Re: Quesa 1.8 broke my app; assertion in E3Set::Add() adding a kQ3AttributeTypeSurfaceShader

[James W. W. <ja...@fr...>]

"Sean McBride" <se...@ro...> wrote:

>Up to recently I've been using Quesa 1.7 from CVS of 2006-03-28.  Now
>I'm trying 1.8 and now my app crashes.  The code is:
>
>	TQ3ShaderObject	shader = Q3NULLIllumination_New();
>
>	TQ3PolygonData	polygon_data;
>	polygon_data.numVertices = ...;
>	polygon_data.vertices = ...;
>	polygon_data.polygonAttributeSet = Q3AttributeSet_New();
>
>	Q3AttributeSet_Add( polygon_data.polygonAttributeSet,
>     kQ3AttributeTypeSurfaceShader,
>     &shader );
>
>And then in E3Set::Add() (called by Q3AttributeSet_Add) this assertion fires:
>
>	Q3_ASSERT( Q3Object_IsType (
>     setData.attributes.surfaceShader,
>			 kQ3ShaderTypeSurface ) ) ;
>
>It crashes a few lines later.  I'm not sure if I built 1.7 with
>assertions, but there was no crash then.
>
>Is this not the right way to add a null shader?  Our goal is to add a
>null illumination shader to a polygon object.

The name kQ3AttributeTypeSurfaceShader suggests that the attribute 
should be a surface shader, but an illumination shader is not a 
surface shader.  One way you can see that is by looking at the 
indentation in Quesa.h:

             kQ3ShapeTypeShader                  = Q3_OBJECT_TYPE('s', 
'h', 'd', 'r'),
                 kQ3ShaderTypeSurface            = Q3_OBJECT_TYPE('s', 
'u', 's', 'h'),
                     kQ3SurfaceShaderTypeTexture = Q3_OBJECT_TYPE('t', 
'x', 's', 'u'),
                 kQ3ShaderTypeIllumination       = Q3_OBJECT_TYPE('i', 
'l', 's', 'h'),
                     kQ3IlluminationTypePhong    = Q3_OBJECT_TYPE('p', 
'h', 'i', 'l'),
                     kQ3IlluminationTypeLambert  = Q3_OBJECT_TYPE('l', 
'm', 'i', 'l'),
                     kQ3IlluminationTypeNULL     = Q3_OBJECT_TYPE('n', 
'u', 'i', 'l'),

I don't think you can add an illumination shader as an attribute.  I 
suggest making a display group, and inserting your illumination 
shader before the polygon.
-- 
   James W. Walker, Innoventive Software LLC
   <http://www.frameforge3d.com/>