Porting MSINGLE Mode Code

OpenGL has no equivalent for MSINGLE, single-matrix mode. Though use of this mode has been discouraged, it is the default for IRIS GL. If your IRIS GL program uses the single-matrix mode, you need to rewrite it to use double-matrix mode only. OpenGL is always in double-matrix mode, and is initially in GL_MODELVIEW mode.

Most IRIS GL code in MSINGLE mode looks like this:

projectionmatrix();

where projectionmatrix is one of: ortho, ortho2, perspective, or window. To port to OpenGL, replace the MSINGLE -mode projectionmatrix function with:

glMatrixMode( GL_PROJECTION ); 
glLoadMatrix( identity matrix ); 
 
/* call one of these functions here: */ 
/* glFrustrum(), glOrtho(), glOrtho2(), gluPerspective()}; */ 
 
glMatrixMode( GL_MODELVIEW ); 
glLoadMatrix( identity matrix );