[Bf-committers] cloud/marble/wood bump patch

Alexander Ewering bf-committers@blender.org
Sun, 11 Jan 2004 00:27:27 +0100 (CET)

On Sat, 10 Jan 2004, car wrote:

> All of this. Is it the method to create Normal mapping ? Or something 
> close ?
> All I know of is that bump mapping does it's thing in the z axis, so at 
> the corners of the mesh the bump detail falls off and loses it's charm. 
> While Normal mapping does it's thing on all axis's x,y,z,
> And this part I was told to do in the source.
> In source/blender/blenkernel/intern/image.c,
> change:
> Code:
> if (tex->nor) return 3;
> else return 1;
> to
> Code:
> return 1;
> at line 711 and line 1485.
> This will of course, make all .blends that use bumpmaps render 
> incorrect - you have to set No RGB in material buttons to get back to 
> bump maps.
> But I do not have a good normal map to test yet.
> I had thought that during the displacement render that the displaced 
> mesh could then have it's detail extracted and made into a normal map.  
> So then whatever Ton and eeshlo are doing here could be used for the 
> extra fine details into blender.
> Or would Blenders renderer need a re-justment ?

trig_dragon, you have a very flawed understanding of bump mapping.

It is of no importance in whatever way you change the normals of the
faces during render, you will never get detail at the "corners" of a mesh,
because there _is_ no detail. 

What do you mean by "does its thing in the Z Axis"? What Z Axis? Texture
mapping never modifies the actual mesh data, so it doesn't make sense to
talk about axes at all. All that is done is rotating normal vectors using
intensity levels, which merely modifies the _shading_ of the rendered faces,
never the geometry.

It makes no sense to "convert" a mesh modified by displacement mapping into
a bump map. You can just skip the whole displacement mapping process
altogether then.

Well, still nobody has answered my question regarding the actual,
visible change the "improved" normal mapping has introduced.

| alexander ewering               instinctive new media
| ae[@]instinctive[.]de   http://www[.]instinctive[.]de