initWithTextureTarget:textureInternalFormat:textureMaxMipMapLevel:pixelsWide:pixelsHigh:

Declaration

- (instancetype) initWithTextureTarget:(GLenum) target textureInternalFormat:(GLenum) format textureMaxMipMapLevel:(GLint) maxLevel pixelsWide:(GLsizei) pixelsWide pixelsHigh:(GLsizei) pixelsHigh;

Parameters

• target:

  The texture object. This value should be one of the following: GL_TEXTURE_2D,GL_TEXTURE_CUBE_MAP, or GL_TEXTURE_RECTANGLE_EXT.

• format:

  The base internal format of the texture. This value should be GL_RGB, GL_RGBA, or GL_DEPTH_COMPONENT.

• maxLevel:

  The desired maximum mipmap level of the structure, starting with zero.

• pixelsWide:

  The width of the texture (in pixels) in the pixel buffer.

• pixelsHigh:

  The height of the texture (in pixels) in the pixel buffer.

Return Value

An initialized NSOpenGLPixelBuffer object or nil if the initialization failed. Initialization can fail if there is inconsistency among the parameter values. See the OpenGL documentation for glTexImage2D for more information.

Discussion

The value you pass to the target parameter defines several other constraints that are then applied to the remaining parameters. The list below gives the values you can pass to target and the additional constraints.

• GL_TEXTURE_2D

• GL_TEXTURE_CUBE_MAP - the values in pixelsWide and pixelsHigh must be equal.

• GL_TEXTURE_RECTANGLE_EXT - maxLevel must be zero.

Normally, when using the GL_TEXTURE_2D and GL_TEXTURE_CUBE_MAP targets, you must specify width and height values that are powers of two. When the ARB_texture_non_power_of_two extension is present, however, some types of hardware can support values that are not powers of two. You should check for the presence of this extension before specifying non power-of-two values.

If the texture map cannot be created, you can use the glGetError function to get the error code.

See Also

Initializing an OpenGL Pixel Buffer

• initWithCGLPBufferObj: