The glDepthRange function specifies the mapping of z values from normalized device coordinates to window coordinates.
void WINAPI glDepthRange( GLclampd zNear, GLclampd zFar );
The mapping of the near clipping plane to window coordinates. The default value is zero.
The mapping of the far clipping plane to window coordinates. The default value is 1.
This function does not return a value.
The following error code can be retrieved by the glGetError function.
||The function was called between a call to glBegin and the corresponding call to glEnd.
After clipping and division by w, z -coordinates range from 0.0 to 1.0, corresponding to the near and far clipping planes. The glDepthRange function specifies a linear mapping of the normalized z-coordinates in this range to window z-coordinates. Regardless of the actual depth buffer implementation, window coordinate depth values are treated as though they range from 0.0 through 1.0 (like color components). Thus, the values accepted by glDepthRange are both clamped to this range before they are accepted.
The default mapping of (0,1) maps the near plane to 0 and the far plane to 1. With this mapping, the depth buffer range is fully utilized.
It is not necessary that zNear be less than zFar. Reverse mappings such as (1,0) are acceptable.
The following function retrieves information related to glDepthRange:
glGet with argument GL_DEPTH_RANGE
|Minimum supported client
||Windows 2000 Professional [desktop apps only]
|Minimum supported server
||Windows 2000 Server [desktop apps only]