glTexSubImage2D
- specify a two-dimensional texture subimage
void glTexSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLsizei width, GLsizei height, GLenum format, GLenum type, const GLvoid * pixels)
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 n
th 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 subimage.
height
Specifies the height of the texture subimage.
format
Specifies the of the pixel data. The following symbolic values are accepted: GL_ALPHA
, GL_RGB
, GL_RGBA
, GL_LUMINANCE
, and GL_LUMINANCE_ALPHA
.
type
Specifies the data type of the pixel data. The following symbolic values are accepted: GL_UNSIGNED_BYTE
, GL_UNSIGNED_SHORT_5_6_5
, GL_UNSIGNED_SHORT_4_4_4_4
, and GL_UNSIGNED_SHORT_5_5_5_1
.
pixels
Specifies a pointer to the image data in memory.
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
. Two-dimensional texturing is initially disabled.
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 yoffset + height - 1, inclusive. This region may not include any texels outside the range of the texture array as it was originally specified. It is not an error to specify a subtexture with zero width or height, but such a specification has no effect.
glPixelStore
affects texture images in exactly the way it affects glTexImage2D
.
glTexSubImage2D
specifies a two-dimensional sub texture for the currently bound texture, specified with glBindTexture
and current texture unit, specified with glActiveTexture
.
GL_INVALID_ENUM
is generated if target
is not GL_TEXTURE_2D
.
GL_INVALID_OPERATION
is generated if the texture array has not been defined by a previous glTexImage2D
or glCopyTexImage2D
operation.
GL_INVALID_VALUE
is generated if level
is less than 0.
GL_INVALID_VALUE
may be generated if level
is greater than log2max, where max is the returned value of GL_MAX_TEXTURE_SIZE
.
GL_INVALID_VALUE
is generated if xoffset < - b, xoffset + width > (w - b) , yoffset < - b, or yoffset + height > (h - b) , where w is the texture width, h is the texture height, and b is the border of the texture image being modified. Note that w and h include twice the border width.
GL_INVALID_VALUE
is generated if width
or height
is less than 0.
GL_INVALID_ENUM
is generated if format
is not an accepted constant.
GL_INVALID_ENUM
is generated if type
is not a type constant.
GL_INVALID_OPERATION
is generated if type
is GL_UNSIGNED_SHORT_5_6_5
and format
is not GL_RGB
.
GL_INVALID_OPERATION
is generated if type
is one of GL_UNSIGNED_SHORT_4_4_4_4
, or GL_UNSIGNED_SHORT_5_5_5_1
and format
is not GL_RGBA
.
glGet
with argument GL_MAX_TEXTURE_SIZE
Copyright © 2003-2004 Silicon Graphics, Inc.
This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.
glActiveTexture
, glBindTexture
, glCompressedTexSubImage2D
, glCopyTexSubImage2D
, glGet
, glPixelStore
, glTexEnv
, glTexImage2D
, glTexParameter