT_texture_array and NV_gpu_program4.||