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Cycles: Fix bump mapping to use object space when used with true displacement

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Bump mapping was happening in world space while displacement happens in object
space, causing shading errors when displacement type was used with bump mapping.

To fix this the proper transforms are added to bump nodes. This is only done
for automatic bump mapping however, to avoid visual changes from other uses of
bump mapping. It would be nice to do this for all bump mapping to be consistent
but that will have to wait till we can break compatibility.

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D2191
This commit is contained in:
Mai Lavelle
2016-09-02 00:41:04 -04:00
parent ac2fe8312b
commit 92a2c49aab
8 changed files with 57 additions and 21 deletions
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27
intern/cycles/kernel/shaders/node_bump.osl
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@@ -21,6 +21,7 @@
surface node_bump(
int invert = 0,
int use_object_space = 0,
normal NormalIn = N,
float Strength = 0.1,
float Distance = 1.0,
@@ -29,12 +30,20 @@ surface node_bump(
float SampleY = 0.0,
output normal NormalOut = N)
{
/* get surface tangents from normal */
vector dPdx = Dx(P);
vector dPdy = Dy(P);
point Ptmp = P;
normal Normal = NormalIn;
vector Rx = cross(dPdy, NormalIn);
vector Ry = cross(NormalIn, dPdx);
if (use_object_space) {
Ptmp = transform("object", Ptmp);
Normal = normalize(transform("object", Normal));
}
/* get surface tangents from normal */
vector dPdx = Dx(Ptmp);
vector dPdy = Dy(Ptmp);
vector Rx = cross(dPdy, Normal);
vector Ry = cross(Normal, dPdx);
/* compute surface gradient and determinant */
float det = dot(dPdx, Rx);
@@ -49,7 +58,11 @@ surface node_bump(
dist *= -1.0;
/* compute and output perturbed normal */
NormalOut = normalize(absdet * NormalIn - dist * sign(det) * surfgrad);
NormalOut = normalize(strength * NormalOut + (1.0 - strength) * NormalIn);
NormalOut = normalize(absdet * Normal - dist * sign(det) * surfgrad);
NormalOut = normalize(strength * NormalOut + (1.0 - strength) * Normal);
if (use_object_space) {
NormalOut = normalize(transform("object", "world", NormalOut));
}
}