On 06/20/11 17:31, Thomas Block wrote:
> Hi all,
> 
>  
> 
> I have implemented drivers for the FillTriangle and TexturedTriangle calls.  
> As you know, the FillTriangle triangles are specified by integer x,y vertices 
> and
> the TextureTriangle triangles are specified by float x,y,z,w,s,t vertices.
> 
>  
> 
> Regardless of vertex description type, my question has to do with the 
> rasterization implementation.  Does DirectFB specify that the rendered 
> triangle not
> include rightmost edge pixels and bottom-most span lines?  Or, does it 
> specify that all pixels within and on each edge be rendered?
> 
>  
> 
> The reason I ask is that I am failing an OpenGL test which is expecting that 
> rightmost pixels and bottom-most lines not be rendered.
> 
>  
> 
> Does anyone have any insight into what triangle rasterization implementation 
> is specified or implied by DirectFB?

We've implemented the triangle rasterisation not including the rightmost pixel 
and bottom most span line,
so that you can have a mesh of triangles without overdraw of a single pixel.

You can look at the df_texture example in DirectFB-examples. Changing its code 
to use semi transparent
triangles does not lead to any artefacts with the software rasteriser.

Same goes for FillTriangles(), check out df_knuckles.

-- 
Best regards,
  Denis Oliver Kropp

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