Rasterize Camera Transform and alpha channel

[Roger H. <rog...@mi...>]

We have been using Q3RasterizeCameraTransform_New for some time to  
draw a square with a background pattern on it, we have also allowed  
the user to do the same thing for a foreground pattern, though that  
was fairly useless as it hid all the 3D Objects. I have now allowed  
patterns with an alpha channel to be used for the foreground, but  
nothing appears.

I have traced the problem down to ir_geom_transparent_add, which  
multiplies all the points
by the Local To Camera matrix (which is a unit matrix at this time),  
and then checks if any of the
z coordinates are <= zero. None are, they are all 0.0001 (Peter tells  
me this is so that they are in front of the clipping plane). Because  
now are <= 0 the routines simply returns (presumably it thinks
the triangle is clipped). If I comment out the test, all is well.

Should this be fixed in ir_geom_transparent_add or should the  
Rasterize Camera Transform set the Local To Camera matrix up  
differently?


Roger