[Bf-blender-cvs] [fb053ae2e56] master: Multires: Correct averaging

Sergey Sharybin noreply at git.blender.org
Fri Jan 18 12:30:35 CET 2019


Commit: fb053ae2e5676e61b7b10d5ee730ee24fd13fa46
Author: Sergey Sharybin
Date:   Thu Jan 17 18:09:47 2019 +0100
Branches: master
https://developer.blender.org/rBfb053ae2e5676e61b7b10d5ee730ee24fd13fa46

Multires: Correct averaging

Before that only normal component was averaged, which is not
really correct.

Unfortunately, the new code is somewhat slower due to more
involved math to deal properly with non-quad faces, but the
plan is to move averaging from runtime to edit time, This
means, that mdisps will always be continuous around the edges
and no averaging on every frame change of animated character
will be needed.

===================================================================

M	source/blender/blenkernel/BKE_subdiv.h
M	source/blender/blenkernel/intern/multires_reshape.c
M	source/blender/blenkernel/intern/subdiv_displacement_multires.c
M	source/blender/blenkernel/intern/subdiv_inline.h

===================================================================

diff --git a/source/blender/blenkernel/BKE_subdiv.h b/source/blender/blenkernel/BKE_subdiv.h
index 28efb159b09..73470b15c61 100644
--- a/source/blender/blenkernel/BKE_subdiv.h
+++ b/source/blender/blenkernel/BKE_subdiv.h
@@ -246,6 +246,11 @@ BLI_INLINE void BKE_subdiv_ptex_face_uv_to_grid_uv(
         const float ptex_u, const float ptex_v,
         float *r_grid_u, float *r_grid_v);
 
+/* Onverse of above. */
+BLI_INLINE void BKE_subdiv_grid_uv_to_ptex_face_uv(
+        const float grid_u, const float grid_v,
+        float *r_ptex_u, float *r_ptex_v);
+
 /* For a given subdivision level (which is NOT refinement level) get size of
  * CCG grid (number of grid points on a side).
  */
diff --git a/source/blender/blenkernel/intern/multires_reshape.c b/source/blender/blenkernel/intern/multires_reshape.c
index aea626b09fb..0c4edf4de9d 100644
--- a/source/blender/blenkernel/intern/multires_reshape.c
+++ b/source/blender/blenkernel/intern/multires_reshape.c
@@ -148,7 +148,7 @@ static void multires_reshape_ensure_grids(Mesh *mesh, const int grid_level)
 
 /* Convert normalized coordinate within a grid to a normalized coordinate within
  * a ptex face. */
-static void multires_reshape_grid_coord_to_ptex(
+static void multires_reshape_corner_coord_to_ptex(
         const MPoly *coarse_poly,
         const int corner, const float corner_u, const float corner_v,
         float *r_ptex_face_u, float *r_ptex_face_v)
@@ -176,8 +176,9 @@ static void multires_reshape_sample_surface(
         float r_P[3], float r_dPdu[3], float r_dPdv[3])
 {
 	float ptex_face_u, ptex_face_v;
-	multires_reshape_grid_coord_to_ptex(coarse_poly, corner, corner_u, corner_v,
-	                                    &ptex_face_u, &ptex_face_v);
+	multires_reshape_corner_coord_to_ptex(
+	        coarse_poly, corner, corner_u, corner_v,
+	        &ptex_face_u, &ptex_face_v);
 	BKE_subdiv_eval_limit_point_and_derivatives(
 	        subdiv,
 	        ptex_face_index, ptex_face_u, ptex_face_v,
diff --git a/source/blender/blenkernel/intern/subdiv_displacement_multires.c b/source/blender/blenkernel/intern/subdiv_displacement_multires.c
index d6865e1826f..5727c8d487b 100644
--- a/source/blender/blenkernel/intern/subdiv_displacement_multires.c
+++ b/source/blender/blenkernel/intern/subdiv_displacement_multires.c
@@ -39,6 +39,7 @@
 
 #include "BKE_customdata.h"
 #include "BKE_multires.h"
+#include "BKE_subdiv_eval.h"
 
 #include "MEM_guardedalloc.h"
 
@@ -48,6 +49,7 @@ typedef struct PolyCornerIndex {
 } PolyCornerIndex;
 
 typedef struct MultiresDisplacementData {
+	Subdiv *subdiv;
 	int grid_size;
 	/* Mesh is used to read external displacement. */
 	Mesh *mesh;
@@ -59,6 +61,9 @@ typedef struct MultiresDisplacementData {
 	 * NOTE: For quad polygon this is an index of first corner only, since
 	 * there we only have one ptex. */
 	PolyCornerIndex *ptex_poly_corner;
+	/* Indexed by coarse face index, returns first ptex face index corresponding
+	 * to that coarse face. */
+	int *face_ptex_offset;
 	/* Sanity check, is used in debug builds.
 	 * Controls that initialize() was called prior to eval_displacement(). */
 	bool is_initialized;
@@ -98,9 +103,10 @@ static int displacement_get_grid_and_coord(
 	return corner;
 }
 
-static const MDisps *displacement_get_next_grid(
+static const MDisps *displacement_get_other_grid(
         SubdivDisplacement *displacement,
-        const int ptex_face_index, const int corner)
+        const int ptex_face_index, const int corner,
+        const int corner_delta)
 {
 	MultiresDisplacementData *data = displacement->user_data;
 	const PolyCornerIndex *poly_corner =
@@ -108,25 +114,11 @@ static const MDisps *displacement_get_next_grid(
 	const MPoly *poly = &data->mpoly[poly_corner->poly_index];
 	const int effective_corner = (poly->totloop == 4) ? corner
 	                                                  : poly_corner->corner;
-	const int next_corner = (effective_corner + 1) % poly->totloop;
+	const int next_corner =
+	        (effective_corner + corner_delta + poly->totloop) % poly->totloop;
 	return &data->mdisps[poly->loopstart + next_corner];
 }
 
-static const MDisps *displacement_get_prev_grid(
-        SubdivDisplacement *displacement,
-        const int ptex_face_index, const int corner)
-{
-	MultiresDisplacementData *data = displacement->user_data;
-	const PolyCornerIndex *poly_corner =
-	        &data->ptex_poly_corner[ptex_face_index];
-	const MPoly *poly = &data->mpoly[poly_corner->poly_index];
-	const int effective_corner = (poly->totloop == 4) ? corner
-	                                                  : poly_corner->corner;
-	const int prev_corner =
-	        (effective_corner - 1 + poly->totloop) % poly->totloop;
-	return &data->mdisps[poly->loopstart + prev_corner];
-}
-
 BLI_INLINE eAverageWith read_displacement_grid(
         const MDisps *displacement_grid,
         const int grid_size,
@@ -152,95 +144,212 @@ BLI_INLINE eAverageWith read_displacement_grid(
 	return AVERAGE_WITH_NONE;
 }
 
-static void average_with_all(
-        SubdivDisplacement *displacement,
+static void average_convert_grid_coord_to_ptex(
+        const MPoly *poly,
+        const int corner, const float grid_u, const float grid_v,
+        float *r_ptex_face_u, float *r_ptex_face_v)
+{
+	if (poly->totloop == 4) {
+		BKE_subdiv_rotate_grid_to_quad(corner, grid_u, grid_v,
+		                               r_ptex_face_u, r_ptex_face_v);
+	}
+	else {
+		BKE_subdiv_grid_uv_to_ptex_face_uv(
+		        grid_u, grid_v,
+		        r_ptex_face_u, r_ptex_face_v);
+	}
+}
+
+static void average_construct_tangent_matrix(
+        Subdiv *subdiv,
+        const MPoly *poly,
         const int ptex_face_index, const int corner,
-        const float UNUSED(grid_u), const float UNUSED(grid_v),
+        const float u, const float v,
+        float r_tangent_matrix[3][3])
+{
+	const bool is_quad = (poly->totloop == 4);
+	const int quad_corner = is_quad ? corner : 0;
+	float dummy_P[3], dPdu[3], dPdv[3];
+	BKE_subdiv_eval_limit_point_and_derivatives(
+	        subdiv, ptex_face_index, u, v, dummy_P, dPdu, dPdv);
+	BKE_multires_construct_tangent_matrix(
+	        r_tangent_matrix, dPdu, dPdv, quad_corner);
+}
+
+static void average_read_displacement_tangent(
+        MultiresDisplacementData *data,
+        const MDisps *other_displacement_grid,
+        const float grid_u, const float grid_v,
         float r_tangent_D[3])
+{
+	read_displacement_grid(
+	        other_displacement_grid, data->grid_size, grid_u, grid_v,
+	        r_tangent_D);
+}
+
+static void average_read_displacement_object(
+        MultiresDisplacementData *data,
+        const MDisps *displacement_grid,
+        const float grid_u, const float grid_v,
+        const int ptex_face_index,
+        const int corner_index,
+        float r_D[3])
+{
+	const PolyCornerIndex *poly_corner =
+	        &data->ptex_poly_corner[ptex_face_index];
+	const MPoly *poly = &data->mpoly[poly_corner->poly_index];
+	/* Get (u, v) coordinate within the other ptex face which corresponds to
+	 * the grid coordinates. */
+	float u, v;
+	average_convert_grid_coord_to_ptex(
+	        poly, corner_index, grid_u, grid_v, &u, &v);
+	/* Construct tangent matrix which corresponds to partial derivatives
+	 * calculated for the other ptex face. */
+	float tangent_matrix[3][3];
+	average_construct_tangent_matrix(
+	        data->subdiv, poly,
+	        ptex_face_index, corner_index, u, v,
+	        tangent_matrix);
+	/* Read displacement from other grid in a tangent space. */
+	float tangent_D[3];
+	average_read_displacement_tangent(
+	        data, displacement_grid, grid_u, grid_v, tangent_D);
+	/* Convert displacement to object space. */
+	mul_v3_m3v3(r_D, tangent_matrix, tangent_D);
+}
+
+static void average_get_other_ptex_and_corner(
+        MultiresDisplacementData *data,
+        const int ptex_face_index, const int corner,
+        const int corner_delta,
+        int *r_other_ptex_face_index, int *r_other_corner_index)
+{
+	const PolyCornerIndex *poly_corner =
+	        &data->ptex_poly_corner[ptex_face_index];
+	const MPoly *poly = &data->mpoly[poly_corner->poly_index];
+	const int num_corners = poly->totloop;
+	const bool is_quad = (num_corners == 4);
+	const int poly_index = poly - data->mpoly;
+	const int start_ptex_face_index = data->face_ptex_offset[poly_index];
+	*r_other_corner_index =
+	        (corner + corner_delta + num_corners) % num_corners;
+	*r_other_ptex_face_index =
+	        is_quad ? start_ptex_face_index
+	                : start_ptex_face_index + *r_other_corner_index;
+}
+
+/* NOTE: Grid coordinates are relatiev to the other grid already. */
+static void average_with_other(SubdivDisplacement *displacement,
+                              const int ptex_face_index, const int corner,
+                              const float grid_u, const float grid_v,
+                              const int corner_delta,
+                              float r_D[3])
+{
+	MultiresDisplacementData *data = displacement->user_data;
+	const MDisps *other_displacement_grid = displacement_get_other_grid(
+	         displacement, ptex_face_index, corner, corner_delta);
+	int other_ptex_face_index, other_corner_index;
+	average_get_other_ptex_and_corner(
+	        data, ptex_face_index, corner, corner_delta,
+	        &other_ptex_face_index, &other_corner_index);
+	/* Get displacement in object space. */
+	float other_D[3];
+	average_read_displacement_object(
+	        data,
+	        other_displacement_grid, grid_u, grid_v,
+	        other_ptex_face_index, other_corner_index,
+	        other_D);
+	/* Average result with the other displacement vector. */
+	add_v3_v3(r_D, other_D);
+	mul_v3_fl(r_D, 0.5f);
+}
+
+
+static void average_with_all(SubdivDisplacement *displacement,
+                             const int ptex_face_index, const int corner,
+                             const float UNUSED(grid_u),
+                             const float UNUSED(grid_v),
+                             float r_D[3])
 {
 	MultiresDisplacementData *data = displacement->user_data;
 	const PolyCornerIndex *poly_corner =
 	        &data->ptex_poly_corner[ptex_face_index];
 	const MPoly *poly = &data->mpoly[poly_corner->poly_index];
-	for (int current_corner = 0;

@@ Diff output truncated at 10240 characters. @@



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