NAME

       glViewportIndexed - set a specified viewport

C SPECIFICATION

       void glViewportIndexedf(GLuint index, GLfloat x, GLfloat y, GLfloat w, GLfloat h);

       void glViewportIndexedfv(GLuint index, const GLfloat *v);

PARAMETERS

       index
           Specify the first viewport to set.

       x, y
           For glViewportIndexedf, specifies the lower left corner of the viewport rectangle, in
           pixels. The initial value is (0,0).

       width, height
           For glViewportIndexedf, specifies the width and height of the viewport. When a GL
           context is first attached to a window, width and height are set to the dimensions of
           that window.

       v
           For glViewportIndexedfv, specifies the address of an array containing the viewport
           parameters.

DESCRIPTION

       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 (x), bottom (y),
       width (w), and height (h) of each viewport, in that order.  x and y give the location of
       the viewport's lower left corner, and w and h give the width and height of the viewport,
       respectively. The viewport specifies the affine transformation of x and y from normalized
       device coordinates to window coordinates. Let x nd y nd be normalized device coordinates.
       Then the window coordinates x w y w are computed as follows:

       x w = x nd + 1 ⁢ width 2 + x

       y w = y nd + 1 ⁢ height 2 + y

       The location of the viewport's bottom left corner, given by (x, y) is clamped to be within
       the implementaiton-dependent viewport bounds range. The viewport bounds range [min, 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:

               void glViewportIndexedf(GLuint index, GLfloat x, GLfloat y, GLfloat w, GLfloat h)
               {
                   const float v[4]  = { x, y, w, h };
                   glViewportArrayv(index, 1, v);
               }

ERRORS

       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 width or height is negative.

ASSOCIATED GETS

       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

SEE ALSO

       glDepthRange(), glViewport(), glViewportArray()

COPYRIGHT

       Copyright © 2010 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.
       http://opencontent.org/openpub/.

AUTHORS

       opengl.org