Ah well, it worked in theory - but not in practice (slim chance really) :(
Looks like the cubic environment mapping in blitz uses the vertex positions not the normals to provide the lookup, I tried several modes, but none of them what I wanted.
So, on to a new theory - even crazier :)
Setup the cubic environment map as normal and every frame render an inverted sphere with the cube map on it from the opposite direction the camera is facing. Then, copy this into a texture to provide as the source for a spherical environment map.
When rendering the object you want both reflection and refraction, you can multitexture with the first stage being the refraction, using the texture setup previously as a spherical environment map, then the reflection using the normal cubic environment map in the second stage.
Works in theory ;) - I'll give it a try...
Looks like the cubic environment mapping in blitz uses the vertex positions not the normals to provide the lookup, I tried several modes, but none of them what I wanted.
So, on to a new theory - even crazier :)
Setup the cubic environment map as normal and every frame render an inverted sphere with the cube map on it from the opposite direction the camera is facing. Then, copy this into a texture to provide as the source for a spherical environment map.
When rendering the object you want both reflection and refraction, you can multitexture with the first stage being the refraction, using the texture setup previously as a spherical environment map, then the reflection using the normal cubic environment map in the second stage.
Works in theory ;) - I'll give it a try...