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Cleanup: move plane array intersection into a function 

Also add check to ensure a point isn't occluded by it's own plane,
which could happen if a small epsilon values are passed in.
This commit is contained in:
Campbell Barton 2020-11-07 20:14:40 +11:00
parent d2c102060d
commit 19a0df25e3
3 changed files with 115 additions and 63 deletions
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8
source/blender/blenlib/BLI_math_geom.h
View File

@ -358,6 +358,14 @@ bool isect_plane_plane_v3(const float plane_a[4],
float r_isect_co[3],
float r_isect_no[3]) ATTR_WARN_UNUSED_RESULT;
bool isect_planes_v3_fn(
const float planes[][4],
const int planes_len,
const float eps_coplanar,
const float eps_isect,
void (*callback_fn)(const float co[3], int i, int j, int k, void *user_data),
void *user_data);
/* line/ray triangle */
bool isect_line_segment_tri_v3(const float p1[3],
const float p2[3],

75
source/blender/blenlib/intern/math_geom.c
View File

@ -2297,6 +2297,81 @@ bool isect_plane_plane_v3(const float plane_a[4],
return false;
}
/**
* Intersect all planes, calling `callback_fn` for each point that intersects
* 3 of the planes that isn't outside any of the other planes.
*
* This can be thought of as calculating a convex-hull from an array of planes.
*
* \param eps_coplanar: Epsilon for testing if two planes are aligned (co-planar).
* \param eps_isect: Epsilon for testing of a point is behind any of the planes.
*
* \warning As complexity is a little under `O(N^3)`, this is only suitable for small arrays.
*
* \note This function could be optimized by some spatial structure.
*/
bool isect_planes_v3_fn(
const float planes[][4],
const int planes_len,
const float eps_coplanar,
const float eps_isect,
void (*callback_fn)(const float co[3], int i, int j, int k, void *user_data),
void *user_data)
{
bool found = false;
float n1n2[3], n2n3[3], n3n1[3];
for (int i = 0; i < planes_len; i++) {
const float *n1 = planes[i];
for (int j = i + 1; j < planes_len; j++) {
const float *n2 = planes[j];
cross_v3_v3v3(n1n2, n1, n2);
if (len_squared_v3(n1n2) <= eps_coplanar) {
continue;
}
for (int k = j + 1; k < planes_len; k++) {
const float *n3 = planes[k];
cross_v3_v3v3(n2n3, n2, n3);
if (len_squared_v3(n2n3) <= eps_coplanar) {
continue;
}
cross_v3_v3v3(n3n1, n3, n1);
if (len_squared_v3(n3n1) <= eps_coplanar) {
continue;
}
const float quotient = -dot_v3v3(n1, n2n3);
if (fabsf(quotient) < eps_coplanar) {
continue;
}
const float co_test[3] = {
((n2n3[0] * n1[3]) + (n3n1[0] * n2[3]) + (n1n2[0] * n3[3])) / quotient,
((n2n3[1] * n1[3]) + (n3n1[1] * n2[3]) + (n1n2[1] * n3[3])) / quotient,
((n2n3[2] * n1[3]) + (n3n1[2] * n2[3]) + (n1n2[2] * n3[3])) / quotient,
};
int i_test;
for (i_test = 0; i_test < planes_len; i_test++) {
const float *np_test = planes[i_test];
if (((dot_v3v3(np_test, co_test) + np_test[3]) > eps_isect)) {
/* For low epsilon values the point could intersect it's own plane. */
if (!ELEM(i_test, i, j, k)) {
break;
}
}
}
if (i_test == planes_len) { /* ok */
callback_fn(co_test, i, j, k, user_data);
found = true;
}
}
}
}
return found;
}
/**
* Intersect two triangles.
*

95
source/blender/python/mathutils/mathutils_geometry.c
View File

@ -1062,6 +1062,20 @@ static PyObject *M_Geometry_barycentric_transform(PyObject *UNUSED(self), PyObje
return Vector_CreatePyObject(pt_dst, 3, NULL);
}
struct PointsInPlanes_UserData {
PyObject *py_verts;
char *planes_used;
};
static void points_in_planes_fn(const float co[3], int i, int j, int k, void *user_data_p)
{
struct PointsInPlanes_UserData *user_data = user_data_p;
PyList_APPEND(user_data->py_verts, Vector_CreatePyObject(co, 3, NULL));
user_data->planes_used[i] = true;
user_data->planes_used[j] = true;
user_data->planes_used[k] = true;
}
PyDoc_STRVAR(M_Geometry_points_in_planes_doc,
".. function:: points_in_planes(planes)\n"
"\n"
@ -1073,7 +1087,6 @@ PyDoc_STRVAR(M_Geometry_points_in_planes_doc,
" :return: two lists, once containing the vertices inside the planes, another "
"containing the plane indices used\n"
" :rtype: pair of lists\n");
/* note: this function could be optimized by some spatial structure */
static PyObject *M_Geometry_points_in_planes(PyObject *UNUSED(self), PyObject *args)
{
PyObject *py_planes;
@ -1090,81 +1103,37 @@ static PyObject *M_Geometry_points_in_planes(PyObject *UNUSED(self), PyObject *a
}
/* note, this could be refactored into plain C easy - py bits are noted */
const float eps = 0.0001f;
const uint len = (uint)planes_len;
uint i, j, k, l;
float n1n2[3], n2n3[3], n3n1[3];
float potentialVertex[3];
char *planes_used = PyMem_Malloc(sizeof(char) * len);
struct PointsInPlanes_UserData user_data = {
.py_verts = PyList_New(0),
.planes_used = PyMem_Malloc(sizeof(char) * planes_len),
};
/* python */
PyObject *py_verts = PyList_New(0);
PyObject *py_plane_index = PyList_New(0);
memset(planes_used, 0, sizeof(char) * len);
memset(user_data.planes_used, 0, sizeof(char) * planes_len);
for (i = 0; i < len; i++) {
const float *N1 = planes[i];
for (j = i + 1; j < len; j++) {
const float *N2 = planes[j];
cross_v3_v3v3(n1n2, N1, N2);
if (len_squared_v3(n1n2) > eps) {
for (k = j + 1; k < len; k++) {
const float *N3 = planes[k];
cross_v3_v3v3(n2n3, N2, N3);
if (len_squared_v3(n2n3) > eps) {
cross_v3_v3v3(n3n1, N3, N1);
if (len_squared_v3(n3n1) > eps) {
const float quotient = dot_v3v3(N1, n2n3);
if (fabsf(quotient) > eps) {
/**
* <pre>
* potentialVertex = (
* (n2n3 * N1[3] + n3n1 * N2[3] + n1n2 * N3[3]) *
* (-1.0 / quotient));
* </pre>
*/
const float quotient_ninv = -1.0f / quotient;
potentialVertex[0] = ((n2n3[0] * N1[3]) + (n3n1[0] * N2[3]) + (n1n2[0] * N3[3])) *
quotient_ninv;
potentialVertex[1] = ((n2n3[1] * N1[3]) + (n3n1[1] * N2[3]) + (n1n2[1] * N3[3])) *
quotient_ninv;
potentialVertex[2] = ((n2n3[2] * N1[3]) + (n3n1[2] * N2[3]) + (n1n2[2] * N3[3])) *
quotient_ninv;
for (l = 0; l < len; l++) {
const float *NP = planes[l];
if ((dot_v3v3(NP, potentialVertex) + NP[3]) > 0.000001f) {
break;
}
}
const float eps_coplanar = 1e-4f;
const float eps_isect = 1e-6f;
if (l == len) { /* ok */
/* python */
PyList_APPEND(py_verts, Vector_CreatePyObject(potentialVertex, 3, NULL));
planes_used[i] = planes_used[j] = planes_used[k] = true;
}
}
}
}
}
const bool has_isect = isect_planes_v3_fn(
planes, planes_len, eps_coplanar, eps_isect, points_in_planes_fn, &user_data);
PyMem_Free(planes);
/* Now make user_data list of used planes. */
if (has_isect) {
for (int i = 0; i < planes_len; i++) {
if (user_data.planes_used[i]) {
PyList_APPEND(py_plane_index, PyLong_FromLong(i));
}
}
}
PyMem_Free(planes);
/* now make a list of used planes */
for (i = 0; i < len; i++) {
if (planes_used[i]) {
PyList_APPEND(py_plane_index, PyLong_FromLong(i));
}
}
PyMem_Free(planes_used);
PyMem_Free(user_data.planes_used);
{
PyObject *ret = PyTuple_New(2);
PyTuple_SET_ITEMS(ret, py_verts, py_plane_index);
PyTuple_SET_ITEMS(ret, user_data.py_verts, py_plane_index);
return ret;
}
}