gfx/angle/extensions/ANGLE_texture_compression_dxt.txt@6474c204b198 (annotated)
gfx/angle/extensions/ANGLE_texture_compression_dxt.txt
Wed, 31 Dec 2014 06:09:35 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Wed, 31 Dec 2014 06:09:35 +0100
- changeset 0
- 6474c204b198
- permissions
- -rw-r--r--
Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.
| michael@0 | 1 | Name |
| michael@0 | 2 | |
| michael@0 | 3 | ANGLE_texture_compression_dxt |
| michael@0 | 4 | |
| michael@0 | 5 | Name Strings |
| michael@0 | 6 | |
| michael@0 | 7 | GL_ANGLE_texture_compression_dxt1 |
| michael@0 | 8 | GL_ANGLE_texture_compression_dxt3 |
| michael@0 | 9 | GL_ANGLE_texture_compression_dxt5 |
| michael@0 | 10 | |
| michael@0 | 11 | Contributors |
| michael@0 | 12 | |
| michael@0 | 13 | Gregg Tavares, Google Inc. |
| michael@0 | 14 | Daniel Koch, TransGaming Inc. |
| michael@0 | 15 | Al Patrick, Google Inc. |
| michael@0 | 16 | |
| michael@0 | 17 | Contacts |
| michael@0 | 18 | |
| michael@0 | 19 | Gregg Tavares, Google Inc. (gman 'at' google 'dot' com) |
| michael@0 | 20 | |
| michael@0 | 21 | Status |
| michael@0 | 22 | |
| michael@0 | 23 | Implemented in ANGLE ES2 |
| michael@0 | 24 | |
| michael@0 | 25 | Version |
| michael@0 | 26 | |
| michael@0 | 27 | Last Modified Date: Sept 22, 2012 |
| michael@0 | 28 | Author Revision: 2 |
| michael@0 | 29 | |
| michael@0 | 30 | Number |
| michael@0 | 31 | |
| michael@0 | 32 | OpenGL ES Extension #111 |
| michael@0 | 33 | |
| michael@0 | 34 | Dependencies |
| michael@0 | 35 | |
| michael@0 | 36 | Requires OpenGL ES 1.0. |
| michael@0 | 37 | |
| michael@0 | 38 | The extension is written against the OpenGL ES 2.0 specification. |
| michael@0 | 39 | |
| michael@0 | 40 | Overview |
| michael@0 | 41 | |
| michael@0 | 42 | These extensions are exactly the same as EXT_texture_compression_dxt1 |
| michael@0 | 43 | except they additionally expose the COMPRESSED_RGBA_S3TC_DXT3_ANGLE and |
| michael@0 | 44 | COMPRESSED_RGBA_S3TC_DXT5_ANGLE formats and have a size restrictions |
| michael@0 | 45 | such that the size must be a multiple of four (except for mip levels |
| michael@0 | 46 | where the dimensions are either 2 or 1). |
| michael@0 | 47 | |
| michael@0 | 48 | See EXT_texture_compression_dxt1 for the full list of changes. Also |
| michael@0 | 49 | see EXT_texture_compression_s3tc for a description of the formats. |
| michael@0 | 50 | |
| michael@0 | 51 | IP Status |
| michael@0 | 52 | |
| michael@0 | 53 | A license to the S3TC Intellectual Property may be necessary for |
| michael@0 | 54 | implementation of this extension. You should consult with your |
| michael@0 | 55 | Attorney to determine the need for a license. |
| michael@0 | 56 | |
| michael@0 | 57 | New Procedures and Functions |
| michael@0 | 58 | |
| michael@0 | 59 | None. |
| michael@0 | 60 | |
| michael@0 | 61 | New Types |
| michael@0 | 62 | |
| michael@0 | 63 | None. |
| michael@0 | 64 | |
| michael@0 | 65 | New Tokens |
| michael@0 | 66 | |
| michael@0 | 67 | Accepted by the <internalformat> parameter of CompressedTexImage2D |
| michael@0 | 68 | and the <format> parameter of CompressedTexSubImage2D: |
| michael@0 | 69 | |
| michael@0 | 70 | COMPRESSED_RGB_S3TC_DXT1_ANGLE 0x83F0 |
| michael@0 | 71 | COMPRESSED_RGBA_S3TC_DXT1_ANGLE 0x83F1 |
| michael@0 | 72 | COMPRESSED_RGBA_S3TC_DXT3_ANGLE 0x83F2 |
| michael@0 | 73 | COMPRESSED_RGBA_S3TC_DXT5_ANGLE 0x83F3 |
| michael@0 | 74 | |
| michael@0 | 75 | Additions to Chapter 3 of the OpenGL ES 2.0 Specification (Rasterization) |
| michael@0 | 76 | |
| michael@0 | 77 | Add the following to Section 3.7.3 (Compressed Texture Images) |
| michael@0 | 78 | (at the end of the description of the CompressedTexImage2D command): |
| michael@0 | 79 | |
| michael@0 | 80 | Compressed Internal Format Base Internal Format |
| michael@0 | 81 | ========================== ==================== |
| michael@0 | 82 | COMPRESSED_RGB_S3TC_DXT1_ANGLE RGB |
| michael@0 | 83 | COMPRESSED_RGBA_S3TC_DXT1_ANGLE RGBA |
| michael@0 | 84 | COMPRESSED_RGBA_S3TC_DXT3_ANGLE RGBA |
| michael@0 | 85 | COMPRESSED_RGBA_S3TC_DXT5_ANGLE RGBA |
| michael@0 | 86 | |
| michael@0 | 87 | Table 3.x: Specific Compressed Internal Formats |
| michael@0 | 88 | |
| michael@0 | 89 | If <internalformat> is one of the S3TC formats listed in Table 3.x, |
| michael@0 | 90 | the compressed texture is stored in the appropriate S3TC compressed |
| michael@0 | 91 | texture format (see Appendix). The GL and the S3TC texture compression |
| michael@0 | 92 | algorithm support only 2D images without borders. |
| michael@0 | 93 | |
| michael@0 | 94 | CompressedTexImage2D will produce the INVALID_OPERATION error when |
| michael@0 | 95 | <internalformat> is one of the values from Table 3.x under the following |
| michael@0 | 96 | conditions: |
| michael@0 | 97 | |
| michael@0 | 98 | * <border> is non-zero. |
| michael@0 | 99 | * <width> is not one, two, or a multiple of four. |
| michael@0 | 100 | * <height> is not one, two, or a multiple of four. |
| michael@0 | 101 | |
| michael@0 | 102 | Add the following to Section 3.7.3 (Compressed Texture Images) |
| michael@0 | 103 | (at the end of the description of the CompressedTexSubImage2D command): |
| michael@0 | 104 | |
| michael@0 | 105 | If the internal format of the texture image being modified is listed |
| michael@0 | 106 | in Table 3.x, the texture is stored in the appropriate S3TC compressed |
| michael@0 | 107 | texture format (see Appendix). Since DXT/S3TC images are easily edited |
| michael@0 | 108 | along 4x4 texel boundaries, the limitations of CompressedTexSubImage2D |
| michael@0 | 109 | are relaxed. CompressedTexSubImage2D will result in an INVALID_OPERATION |
| michael@0 | 110 | error only if one of the following conditions occurs: |
| michael@0 | 111 | |
| michael@0 | 112 | * <width> is not a multiple of four or equal to TEXTURE_WIDTH. |
| michael@0 | 113 | * <height> is not a multipls of four or equal to TEXTURE_HEIGHT. |
| michael@0 | 114 | * <xoffset> or <yoffset> is not a multiple of four. |
| michael@0 | 115 | * <format> does not match the internal format of the texture image |
| michael@0 | 116 | being modified. |
| michael@0 | 117 | |
| michael@0 | 118 | The following restrictions at the end of section 3.7.3 do not apply |
| michael@0 | 119 | to S3TC DXT texture formats, since subimage modification is straightforward |
| michael@0 | 120 | as long as the subimage is properly aligned. |
| michael@0 | 121 | |
| michael@0 | 122 | Errors |
| michael@0 | 123 | |
| michael@0 | 124 | INVALID_OPERATION is generated by CompressedTexImage2D if <internalformat> |
| michael@0 | 125 | is one of the compressed internal formats from Table 3.x and any of the |
| michael@0 | 126 | following apply: |
| michael@0 | 127 | - <border> is not equal to zero. |
| michael@0 | 128 | - <width> is not one, two, or a multiple of four. |
| michael@0 | 129 | - <height> is not one, two, or a multiple of four. |
| michael@0 | 130 | |
| michael@0 | 131 | INVALID_OPERATION is generated by TexImage2D and CopyTexImage2D if |
| michael@0 | 132 | <internalformat> is one of the compressed internal formats from |
| michael@0 | 133 | Table 3.x. |
| michael@0 | 134 | |
| michael@0 | 135 | INVALID_OPERATION is generated by TexSubImage2D and CopyTexSubImage2D |
| michael@0 | 136 | if the internal format of the texture currently bound to <target> is |
| michael@0 | 137 | one of the compressed internal formats from Table 3.x. |
| michael@0 | 138 | |
| michael@0 | 139 | INVALID_OPERATION is generated by CompressedTexSubImage2D if <format> |
| michael@0 | 140 | is one of the compressed interal formats from Table 3.x and any of the |
| michael@0 | 141 | following apply: |
| michael@0 | 142 | - <width> is not a multiple of four or equal to TEXTURE_WIDTH; |
| michael@0 | 143 | - <height> is not a multiple of four or equal to TEXTURE_HEIGHT; |
| michael@0 | 144 | - <xoffset> or <yoffset> is not a multiple of four; |
| michael@0 | 145 | - <format> does not match the internal format of the texture image |
| michael@0 | 146 | being modified. |
| michael@0 | 147 | |
| michael@0 | 148 | New State |
| michael@0 | 149 | |
| michael@0 | 150 | None. |
| michael@0 | 151 | |
| michael@0 | 152 | Appendix: |
| michael@0 | 153 | |
| michael@0 | 154 | The format for the S3TC Compressed Texture Images Formats is documented |
| michael@0 | 155 | in the appendix of EXT_texture_compression_s3tc. |
| michael@0 | 156 | |
| michael@0 | 157 | Revision History |
| michael@0 | 158 | |
| michael@0 | 159 | Revision 1, 2010/08/06 - gman |
| michael@0 | 160 | - Initial revision |
| michael@0 | 161 | Revision 2, 2012/09/22 - dgkoch |
| michael@0 | 162 | - Added DXT1 formats and documented multiple of 4 restriction. |
| michael@0 | 163 |
