Add material storage to derivedmesh.

The variables are considered invalid unless DM_update_materials is
called prior to use. Only use case currently is
mesh drawing. This helps with excessive allocation on the stack during
GPUObject creation, but may help elsewhere in the future as well.

1 files changed, 16 insertions, 7 deletions

diff --git a/source/blender/gpu/intern/gpu_buffers.c b/source/blender/gpu/intern/gpu_buffers.c
index 22cfc712df3..dc986badb16 100644
--- a/source/blender/gpu/intern/gpu_buffers.c
+++ b/source/blender/gpu/intern/gpu_buffers.c
@@ -422,11 +422,13 @@ static void gpu_drawobject_add_triangle(GPUDrawObject *gdo,
 
 /* for each vertex, build a list of points related to it; these lists
  * are stored in an array sized to the number of vertices */
-static void gpu_drawobject_init_vert_points(GPUDrawObject *gdo, MFace *f, int totface)
+static void gpu_drawobject_init_vert_points(GPUDrawObject *gdo, MFace *f, int totface, int totmat)
 {
 	GPUBufferMaterial *mat;
-	int i, mat_orig_to_new[MAX_MATERIALS];
+	int i, *mat_orig_to_new;
 
+	mat_orig_to_new = MEM_callocN(sizeof(*mat_orig_to_new) * totmat,
+	                                             "GPUDrawObject.mat_orig_to_new");
 	/* allocate the array and space for links */
 	gdo->vert_points = MEM_callocN(sizeof(GPUVertPointLink) * gdo->totvert,
 	                               "GPUDrawObject.vert_points");
@@ -466,6 +468,8 @@ static void gpu_drawobject_init_vert_points(GPUDrawObject *gdo, MFace *f, int to
 			gdo->tot_loose_point++;
 		}
 	}
+
+	MEM_freeN(mat_orig_to_new);
 }
 
 /* see GPUDrawObject's structure definition for a description of the
@@ -474,15 +478,19 @@ GPUDrawObject *GPU_drawobject_new(DerivedMesh *dm)
 {
 	GPUDrawObject *gdo;
 	MFace *mface;
-	int points_per_mat[MAX_MATERIALS];
+	int totmat = dm->totmat;
+	int *points_per_mat;
 	int i, curmat, curpoint, totface;
 
+	/* object contains at least one material (default included) so zero means uninitialized dm */
+	BLI_assert(totmat != 0);
+
 	mface = dm->getTessFaceArray(dm);
 	totface = dm->getNumTessFaces(dm);
 
 	/* get the number of points used by each material, treating
 	 * each quad as two triangles */
-	memset(points_per_mat, 0, sizeof(int) * MAX_MATERIALS);
+	points_per_mat = MEM_callocN(sizeof(*points_per_mat) * totmat, "GPU_drawobject_new.mat_orig_to_new");
 	for (i = 0; i < totface; i++)
 		points_per_mat[mface[i].mat_nr] += mface[i].v4 ? 6 : 3;
 
@@ -492,7 +500,7 @@ GPUDrawObject *GPU_drawobject_new(DerivedMesh *dm)
 	gdo->totedge = dm->getNumEdges(dm);
 
 	/* count the number of materials used by this DerivedMesh */
-	for (i = 0; i < MAX_MATERIALS; i++) {
+	for (i = 0; i < totmat; i++) {
 		if (points_per_mat[i] > 0)
 			gdo->totmaterial++;
 	}
@@ -502,7 +510,7 @@ GPUDrawObject *GPU_drawobject_new(DerivedMesh *dm)
 	                             "GPUDrawObject.materials");
 
 	/* initialize the materials array */
-	for (i = 0, curmat = 0, curpoint = 0; i < MAX_MATERIALS; i++) {
+	for (i = 0, curmat = 0, curpoint = 0; i < totmat; i++) {
 		if (points_per_mat[i] > 0) {
 			gdo->materials[curmat].start = curpoint;
 			gdo->materials[curmat].totpoint = 0;
@@ -519,7 +527,8 @@ GPUDrawObject *GPU_drawobject_new(DerivedMesh *dm)
 	gdo->triangle_to_mface = MEM_mallocN(sizeof(int) * (gdo->tot_triangle_point / 3),
 	                                     "GPUDrawObject.triangle_to_mface");
 
-	gpu_drawobject_init_vert_points(gdo, mface, totface);
+	gpu_drawobject_init_vert_points(gdo, mface, totface, totmat);
+	MEM_freeN(points_per_mat);
 
 	return gdo;
 }