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Fix T103469: improve uv cylinder projection and uv sphere projection

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Multiple improvements to UV Cylinder and UV Sphere projection including:

 * New option "Pinch" or "Fan" to improve unwrap of faces at the poles.
 * Support for "Polar ZY" option on "View On Equator" and "Align To Object"
 * Better handling of inputs with round-off error.
 * Improved handling of faces touching the unit square border.
 * Improved handling of very wide quads spanning the right hand border.
 * Improved accuracy near to (0, 0).
 * Code cleanup and simplification.

Differential Revision: https://developer.blender.org/D16869
This commit is contained in:
Chris Blackbourn
2023-01-06 17:10:28 +13:00
parent 8d0c98740a
commit 280502e630
3 changed files with 207 additions and 133 deletions
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4
source/blender/blenlib/BLI_math_geom.h
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@@ -1164,8 +1164,8 @@ void box_minmax_bounds_m4(float min[3], float max[3], float boundbox[2][3], floa
/** \name Mapping
* \{ */
void map_to_tube(float *r_u, float *r_v, float x, float y, float z);
void map_to_sphere(float *r_u, float *r_v, float x, float y, float z);
bool map_to_tube(float *r_u, float *r_v, float x, float y, float z);
bool map_to_sphere(float *r_u, float *r_v, float x, float y, float z);
void map_to_plane_v2_v3v3(float r_co[2], const float co[3], const float no[3]);
void map_to_plane_axis_angle_v2_v3v3fl(float r_co[2],
const float co[3],

68
source/blender/blenlib/intern/math_geom.c
View File

@@ -4914,39 +4914,59 @@ void box_minmax_bounds_m4(float min[3], float max[3], float boundbox[2][3], floa
/********************************** Mapping **********************************/
void map_to_tube(float *r_u, float *r_v, const float x, const float y, const float z)
static float snap_coordinate(float u)
{
float len;
*r_v = (z + 1.0f) / 2.0f;
len = sqrtf(x * x + y * y);
if (len > 0.0f) {
*r_u = (1.0f - (atan2f(x / len, y / len) / (float)M_PI)) / 2.0f;
/* Adjust a coordinate value `u` to obtain a value inside the (closed) unit interval.
* i.e. 0.0 <= snap_coordinate(u) <= 1.0.
* Due to round-off errors, it is possible that the value of `u` may be close to the boundary of
* the unit interval, but not exactly on it. In order to handle these cases, `snap_coordinate`
* checks whether `u` is within `epsilon` of the boundary, and if so, it snaps the return value
* to the boundary. */
if (u < 0.0f) {
u += 1.0f; /* Get back into the unit interval. */
}
else {
*r_v = *r_u = 0.0f; /* to avoid un-initialized variables */
BLI_assert(0.0f <= u);
BLI_assert(u <= 1.0f);
const float epsilon = 0.25f / 65536.0f; /* i.e. Quarter of a texel on a 65536 x 65536 texture. */
if (u < epsilon) {
return 0.0f; /* `u` is close to 0, just return 0. */
}
if (1.0f - epsilon < u) {
return 1.0f; /* `u` is close to 1, just return 1. */
}
return u;
}
void map_to_sphere(float *r_u, float *r_v, const float x, const float y, const float z)
bool map_to_tube(float *r_u, float *r_v, const float x, const float y, const float z)
{
float len;
len = sqrtf(x * x + y * y + z * z);
if (len > 0.0f) {
if (UNLIKELY(x == 0.0f && y == 0.0f)) {
*r_u = 0.0f; /* Otherwise domain error. */
}
else {
*r_u = (1.0f - atan2f(x, y) / (float)M_PI) / 2.0f;
}
*r_v = 1.0f - saacos(z / len) / (float)M_PI;
bool regular = true;
if (x * x + y * y < 1e-6f * 1e-6f) {
regular = false; /* We're too close to the cylinder's axis. */
*r_u = 0.5f;
}
else {
*r_v = *r_u = 0.0f; /* to avoid un-initialized variables */
/* The "Regular" case, just compute the coordinate. */
*r_u = snap_coordinate(atan2f(x, -y) / (float)(2.0f * M_PI));
}
*r_v = (z + 1.0f) / 2.0f;
return regular;
}
bool map_to_sphere(float *r_u, float *r_v, const float x, const float y, const float z)
{
bool regular = true;
const float epsilon = 0.25f / 65536.0f; /* i.e. Quarter of a texel on a 65536 x 65536 texture. */
const float len_xy = sqrtf(x * x + y * y);
if (len_xy <= fabsf(z) * epsilon) {
regular = false; /* We're on the line that runs through the north and south poles. */
*r_u = 0.5f;
}
else {
/* The "Regular" case, just compute the coordinate. */
*r_u = snap_coordinate(atan2f(x, -y) / (float)(2.0f * M_PI));
}
*r_v = snap_coordinate(atan2f(len_xy, -z) / (float)M_PI);
return regular;
}
void map_to_plane_v2_v3v3(float r_co[2], const float co[3], const float no[3])

268
source/blender/editors/uvedit/uvedit_unwrap_ops.c
View File

@@ -1318,6 +1318,9 @@ void ED_uvedit_live_unwrap_end(short cancel)
#define POLAR_ZX 0
#define POLAR_ZY 1
#define PINCH 0
#define FAN 1
static void uv_map_transform_calc_bounds(BMEditMesh *em, float r_min[3], float r_max[3])
{
BMFace *efa;
@@ -1457,50 +1460,37 @@ static void uv_map_rotation_matrix_ex(float result[4][4],
mul_m4_series(result, rotup, rotside, viewmatrix, rotobj);
}
static void uv_map_rotation_matrix(float result[4][4],
RegionView3D *rv3d,
Object *ob,
float upangledeg,
float sideangledeg,
float radius)
static void uv_map_transform(bContext *C, wmOperator *op, float rotmat[3][3])
{
const float offset[4] = {0};
uv_map_rotation_matrix_ex(result, rv3d, ob, upangledeg, sideangledeg, radius, offset);
}
static void uv_map_transform(bContext *C, wmOperator *op, float rotmat[4][4])
{
/* context checks are messy here, making it work in both 3d view and uv editor */
Object *obedit = CTX_data_edit_object(C);
RegionView3D *rv3d = CTX_wm_region_view3d(C);
/* common operator properties */
int align = RNA_enum_get(op->ptr, "align");
int direction = RNA_enum_get(op->ptr, "direction");
float radius = RNA_struct_find_property(op->ptr, "radius") ? RNA_float_get(op->ptr, "radius") :
1.0f;
float upangledeg, sideangledeg;
if (direction == VIEW_ON_EQUATOR) {
upangledeg = 90.0f;
sideangledeg = 0.0f;
}
else {
upangledeg = 0.0f;
if (align == POLAR_ZY) {
sideangledeg = 0.0f;
}
else {
sideangledeg = 90.0f;
}
}
const int align = RNA_enum_get(op->ptr, "align");
const int direction = RNA_enum_get(op->ptr, "direction");
const float radius = RNA_struct_find_property(op->ptr, "radius") ?
RNA_float_get(op->ptr, "radius") :
1.0f;
/* be compatible to the "old" sphere/cylinder mode */
/* Be compatible to the "old" sphere/cylinder mode. */
if (direction == ALIGN_TO_OBJECT) {
unit_m4(rotmat);
}
else {
uv_map_rotation_matrix(rotmat, rv3d, obedit, upangledeg, sideangledeg, radius);
unit_m3(rotmat);
if (align == POLAR_ZY) {
rotmat[0][0] = 0.0f;
rotmat[0][1] = 1.0f;
rotmat[1][0] = -1.0f;
rotmat[1][1] = 0.0f;
}
return;
}
const float up_angle_deg = (direction == VIEW_ON_EQUATOR) ? 90.0f : 0.0f;
const float side_angle_deg = (align == POLAR_ZY) == (direction == VIEW_ON_EQUATOR) ? 90.0f :
0.0f;
const float offset[4] = {0};
float rotmat4[4][4];
uv_map_rotation_matrix_ex(rotmat4, rv3d, obedit, up_angle_deg, side_angle_deg, radius, offset);
copy_m3_m4(rotmat, rotmat4);
}
static void uv_transform_properties(wmOperatorType *ot, int radius)
@@ -1521,6 +1511,12 @@ static void uv_transform_properties(wmOperatorType *ot, int radius)
{0, NULL, 0, NULL, NULL},
};
static const EnumPropertyItem pole_items[] = {
{PINCH, "PINCH", 0, "Pinch", "UVs are pinched at the poles"},
{FAN, "FAN", 0, "Fan", "UVs are fanned at the poles"},
{0, NULL, 0, NULL, NULL},
};
RNA_def_enum(ot->srna,
"direction",
direction_items,
@@ -1530,9 +1526,10 @@ static void uv_transform_properties(wmOperatorType *ot, int radius)
RNA_def_enum(ot->srna,
"align",
align_items,
VIEW_ON_EQUATOR,
POLAR_ZX,
"Align",
"How to determine rotation around the pole");
RNA_def_enum(ot->srna, "pole", pole_items, PINCH, "Pole", "How to handle faces at the poles");
if (radius) {
RNA_def_float(ot->srna,
"radius",
@@ -2730,55 +2727,120 @@ void UV_OT_reset(wmOperatorType *ot)
/** \name Sphere UV Project Operator
* \{ */
static void uv_sphere_project(float target[2],
const float source[3],
const float center[3],
const float rotmat[4][4])
static void uv_map_mirror(BMFace *efa,
const bool *regular,
const bool fan,
const int cd_loop_uv_offset)
{
float pv[3];
/* A heuristic to improve alignment of faces near the seam.
* In simple terms, we're looking for faces which span more
* than 0.5 units in the *u* coordinate.
* If we find such a face, we try and improve the unwrapping
* by adding (1.0, 0.0) onto some of the face's UVs.
sub_v3_v3v3(pv, source, center);
mul_m4_v3(rotmat, pv);
* Note that this is only a heuristic. The property we're
* attempting to maintain is that the winding of the face
* in UV space corresponds with the handedness of the face
* in 3D space w.r.t to the unwrapping. Even for triangles,
* that property is somewhat complicated to evaluate.
*/
map_to_sphere(&target[0], &target[1], pv[0], pv[1], pv[2]);
/* split line is always zero */
if (target[0] >= 1.0f) {
target[0] -= 1.0f;
}
}
static void uv_map_mirror(BMEditMesh *em, BMFace *efa)
{
float right_u = -1.0e30f;
BMLoop *l;
BMIter liter;
MLoopUV *luv;
float **uvs = BLI_array_alloca(uvs, efa->len);
float dx;
int i, mi;
const int cd_loop_uv_offset = CustomData_get_offset(&em->bm->ldata, CD_MLOOPUV);
BM_ITER_ELEM_INDEX (l, &liter, efa, BM_LOOPS_OF_FACE, i) {
luv = BM_ELEM_CD_GET_VOID_P(l, cd_loop_uv_offset);
uvs[i] = luv->uv;
int j;
BM_ITER_ELEM_INDEX (l, &liter, efa, BM_LOOPS_OF_FACE, j) {
MLoopUV *luv = BM_ELEM_CD_GET_VOID_P(l, cd_loop_uv_offset);
uvs[j] = luv->uv;
if (luv->uv[0] >= 1.0f) {
luv->uv[0] -= 1.0f;
}
right_u = max_ff(right_u, luv->uv[0]);
}
mi = 0;
for (i = 1; i < efa->len; i++) {
if (uvs[i][0] > uvs[mi][0]) {
mi = i;
float left_u = 1.0e30f;
BM_ITER_ELEM (l, &liter, efa, BM_LOOPS_OF_FACE) {
MLoopUV *luv = BM_ELEM_CD_GET_VOID_P(l, cd_loop_uv_offset);
if (right_u <= luv->uv[0] + 0.5f) {
left_u = min_ff(left_u, luv->uv[0]);
}
}
for (i = 0; i < efa->len; i++) {
if (i != mi) {
dx = uvs[mi][0] - uvs[i][0];
if (dx > 0.5f) {
uvs[i][0] += 1.0f;
BM_ITER_ELEM (l, &liter, efa, BM_LOOPS_OF_FACE) {
MLoopUV *luv = BM_ELEM_CD_GET_VOID_P(l, cd_loop_uv_offset);
if (luv->uv[0] + 0.5f < right_u) {
if (2 * luv->uv[0] + 1.0f < left_u + right_u) {
luv->uv[0] += 1.0f;
}
}
}
if (!fan) {
return;
}
/* Another heuristic, this time, we attempt to "fan"
* the UVs of faces which pass through one of the poles
* of the unwrapping. */
/* Need to recompute min and max. */
float minmax_u[2] = {1.0e30f, -1.0e30f};
int pole_count = 0;
for (int i = 0; i < efa->len; i++) {
if (regular[i]) {
minmax_u[0] = min_ff(minmax_u[0], uvs[i][0]);
minmax_u[1] = max_ff(minmax_u[1], uvs[i][0]);
}
else {
pole_count++;
}
}
if (pole_count == 0 || pole_count == efa->len) {
return;
}
for (int i = 0; i < efa->len; i++) {
if (regular[i]) {
continue;
}
float u = 0.0f;
float sum = 0.0f;
const int i_plus = (i + 1) % efa->len;
const int i_minus = (i + efa->len - 1) % efa->len;
if (regular[i_plus]) {
u += uvs[i_plus][0];
sum += 1.0f;
}
if (regular[i_minus]) {
u += uvs[i_minus][0];
sum += 1.0f;
}
if (sum == 0) {
u += minmax_u[0] + minmax_u[1];
sum += 2.0f;
}
uvs[i][0] = u / sum;
}
}
static void uv_sphere_project(BMFace *efa,
const float center[3],
const float rotmat[3][3],
const bool fan,
const int cd_loop_uv_offset)
{
bool *regular = BLI_array_alloca(regular, efa->len);
int i;
BMLoop *l;
BMIter iter;
BM_ITER_ELEM_INDEX (l, &iter, efa, BM_LOOPS_OF_FACE, i) {
MLoopUV *luv = BM_ELEM_CD_GET_VOID_P(l, cd_loop_uv_offset);
float pv[3];
sub_v3_v3v3(pv, l->v->co, center);
mul_m3_v3(rotmat, pv);
regular[i] = map_to_sphere(&luv->uv[0], &luv->uv[1], pv[0], pv[1], pv[2]);
}
uv_map_mirror(efa, regular, fan, cd_loop_uv_offset);
}
static int sphere_project_exec(bContext *C, wmOperator *op)
@@ -2800,9 +2862,7 @@ static int sphere_project_exec(bContext *C, wmOperator *op)
Object *obedit = objects[ob_index];
BMEditMesh *em = BKE_editmesh_from_object(obedit);
BMFace *efa;
BMLoop *l;
BMIter iter, liter;
MLoopUV *luv;
BMIter iter;
if (em->bm->totfacesel == 0) {
continue;
@@ -2814,11 +2874,13 @@ static int sphere_project_exec(bContext *C, wmOperator *op)
}
const int cd_loop_uv_offset = CustomData_get_offset(&em->bm->ldata, CD_MLOOPUV);
float center[3], rotmat[4][4];
float center[3], rotmat[3][3];
uv_map_transform(C, op, rotmat);
uv_map_transform_center(scene, v3d, obedit, em, center, NULL);
const bool fan = RNA_enum_get(op->ptr, "pole");
BM_ITER_MESH (efa, &iter, em->bm, BM_FACES_OF_MESH) {
if (!BM_elem_flag_test(efa, BM_ELEM_SELECT)) {
continue;
@@ -2831,13 +2893,7 @@ static int sphere_project_exec(bContext *C, wmOperator *op)
}
}
BM_ITER_ELEM (l, &liter, efa, BM_LOOPS_OF_FACE) {
luv = BM_ELEM_CD_GET_VOID_P(l, cd_loop_uv_offset);
uv_sphere_project(luv->uv, l->v->co, center, rotmat);
}
uv_map_mirror(em, efa);
uv_sphere_project(efa, center, rotmat, fan, cd_loop_uv_offset);
}
const bool per_face_aspect = true;
@@ -2875,22 +2931,25 @@ void UV_OT_sphere_project(wmOperatorType *ot)
/** \name Cylinder UV Project Operator
* \{ */
static void uv_cylinder_project(float target[2],
const float source[3],
static void uv_cylinder_project(BMFace *efa,
const float center[3],
const float rotmat[4][4])
const float rotmat[3][3],
const bool fan,
const int cd_loop_uv_offset)
{
float pv[3];
sub_v3_v3v3(pv, source, center);
mul_m4_v3(rotmat, pv);
map_to_tube(&target[0], &target[1], pv[0], pv[1], pv[2]);
/* split line is always zero */
if (target[0] >= 1.0f) {
target[0] -= 1.0f;
bool *regular = BLI_array_alloca(regular, efa->len);
int i;
BMLoop *l;
BMIter iter;
BM_ITER_ELEM_INDEX (l, &iter, efa, BM_LOOPS_OF_FACE, i) {
MLoopUV *luv = BM_ELEM_CD_GET_VOID_P(l, cd_loop_uv_offset);
float pv[3];
sub_v3_v3v3(pv, l->v->co, center);
mul_m3_v3(rotmat, pv);
regular[i] = map_to_tube(&luv->uv[0], &luv->uv[1], pv[0], pv[1], pv[2]);
}
uv_map_mirror(efa, regular, fan, cd_loop_uv_offset);
}
static int cylinder_project_exec(bContext *C, wmOperator *op)
@@ -2912,9 +2971,7 @@ static int cylinder_project_exec(bContext *C, wmOperator *op)
Object *obedit = objects[ob_index];
BMEditMesh *em = BKE_editmesh_from_object(obedit);
BMFace *efa;
BMLoop *l;
BMIter iter, liter;
MLoopUV *luv;
BMIter iter;
if (em->bm->totfacesel == 0) {
continue;
@@ -2926,11 +2983,13 @@ static int cylinder_project_exec(bContext *C, wmOperator *op)
}
const int cd_loop_uv_offset = CustomData_get_offset(&em->bm->ldata, CD_MLOOPUV);
float center[3], rotmat[4][4];
float center[3], rotmat[3][3];
uv_map_transform(C, op, rotmat);
uv_map_transform_center(scene, v3d, obedit, em, center, NULL);
const bool fan = RNA_enum_get(op->ptr, "pole");
BM_ITER_MESH (efa, &iter, em->bm, BM_FACES_OF_MESH) {
if (!BM_elem_flag_test(efa, BM_ELEM_SELECT)) {
continue;
@@ -2941,12 +3000,7 @@ static int cylinder_project_exec(bContext *C, wmOperator *op)
continue;
}
BM_ITER_ELEM (l, &liter, efa, BM_LOOPS_OF_FACE) {
luv = BM_ELEM_CD_GET_VOID_P(l, cd_loop_uv_offset);
uv_cylinder_project(luv->uv, l->v->co, center, rotmat);
}
uv_map_mirror(em, efa);
uv_cylinder_project(efa, center, rotmat, fan, cd_loop_uv_offset);
}
const bool per_face_aspect = true;