glDepthRangeIndexed

glDepthRangeIndexed: man4/glDepthRangeIndexed.xml

After clipping and division by, depth coordinates range from -1 to 1, corresponding to the near and far clipping planes. Each viewport has an independent depth range specified as 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). glDepthRangeIndexed specifies a linear mapping of the normalized depth coordinates in this range to window depth coordinates for a specified viewport. Thus, the values accepted by glDepthRangeIndexed are both clamped to this range before they are accepted. The index parameter specifies the index of first viewport whose depth range to modify and must be less than the value of GL_MAX_VIEWPORTS. nearVal and farVal specify near and far values of the depth range for the specified viewport, respectively. The setting 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 the near plane distance be less than the far plane distance. Reverse mappings such as nearVal = 1, and farVal = 0 are acceptable. The type of the nearVal and farVal parameters was changed from GLclampd to GLdouble. This change is transparent to user code and is described in detail on the removedTypes page.