glCompressedTexImage2D

Name

glCompressedTexImage2D - specify a two-dimensional compressed texture image

C Specification

void glCompressedTexImage2D(GLenum target,
    GLint level,
    GLint internalformat,
    GLsizei width,
    GLsizei height,
    GLint border,
    GLsizei imageSize,
    const GLvoid * data)

Parameters

target: Specifies the target texture. Must be GL_TEXTURE_2D.
level: Specifies the level-of-detail number. Must be less than or equal to 0. Level 0 indicates a single mip-level. Negative values indicate how many mip-levels are described by data.
internalformat: Specifies the color components in the texture. The following symbolic constants are accepted: GL_PALETTE4_RGB8_OES, GL_PALETTE4_RGBA8_OES, GL_PALETTE4_R5_G6_B5_OES, GL_PALETTE4_RGBA4_OES, GL_PALETTE4_RGB5_A1_OES, GL_PALETTE8_RGB8_OES, GL_PALETTE8_RGBA8_OES, GL_PALETTE8_R5_G6_B5_OES, GL_PALETTE8_RGBA4_OES, and GL_PALETTE8_RGB5_A1_OES.
width: Specifies the width of the texture image. Must be 2ⁿ + 2border for some integer n. All implementations support texture images that are at least 64 texels wide.
height: Specifies the height of the texture image. Must be 2^m + 2border for some integer m. All implementations support texture images that are at least 64 texels high.
border: Specifies the width of the border. Must be 0.
imageSize: Specifies the size of the compressed image data in bytes.
data: Specifies a pointer to the compressed image data in memory.

Description

glCompressedTexImage2D defines a two-dimensional texture image in compressed format.

The supported compressed formats are paletted textures. The layout of the compressed image is a palette followed by multiple mip-levels of texture indices used for lookup into the palette. The palette format can be one of R5_G6_B5, RGBA4, RGB5_A1, RGB8, or RGBA8. The texture indices can have a resolution of 4 or 8 bits. As a result, the number of palette entries is either 16 or 256. If level is 0, only one mip-level of texture indices is described in data. Otherwise, the negative value of level specifies up to which mip-level the texture indices are described. A possibly remaining pad nibble for the lowest resolution mip-level is ignored.

Notes

glPixelStore has no effect on compressed texture images.

glCompressedTexImage2D specifies the two-dimensional texture for the currently bound texture, specified with glBindTexture, and the current texture unit, specified with glActiveTexture.

Errors

GL_INVALID_ENUM is generated if target is not GL_TEXTURE_2D.

GL_INVALID_VALUE may be generated if if level is greater than 0 or the absolute value of level is greater than log₂max, where max is the returned value of GL_MAX_TEXTURE_SIZE.

GL_INVALID_VALUEis generated if internalformat is not one of the accepted symbolic constants.

GL_INVALID_VALUE is generated if width or height is less than 0 or greater than 2 + GL_MAX_TEXTURE_SIZE, or if either cannot be represented as 2^k + 2border for some integer k.

GL_INVALID_VALUEis generated if border is not 0.

GL_INVALID_VALUEis generated if imageSize is not consistent with format, dimentions, and contents of the compressed image.

Copyright

This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.