Draw individual face's material and shading correctly in the PBVH.

Previously, the shading and material was set once per PBVHNode when
drawing. This is still the case, but PBVHNodes are now built to
contain only one material and shading mode.

This is done with an extra partitioning step; once the number of
primitives in the node falls below the PBVH leaf limit, it's
primitives are checked for matching materials. If more than one
material or shading mode is present in the node, it is split and
partitioned (partitioned by material rather than 3D location.)

Given a sufficiently 'annoying' input, like a dense mesh with
thousands of materials randomly scattered across it, this could
greatly increase PBVH build time (since nodes might end up containing
a single primitive), but in general this shouldn't come up.

In order to support materials for grids, the CCGDM is building another
grid array (of DMFaceMat structs). This could be used to replace
CCGDM.faceFlag for some small memory savings (TODO).

2 files changed, 37 insertions, 15 deletions

diff --git a/source/blender/gpu/GPU_buffers.h b/source/blender/gpu/GPU_buffers.h
index b89219c2d56..2e260ab8a2e 100644
--- a/source/blender/gpu/GPU_buffers.h
+++ b/source/blender/gpu/GPU_buffers.h
@@ -40,6 +40,7 @@
 #endif
 
 struct DerivedMesh;
+struct DMFlagMat;
 struct DMGridData;
 struct GHash;
 struct DMGridData;
@@ -161,14 +162,15 @@ GPU_Buffers *GPU_build_mesh_buffers(int (*face_vert_indices)[4],
 			struct MFace *mface, int *face_indices, int totface);
 
 void GPU_update_mesh_buffers(GPU_Buffers *buffers, struct MVert *mvert,
-			int *vert_indices, int totvert, int smooth);
+			int *vert_indices, int totvert);
 
 GPU_Buffers *GPU_build_grid_buffers(int totgrid, int gridsize);
 
 void GPU_update_grid_buffers(GPU_Buffers *buffers, struct DMGridData **grids,
-	int *grid_indices, int totgrid, int gridsize, int smooth);
+							 const struct DMFlagMat *grid_flag_mats,
+							 int *grid_indices, int totgrid, int gridsize);
 
-void GPU_draw_buffers(GPU_Buffers *buffers);
+void GPU_draw_buffers(GPU_Buffers *buffers, int (*setMaterial)(int, void *attribs));
 
 void GPU_free_buffers(GPU_Buffers *buffers);
 
diff --git a/source/blender/gpu/intern/gpu_buffers.c b/source/blender/gpu/intern/gpu_buffers.c
index 6e7ec98e65b..cd931450497 100644
--- a/source/blender/gpu/intern/gpu_buffers.c
+++ b/source/blender/gpu/intern/gpu_buffers.c
@@ -1277,16 +1277,16 @@ struct GPU_Buffers {
 
 	/* grid pointers */
 	DMGridData **grids;
+	const DMFlagMat *grid_flag_mats;
 	int *grid_indices;
 	int totgrid;
 	int gridsize;
 
 	unsigned int tot_tri, tot_quad;
-	int smooth;
 };
 
 void GPU_update_mesh_buffers(GPU_Buffers *buffers, MVert *mvert,
-			int *vert_indices, int totvert, int smooth)
+			int *vert_indices, int totvert)
 {
 	VertexBufferFormat *vert_data;
 	int i;
@@ -1319,7 +1319,6 @@ void GPU_update_mesh_buffers(GPU_Buffers *buffers, MVert *mvert,
 	}
 
 	buffers->mvert = mvert;
-	buffers->smooth = smooth;
 }
 
 GPU_Buffers *GPU_build_mesh_buffers(int (*face_vert_indices)[4],
@@ -1390,7 +1389,7 @@ GPU_Buffers *GPU_build_mesh_buffers(int (*face_vert_indices)[4],
 }
 
 void GPU_update_grid_buffers(GPU_Buffers *buffers, DMGridData **grids,
-	int *grid_indices, int totgrid, int gridsize, int smooth)
+	const DMFlagMat *grid_flag_mats, int *grid_indices, int totgrid, int gridsize)
 {
 	DMGridData *vert_data;
 	int i, j, k, totvert;
@@ -1399,6 +1398,8 @@ void GPU_update_grid_buffers(GPU_Buffers *buffers, DMGridData **grids,
 
 	/* Build VBO */
 	if(buffers->vert_buf) {
+		int smooth = grid_flag_mats[grid_indices[0]].flag & ME_SMOOTH;
+
 		glBindBufferARB(GL_ARRAY_BUFFER_ARB, buffers->vert_buf);
 		glBufferDataARB(GL_ARRAY_BUFFER_ARB,
 		                sizeof(DMGridData) * totvert,
@@ -1442,7 +1443,7 @@ void GPU_update_grid_buffers(GPU_Buffers *buffers, DMGridData **grids,
 	buffers->grid_indices = grid_indices;
 	buffers->totgrid = totgrid;
 	buffers->gridsize = gridsize;
-	buffers->smooth = smooth;
+	buffers->grid_flag_mats = grid_flag_mats;
 
 	//printf("node updated %p\n", buffers);
 }
@@ -1524,7 +1525,7 @@ GPU_Buffers *GPU_build_grid_buffers(int totgrid, int gridsize)
 
 #undef FILL_QUAD_BUFFER
 
-static void gpu_draw_buffers_legacy_mesh(GPU_Buffers *buffers)
+static void gpu_draw_buffers_legacy_mesh(GPU_Buffers *buffers, int smooth)
 {
 	const MVert *mvert = buffers->mvert;
 	int i, j;
@@ -1536,7 +1537,7 @@ static void gpu_draw_buffers_legacy_mesh(GPU_Buffers *buffers)
 
 		glBegin((f->v4)? GL_QUADS: GL_TRIANGLES);
 
-		if(buffers->smooth) {
+		if(smooth) {
 			for(j = 0; j < S; j++) {
 				glNormal3sv(mvert[fv[j]].no);
 				glVertex3fv(mvert[fv[j]].co);
@@ -1562,11 +1563,11 @@ static void gpu_draw_buffers_legacy_mesh(GPU_Buffers *buffers)
 	}
 }
 
-static void gpu_draw_buffers_legacy_grids(GPU_Buffers *buffers)
+static void gpu_draw_buffers_legacy_grids(GPU_Buffers *buffers, int smooth)
 {
 	int i, x, y, gridsize = buffers->gridsize;
 
-	if(buffers->smooth) {
+	if(smooth) {
 		for(i = 0; i < buffers->totgrid; ++i) {
 			DMGridData *grid = buffers->grids[buffers->grid_indices[i]];
 
@@ -1612,8 +1613,27 @@ static void gpu_draw_buffers_legacy_grids(GPU_Buffers *buffers)
 	}
 }
 
-void GPU_draw_buffers(GPU_Buffers *buffers)
+void GPU_draw_buffers(GPU_Buffers *buffers, int (*setMaterial)(int, void *attribs))
 {
+	int smooth = 0;
+
+	if(buffers->totface) {
+		const MFace *f = &buffers->mface[buffers->face_indices[0]];
+		if(!setMaterial(f->mat_nr+1, NULL))
+			return;
+
+		smooth = f->flag & ME_SMOOTH;
+		glShadeModel(smooth ? GL_SMOOTH: GL_FLAT);
+	}
+	else if(buffers->totgrid) {
+		const DMFlagMat *f = &buffers->grid_flag_mats[buffers->grid_indices[0]];
+		if(!setMaterial(f->mat_nr+1, NULL))
+			return;
+
+		smooth = f->flag & ME_SMOOTH;
+		glShadeModel(smooth ? GL_SMOOTH: GL_FLAT);
+	}
+
 	if(buffers->vert_buf && buffers->index_buf) {
 		glEnableClientState(GL_VERTEX_ARRAY);
 		glEnableClientState(GL_NORMAL_ARRAY);
@@ -1642,10 +1662,10 @@ void GPU_draw_buffers(GPU_Buffers *buffers)
 	}
 	/* fallbacks if we are out of memory or VBO is disabled */
 	else if(buffers->totface) {
-		gpu_draw_buffers_legacy_mesh(buffers);
+		gpu_draw_buffers_legacy_mesh(buffers, smooth);
 	}
 	else if(buffers->totgrid) {
-		gpu_draw_buffers_legacy_grids(buffers);
+		gpu_draw_buffers_legacy_grids(buffers, smooth);
 	}
 }