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[spline/bezier]Improve tessellator more generic.

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xebra committed Feb 1, 2018
1 parent 07888d7 commit ca4e246680f42ef9d1052c6d23265e8726573089
Showing with 46 additions and 42 deletions.
  1. +46 −42 GPU/Common/SplineCommon.cpp
@@ -495,33 +495,43 @@ void TessellateSplinePatch(u8 *&dest, u16 *indices, int &count, const SplinePatc
}
}
template <typename T>
struct PrecomputedCurves {
PrecomputedCurves(const T *const p[16]) : p(p) {
}
// Tessellate single patch (4x4 control points)
template<typename T>
class Tessellator {
private:
const T *const p[4]; // T p[v][u]; 4x4 control points
T u[4]; // Pre-tessellated U lines
public:
Tessellator(const T *p, const int idx[4]) : p{ p + idx[0], p + idx[1], p + idx[2], p + idx[3] } {}
// http://en.wikipedia.org/wiki/Bernstein_polynomial
template<class T>
static T Bernstein3D(const T p[4], const float w[4]) {
if (w[0] == 1) return p[0];
if (w[3] == 1) return p[3];
// Linear combination
// Linear combination
T Sample(const T p[4], const float w[4]) {
return p[0] * w[0] + p[1] * w[1] + p[2] * w[2] + p[3] * w[3];
}
void Bernstein3D_U(const float w[4]) {
horiz[0] = Bernstein3D(p[0], w);
horiz[1] = Bernstein3D(p[4], w);
horiz[2] = Bernstein3D(p[8], w);
horiz[3] = Bernstein3D(p[12], w);
void SampleEdgeU(int idx) {
u[0] = p[0][idx];
u[1] = p[1][idx];
u[2] = p[2][idx];
u[3] = p[3][idx];
}
T Bernstein3D_V(const float w[4]) {
return Bernstein3D(horiz, w);
void SampleU(const float weights[4]) {
if (weights[0] == 1.0f) { SampleEdgeU(0); return; } // weights = {1,0,0,0}, first edge is open.
if (weights[3] == 1.0f) { SampleEdgeU(3); return; } // weights = {0,0,0,1}, last edge is open.
u[0] = Sample(p[0], weights);
u[1] = Sample(p[1], weights);
u[2] = Sample(p[2], weights);
u[3] = Sample(p[3], weights);
}
const T *const *p;
T horiz[4];
T SampleV(const float weights[4]) {
if (weights[0] == 1.0f) return u[0]; // weights = {1,0,0,0}, first edge is open.
if (weights[3] == 1.0f) return u[3]; // weights = {0,0,0,1}, last edge is open.
return Sample(u, weights);
}
};
static void _BezierPatchHighQuality(u8 *&dest, u16 *&indices, int &count, int tess_u, int tess_v, const BezierPatch &patch, u32 origVertType) {
@@ -541,53 +551,47 @@ static void _BezierPatchHighQuality(u8 *&dest, u16 *&indices, int &count, int te
int num_patches_v = (patch.count_v - 1) / 3;
for (int patch_u = 0; patch_u < num_patches_u; ++patch_u) {
for (int patch_v = 0; patch_v < num_patches_v; ++patch_v) {
// Precompute the horizontal curves to we only have to evaluate the vertical ones.
Vec3f *_pos[16];
Vec4f *_col[16];
Vec2f *_tex[16];
for (int point = 0; point < 16; ++point) {
int idx = (patch_u * 3 + point % 4) + (patch_v * 3 + point / 4) * patch.count_u;
_pos[point] = &patch.pos[idx];
_col[point] = &patch.col[idx];
_tex[point] = &patch.tex[idx];
}
PrecomputedCurves<Vec3f> prepos(_pos);
PrecomputedCurves<Vec4f> precol(_col);
PrecomputedCurves<Vec2f> pretex(_tex);
PrecomputedCurves<Vec3f> prederivU(_pos);
// Prepare 4x4 control points to tessellate
const int idx = patch_v * 3 * patch.count_u + patch_u * 3;
const int idx_v[4] = { idx, idx + patch.count_u, idx + patch.count_u * 2, idx + patch.count_u * 3 };
Tessellator<Vec3f> tess_pos(patch.pos, idx_v);
Tessellator<Vec4f> tess_col(patch.col, idx_v);
Tessellator<Vec2f> tess_tex(patch.tex, idx_v);
Tessellator<Vec3f> tess_nrm(patch.pos, idx_v);
for (int tile_u = 0; tile_u < tess_u + 1; ++tile_u) {
const Weight &wu = weights.u[tile_u];
prepos.Bernstein3D_U(wu.weights);
tess_pos.SampleU(wu.weights);
if (sampleColors)
precol.Bernstein3D_U(wu.weights);
tess_col.SampleU(wu.weights);
if (sampleTexcoords)
pretex.Bernstein3D_U(wu.weights);
tess_tex.SampleU(wu.weights);
if (computeNormals)
prederivU.Bernstein3D_U(wu.derivs);
tess_nrm.SampleU(wu.derivs);
for (int tile_v = 0; tile_v < tess_v + 1; ++tile_v) {
const Weight &wv = weights.v[tile_v];
SimpleVertex &vert = vertices[tile_v * (tess_u + 1) + tile_u];
vert.pos = prepos.Bernstein3D_V(wv.weights);
vert.pos = tess_pos.SampleV(wv.weights);
if (sampleColors) {
vert.color_32 = precol.Bernstein3D_V(wv.weights).ToRGBA();
vert.color_32 = tess_col.SampleV(wv.weights).ToRGBA();
} else {
vert.color_32 = patch.defcolor;
}
if (sampleTexcoords) {
pretex.Bernstein3D_V(wv.weights).Write(vert.uv);
tess_tex.SampleV(wv.weights).Write(vert.uv);
} else {
// Generate texcoord
vert.uv[0] = patch_u + tile_u * inv_u;
vert.uv[1] = patch_v + tile_v * inv_v;
}
if (computeNormals) {
const Vec3f derivU = prederivU.Bernstein3D_V(wv.weights);
const Vec3f derivV = prepos.Bernstein3D_V(wv.derivs);
const Vec3f derivU = tess_nrm.SampleV(wv.weights);
const Vec3f derivV = tess_pos.SampleV(wv.derivs);
vert.nrm = Cross(derivU, derivV).Normalized();
if (patch.patchFacing)

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