Function glGetTexLevelParameteriv

glGetTexLevelParameter returns in params texture parameter values for a specific level-of-detail value, specified as level. target defines the target texture, either GL_TEXTURE_1D, GL_TEXTURE_2D, GL_TEXTURE_3D, GL_PROXY_TEXTURE_1D, GL_PROXY_TEXTURE_2D, GL_PROXY_TEXTURE_3D, GL_TEXTURE_CUBE_MAP_POSITIVE_X, GL_TEXTURE_CUBE_MAP_NEGATIVE_X, GL_TEXTURE_CUBE_MAP_POSITIVE_Y, GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, GL_TEXTURE_CUBE_MAP_POSITIVE_Z, GL_TEXTURE_CUBE_MAP_NEGATIVE_Z, or GL_PROXY_TEXTURE_CUBE_MAP.

GL_MAX_TEXTURE_SIZE, and GL_MAX_3D_TEXTURE_SIZE are not really descriptive enough. It has to report the largest square texture image that can be accommodated with mipmaps but a long skinny texture, or a texture without mipmaps may easily fit in texture memory. The proxy targets allow the user to more accurately query whether the GL can accommodate a texture of a given configuration. If the texture cannot be accommodated, the texture state variables, which may be queried with glGetTexLevelParameter, are set to 0. If the texture can be accommodated, the texture state values will be set as they would be set for a non-proxy target.

pname specifies the texture parameter whose value or values will be returned.

The accepted parameter names are as follows:

• GL_TEXTURE_WIDTH params returns a single value, the width of the texture image. The initial value is 0.

• GL_TEXTURE_HEIGHT params returns a single value, the height of the texture image. The initial value is 0.

• GL_TEXTURE_DEPTH params returns a single value, the depth of the texture image. The initial value is 0.

• GL_TEXTURE_INTERNAL_FORMAT params returns a single value, the internal format of the texture image.

• GL_TEXTURE_RED_TYPE, GL_TEXTURE_GREEN_TYPE, GL_TEXTURE_BLUE_TYPE, GL_TEXTURE_ALPHA_TYPE, GL_TEXTURE_DEPTH_TYPE The data type used to store the component. The types GL_NONE, GL_SIGNED_NORMALIZED, GL_UNSIGNED_NORMALIZED, GL_FLOAT, GL_INT, and GL_UNSIGNED_INT may be returned to indicate signed normalized fixed-point, unsigned normalized fixed-point, floating-point, integer unnormalized, and unsigned integer unnormalized components, respectively.

• GL_TEXTURE_RED_SIZE, GL_TEXTURE_GREEN_SIZE, GL_TEXTURE_BLUE_SIZE, GL_TEXTURE_ALPHA_SIZE, GL_TEXTURE_DEPTH_SIZE The internal storage resolution of an individual component. The resolution chosen by the GL will be a close match for the resolution requested by the user with the component argument of glTexImage1D, glTexImage2D, glTexImage3D, glCopyTexImage1D, and glCopyTexImage2D. The initial value is 0.

• GL_TEXTURE_COMPRESSED params returns a single boolean value indicating if the texture image is stored in a compressed internal format. The initiali value is GL_FALSE.

• GL_TEXTURE_COMPRESSED_IMAGE_SIZE params returns a single integer value, the number of unsigned bytes of the compressed texture image that would be returned from glGetCompressedTexImage.

Summary

return texture parameter values for a specific level of detail

Tutorial

Sébastien Dominé - Using Texture Compression in OpenGL

See

glGetTexLevelParameter