Name OES_texture_cube_map Name Strings GL_OES_texture_cube_map Contact Benj Lipchak (benj.lipchak 'at' amd.com) Notice Copyright (c) 2007-2013 The Khronos Group Inc. Copyright terms at http://www.khronos.org/registry/speccopyright.html Specification Update Policy Khronos-approved extension specifications are updated in response to issues and bugs prioritized by the Khronos OpenGL ES Working Group. For extensions which have been promoted to a core Specification, fixes will first appear in the latest version of that core Specification, and will eventually be backported to the extension document. This policy is described in more detail at https://www.khronos.org/registry/OpenGL/docs/update_policy.php Status Ratified by the Khronos BOP Version Version 2, April 16, 2015 Number OpenGL ES Extension #20 Dependencies OpenGL ES 1.0 is required. This extension is based on the ARB_texture_cube_map extension specification. Overview This extension provides a new texture generation scheme for cube map textures. Instead of the current texture providing a 1D, 2D, or 3D lookup into a 1D, 2D, or 3D texture image, the texture is a set of six 2D images representing the faces of a cube. The (s,t,r) texture coordinates are treated as a direction vector emanating from the center of a cube. At texture generation time, the interpolated per-fragment (s,t,r) selects one cube face 2D image based on the largest magnitude coordinate (the major axis). A new 2D (s,t) is calculated by dividing the two other coordinates (the minor axes values) by the major axis value. Then the new (s,t) is used to lookup into the selected 2D texture image face of the cube map. Unlike a standard 1D, 2D, or 3D texture that have just one target, a cube map texture has six targets, one for each of its six 2D texture image cube faces. All these targets must be consistent, complete, and have equal width and height (ie, square dimensions). This extension also provides two new texture coordinate generation modes for use in conjunction with cube map texturing. The reflection map mode generates texture coordinates (s,t,r) matching the vertex's eye-space reflection vector. The reflection map mode is useful for environment mapping without the singularity inherent in sphere mapping. The normal map mode generates texture coordinates (s,t,r) matching the vertex's transformed eye-space normal. The normal map mode is useful for sophisticated cube map texturing-based diffuse lighting models. The intent of the new texgen functionality is that an application using cube map texturing can use the new texgen modes to automatically generate the reflection or normal vectors used to look up into the cube map texture. An application note: When using cube mapping with dynamic cube maps (meaning the cube map texture is re-rendered every frame), by keeping the cube map's orientation pointing at the eye position, the texgen-computed reflection or normal vector texture coordinates can be always properly oriented for the cube map. However if the cube map is static (meaning that when view changes, the cube map texture is not updated), the texture matrix must be used to rotate the texgen-computed reflection or normal vector texture coordinates to match the orientation of the cube map. The rotation can be computed based on two vectors: 1) the direction vector from the cube map center to the eye position (both in world coordinates), and 2) the cube map orientation in world coordinates. The axis of rotation is the cross product of these two vectors; the angle of rotation is the arcsin of the dot product of these two vectors. Issues Please refer to the ARB_texture_cube_map extension specification. New Procedures and Functions void glTexGenfOES(GLenum coord, GLenum pname, GLfloat param); void glTexGenfvOES(GLenum coord, GLenum pname, const GLfloat *params); void glTexGeniOES(GLenum coord, GLenum pname, GLint param); void glTexGenivOES(GLenum coord, GLenum pname, const GLint *params); void glTexGenxOES(GLenum coord, GLenum pname, GLfixed param); void glTexGenxvOES(GLenum coord, GLenum pname, const GLfixed *params); void glGetTexGenfvOES(GLenum coord, GLenum pname, GLfloat *params); void glGetTexGenivOES(GLenum coord, GLenum pname, GLint *params); void glGetTexGenxvOES(GLenum coord, GLenum pname, GLfixed *params); New Tokens Accepted by the parameter of TexGenfOES, TexGeniOES, TexGenxOES, TexGenfvOES, TexGenivOES, TexGenxvOES, GetTexGenfvOES, GetTexGenivOES, and GetTexGenxvOES: TEXTURE_GEN_MODE_OES 0x2500 Accepted by the parameter of TexGenfOES, TexGeniOES, TexGenxOES, TexGenfvOES, TexGenivOES, and TexGenxvOES when parameter is TEXTURE_GEN_MODE_OES: NORMAL_MAP_OES 0x8511 REFLECTION_MAP_OES 0x8512 Accepted by the parameter of Enable, Disable, IsEnabled, by the parameter of GetBooleanv, GetIntegerv, GetFloatv, and GetFixedv, and by the parameter of BindTexture, GetTexParameterfv, GetTexParameteriv, GetTexParameterxv, TexParameterf, TexParameteri, TexParameterx, TexParameterfv, TexParameteriv, and TexParameterxv: TEXTURE_CUBE_MAP_OES 0x8513 Accepted by the parameter of Enable, Disable, IsEnabled, by the parameter of GetBooleanv, GetIntegerv, GetFloatv, and GetFixedv, and by the parameter of TexGenfOES, TexGeniOES, TexGenxOES, TexGenfvOES, TexGenivOES, TexGenxvOES, GetTexGenfvOES, GetTexGenivOES, and GetTexGenxvOES: TEXTURE_GEN_STR_OES 0x8D60 Accepted by the parameter of GetBooleanv, GetIntegerv, GetFloatv, and GetDoublev: TEXTURE_BINDING_CUBE_MAP_OES 0x8514 Accepted by the parameter of TexImage2D, CopyTexImage2D, TexSubImage2D, and CopySubTexImage2D: TEXTURE_CUBE_MAP_POSITIVE_X_OES 0x8515 TEXTURE_CUBE_MAP_NEGATIVE_X_OES 0x8516 TEXTURE_CUBE_MAP_POSITIVE_Y_OES 0x8517 TEXTURE_CUBE_MAP_NEGATIVE_Y_OES 0x8518 TEXTURE_CUBE_MAP_POSITIVE_Z_OES 0x8519 TEXTURE_CUBE_MAP_NEGATIVE_Z_OES 0x851A Accepted by the parameter of GetBooleanv, GetDoublev, GetIntegerv, and GetFloatv: MAX_CUBE_MAP_TEXTURE_SIZE_OES 0x851C Additions to Chapter 2 of the OpenGL 1.5 Specification (OpenGL Operation) -- Section 2.11.4 "Generating Texture Coordinates" Change the last sentence in the 1st paragraph (page 37) to: "If is TEXTURE_GEN_MODE_OES, then either points to or is an integer that is one of the symbolic constants REFLECTION_MAP_OES, or NORMAL_MAP_OES." OBJECT_LINEAR, EYE_LINEAR, and SPHERE_MAP texture coordinate generation modes are not supported. Add these paragraphs after the 4th paragraph (page 38): "If TEXTURE_GEN_MODE_OES indicates REFLECTION_MAP_OES, compute the reflection vector r as described for the SPHERE_MAP mode. Then the value assigned to an s coordinate is s = rx; the value assigned to a t coordinate is t = ry; and the value assigned to a r coordinate is r = rz. If TEXTURE_GEN_MODE_OES indicates NORMAL_MAP_OES, compute the normal vector nf as described in section 2.10.3. Then the value assigned to an s coordinate is s = nfx; the value assigned to a t coordinate is t = nfy; and the value assigned to a r coordinate is r = nfz. (The values nfx, nfy, and nfz are the components of nf.) A texture coordinate generation function is enabled or disabled using Enable and Disable with an argument of TEXTURE_GEN_STR_OES. TEXTURE_GEN_S, TEXTURE_GEN_T, TEXTURE_GEN_R and TEXTURE_GEN_Q argument values to Enable and Disable are not supported. The last paragraph's last sentence (page 38) should be changed to: "Initially all texture generation modes are set to REFLECTION_MAP_OES" Additions to Chapter 3 of the 1.5 Specification (Rasterization) -- Section 3.8.1 "Texture Image Specification" Change the second and third to last sentences on page 116 to: " must be one of TEXTURE_2D for a 2D texture, or one of TEXTURE_CUBE_MAP_POSITIVE_X_OES, TEXTURE_CUBE_MAP_NEGATIVE_X_OES, TEXTURE_CUBE_MAP_POSITIVE_Y_OES, TEXTURE_CUBE_MAP_NEGATIVE_Y_OES, TEXTURE_CUBE_MAP_POSITIVE_Z_OES, or TEXTURE_CUBE_MAP_NEGATIVE_Z_OES for a cube map texture." Add the following paragraphs after the first paragraph on page 117: "A 2D texture consists of a single 2D texture image. A cube map texture is a set of six 2D texture images. The six cube map texture targets form a single cube map texture though each target names a distinct face of the cube map. The TEXTURE_CUBE_MAP_*_OES targets listed above update their appropriate cube map face 2D texture image. Note that the six cube map 2D image tokens such as TEXTURE_CUBE_MAP_POSITIVE_X_OES are used when specifying, updating, or querying one of a cube map's six 2D image, but when enabling cube map texturing or binding to a cube map texture object (that is when the cube map is accessed as a whole as opposed to a particular 2D image), the TEXTURE_CUBE_MAP_OES target is specified. When the target parameter to TexImage2D is one of the six cube map 2D image targets, the error INVALID_VALUE is generated if the width and height parameters are not equal. If cube map texturing is enabled at the time a primitive is rasterized and if the set of six targets are not "cube complete", then it is as if texture mapping were disabled. The targets of a cube map texture are "cube complete" if the array 0 of all six targets have identical, positive, and square dimensions, the array 0 of all six targets were specified with the same internalformat, and the array 0 of all six targets have the same border width." After the 14th paragraph (page 116) add: "In a similiar fashion, the maximum allowable width and height (they must be the same) of a cube map texture must be at least 2^(k-lod) for image arrays level 0 through k, where k is the log base 2 of MAX_CUBE_MAP_TEXTURE_SIZE_OES." -- Section 3.8.2 "Alternate Texture Image Specification Commands" Update the second paragraph (page 120) to say: ... "Currently, must be TEXTURE_2D, TEXTURE_CUBE_MAP_POSITIVE_X_OES, TEXTURE_CUBE_MAP_NEGATIVE_X_OES, TEXTURE_CUBE_MAP_POSITIVE_Y_OES, TEXTURE_CUBE_MAP_NEGATIVE_Y_OES, TEXTURE_CUBE_MAP_POSITIVE_Z_OES, or TEXTURE_CUBE_MAP_NEGATIVE_Z_OES." ... Add after the second paragraph (page 120), the following: "When the target parameter to CopyTexImage2D is one of the six cube map 2D image targets, the error INVALID_VALUE is generated if the width and height parameters are not equal." -- Section 3.8.3 "Texture Parameters" Change paragraph one (page 124) to say: ... " is the target, either TEXTURE_2D or TEXTURE_CUBE_MAP_OES." Add a final paragraph saying: "Texture parameters for a cube map texture apply to cube map as a whole; the six distinct 2D texture images use the texture parameters of the cube map itself. -- Section 3.8.5 "Texture Minification" under "Mipmapping" Change the first full paragraph on page 130 to: ... "If texturing is enabled for two-dimensional texturing but not cube map texturing (and TEXTURE_MIN_FILTER is one that requires a mipmap) at the time a primitive is rasterized and if the set of arrays TEXTURE_BASE_LEVEL through q = min{p,TEXTURE_MAX_LEVEL} is incomplete, based on the dimensions of array 0, then it is as if texture mapping were disabled." Follow the first full paragraph on page 130 with: "If cube map texturing is enabled and TEXTURE_MIN_FILTER is one that requires mipmap levels at the time a primitive is rasterized and if the set of six targets are not "mipmap cube complete", then it is as if texture mapping were disabled. The targets of a cube map texture are "mipmap cube complete" if the six cube map targets are "cube complete" and the set of arrays TEXTURE_BASE_LEVEL through q are not incomplete (as described above)." -- Section 3.8.7 "Texture State and Proxy State" Change the first sentence of the first paragraph (page 131) to say: "The state necessary for texture can be divided into two categories. First, there are the nine sets of mipmap arrays (one each for the one-, two-, and three-dimensional texture targets and six for the cube map texture targets) and their number." ... Change the second paragraph (page 132) to say: "In addition to the one-, two-, three-dimensional, and the six cube map sets of image arrays, the partially instantiated one-, two-, and three-dimensional and one cube map sets of proxy image arrays are maintained." ... -- Section 3.8.8 "Texture Objects" Change the first sentence of the first paragraph (page 132) to say: "In addition to the default textures TEXTURE_2D and TEXTURE_CUBE_MAP_OES, named two-dimensional texture objects and cube map texture objects can be created and operated on." ... Change the second paragraph (page 132) to say: "A texture object is created by binding an unused name to TEXTURE_2D or TEXTURE_CUBE_MAP_OES." ... "If the new texture object is bound to TEXTURE_2D or TEXTURE_CUBE_MAP_OES, it remains a two-dimensional or cube map texture until it is deleted." Change the third paragraph (page 133) to say: "BindTexture may also be used to bind an existing texture object to either TEXTURE_2D or TEXTURE_CUBE_MAP_OES." Change paragraph five (page 133) to say: "In the initial state, TEXTURE_2D and TEXTURE_CUBE_MAP_OES have two- dimensional and cube map state vectors associated with them respectively." ... "The initial two-dimensional and cube map texture is therefore operated upon, queried, and applied as TEXTUER_2D and TEXTURE_CUBE_MAP_OES respectively while 0 is bound to the corresponding targets." Change paragraph six (page 133) to say: ... "If a texture that is currently bound to one of the targets TEXTURE_2D or TEXTURE_CUBE_MAP_OES is deleted, it is as though BindTexture has been executed with the same and zero." ... -- Section 3.8.10 "Texture Application" Replace the beginning sentences of the first paragraph (page 138) with: "Texturing is enabled or disabled using the generic Enable and Disable commands, respectively, with the symbolic constants TEXTURE_2D or TEXTURE_CUBE_MAP_OES to enable the two-dimensional or cube map texturing respectively. If the cube map texture and the two- dimensional texture are enabled, then cube map texturing is used. If texturing is disabled, a rasterized fragment is passed on unaltered to the next stage of the GL (although its texture coordinates may be discarded). Otherwise, a texture value is found according to the parameter values of the currently bound texture image of the appropriate dimensionality. However, when cube map texturing is enabled, the rules are more complicated. For cube map texturing, the (s,t,r) texture coordinates are treated as a direction vector (rx,ry,rz) emanating from the center of a cube. (The q coordinate can be ignored since it merely scales the vector without affecting the direction.) At texture application time, the interpolated per-fragment (s,t,r) selects one of the cube map face's 2D image based on the largest magnitude coordinate direction (the major axis direction). If two or more coordinates have the identical magnitude, the implementation may define the rule to disambiguate this situation. The rule must be deterministic and depend only on (rx,ry,rz). The target column in the table below explains how the major axis direction maps to the 2D image of a particular cube map target. major axis direction target sc tc ma ---------- ------------------------------- --- --- --- +rx TEXTURE_CUBE_MAP_POSITIVE_X_OES -rz -ry rx -rx TEXTURE_CUBE_MAP_NEGATIVE_X_OES +rz -ry rx +ry TEXTURE_CUBE_MAP_POSITIVE_Y_OES +rx +rz ry -ry TEXTURE_CUBE_MAP_NEGATIVE_Y_OES +rx -rz ry +rz TEXTURE_CUBE_MAP_POSITIVE_Z_OES +rx -ry rz -rz TEXTURE_CUBE_MAP_NEGATIVE_Z_OES -rx -ry rz Using the sc, tc, and ma determined by the major axis direction as specified in the table above, an updated (s,t) is calculated as follows s = ( sc/|ma| + 1 ) / 2 t = ( tc/|ma| + 1 ) / 2 This new (s,t) is used to find a texture value in the determined face's 2D texture image using the rules given in sections 3.8.5 and 3.8.6." ... Additions to Chapter 4 of the 1.2 Specification (Per-Fragment Operations and the Frame Buffer) None Additions to Chapter 5 of the 1.2 Specification (Special Functions) Additions to Chapter 6 of the 1.2 Specification (State and State Requests) -- Section 6.1.3 "Enumerated Queries" Change the fourth paragraph (page 183) to say: "The GetTexParameter parameter may be one of TEXTURE_2D, or TEXTURE_CUBE_MAP_OES, indicating the currently bound two-dimensional or cube map texture object." Additions to the GLX Specification None Errors INVALID_VALUE is generated when the target parameter to TexImage2D or CopyTexImage2D is one of the six cube map 2D image targets and the width and height parameters are not equal. New State (table 6.12, p202) add the following entries: Get Value Type Get Command Initial Value Description Sec Attribute --------- ---- ----------- ------------- ----------- ------ -------------- TEXTURE_CUBE_MAP_OES B IsEnabled False True if cube map 3.8.10 texture/enable texturing is enabled TEXTURE_BINDING_CUBE_MAP_OES Z+ GetIntegerv 0 Texture object 3.8.8 texture for TEXTURE_CUBE_MAP TEXTURE_CUBE_MAP_POSITIVE_X_OES nxI N/A see 3.8 positive x face 3.8 - cube map texture image at lod i TEXTURE_CUBE_MAP_NEGATIVE_X_OES nxI N/A see 3.8 negative x face 3.8 - cube map texture image at lod i TEXTURE_CUBE_MAP_POSITIVE_Y_OES nxI N/A see 3.8 positive y face 3.8 - cube map texture image at lod i TEXTURE_CUBE_MAP_NEGATIVE_Y_OES nxI N/A see 3.8 negative y face 3.8 - cube map texture image at lod i TEXTURE_CUBE_MAP_POSITIVE_Z_OES nxI N/A see 3.8 positive z face 3.8 - cube map texture image at lod i TEXTURE_CUBE_MAP_NEGATIVE_Z_OES nxI N/A see 3.8 negative z face 3.8 - cube map texture image at lod i (table 6.14, p204) add the following entries: Get Value Type Get Command Initial Value Description Sec Attribute --------- ---- ----------- ------------- ----------- ------ --------- TEXTURE_GEN_MODE_OES Z2 GetTexGenivOES REFLECTION_MAP_OES Function used for 2.10.4 texture texgen (for s,t,r) TEXTURE_GEN_STR_OES B IsEnabled FALSE True if texgen is 2.10.4 texture enabled (for s,t,r) New Implementation Dependent State (table 6.24, p214) add the following entry: Get Value Type Get Command Minimum Value Description Sec Attribute --------- ---- ----------- ------------- ----------- ------ -------------- MAX_CUBE_MAP_TEXTURE_SIZE_OES Z+ GetIntegerv 16 Maximum cube map 3.8.1 - texture image dimension Revision History Version 1, November 8, 2007 (Benj Lipchak) - First version cleaned up for ES Version 2, April 16, 2015 (Jon Leech) - Remove border width term bt (nonexistent in ES)