📄 viewport.html
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<HTML><BODY><PRE> <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></PRE></BODY></HTML>⌨️ 快捷键说明
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