DRW/Eevee: Add correct support for Orco

Until now, Orcos were computed by the gpu (GLSL) and were not taking into
account the modifier stack (breaking orco for deformed mesh).

Now Orco is now computed on CPU but only if a modifier stack is present.

Tagging that an ORCO layer is present is done via a 4th component, which is
a waste of memory/bandwidth. Best would be to do the same as auto attrib
color space and save a bool uniform somewhere but for now it's too
disruptive.

1 files changed, 60 insertions, 8 deletions

diff --git a/source/blender/draw/intern/draw_cache_impl_mesh.c b/source/blender/draw/intern/draw_cache_impl_mesh.c
index a50951c98d8..bc5c4f8aeb0 100644
--- a/source/blender/draw/intern/draw_cache_impl_mesh.c
+++ b/source/blender/draw/intern/draw_cache_impl_mesh.c
@@ -1822,6 +1822,7 @@ typedef struct MeshBatchCache {
 		GPUVertBuf *loop_uv_tan;
 		GPUVertBuf *loop_vcol;
 		GPUVertBuf *loop_edge_fac;
+		GPUVertBuf *loop_orco;
 	} ordered;
 
 	/* Edit Mesh Data:
@@ -2033,8 +2034,7 @@ static void mesh_batch_cache_discard_shaded_tri(MeshBatchCache *cache)
 	GPU_VERTBUF_DISCARD_SAFE(cache->ordered.loop_pos_nor);
 	GPU_VERTBUF_DISCARD_SAFE(cache->ordered.loop_uv_tan);
 	GPU_VERTBUF_DISCARD_SAFE(cache->ordered.loop_vcol);
-	/* TODO */
-	// GPU_VERTBUF_DISCARD_SAFE(cache->ordered.loop_orco);
+	GPU_VERTBUF_DISCARD_SAFE(cache->ordered.loop_orco);
 
 	if (cache->surf_per_mat_tris) {
 		for (int i = 0; i < cache->mat_len; i++) {
@@ -2966,6 +2966,46 @@ static void mesh_create_loop_pos_and_nor(MeshRenderData *rdata, GPUVertBuf *vbo)
 	}
 }
 
+static void mesh_create_loop_orco(MeshRenderData *rdata, GPUVertBuf *vbo)
+{
+	const uint loops_len = mesh_render_data_loops_len_get(rdata);
+
+	/* initialize vertex format */
+	GPUVertFormat format = { 0 };
+	GPUVertBufRaw vbo_step;
+
+	/* FIXME(fclem): We use the last component as a way to differentiate from generic vertex attribs.
+	 * This is a substential waste of Vram and should be done another way. Unfortunately,
+	 * at the time of writting, I did not found any other "non disruptive" alternative. */
+	uint attr_id = GPU_vertformat_attr_add(&format, "orco", GPU_COMP_F32, 4, GPU_FETCH_FLOAT);
+
+	GPU_vertbuf_init_with_format(vbo, &format);
+	GPU_vertbuf_data_alloc(vbo, loops_len);
+	GPU_vertbuf_attr_get_raw_data(vbo, attr_id, &vbo_step);
+
+	if (rdata->edit_bmesh) {
+		BMesh *bm = rdata->edit_bmesh->bm;
+		BMIter iter_efa, iter_loop;
+		BMFace *efa;
+		BMLoop *loop;
+
+		BM_ITER_MESH (efa, &iter_efa, bm, BM_FACES_OF_MESH) {
+			BM_ITER_ELEM (loop, &iter_loop, efa, BM_LOOPS_OF_FACE) {
+				float *data = (float *)GPU_vertbuf_raw_step(&vbo_step);
+				copy_v3_v3(data, rdata->orco[BM_elem_index_get(loop->v)]);
+				data[3] = 0.0; /* Tag as not a generic attrib */
+			}
+		}
+	}
+	else {
+		for (uint l = 0; l < loops_len; l++) {
+			float *data = (float *)GPU_vertbuf_raw_step(&vbo_step);
+			copy_v3_v3(data, rdata->orco[rdata->mloop[l].v]);
+			data[3] = 0.0; /* Tag as not a generic attrib */
+		}
+	}
+}
+
 static void mesh_create_loop_uv_and_tan(MeshRenderData *rdata, GPUVertBuf *vbo)
 {
 	const uint loops_len = mesh_render_data_loops_len_get(rdata);
@@ -4593,8 +4633,7 @@ void DRW_mesh_batch_cache_create_requested(
 						GPU_VERTBUF_DISCARD_SAFE(cache->ordered.loop_vcol);
 						break;
 					case CD_ORCO:
-						/* TODO */
-						// GPU_VERTBUF_DISCARD_SAFE(cache->ordered.loop_orco);
+						GPU_VERTBUF_DISCARD_SAFE(cache->ordered.loop_orco);
 						break;
 				}
 			}
@@ -4784,10 +4823,19 @@ void DRW_mesh_batch_cache_create_requested(
 			if (cache->cd_lused[CD_MLOOPCOL] != 0) {
 				DRW_vbo_request(cache->surf_per_mat[i], &cache->ordered.loop_vcol);
 			}
-			/* TODO */
-			// if (cache->cd_vused[CD_ORCO] != 0) {
-			// 	DRW_vbo_request(cache->surf_per_mat[i], &cache->ordered.loop_orco);
-			// }
+			if (cache->cd_vused[CD_ORCO] != 0) {
+				/* OPTI : Only do that if there is modifiers that modify orcos. */
+				CustomData *cd_vdata = (me->edit_mesh) ? &me->edit_mesh->bm->vdata : &me->vdata;
+				if (CustomData_get_layer(cd_vdata, CD_ORCO) != NULL &&
+				    ob->modifiers.first != NULL)
+				{
+					DRW_vbo_request(cache->surf_per_mat[i], &cache->ordered.loop_orco);
+				}
+				else if ((cache->cd_lused[CD_TANGENT] & DM_TANGENT_MASK_ORCO) == 0) {
+					/* Skip orco calculation if not needed by tangent generation. */
+					cache->cd_vused[CD_ORCO] = 0;
+				}
+			}
 		}
 	}
 
@@ -4797,6 +4845,7 @@ void DRW_mesh_batch_cache_create_requested(
 	DRW_ADD_FLAG_FROM_VBO_REQUEST(mr_flag, cache->ordered.weights, MR_DATATYPE_VERT | MR_DATATYPE_DVERT);
 	DRW_ADD_FLAG_FROM_VBO_REQUEST(mr_flag, cache->ordered.loop_pos_nor, MR_DATATYPE_VERT | MR_DATATYPE_POLY | MR_DATATYPE_LOOP);
 	DRW_ADD_FLAG_FROM_VBO_REQUEST(mr_flag, cache->ordered.loop_uv_tan, MR_DATATYPE_VERT | MR_DATATYPE_POLY | MR_DATATYPE_LOOP | MR_DATATYPE_SHADING);
+	DRW_ADD_FLAG_FROM_VBO_REQUEST(mr_flag, cache->ordered.loop_orco, MR_DATATYPE_VERT | MR_DATATYPE_POLY | MR_DATATYPE_LOOP | MR_DATATYPE_SHADING);
 	DRW_ADD_FLAG_FROM_VBO_REQUEST(mr_flag, cache->ordered.loop_vcol, MR_DATATYPE_VERT | MR_DATATYPE_POLY | MR_DATATYPE_LOOP | MR_DATATYPE_SHADING);
 	DRW_ADD_FLAG_FROM_VBO_REQUEST(mr_flag, cache->ordered.loop_edge_fac, MR_DATATYPE_VERT | MR_DATATYPE_POLY | MR_DATATYPE_EDGE | MR_DATATYPE_LOOP);
 	DRW_ADD_FLAG_FROM_IBO_REQUEST(mr_flag, cache->ibo.surf_tris, MR_DATATYPE_VERT | MR_DATATYPE_LOOP |  MR_DATATYPE_POLY | MR_DATATYPE_LOOPTRI);
@@ -4863,6 +4912,9 @@ void DRW_mesh_batch_cache_create_requested(
 	if (DRW_vbo_requested(cache->ordered.loop_uv_tan)) {
 		mesh_create_loop_uv_and_tan(rdata, cache->ordered.loop_uv_tan);
 	}
+	if (DRW_vbo_requested(cache->ordered.loop_orco)) {
+		mesh_create_loop_orco(rdata, cache->ordered.loop_orco);
+	}
 	if (DRW_vbo_requested(cache->ordered.loop_vcol)) {
 		mesh_create_loop_vcol(rdata, cache->ordered.loop_vcol);
 	}