GLORTHO() GLORTHO() NAME glOrtho - multiply the current matrix with an orthographic matrix C SPECIFICATION void glOrtho( GLdouble left, GLdouble right, GLdouble bottom, GLdouble top, GLdouble zNear, GLdouble zFar ) PARAMETERS left, right Specify the coordinates for the left and right vertical clip- ping planes. bottom, top Specify the coordinates for the bottom and top horizontal clip- ping planes. zNear, zFar Specify the distances to the nearer and farther depth clipping planes. These values are negative if the plane is to be behind the viewer. DESCRIPTION glOrtho describes a transformation that produces a parallel projection. The current matrix (see glMatrixMode) is multiplied by this matrix and the result replaces the current matrix, as if glMultMatrix were called with the following matrix as its argument: left ( matrix { ccol { {2 over {"right" - "left"}} above 0 above 0 above 0 } ccol { 0 above {2 over {"top" - "bottom"}} above 0 above 0 } ccol { 0 above 0 above {-2 over {"zFar" - "zNear"}} above 0 } ccol { {t sub x}~ above {t sub y}~ above {t sub z}~ above 1~ } } right ) where t sub x ~=~ -{{"right" + "left"} over {"right" - "left"}} t sub y ~=~ -{{"top" + "bottom"} over {"top" - "bottom"}} t sub z ~=~ -{{"zFar" + "zNear"} over {"zFar" - "zNear"}} Typically, the matrix mode is GL_PROJECTION, and (left, bottom, -zNear) and (right, top, -zNear) specify the points on the near clipping plane that are mapped to the lower left and upper right corners of the window, respectively, assuming that the eye is located at (0, 0, 0). -zFar speci- fies the location of the far clipping plane. Both zNear and zFar can be either positive or negative. Use glPushMatrix and glPopMatrix to save and restore the current matrix stack. ERRORS GL_INVALID_OPERATION is generated if glOrtho is executed between the execu- tion of glBegin and the corresponding execution of glEnd. ASSOCIATED GETS glGet with argument GL_MATRIX_MODE glGet with argument GL_MODELVIEW_MATRIX glGet with argument GL_PROJECTION_MATRIX glGet with argument GL_TEXTURE_MATRIX SEE ALSO glFrustum, glMatrixMode, glMultMatrix, glPushMatrix, glViewport GLORTHO()
NAME | C SPECIFICATION | PARAMETERS | DESCRIPTION | ERRORS | ASSOCIATED GETS | SEE ALSO
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