glTexSubImage2D

Name

glTexSubImage2D — specify a two-dimensional texture subimage

C Specification

`void glTexSubImage2D(`	GLenum `target`,
	GLint `level`,
	GLint `xoffset`,
	GLint `yoffset`,
	GLsizei `width`,
	GLsizei `height`,
	GLenum `format`,
	GLenum `type`,
	const GLvoid * `data)`;

Parameters

target: Specifies the target texture of the active texture unit. Must be GL_TEXTURE_2D, 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, or GL_TEXTURE_CUBE_MAP_NEGATIVE_Z.
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 subimage.
height: Specifies the height of the texture subimage.
format: Specifies the format 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.
data: 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 active. Texturing is active when the current fragment shader or vertex shader makes use of built-in texture lookup functions.

glTexSubImage2D redefines a contiguous subregion of an existing two-dimensional texture image. The texels referenced by data 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.

Notes

Storage parameter GL_UNPACK_ALIGNMENT, set by glPixelStorei, affects the way that data is read out of client memory. See glPixelStorei for a description.

glTexSubImage2D specifies a two-dimensional or cube-map subtexture for the current texture unit, specified with glActiveTexture.

Errors

GL_INVALID_ENUM is generated if target is not GL_TEXTURE_2D, 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, or GL_TEXTURE_CUBE_MAP_NEGATIVE_Z.

GL_INVALID_ENUM is generated if format or type is not an accepted value.

GL_INVALID_VALUE is generated if level is less than 0.

GL_INVALID_VALUE may be generated if level is greater than log 2 max, where max is the returned value of GL_MAX_TEXTURE_SIZE.

GL_INVALID_VALUE is generated if xoffset < 0 , xoffset + width > w , yoffset < 0 , or yoffset + height > h , where w is the width and h is the height of the texture image being modified.

GL_INVALID_VALUE is generated if width or height is less than 0.

GL_INVALID_OPERATION is generated if the texture array has not been defined by a previous glTexImage2D or glCopyTexImage2D operation whose internalformat matches the format of glTexSubImage2D.

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 GL_UNSIGNED_SHORT_4_4_4_4 or GL_UNSIGNED_SHORT_5_5_5_1 and format is not GL_RGBA.

Associated Gets

glGet with argument GL_MAX_TEXTURE_SIZE or GL_MAX_CUBE_MAP_TEXTURE_SIZE