Native bindings to the EXT_clear_texture extension.

Texture objects are fundamental to the operation of OpenGL. They are used as a source for texture sampling and destination for rendering as well as being accessed in shaders for image load/store operations It is also possible to invalidate the contents of a texture. It is currently only possible to set texture image data to known values by uploading some or all of a image array from application memory or by attaching it to a framebuffer object and using the Clear or ClearBuffer commands.

Both uploading initial texture data and clearing by attaching to a framebuffer have potential disadvantages when one simply wants to initialize texture data to a known value. Uploading initial data requires the application to allocate a (potentially large) chunk of memory and transferring that to the GL. This can be a costly operation both in terms of memory bandwidth and power usage. Alternatively, attaching a texture level to a framebuffer to clear it may not be possible if the texture format isn't supported for rendering, or even if it is, attaching the image to a framebuffer object may cause the texture to be allocated in certain types of memory, which it may otherwise not need to be placed in.

This extension solves these problems by providing a mechanism whereby the contents of a texture image array can be set to known values by using the ClearTexImageEXT or ClearTexSubImageEXT commands. These commands can also be useful for initializing an image that will be used for atomic shader operations.

Requires GLES 3.1.