| Name |
| |
| ARB_texture_mirror_clamp_to_edge |
| |
| Name Strings |
| |
| GL_ARB_texture_mirror_clamp_to_edge |
| |
| Contact |
| |
| Daniel Koch, NVIDIA Corporation (dkoch 'at' nvidia.com) |
| |
| Contributors |
| |
| Contributors to ATI_texture_mirror_once |
| Contributors to EXT_texture_mirror_clamp |
| Ian Romanick, Intel |
| Members of the ARB working group |
| |
| Notice |
| |
| Copyright (c) 2013 The Khronos Group Inc. Copyright terms at |
| http://www.khronos.org/registry/speccopyright.html |
| |
| Status |
| |
| Complete. Approved by the ARB on June 3, 2013. |
| Ratified by the Khronos Board of Promoters on July 19, 2013. |
| |
| Version |
| |
| Last Modified Date: April 22, 2013 |
| Revision 4 |
| |
| Number |
| |
| ARB Extension #149 |
| |
| Dependencies |
| |
| OpenGL 1.4 is required. |
| |
| This extension is written against the OpenGL 4.3 (Core Profile) |
| Specification (October 18, 2012). |
| |
| This extension interacts with EXT_texture3D. |
| |
| This extension interacts with ARB_texture_rectangle. |
| |
| This extension interacts with ARB_sampler_objects. |
| |
| Overview |
| |
| ARB_texture_mirror_clamp_to_edge extends the set of texture wrap modes to |
| include an additional mode (GL_MIRROR_CLAMP_TO_EDGE) that effectively uses |
| a texture map twice as large as the original image in which the additional |
| half of the new image is a mirror image of the original image. |
| |
| This new mode relaxes the need to generate images whose opposite edges |
| match by using the original image to generate a matching "mirror image". |
| This mode allows the texture to be mirrored only once in the negative |
| s, t, and r directions. |
| |
| New Procedure and Functions |
| |
| None |
| |
| New Tokens |
| |
| Accepted by the <param> parameter of TexParameter{if}, SamplerParameter{if} |
| and SamplerParameter{if}v, and by the <params> parameter of |
| TexParameter{if}v, TexParameterI{i ui}v and SamplerParameterI{i ui}v when |
| their <pname> parameter is TEXTURE_WRAP_S, TEXTURE_WRAP_T, or |
| TEXTURE_WRAP_R: |
| |
| MIRROR_CLAMP_TO_EDGE 0x8743 (same value as MIRROR_CLAMP_TO_EDGE_ATI/EXT) |
| |
| Additions to Chapter 8 if the OpenGL 4.3 (Core Profile) Specification |
| (Textures and Samplers) |
| |
| In section 8.2 (Sampler Objects) modify the second sentence of the |
| sixth paragraph (reading "For example, if..") to read as follows: |
| |
| "For example, if TEXTURE_WRAP_S or TEXTURE_WRAP_T is set to REPEAT, |
| MIRRORED_REPEAT, or MIRROR_CLAMP_TO_EDGE on the sampler object bound |
| to a texture unit and the texture bond to that unit is a rectangle |
| texture, the texture will be considered incomplete." |
| |
| In section 8.10 (Texture Parameters) modify the table entries for Table 8.16 |
| (Texture parameters and their values) for TEXTURE_WRAP_S, TEXTURE_WRAP_T, |
| and TEXTURE_WRAP_R and add the following to the "Legal Values" column: |
| |
| Name Type Legal Values |
| --------------- ---- ------------ |
| TEXTURE_WRAP_S enum (.. as before) |
| MIRROR_CLAMP_TO_EDGE |
| TEXTURE_WRAP_T enum (.. as before) |
| MIRROR_CLAMP_TO_EDGE |
| TEXTURE_WRAP_R enum (.. as before) |
| MIRROR_CLAMP_TO_EDGE |
| |
| In section 8.14.2 (Coordinate Wrapping and Texel Selection) add the |
| following row to Table 8.19 (Texel location wrap mode application): |
| |
| Wrap mode Result of wrap(coord) |
| --------- --------------------- |
| (previous entries..) |
| MIRROR_CLAMP_TO_EDGE min(1-1/(2*size), max(1/(2*size), abs(coord))) |
| |
| Additions to the GLX Specification |
| |
| None |
| |
| GLX Protocol |
| |
| None |
| |
| Errors |
| |
| The error INVALID_ENUM is generated when TexParameter* is called |
| with a target of TEXTURE_RECTANGLE and the TEXTURE_WRAP_S, |
| TEXTURE_WRAP_T, or TEXTURE_WRAP_R parameter is set to REPEAT, |
| MIRRORED_REPEAT, or MIRROR_CLAMP_TO_EDGE. |
| |
| Dependencies on EXT_texture3D or equivalent |
| |
| If EXT_texture3D or equivalent functionality is not implemented, |
| then the references to clamping of 3D textures in this file are |
| invalid, and references to TEXTURE_WRAP_R should be ignored. |
| |
| Dependencies on ARB_texture_rectangle or equivalent |
| |
| If ARB_texture_rectangle or equivalent functionality is not |
| implemented, then ignore all references to rectangle textures. |
| |
| Dependencies on ARB_sampler_objects or equivalent |
| |
| If ARB_sampler_objects or equivalent functionality is not supported, |
| then ignore all references to sampler objects and SamplerParameter* |
| functions. |
| |
| New State |
| |
| Only the type information changes for these parameters: |
| |
| Update Table 23.14 (Textures - state per texture object) |
| Get Value Get Command Type Initial Value (...) |
| --------- ----------- ---- ------------- |
| TEXTURE_WRAP_S GetTexParameter n x Z5 see sec 8.21 (...) |
| TEXTURE_WRAP_T GetTexParameter n x Z5 see sec 8.21 (...) |
| TEXTURE_WRAP_R GetTexParameter n x Z5 see sec 8.21 (...) |
| |
| Update Table 23.18 (Textures - state per sampler object) |
| Get Value Get Command Type Initial Value (...) |
| --------- ----------- ---- ------------- |
| TEXTURE_WRAP_S GetSamplerParameteriv n x Z5 see sec 8.21 (...) |
| TEXTURE_WRAP_T GetSamplerParameteriv n x Z5 see sec 8.21 (...) |
| TEXTURE_WRAP_R GetSamplerParameteriv n x Z5 see sec 8.21 (...) |
| |
| New Implementation Dependent State |
| |
| None |
| |
| Issues |
| |
| 1. Should we include MIRROR_CLAMP for compatibility profiles? |
| What about MIRROR_CLAMP_TO_BORDER? (And more importantly can all |
| vendors support it?) |
| |
| RESOLVED. No. Some vendors stated that they can't support |
| MIRROR_CLAMP_TO_BORDER and MIRROR_CLAMP (although it's not clear if |
| they'd ever ship a compatibility profile with this extension), but |
| regardless we'll leave them out of this extension. |
| |
| Revision History |
| |
| Revision 4, April 22, 2013 (Daniel Koch) |
| - fix interactions and remove ARB suffixes |
| Revision 3, April 21, 2013 (Daniel Koch) |
| - formatting, updates to Table 23.14 |
| Revision 2, March 19, 2013 (Daniel Koch) |
| - remove MIRROR_CLAMP functionality and rename extension |
| Revision 1, January 20, 2013 (Daniel Koch) |
| - Initial ARB version based on ATI_texture_mirror_once and |
| EXT_texture_mirror_clamp. |
| Revision 0.9, January 3, 2013 (Ian Romanick) |
| - Add interactions with OpenGL contexts that have removed GL_CLAMP |
| and friends. |
