[Bf-blender-cvs] [6a1b7fa] master: GPU_pbvh_buffers: Use triangles to render multires.

[Antony Riakiotakis]

Commit: 6a1b7facf97e8196f0c3e38cf2261e48d99d84c5
Author: Antony Riakiotakis
Date:   Sat Mar 29 11:39:25 2014 +0200
https://developer.blender.org/rB6a1b7facf97e8196f0c3e38cf2261e48d99d84c5

GPU_pbvh_buffers: Use triangles to render multires.

A question here might be: why?

The answer is that GPUs will convert this to triangles so we are wasting
memory during conversion of the element buffer to a triangle buffer
anyway.

The second reason is that some modern GPUs are slower rendering GL_QUADS

The third reason is that due to element caching, this should not in
theory be slower (cached elements do not get recalculated on the GPU).

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

M	source/blender/gpu/intern/gpu_buffers.c

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

diff --git a/source/blender/gpu/intern/gpu_buffers.c b/source/blender/gpu/intern/gpu_buffers.c
index fea0390..ad7aeb2 100644
--- a/source/blender/gpu/intern/gpu_buffers.c
+++ b/source/blender/gpu/intern/gpu_buffers.c
@@ -1702,7 +1702,7 @@ void GPU_update_grid_pbvh_buffers(GPU_PBVH_Buffers *buffers, CCGElem **grids,
 				}
 				
 				if (!smooth) {
-					/* for flat shading, recalc normals and set the last vertex of
+					/* for flat shading, recalc normals and set the first vertex of
 					 * each quad in the index buffer to have the flat normal as
 					 * that is what opengl will use */
 					for (j = 0; j < key->grid_size - 1; j++) {
@@ -1721,7 +1721,7 @@ void GPU_update_grid_pbvh_buffers(GPU_PBVH_Buffers *buffers, CCGElem **grids,
 							               CCG_elem_co(key, elems[2]),
 							               CCG_elem_co(key, elems[3]));
 
-							vd = vert_data + (j + 1) * key->grid_size + (k + 1);
+							vd = vert_data + (j + 1) * key->grid_size + k;
 							normal_float_to_short_v3(vd->no, fno);
 
 							if (has_mask) {
@@ -1798,7 +1798,7 @@ static int gpu_count_grid_quads(BLI_bitmap **grid_hidden,
 		int i, j, k;                                                    \
 		                                                                \
 		glBufferDataARB(GL_ELEMENT_ARRAY_BUFFER_ARB,                    \
-		                sizeof(type_) * (tot_quad_) * 4, NULL,          \
+						sizeof(type_) * (tot_quad_) * 6, NULL,          \
 		                GL_STATIC_DRAW_ARB);                            \
 		                                                                \
 		/* Fill the quad buffer */                                      \
@@ -1822,6 +1822,8 @@ static int gpu_count_grid_quads(BLI_bitmap **grid_hidden,
 						*(quad_data++) = offset + j * gridsize + k;     \
 						*(quad_data++) = offset + (j + 1) * gridsize + k; \
 						*(quad_data++) = offset + (j + 1) * gridsize + k + 1; \
+						*(quad_data++) = offset + j * gridsize + k + 1; \
+						*(quad_data++) = offset + (j + 1) * gridsize + k; \
 					}                                                   \
 				}                                                       \
 																		\
@@ -2439,7 +2441,7 @@ void GPU_draw_pbvh_buffers(GPU_PBVH_Buffers *buffers, DMSetMaterial setMaterial,
 				glColorPointer(3, GL_UNSIGNED_BYTE, sizeof(VertexBufferFormat),
 				               offset + offsetof(VertexBufferFormat, color));
 				
-				glDrawElements(GL_QUADS, buffers->tot_quad * 4, buffers->index_type, 0);
+				glDrawElements(GL_TRIANGLES, buffers->tot_quad * 6, buffers->index_type, 0);
 
 				offset += buffers->gridkey.grid_area * sizeof(VertexBufferFormat);
 			}