Name EXT_texture_from_pixmap Name Strings GLX_EXT_texture_from_pixmap Contributors James Jones, NVIDIA Aaron Plattner, NVIDIA Andy Ritger, NVIDIA Contact David Reveman, Novell, Inc. (davidr 'at' novell.com) Status Complete Version 17 (10 Feb 2009) Number 344 Dependencies OpenGL 1.1 is required. GLX 1.3 is required. GL_EXT_framebuffer_object affects the definition of this extension. GL_ARB_texture_rectangle affects the definition of this extension. GL_ARB_texture_non_power_of_two affects the definition of this extension. GL_SGIS_generate_mipmap affects the definition of this extension. Overview This extension allows a color buffer to be used for both rendering and texturing. Only color buffers of pixmaps can be used for texturing by this extension but other types of drawables can be supported by future extensions layered on top of this extension. The functionality of this extension is similar to WGL_ARB_render_texture. However, the purpose of this extension is not to provide "render to texture" like functionality but rather the ability to bind an existing X drawable to a texture. Though, there is nothing that prohibits it from being used for "render to texture". - Windows are problematic as they can change size and therefore are not supported by this extension. - Only a color buffer of a GLX pixmap created using an FBConfig with attribute GLX_BIND_TO_TEXTURE_RGB_EXT or GLX_BIND_TO_TEXTURE_RGBA_EXT set to TRUE can be bound as a texture. - The texture internal format is determined when the color buffer is associated with the texture, guaranteeing that the color buffer format is equivalent to the texture internal format. - A client can create a complete set of mipmap images if EXT_framebuffer_object is supported. IP Status There are no known IP issues. Issues 1. What should this extension be called? Even though it is very similar to WGL_ARB_render_texture that name is not appropriate as the intention of this extension is not "render to texture" like functionality. EXT_texture_from_pixmap seams most appropriate. Layering of future extensions on top of this extension for using other type of drawables as textures follows the same conventions as vertex/pixel buffer objects and vertex/fragment programs. 2. Should we allow applications to render to different mipmap levels and cube map faces? In order to discourage the use of this extension as a render to texture mechanism, cube maps and rendering directly to mip-map levels > 0 will not be supported. A new FBConfig attribute is introduced that specifies whether or not drawables created with that config will support multiple mipmap levels when bound to a texture. The other mipmap levels can be filled in by the EXT_framebuffer_object GenerateMipmapEXT function. Specifying which level of a pixmap was being rendered to on a per-drawable basis, as was done in the WGL_ARB_render_texture extension, also introduces concurrency issues. The state of the drawable when it was being rendered two by two separate threads of execution and both were changing the mipmap level was difficult to define. It is also desireable to keep this extension as simple as possible. Adding functionality that complicates the implementation and that is not directly relevenat to the goal of exposing a mechanism for texturing from arbitrary X pixmaps is not productive. If the ability to render directly to all levels of a texture is needed, EXT_framebuffer_object is the extension that should be used. 3. Should 1D textures be supported? X servers layered on top of an OpenGL implementation might not be able to support this. A new FBConfig attribute is introduced specifying which texture targets a drawable created with the given FBConfig can be bound to. 4. What should the default value for GLX_TEXTURE_TARGET_EXT be? Should users be required to set this value if GLX_TEXTURE_FORMAT_EXT is not GLX_TEXTURE_FORMAT_NONE_EXT? The implementation is capable of choosing a reasonable default, we simply need to specify the correct way to do so. We can base the ordering on the properties of the pixmap and the texturing capabilities of the pixmap's FBConfig and the implementation. The order is: - If GL_ARB_texture_non_power_of_two is supported GL_TEXTURE_2D will be used for all pixmap sizes. - If only GL_ARB_texture_rectangle is supported GL_TEXTURE_2D will be used for all power of two pixmap sizes and GL_TEXTURE_RECTANGLE_ARB will be used for all non power of two pixmap sizes. 5. Should users be required to re-bind the drawable to a texture after the drawable has been rendered to? It is difficult to define what the contents of the texture would be if we don't require this. Also, requiring this would allow implementations to perform an implicit copy at this point if they could not support texturing directly out of renderable memory. The problem with defining the contents of the texture after rendering has occured to the associated drawable is that there is no way to synchronize the use of the buffer as a source and as a destination. Direct OpenGL rendering is not necessarily done in the same command stream as X rendering. At the time the pixmap is used as the source for a texturing operation, it could be in a state halfway through a copyarea operation in which half of it is say, white, and half is the result of the copyarea operation. How is this defined? Worse, some other OpenGL application could be halfway through a frame of rendering when the composite manager sources from it. The buffer might just contain the results of a "glClear" operation at that point. To gurantee tear-free rendering, a composite manager would run as follows: -receive request for compositing: XGrabServer() glXWaitX() or XSync() glXBindTexImageEXT() glXReleaseTexImageEXT() XUngrabServer() Apps that don't synchronize like this would get what's available, and that may or may not be what they expect. 6. What is the result of calling GenerateMipmapEXT on a drawable that was not created with mipmap levels? The results are undefined. 7. Rendering done by the window system may be y-inverted compared to the standard OpenGL texture representation. More specifically: the X Window system uses a coordinate system where the origin is in the upper left; however, the GL uses a coordinate system where the origin is in the lower left. Should we define the contents of the texture as the y-inverted contents of the drawable? X implementations may represent their drawables differently internally, so y-inversion should be exposed as an FBConfig attribute. Applications will need to query this attribute and adjust their rendering appropriately. If a drawables is y-inverted and is bound to a texture, the contents of the texture will be y-inverted with respect to the standard GL memory layout. This means the contents of a pixmap of size (width, height) at pixmap coordinate (x, y) will be at location (x, height-y-1) in the texture. Applications will need to adjust their texture coordinates accordingly to avoid drawing the texture contents upside down. 8. Why wasn't this extension based on FBO instead of ARB_render_texture? Isn't the render_texture extension deprecated? At first glance, FBO may seem like the perfect framework to base a spec for texturing from pixmap surfaces on. It replaced the WGL_ARB_render_texture specification, which provided a mechanism to texture from pbuffer surfaces. However, this train of thought is another side effect of the unfortunate naming of the WGL_ARB_render_texture specification. FBO and the orginal render_texture specification were two different solutions to the problem of how to render to and texture from the same surface. WGL_ARB_render_texture provided a method to bind a texture to a drawable surface, as this extension does. FBO provides the opposite solution, allowing rendering to arbitrary surfaces including textures. In the case of FBO, the application doing the rendering knows that it needs to render to an alternate surface. In our usage case, the application doing the rendering is arbitrary, and has no knowledge that another application wants to use the surface it is rendering to as a texture. The only application able to name the surface is the one texturing from it. Therefore, it makes sense to provide a mechanism for binding a texture to an arbitrary surface in general, and a pixmap in this particular case. 9. Why not allow binding directly to an X pixmap without creating an intermediate GLX pixmap? Architecturally, GLX has moved away from operating directly on X drawables. This allows GLX specific attributes to be associated with the GLX drawables. In this case, it is important to associate an FBConfig with the drawable. The FBConfig contains attributes specifying the internal format the GL will use when utilizing the drawable's framebuffer as a texture. New Procedures and Functions void glXBindTexImageEXT (Display *display, GLXDrawable drawable, int buffer, const int *attrib_list) void glXReleaseTexImageEXT (Display *display, GLXDrawable drawable, int buffer) New Tokens Accepted by the parameter of glXGetFBConfigAttrib and the parameter of glXChooseFBConfig: GLX_BIND_TO_TEXTURE_RGB_EXT 0x20D0 GLX_BIND_TO_TEXTURE_RGBA_EXT 0x20D1 GLX_BIND_TO_MIPMAP_TEXTURE_EXT 0x20D2 GLX_BIND_TO_TEXTURE_TARGETS_EXT 0x20D3 GLX_Y_INVERTED_EXT 0x20D4 Accepted as an attribute in the parameter of glXCreatePixmap, and by the parameter of glXQueryDrawable: GLX_TEXTURE_FORMAT_EXT 0x20D5 GLX_TEXTURE_TARGET_EXT 0x20D6 GLX_MIPMAP_TEXTURE_EXT 0x20D7 Accepted as a value in the parameter of glXCreatePixmap and returned in the parameter of glXQueryDrawable when is GLX_TEXTURE_FORMAT_EXT: GLX_TEXTURE_FORMAT_NONE_EXT 0x20D8 GLX_TEXTURE_FORMAT_RGB_EXT 0x20D9 GLX_TEXTURE_FORMAT_RGBA_EXT 0x20DA Accepted as bits in the GLX_BIND_TO_TEXTURE_TARGETS_EXT variable: GLX_TEXTURE_1D_BIT_EXT 0x00000001 GLX_TEXTURE_2D_BIT_EXT 0x00000002 GLX_TEXTURE_RECTANGLE_BIT_EXT 0x00000004 Accepted as a value in the parameter of glXCreatePixmap and returned in the parameter of glXQueryDrawable when is GLX_TEXTURE_TARGET_EXT: GLX_TEXTURE_1D_EXT 0x20DB GLX_TEXTURE_2D_EXT 0x20DC GLX_TEXTURE_RECTANGLE_EXT 0x20DD Accepted by the parameter of glXBindTexImageEXT and glXReleaseTexImageEXT: GLX_FRONT_LEFT_EXT 0x20DE GLX_FRONT_RIGHT_EXT 0x20DF GLX_BACK_LEFT_EXT 0x20E0 GLX_BACK_RIGHT_EXT 0x20E1 GLX_FRONT_EXT GLX_FRONT_LEFT_EXT GLX_BACK_EXT GLX_BACK_LEFT_EXT GLX_AUX0_EXT 0x20E2 GLX_AUX1_EXT 0x20E3 GLX_AUX2_EXT 0x20E4 GLX_AUX3_EXT 0x20E5 GLX_AUX4_EXT 0x20E6 GLX_AUX5_EXT 0x20E7 GLX_AUX6_EXT 0x20E8 GLX_AUX7_EXT 0x20E9 GLX_AUX8_EXT 0x20EA GLX_AUX9_EXT 0x20EB GLX Protocol Two new GLX protocol commands are added. BindTexImageEXT 1 CARD8 opcode (X assigned) 1 16 GLX opcode (glXVendorPrivate) 2 6+n request length 4 1330 vendor specific opcode 4 CARD32 context tag 4 GLX_DRAWABLE drawable 4 INT32 buffer 4 CARD32 num_attributes 4*n LISTofATTRIBUTE_PAIR attribute, value pairs. ReleaseTexImageEXT 1 CARD8 opcode (X assigned) 1 16 GLX opcode (glXVendorPrivate) 2 5 request length 4 1331 vendor specific opcode 4 CARD32 context tag 4 GLX_DRAWABLE drawable 4 INT32 buffer Errors Additions to Chapter 2 of the OpenGL 1.2.1 Specification (OpenGL Operation) None. Additions to Chapter 3 of the OpenGL 1.2.1 Specification (Rasterization) None. Additions to Chapter 4 of the OpenGL 1.2.1 Specification (Per-Fragment Operations and the Frame Buffer) None. Additions to Chapter 5 of the OpenGL 1.2.1 Specification (Special Functions) None. Additions to Chapter 6 of the OpenGL 1.2.1 Specification (State and State Requests) None. Additions to the GLX Specification Add to table 3.1, GLXFBConfig Attributes: Attribute Type Notes ------------------------------- ------- ------------------------------------------------------------------- GLX_BIND_TO_TEXTURE_RGB_EXT boolean True if color buffers can be bound to RGB texture GLX_BIND_TO_TEXTURE_RGBA_EXT boolean True if color buffers can be bound to RGBA texture GLX_BIND_TO_MIPMAP_TEXTURE_EXT boolean True if color buffers can be bound to textures with multiple levels GLX_BIND_TO_TEXTURE_TARGETS_EXT bitmask Bitmask of texture targets color buffers can be bound to GLX_Y_INVERTED_EXT boolean True if the drawable's framebuffer is y-inverted. This can be used to determine if y-inverted texture coordinates need to be used when texturing from this drawable when it is bound to a texture target. Additions to table 3.4, Default Match Criteria for GLXFBConfig attributes: Attribute Default Selection Criteria Priority ------------------------------- -------------------- ------------------ --------- GLX_BIND_TO_TEXTURE_RGB_EXT GLX_DONT_CARE Exact GLX_BIND_TO_TEXTURE_RGBA_EXT GLX_DONT_CARE Exact GLX_BIND_TO_MIPMAP_TEXTURE_EXT GLX_DONT_CARE Exact GLX_BIND_TO_TEXTURE_TARGETS_EXT - Mask GLX_Y_INVERTED_EXT GLX_DONT_CARE Exact Modifications to 3.3.3, "Configuration Management" Add after paragraph 17 in the description of FBConfigs: GLX_Y_INVERTED_EXT is a boolean describing the memory layout used for drawables created with the GLXFBConfig. The attribute is True if the drawable's framebuffer will be y-inverted. This can be used to determine if y-inverted texture coordinates need to be used when texturing from this drawable when it is bound to a texture target. Modifications to 3.3.5, "Offscreen Rendering" Modify paragraph 3 of the description of glXCreatePixmap: specifies a list of attributes for the pixmap. The list has the same structure as described for glXChooseFBConfig. Currently the following attributes can be specified in attrib_list: GLX_TEXTURE_FORMAT_EXT, GLX_TEXTURE_TARGET_EXT, GLX_MIPMAP_TEXTURE_EXT, attrib_list may be NULL or empty (first attribute of None), in which case all attributes assume their default values as described below. GLX_TEXTURE_FORMAT_EXT describes the texture format this pixmap can be bound to. Valid values are GLX_TEXTURE_FORMAT_RGB_EXT, GLX_TEXTURE_FORMAT_RGBA_EXT, and GLX_TEXTURE_FORMAT_NONE_EXT. GLX_TEXTURE_TARGET_EXT can be set to GLX_TEXTURE_1D_EXT, GLX_TEXTURE_2D_EXT, or GLX_TEXTURE_RECTANGLE_EXT; it indicates the type of texture that will be created when GLX_TEXTURE_FORMAT_EXT is not GLX_TEXTURE_FORMAT_NONE_EXT. The default value of GLX_TEXTURE_TARGET_EXT depends on the capabilities in and the dimensions of the pixmap. If has GLX_TEXTURE_2D_BIT set and one or more of the following is true: * GLX_TEXTURE_RECTANGLE_BIT_EXT is not set in * GL_ARB_texture_non_power_of_two is supported * the pixmap's width and height are powers of 2 the default value for GLX_TEXTURE_TARGET_EXT is GLX_TEXTURE_2D_EXT. Otherwise, the first supported target is chosen in this order: GLX_TEXTURE_RECTANGLE_EXT, GLX_TEXTURE_1D_EXT. GLX_MIPMAP_TEXTURE_EXT indicates that storage for mipmaps should be allocated. Space for mipmaps will be set aside if GLX_TEXTURE_FORMAT_EXT is not GLX_TEXTURE_FORMAT_NONE_EXT and GLX_MIPMAP_TEXTURE_EXT is TRUE. The default value is FALSE. Modify paragraph 5 of the description of glXCreatePixmap: ...If is not a valid Pixmap XID, then a BadPixmap error is generated. A BadConfig error is generated if any of the following conditions are true: * GLX_TEXTURE_FORMAT_EXT is GLX_TEXTURE_FORMAT_RGB_EXT and does not have GLX_BIND_TO_TEXTURE_RGB set to TRUE. * GLX_TEXTURE_FORMAT_EXT is GLX_TEXTURE_FORMAT_RGBA_EXT and does not have GLX_BIND_TO_TEXTURE_RGBA set to TRUE. * GLX_MIPMAP_TEXTURE_EXT is set to TRUE and does not have GLX_BIND_TO_MIPMAP_EXT set to TRUE. * GLX_TEXTURE_TARGET_EXT is set to GLX_TEXTURE_1D_EXT and does not have GLX_TEXTURE_1D_BIT_EXT set. * GLX_TEXTURE_TARGET_EXT is set to GLX_TEXTURE_2D_EXT and does not have GLX_TEXTURE_2D_BIT_EXT set. * GLX_TEXTURE_TARGET_EXT is set to GLX_TEXTURE_RECTANGLE_EXT and does not have GLX_TEXTURE_RECTANGLE_BIT_EXT set. A BadValue error is generated if GLX_TEXTURE_FORMAT_EXT is not GLX_TEXTURE_FORMAT_NONE_EXT and the width or height of are incompatible with the specified value of GLX_TEXTURE_TARGET_EXT on this implementation. (e.g., the pixmap size is not a power of 2 and GL_ARB_texture_rectangle is not supported). Modify paragraph 1 of the description of glXDestroyPixmap: ...The storage for the GLX pixmap will be freed when it is not current to any client and all color buffers that are bound to a texture object have been released. Modifications to seciton 3.3.6, "Querying Attributes" Modify paragraph 1 of the description of glXQueryDrawable: ... must be set to one of GLX_WIDTH, GLX_HEIGHT, GLX_PRESERVED_CONTENTS, GLX_LARGEST_PBUFFER, GLX_FBCONFIG_ID, GLX_TEXTURE_FORMAT_EXT, GLX_TEXTURE_TARGET_EXT or GLX_MIPMAP_TEXTURE_EXT or a BadValue error is generated. Modify paragraph 3 of the description of glXQueryDrawable: ...If is a GLXWindow or GLXPixmap and is set to GLX_PRESERVED_CONTENTS or GLX_LARGEST_PBUFFER, or if is a GLXWindow or GLXPbuffer and is set to GLX_TEXTURE_FORMAT_EXT, GLX_TEXTURE_TARGET_EXT, or GLX_MIPMAP_TEXTURE_EXT, the contents of are undefined. Add a new section 3.3.6.1, "Texturing From Drawables" The command void glXBindTexImageEXT (Display *dpy, GLXDrawable draw, int buffer, int *attrib_list); defines a one- or two-dimensional texture image. The texture image is taken from and need not be copied. The texture target, the texture format, and the size of the texture components are derived from attributes of . The drawable attribute GLX_TEXTURE_FORMAT_EXT determines the base internal format of the texture. The component sizes are also determined by drawable attributes as shown in table 3.4a. Add new table 3.4a: Size of texture components: Texture component Size ----------------- -------------- R GLX_RED_SIZE G GLX_GREEN_SIZE B GLX_BLUE_SIZE A GLX_ALPHA_SIZE The texture target is derived from the GLX_TEXTURE_TARGET_EXT attribute of . If the texture target for the drawable is GLX_TEXTURE_2D_EXT or GLX_TEXTURE_RECTANGLE_EXT, then buffer defines a 2D texture for the current 2D or rectangle texture object respectively; if the texture target is GLX_TEXTURE_1D_EXT, then buffer defines a 1D texture for the current 1D texture object. If is not one of GLX_FRONT_LEFT_EXT, GLX_FRONT_RIGHT_EXT, GLX_BACK_LEFT_EXT, GLX_BACK_RIGHT_EXT, or GLX_AUX0_EXT through GLX_AUXn_EXT, where n is one less than the number of AUX buffers supported by the FBConfig used to create , or if the requested buffer is missing, a BadValue error is generated. specifies a list of attributes for the texture. The list has the same structure as described for glXChooseFBConfig. If is NULL or empty (first attribute of None), then all attributes assume their default values. must be NULL or empty. If and are the display and drawable for the calling thread's current context, glXBindTexImageEXT performs an implicit glFlush. The contents of the texture after the drawable has been bound are defined as the result of all rendering that has completed before the call to glXBindTexImageEXT. In other words, the results of any operation which has caused damage on the drawable prior to the glXBindTexImageEXT call will be represented in the texture. Rendering to the drawable while it is bound to a texture will leave the contents of the texture in an undefined state. However, no synchronization between rendering and texturing is done by GLX. It is the application's responsibility to implement any synchronization required. If a texture object is deleted before glXReleaseTexImageEXT is called, the color buffer is released. It is not an error to call TexImage2D, TexImage1D, CopyTexImage1D, or CopyTexImage2D to replace an image of a texture object that has a color buffer bound to it. However, these calls will cause the color buffer to be released and new memory to be allocated for the texture. Note that the color buffer is released even if the image that is being defined is a mipmap level that was not defined by the color buffer. GenerateMipmapEXT is an exception. GenerateMipmapEXT can be used to define mipmap levels for drawables that have been created with GLX_MIPMAP_TEXTURE_EXT set. Calling GenerateMipmapEXT on a drawable that was created without GLX_MIPMAP_TEXTURE_EXT is undefined. The results of calling glXBindTexImageEXT when GENERATE_MIPMAP_SGIS is TRUE are undefined. If glXBindTexImageEXT is called and the drawable attribute GLX_TEXTURE_FORMAT_EXT is GLX_TEXTURE_FORMAT_NONE_EXT, then a BadMatch error is generated. Currently, only pixmaps can be bound to textures. If is not a valid GLXPixmap, then a GLXBadPixmap error is generated. glXBindTexImageEXT is ignored if there is no current GLX rendering context. To release a color buffer that is being used as a texture, call void glXReleaseTexImageEXT (Dislpay *dpy, GLXDrawable draw, int buffer); must be one of GLX_FRONT_LEFT_EXT, GLX_FRONT_RIGHT_EXT, GLX_BACK_LEFT_EXT, GLX_BACK_RIGHT_EXT, and GLX_AUX0_EXT through GLX_AUXn_EXT, where n is one less than the number of AUX buffers supported by the FBConfig used to create or a BadValue error is generated. The contents of the color buffer are unaffected by glXReleaseTexImageEXT. If the specified color buffer is no longer bound to a texture (e.g., because the texture object was deleted), then glXReleaseTexImageEXT has no effect; no error is generated. When a color buffer is released (e.g., by calling glXReleaseTexImageEXT or implicitly by calling a routine such as TexImage2D), all textures that were defined by the color buffer become NULL. If glXReleaseTexImageEXT is called and the drawable attribute GLX_TEXTURE_FORMAT_EXT is GLX_TEXTURE_FORMAT_NONE_EXT, then a BadMatch error is generated. Currently, only pixmaps can be bound to textures. If is not a valid GLXPixmap, then a GLXBadPixmap error is generated. Usage Examples Example 1: Bind redirected window to texture: XGetWindowAttributes (display, window, &attrib); visualid = XVisualIDFromVisual (attrib.visual); fbconfigs = glXGetFBConfigs (display, screen, &nfbconfigs); for (i = 0; i < nfbconfigs; i++) { visinfo = glXGetVisualFromFBConfig (display, fbconfigs[i]); if (!visinfo || visinfo->visualid != visualid) continue; glXGetFBConfigAttrib (display, fbconfigs[i], GLX_DRAWABLE_TYPE, &value); if (!(value & GLX_PIXMAP_BIT)) continue; glXGetFBConfigAttrib (display, fbconfigs[i], GLX_BIND_TO_TEXTURE_TARGETS_EXT, &value); if (!(value & GLX_TEXTURE_2D_BIT_EXT)) continue; glXGetFBConfigAttrib (display, fbconfigs[i], GLX_BIND_TO_TEXTURE_RGBA_EXT, &value); if (value == FALSE) { glXGetFBConfigAttrib (display, fbconfigs[i], GLX_BIND_TO_TEXTURE_RGB_EXT, &value); if (value == FALSE) continue; } glXGetFBConfigAttrib (display, fbconfigs[i], GLX_Y_INVERTED_EXT, &value); if (value == TRUE) { top = 0.0f; bottom = 1.0f; } else { top = 1.0f; bottom = 0.0f; } break; } if (i == nfbconfigs) /* error 1 */ pixmap = XCompositeNameWindowPixmap (display, window); pixmapAttribs = { GLX_TEXTURE_TARGET_EXT, GLX_TEXTURE_2D_EXT, GLX_TEXTURE_FORMAT_EXT, GLX_TEXTURE_FORMAT_RGBA_EXT, None }; glxpixmap = glXCreatePixmap (display, fbconfigs[i], pixmap, pixmapAttribs); glGenTextures (1, &texture); glBindTexture (GL_TEXTURE_2D, texture); glXBindTexImageEXT (display, glxpixmap, GLX_FRONT_LEFT_EXT, NULL); glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); /* draw using pixmap as texture */ glBegin (GL_QUADS); glTexCoord2d (0.0f, bottom); glVertex2d (0.0f, 0.0f); glTexCoord2d (0.0f, top); glVertex2d (0.0f, 1.0f); glTexCoord2d (1.0f, top); glVertex2d (1.0f, 1.0f); glTexCoord2d (1.0f, bottom); glVertex2d (1.0f, 0.0f); glEnd (); glXReleaseTexImageEXT (display, glxpixmap, GLX_FRONT_LEFT_EXT); Version History 1. 26 Nov 2005 - DavidR Initial version 2. 01 Dec 2005 - JamesJ -Adapted spec language from draft version of GLX_ARB_render_texture. -Added glXDrawableAttribute to set attributes. -Modified glXBindTexImageEXT to take an attrib_list parameter. -Added support for cubemap and 1D texture targets. -Added attribute to set the texture target when creating the drawable. -Updated the issues section. -Added mipmap support. Support is not required. -Specified results of texturing from a drawable when it has been rendered to while bound to a texture as undefined until glXReleaseTexImageEXT has been called. Allows implementations that need to perform an implicit copy after rendering occurs to be compatible with this specification. 3. 04 Dec 2005 - DavidR -Changed name to GLX_EXT_texture_from_pixmap. -Changed spec regarding what happens when a pixmap that is bound to a texture is rendered to. Having textures be undefined once they are rendered to makes it useless for a compositing manager, which is a major use case for this extension. -Added support for not specifying texture target when creating a pixmap. Allows implementations to select whatever target it finds most suitable. 4. 05 Dec 2005 - JamesJ -Changed the default value of GLX_TEXTURE_TARGET_EXT from GLX_NO_TEXTURE_EXT to something usable. Eliminated GLX_NO_TEXTURE_EXT. -Eliminated GLX_TEXTURE_NONE_EXT. -Removed language referring to sharing of color buffers when pixmaps are bound to textures. -Updated issues. 5. 13 Dec 2005 - JamesJ -Removed cube map support and rendering to multiple mipmap levels support. 6. 20 Jan 2006 - JamesJ -Specified textures are y-inverted. 7. 23 Jan 2006 - AaronP -Fix typos, make some things clearer. Replace ocurrences of "released back to the drawable" with "released". 8. 01 Feb 2006 - AndyR -Fix minor typos. 9. 03 Feb 2006 - JamesJ -Added some new issues and their resolutions. -Finalized some issues that had been in discussion. -Made drawable y-inversion a queryable attribute of the drawable. -Moved detailed explanation of y-inverted addressing to the issues section -Updated example to demonstrate proper use of the y-inverted attribute. 10. 06 Feb 2006 - DavidR -Made GLX_Y_INVERTED_EXT an FBConfig attribute instead of a drawable attribute. -Removed GLX_TEXTURE_CUBE_MAP_EXT. -Fix minor typo. 11. 07 Feb 2006 - JamesJ -Added description of GLX_Y_INVERTED_EXT GLXFBConfig attribute, based on description of the drawable attribute of the same name from and earlier version of the specification. -Removed language requiring applications to re-bind a pixmap to a texture to gurantee contents of the texture are updated after a pixmap has been rendered to. -Added Aaron Plattner and Andy Ritger to contributors section. 12. 14 Feb 2006 - JamesJ -Disallowed rendering to a drawable while it is bound as a texture and defined the exact contents of a texture after a drawable has been bound to it. 13. 09 Mar 2006 - JamesJ -Add a context tag member to the vendor private requests. This field is part of the vendor private header, and is needed to specify which context the BindTexImageEXT and ReleaseTexImageEXT requests correspond to. -Changed texture target bitfield values to not skip numbers removed in earlier updates. 14. 13 Mar 2006 - JamesJ -Only require GLX_SGIX_fbconfig + GLX 1.2. -Clarify language regarding the result of rendering to drawables bound to textures. -Added GLX_FRONT_EXT and GLX_BACK_EXT tokens. 15. 18 Apr 2006 - JamesJ -Allocated enum values and opcodes. -Require GLX 1.3. GLX_SGIX_fbconfig doesn't allow creating pixmaps with attributes. -Added more arguments for not supporting rendering to multiple levels of a texture with this extension. -Fixed the inconsistencies in the return type of glXBindTexImageEXT and glXReleaseTexImageEXT. It is now listed as void throughout. 16. 12 Sep 2006 - JamesJ -Fix ordering of GLX protocol 17. 10 Feb 2009 - Jon Leech -Fix typo reported by Jonathan Knispel.