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<STRONG>NAME</STRONG>
<STRONG>glViewport</STRONG> - set the viewport
<STRONG>C</STRONG> <STRONG>SPECIFICATION</STRONG>
void <STRONG>glViewport</STRONG>( GLint <EM>x</EM>,
GLint <EM>y</EM>,
GLsizei <EM>width</EM>,
GLsizei <EM>height</EM> )
<STRONG>PARAMETERS</STRONG>
<EM>x</EM>, <EM>y</EM> Specify the lower left corner of the viewport
rectangle, in pixels. The initial value is (0,0).
<EM>width</EM>, <EM>height</EM>
Specify the width and height of the viewport. When a
GL context is first attached to a window, <EM>width</EM> and
<EM>height</EM> are set to the dimensions of that window.
<STRONG>DESCRIPTION</STRONG>
<STRONG>glViewport</STRONG> specifies the affine transformation of x and y
from normalized device coordinates to window coordinates.
Let (x , y ) be normalized device coordinates. Then the
windown<STRONG>c</STRONG>oor<STRONG>di</STRONG>nates (x , y ) are computed as follows:
w w
x = (x +1)(<STRONG>_____</STRONG>) + x
w nd ( 2 )
y = (y +1)(<STRONG>______</STRONG>) + y
w nd ( 2 )
Viewport width and height are silently clamped to a range
that depends on the implementation. To query this range,
call <STRONG>glGet</STRONG> with argument <STRONG>GL_MAX_VIEWPORT_DIMS</STRONG>.
<STRONG>ERRORS</STRONG>
<STRONG>GL_INVALID_VALUE</STRONG> is generated if either <EM>width</EM> or <EM>height</EM> is
negative.
<STRONG>GL_INVALID_OPERATION</STRONG> is generated if <STRONG>glViewport</STRONG> is executed
between the execution of <STRONG>glBegin</STRONG> and the corresponding
execution of <STRONG>glEnd</STRONG>.
<STRONG>ASSOCIATED</STRONG> <STRONG>GETS</STRONG>
<STRONG>glGet</STRONG> with argument <STRONG>GL_VIEWPORT</STRONG>
<STRONG>glGet</STRONG> with argument <STRONG>GL_MAX_VIEWPORT_DIMS</STRONG>
<STRONG>SEE</STRONG> <STRONG>ALSO</STRONG>
<STRONG>glDepthRange</STRONG>
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