glDepthRange

NAME

glDepthRange - specify mapping of depth values from normalized device coordinates to window coordinates

C SPECIFICATION

void glDepthRange(GLclampd zNear,
                  GLclampd zFar)

PARAMETERS

zNear	Specifies the mapping of the near clipping plane to window coordinates. The initial value is 0.
zFar	Specifies the mapping of the far clipping plane to window coordinates. The initial value is 1.

DESCRIPTION

After clipping and division by w, depth coordinates range [-1,1], corresponding to the near and far clipping planes. glDepthRange specifies a linear mapping of the normalized depth coordinates in this range to window depth coordinates. Regardless of the actual depth buffer implementation, window coordinate depth values are treated as though they range from 0 through 1 (like color components). Thus, the values accepted by glDepthRange are both clamped to this range before they are accepted.

The setting of (0.0,1.0) maps the near plane to 0.0 and the far plane to 1.0. With this mapping, the depth buffer range is fully utilized.

NOTES

It is not necessary that zNear be less than zFar. Reverse mappings such as zNear set to 1.0, and zFar set to 0.0 are acceptable.

ERRORS

GL_INVALID_OPERATION is generated if glDepthRange is executed between the execution of glBegin and the corresponding execution of glEnd.

ASSOCIATED GETS

glGet with argument GL_DEPTH_RANGE