[Milkymist-devel] A Quadrilateral Rendering Primitive

[Sébastien Bourdeauducq]

Thanks Bengt for pointing out this interesting paper:
http://vcg.isti.cnr.it/publications/papers/quadrendering.pdf

Abstract
The only surface primitives that are supported by common graphics hardware are 
triangles and more complex shapes have to be triangulated before being sent to 
the rasterizer. Even quadrilaterals, which are frequently used in many 
applications, are rendered as a pair of triangles after splitting them along 
either diagonal. This creates an undesirable C1 -discontinuity that is visible 
in the shading or texture signal. We propose a new method that overcomes this 
drawback and is designed to be implemented in hardware as a new rasterizer. It 
processes a potentially non-planar quadrilateral directly without any 
splitting and interpolates attributes smoothly inside the quadrilateral. This 
interpolation is based on a recent generalization of barycentric coordinates 
that we adapted to handle perspective correction and situations in which a 
quadrilateral is partially behind the point of view.


It would be interesting to implement the presented method in Milkymist's TMU. 
Probably not straight in Verilog as it would not be productive. I'm rather 
thinking of using some higher-level dataflow language (such as Lucid) that 
would be "compiled" into Verilog. But that's for way later.

Sébastien