fglOrtho(3G)
fglOrtho - multiply the current matrix with an orthographic matrix
As shipped in IRIX 6.5.5. Unchanged since IRIX 6.5.
NAME fglOrtho - multiply the current matrix with an orthographic matrix FORTRAN SPECIFICATION SUBROUTINE fglOrtho( REAL*4 left, REAL*4 right, REAL*4 bottom, REAL*4 top, REAL*4 near, REAL*4 far ) PARAMETERS left, right Specify the coordinates for the left and right vertical clipping planes. bottom, top Specify the coordinates for the bottom and top horizontal clipping planes. near, far 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 fglOrtho describes a transformation that produces a parallel projection. The current matrix (see fglMatrixMode) is multiplied by this matrix and the result replaces the current matrix, as if fglMultMatrix were called with the following matrix as its argument: | | __________ | 0 0 t | right-left x | | | __________ | 0 0 t | top-bottom y | | | ________ | 0 0 t | far-near z | | | 0 0 0 1 | | | where __________ t = - x right-left __________ t = - y top-bottom ________ t = - z far-near Typically, the matrix mode is GL_PROJECTION, and (left, bottom, -near) and (right, top, -near) 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). -far specifies the location of the far clipping plane. Both near and far can be either positive or negative. Use fglPushMatrix and fglPopMatrix to save and restore the current matrix stack. ERRORS GL_INVALID_OPERATION is generated if fglOrtho is executed between the execution of fglBegin and the corresponding execution of fglEnd. ASSOCIATED GETS fglGet with argument GL_MATRIX_MODE fglGet with argument GL_MODELVIEW_MATRIX fglGet with argument GL_PROJECTION_MATRIX fglGet with argument GL_TEXTURE_MATRIX SEE ALSO fglFrustum, fglMatrixMode, fglMultMatrix, fglPushMatrix, fglViewport