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New resolve_tri_uv_v3 util function

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Compute barycentric coordinates (u, v) for a point with respect to a
triangle.

This is needed for Cycles baking but we decided to push this
independently of the upcoming main baking changes.

Code adapted from Christer Ericson's Real-Time Collision Detection.

Cleanup, refactoring and review from Campbell Barton.
This commit is contained in:
Dalai Felinto 2014-03-25 21:57:34 -03:00
parent a7242c3162
commit b4d259f044
2 changed files with 40 additions and 3 deletions
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1
source/blender/blenlib/BLI_math_geom.h
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@ -219,6 +219,7 @@ bool barycentric_coords_v2(const float v1[2], const float v2[2], const float v3[
int barycentric_inside_triangle_v2(const float w[3]);
void resolve_tri_uv_v2(float r_uv[2], const float st[2], const float st0[2], const float st1[2], const float st2[2]);
void resolve_tri_uv_v3(float r_uv[2], const float st[3], const float st0[3], const float st1[3], const float st2[3]);
void resolve_quad_uv_v2(float r_uv[2], const float st[2], const float st0[2], const float st1[2], const float st2[2], const float st3[2]);
void resolve_quad_uv_v2_deriv(float r_uv[2], float r_deriv[2][2],
const float st[2], const float st0[2], const float st1[2], const float st2[2], const float st3[2]);

42
source/blender/blenlib/intern/math_geom.c
View File

@ -2686,7 +2686,7 @@ void interp_cubic_v3(float x[3], float v[3], const float x1[3], const float v1[3
/**
* Barycentric reverse
*
* Compute coordinates (u, v) for point \a st with respect to triangle (\a st0, \a st1, \a st2)"
* Compute coordinates (u, v) for point \a st with respect to triangle (\a st0, \a st1, \a st2)
*/
void resolve_tri_uv_v2(float r_uv[2], const float st[2],
const float st0[2], const float st1[2], const float st2[2])
@ -2698,8 +2698,9 @@ void resolve_tri_uv_v2(float r_uv[2], const float st[2],
const double c = st0[1] - st2[1], d = st1[1] - st2[1];
const double det = a * d - c * b;
if (IS_ZERO(det) == 0) { /* det should never be zero since the determinant is the signed ST area of the triangle. */
const double x[] = {st[0] - st2[0], st[1] - st2[1]};
/* det should never be zero since the determinant is the signed ST area of the triangle. */
if (IS_ZERO(det) == 0) {
const double x[2] = {st[0] - st2[0], st[1] - st2[1]};
r_uv[0] = (float)((d * x[0] - b * x[1]) / det);
r_uv[1] = (float)(((-c) * x[0] + a * x[1]) / det);
@ -2709,6 +2710,41 @@ void resolve_tri_uv_v2(float r_uv[2], const float st[2],
}
}
/**
* Barycentric reverse 3d
*
* Compute coordinates (u, v) for point \a st with respect to triangle (\a st0, \a st1, \a st2)
*/
void resolve_tri_uv_v3(float r_uv[2], const float st[3], const float st0[3], const float st1[3], const float st2[3])
{
float v0[3], v1[3], v2[3];
double d00, d01, d11, d20, d21, det;
sub_v3_v3v3(v0, st1, st0);
sub_v3_v3v3(v1, st2, st0);
sub_v3_v3v3(v2, st, st0);
d00 = dot_v3v3(v0, v0);
d01 = dot_v3v3(v0, v1);
d11 = dot_v3v3(v1, v1);
d20 = dot_v3v3(v2, v0);
d21 = dot_v3v3(v2, v1);
det = d00 * d11 - d01 * d01;
/* det should never be zero since the determinant is the signed ST area of the triangle. */
if (IS_ZERO(det) == 0) {
float w;
w = (float)((d00 * d21 - d01 * d20) / det);
r_uv[1] = (float)((d11 * d20 - d01 * d21) / det);
r_uv[0] = 1.0f - r_uv[1] - w;
}
else {
zero_v2(r_uv);
}
}
/* bilinear reverse */
void resolve_quad_uv_v2(float r_uv[2], const float st[2],
const float st0[2], const float st1[2], const float st2[2], const float st3[2])