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glTexSubImage2D
Chapter 18
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glTexSubImage2D
glTexSubImage2D: specify a two-dimensional texture sub-image.
C Specification
void glTexSubImage2D(
GLenum target,
GLint level,
GLint xoffset,
GLint yoffset,
GLsizei width,
GLsizei height,
GLenum format,
GLenum type,
const GLvoid *pixels)
Parameters
target Specifies the target texture. Must be GL_TEXTURE_2D.
level Specifies the level-of-detail number. Level 0 is the base image level.
Level n is the nth mipmap reduction image.
xoffset Specifies a texel offset in the x direction within the texture array.
yoffset Specifies a texel offset in the y direction within the texture array.
width Specifies the width of the texture sub-image.
height Specifies the height of the texture sub-image.
format Specifies the format of the pixel data. The following symbolic values
are accepted: GL_COLOR_INDEX, GL_RED, GL_GREEN, GL_BLUE,
GL_ALPHA, GL_RGB, GL_RGBA, GL_LUMINANCE, and
GL_LUMINANCE_ALPHA. If the extension GL_EXT_shadow is
supported, then the symbolic value GL_DEPTH_COMPONENT is also
accepted.
type Specifies the data type of the pixel data. The following symbolic values
are accepted: GL_UNSIGNED_BYTE, GL_BYTE, GL_BITMAP,
GL_UNSIGNED_SHORT, GL_SHORT, GL_UNSIGNED_INT,
GL_INT, and GL_FLOAT.
pixels Specifies a pointer to the image data in memory.
Description
Texturing maps a portion of a specified texture image onto each graphical primitive for
which texturing is enabled. To enable and disable two-dimensional texturing, call
glEnable and glDisable with argument GL_TEXTURE_2D.
glTexSubImage2D redefines a contiguous subregion of an existing two-dimensional
texture image. The texels referenced by pixels replace the portion of the existing texture
array with X indices xoffset and xoffset + width - 1, inclusive, and Y indices yoffset and