glTexImage2DMultisample

glTexImage2DMu is a function in the OpenGL Shading Language (GLSL) used within compute shaders to upload data to a texture in a multi-threaded environment. It serves as a multi-threaded variant of the standard `glTexImage2D` function, allowing multiple threads within a compute shader to safely write to different regions of a texture without causing data races.

The primary purpose of glTexImage2DMu is to enable efficient parallel data transfer from shader invocations to textures. Unlike the standard `glTexImage2D`, which is called from the host (CPU) and blocks until the operation completes, glTexImage2DMu is invoked from within a compute shader and operates asynchronously. This function is particularly useful in scenarios where large datasets need to be processed in parallel, such as in ray tracing, image processing, or simulation applications.

The function signature for glTexImage2DMu is as follows:

`void glTexImage2DMu(Texture texture, int level, int internalformat, int width, int height, int border, int format, int type, void* pixels);`

Key parameters include:

- `texture`: The texture object being updated.

- `level`: The mipmap level to update (0 for the base level).

- `internalformat`: The internal format of the texture (e.g., `GL_RGBA8`).

- `width` and `height`: Dimensions of the texture region being updated.

- `border`: Must be 0 for non-border textures.

- `format`: The format of the pixel data (e.g., `GL_RGBA`).

- `type`: The data type of the pixel values (e.g., `GL_UNSIGNED_BYTE`).

- `pixels`: A pointer to the pixel data being uploaded.

This function is part of the OpenGL 4.6 specification and later versions, introduced to support multi-threaded texture updates within compute shaders. It is commonly used in conjunction with `glDispatchCompute` to parallelize texture operations, improving performance in compute-intensive applications.