glViewportIndexed

glViewportIndexedf and glViewportIndexedfv specify the parameters for a single viewport. index specifies the index of the viewport to modify. index must be less than the value of GL_MAX_VIEWPORTS . For glViewportIndexedf , x , y , w , and h specify the left, bottom, width and height of the viewport in pixels, respectively. For glViewportIndexedfv , v contains the address of an array of floating point values specifying the left ( $\mathit{x}$ ), bottom ( $\mathit{y}$ ), width ( $\mathit{w}$ ), and height ( $\mathit{h}$ ) of each viewport, in that order. $\mathit{x}$ and $\mathit{y}$ give the location of the viewport's lower left corner, and $\mathit{w}$ and $\mathit{h}$ give the width and height of the viewport, respectively. The viewport specifies the affine transformation of $\mathit{x}$ and $\mathit{y}$ from normalized device coordinates to window coordinates. Let $\left({\mathit{x}}_{\mathit{nd}},{\mathit{y}}_{\mathit{nd}}\right)$ be normalized device coordinates. Then the window coordinates $\left({\mathit{x}}_{\mathit{w}},{\mathit{y}}_{\mathit{w}}\right)$ are computed as follows:

The location of the viewport's bottom left corner, given by ( $\mathit{x}$ , $\mathit{y}$ ) is clamped to be within the implementaiton-dependent viewport bounds range. The viewport bounds range [ $\mathit{min}$ , $\mathit{max}$ ] can be determined by calling glGet with argument GL_VIEWPORT_BOUNDS_RANGE . Viewport width and height are silently clamped to a range that depends on the implementation. To query this range, call glGet with argument GL_MAX_VIEWPORT_DIMS .

The precision with which the GL interprets the floating point viewport bounds is implementation-dependent and may be determined by querying the impementation-defined constant GL_VIEWPORT_SUBPIXEL_BITS .

Calling glViewportIndexedfv is equivalent to calling glViewportArray with first set to index , count set to 1 and v passsed directly. glViewportIndexedf is equivalent to:

GL_INVALID_VALUE is generated if index is greater than or equal to the value of GL_MAX_VIEWPORTS .

GL_INVALID_VALUE is generated if either w or h is negative.

glGet with argument GL_VIEWPORT

glGet with argument GL_MAX_VIEWPORT_DIMS

glGet with argument GL_VIEWPORT_BOUNDS_RANGE

glGet with argument GL_VIEWPORT_SUBPIXEL_BITS

glDepthRange , glViewport , glViewportArray

Copyright 2010-2014 Khronos Group. This material may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1.0, 8 June 1999. .