GLVIEWPORT(3G)GLVIEWPORT(3G)NAMEglViewport - set the viewport
C SPECIFICATION
void glViewport( GLint x,
GLint y,
GLsizei width,
GLsizei height )
PARAMETERS
x, y Specify the lower left corner of the viewport rectangle, in pix‐
els. The initial value is (0,0).
width, height
Specify 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.
DESCRIPTIONglViewport specifies the affine transformation of x and y from normal‐
ized device coordinates to window coordinates. Let (xnd, ynd) be nor‐
malized device coordinates. Then the window coordinates (xw, yw) are
computed as follows:
xw=(xnd+1)⎝_____⎠+x
yw=(ynd+1)⎝______⎠+y
Viewport width and height are silently clamped to a range that depends on theimplementation. To query this range, call glGet with argument
GL_MAX_VIEWPORT_DIMS.ERRORS
GL_INVALID_VALUE is generated if either width or height is negative.
GL_INVALID_OPERATION is generated if glViewport is executed between the
execution of glBegin and the corresponding execution of glEnd.
ASSOCIATED GETS
glGet with argument GL_VIEWPORT
glGet with argument GL_MAX_VIEWPORT_DIMS
SEE ALSOglDepthRange(3G)GLVIEWPORT(3G)