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Cycles microdisplacement: preserve smooth normals for linear subdivison

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This way we prevent cracks in the model due to discontinuous normals, by using
smooth normals for displacement instead of always getting flat normals after
linear subdivision.

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D1916
This commit is contained in:
Mai Lavelle 2016-04-13 01:17:34 +02:00 committed by Brecht Van Lommel
parent 068ee2cd98
commit c1a27a76cf
5 changed files with 76 additions and 22 deletions
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48
intern/cycles/render/mesh.cpp
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@ -1451,31 +1451,63 @@ void Mesh::tessellate(DiagSplit *split)
{
int num_faces = triangles.size();
add_face_normals();
add_vertex_normals();
Attribute *attr_fN = attributes.find(ATTR_STD_FACE_NORMAL);
float3 *fN = attr_fN->data_float3();
Attribute *attr_vN = attributes.find(ATTR_STD_VERTEX_NORMAL);
float3 *vN = attr_vN->data_float3();
for(int f = 0; f < num_faces; f++) {
if(!forms_quad[f]) {
/* triangle */
LinearTrianglePatch* patch = new LinearTrianglePatch();
float3 *hull = patch->hull;
LinearTrianglePatch patch;
float3 *hull = patch.hull;
float3 *normals = patch.normals;
for(int i = 0; i < 3; i++) {
hull[i] = verts[triangles[f].v[i]];
}
split->split_triangle(patch);
delete patch;
if(smooth[f]) {
for(int i = 0; i < 3; i++) {
normals[i] = vN[triangles[f].v[i]];
}
}
else {
for(int i = 0; i < 3; i++) {
normals[i] = fN[f];
}
}
split->split_triangle(&patch);
}
else {
/* quad */
LinearQuadPatch* patch = new LinearQuadPatch();
float3 *hull = patch->hull;
LinearQuadPatch patch;
float3 *hull = patch.hull;
float3 *normals = patch.normals;
hull[0] = verts[triangles[f ].v[0]];
hull[1] = verts[triangles[f ].v[1]];
hull[3] = verts[triangles[f ].v[2]];
hull[2] = verts[triangles[f+1].v[2]];
split->split_quad(patch);
delete patch;
if(smooth[f]) {
normals[0] = vN[triangles[f ].v[0]];
normals[1] = vN[triangles[f ].v[1]];
normals[3] = vN[triangles[f ].v[2]];
normals[2] = vN[triangles[f+1].v[2]];
}
else {
for(int i = 0; i < 4; i++) {
normals[i] = fN[f];
}
}
split->split_quad(&patch);
// consume second triangle in quad
f++;

9
intern/cycles/subd/subd_dice.cpp
View File

@ -58,10 +58,9 @@ void EdgeDice::reserve(int num_verts, int num_tris)
int EdgeDice::add_vert(Patch *patch, float2 uv)
{
float3 P, N, dPdu, dPdv;
float3 P, N;
patch->eval(&P, &dPdu, &dPdv, uv.x, uv.y);
N = normalize(cross(dPdu, dPdv));
patch->eval(&P, NULL, NULL, &N, uv.x, uv.y);
assert(vert_offset < params.mesh->verts.size());
@ -81,7 +80,7 @@ int EdgeDice::add_vert(Patch *patch, float2 uv)
void EdgeDice::add_triangle(Patch *patch, int v0, int v1, int v2)
{
params.mesh->add_triangle(v0, v1, v2, params.shader, params.smooth);
params.mesh->add_triangle(v0, v1, v2, params.shader, params.smooth, false);
if(params.ptex) {
Attribute *attr_ptex_face_id = params.mesh->attributes.add(ATTR_STD_PTEX_FACE_ID);
@ -159,7 +158,7 @@ float3 QuadDice::eval_projected(SubPatch& sub, float u, float v)
float2 uv = map_uv(sub, u, v);
float3 P;
sub.patch->eval(&P, NULL, NULL, uv.x, uv.y);
sub.patch->eval(&P, NULL, NULL, NULL, uv.x, uv.y);
if(params.camera)
P = transform_perspective(&params.camera->worldtoraster, P);

29
intern/cycles/subd/subd_patch.cpp
View File

@ -57,7 +57,7 @@ static void decasteljau_bicubic(float3 *P, float3 *du, float3 *dv, const float3
/* Linear Quad Patch */
void LinearQuadPatch::eval(float3 *P, float3 *dPdu, float3 *dPdv, float u, float v)
void LinearQuadPatch::eval(float3 *P, float3 *dPdu, float3 *dPdv, float3 *N, float u, float v)
{
float3 d0 = interp(hull[0], hull[1], u);
float3 d1 = interp(hull[2], hull[3], u);
@ -68,6 +68,10 @@ void LinearQuadPatch::eval(float3 *P, float3 *dPdu, float3 *dPdv, float u, float
*dPdu = interp(hull[1] - hull[0], hull[3] - hull[2], v);
*dPdv = interp(hull[2] - hull[0], hull[3] - hull[1], u);
}
if(N) {
*N = normalize(interp(interp(normals[0], normals[1], u), interp(normals[2], normals[3], u), v));
}
}
BoundBox LinearQuadPatch::bound()
@ -82,7 +86,7 @@ BoundBox LinearQuadPatch::bound()
/* Linear Triangle Patch */
void LinearTrianglePatch::eval(float3 *P, float3 *dPdu, float3 *dPdv, float u, float v)
void LinearTrianglePatch::eval(float3 *P, float3 *dPdu, float3 *dPdv, float3 *N, float u, float v)
{
*P = u*hull[0] + v*hull[1] + (1.0f - u - v)*hull[2];
@ -90,6 +94,10 @@ void LinearTrianglePatch::eval(float3 *P, float3 *dPdu, float3 *dPdv, float u, f
*dPdu = hull[0] - hull[2];
*dPdv = hull[1] - hull[2];
}
if(N) {
*N = normalize(u*normals[0] + v*normals[1] + (1.0f - u - v)*normals[2]);
}
}
BoundBox LinearTrianglePatch::bound()
@ -104,9 +112,22 @@ BoundBox LinearTrianglePatch::bound()
/* Bicubic Patch */
void BicubicPatch::eval(float3 *P, float3 *dPdu, float3 *dPdv, float u, float v)
void BicubicPatch::eval(float3 *P, float3 *dPdu, float3 *dPdv, float3 *N, float u, float v)
{
decasteljau_bicubic(P, dPdu, dPdv, hull, u, v);
if (N) {
float3 dPdu_, dPdv_;
decasteljau_bicubic(P, &dPdu_, &dPdv_, hull, u, v);
if (dPdu && dPdv) {
*dPdu = dPdu_;
*dPdv = dPdv_;
}
*N = normalize(cross(dPdu_, dPdv_));
}
else {
decasteljau_bicubic(P, dPdu, dPdv, hull, u, v);
}
}
BoundBox BicubicPatch::bound()

10
intern/cycles/subd/subd_patch.h
View File

@ -25,7 +25,7 @@ CCL_NAMESPACE_BEGIN
class Patch {
public:
virtual ~Patch() {}
virtual void eval(float3 *P, float3 *dPdu, float3 *dPdv, float u, float v) = 0;
virtual void eval(float3 *P, float3 *dPdu, float3 *dPdv, float3 *N, float u, float v) = 0;
virtual bool is_triangle() { return false; }
virtual BoundBox bound() = 0;
virtual int ptex_face_id() { return -1; }
@ -36,8 +36,9 @@ public:
class LinearQuadPatch : public Patch {
public:
float3 hull[4];
float3 normals[4];
void eval(float3 *P, float3 *dPdu, float3 *dPdv, float u, float v);
void eval(float3 *P, float3 *dPdu, float3 *dPdv, float3 *N, float u, float v);
bool is_triangle() { return false; }
BoundBox bound();
};
@ -47,8 +48,9 @@ public:
class LinearTrianglePatch : public Patch {
public:
float3 hull[3];
float3 normals[3];
void eval(float3 *P, float3 *dPdu, float3 *dPdv, float u, float v);
void eval(float3 *P, float3 *dPdu, float3 *dPdv, float3 *N, float u, float v);
bool is_triangle() { return true; }
BoundBox bound();
};
@ -59,7 +61,7 @@ class BicubicPatch : public Patch {
public:
float3 hull[16];
void eval(float3 *P, float3 *dPdu, float3 *dPdv, float u, float v);
void eval(float3 *P, float3 *dPdu, float3 *dPdv, float3 *N, float u, float v);
bool is_triangle() { return false; }
BoundBox bound();
};

2
intern/cycles/subd/subd_split.cpp
View File

@ -50,7 +50,7 @@ float3 DiagSplit::to_world(Patch *patch, float2 uv)
{
float3 P;
patch->eval(&P, NULL, NULL, uv.x, uv.y);
patch->eval(&P, NULL, NULL, NULL, uv.x, uv.y);
if(params.camera)
P = transform_point(&params.objecttoworld, P);