[Bf-blender-cvs] [735ad525a6e] blender2.8: Fix T53750: Mirrored UV have bad tangent space

[Clément Foucault]

Commit: 735ad525a6e72a7a52bf4e81ca03a7b1c435a857
Author: Clément Foucault
Date:   Sat Nov 17 14:52:03 2018 +0100
Branches: blender2.8
https://developer.blender.org/rB735ad525a6e72a7a52bf4e81ca03a7b1c435a857

Fix T53750: Mirrored UV have bad tangent space

I feel silly because it was my fault all along! (see the WATCH IT warning)

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

M	source/blender/draw/intern/draw_cache_impl_mesh.c

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

diff --git a/source/blender/draw/intern/draw_cache_impl_mesh.c b/source/blender/draw/intern/draw_cache_impl_mesh.c
index 4615810e31d..a24702368de 100644
--- a/source/blender/draw/intern/draw_cache_impl_mesh.c
+++ b/source/blender/draw/intern/draw_cache_impl_mesh.c
@@ -2418,7 +2418,6 @@ void DRW_mesh_batch_cache_free(Mesh *me)
 static GPUVertBuf *mesh_batch_cache_get_tri_shading_data(MeshRenderData *rdata, MeshBatchCache *cache)
 {
 	BLI_assert(rdata->types & (MR_DATATYPE_VERT | MR_DATATYPE_LOOPTRI | MR_DATATYPE_LOOP | MR_DATATYPE_POLY));
-#define USE_COMP_MESH_DATA
 
 	if (cache->shaded_triangles_data == NULL) {
 		const uint uv_len = rdata->cd.layers.uv_len;
@@ -2466,6 +2465,8 @@ static GPUVertBuf *mesh_batch_cache_get_tri_shading_data(MeshRenderData *rdata,
 		cache->auto_layer_names = MEM_callocN(auto_names_len * sizeof(char), "Auto layer name buf");
 		cache->auto_layer_is_srgb = MEM_mallocN(cache->auto_layer_len * sizeof(int), "Auto layer value buf");
 
+#define USE_COMP_MESH_DATA
+
 		for (uint i = 0; i < uv_len; i++) {
 			/* UV */
 			const char *attrib_name = mesh_render_data_uv_layer_uuid_get(rdata, i);
@@ -2491,13 +2492,11 @@ static GPUVertBuf *mesh_batch_cache_get_tri_shading_data(MeshRenderData *rdata,
 
 		for (uint i = 0; i < tangent_len; i++) {
 			const char *attrib_name = mesh_render_data_tangent_layer_uuid_get(rdata, i);
-			/* WATCH IT : only specifying 3 component instead of 4 (4th is sign).
-			 * That may cause some problem but I could not make it to fail (fclem) */
 #ifdef USE_COMP_MESH_DATA
 			/* Tangents need more precision than 10_10_10 */
-			tangent_id[i] = GPU_vertformat_attr_add(format, attrib_name, GPU_COMP_I16, 3, GPU_FETCH_INT_TO_FLOAT_UNIT);
+			tangent_id[i] = GPU_vertformat_attr_add(format, attrib_name, GPU_COMP_I16, 4, GPU_FETCH_INT_TO_FLOAT_UNIT);
 #else
-			tangent_id[i] = GPU_vertformat_attr_add(format, attrib_name, GPU_COMP_F32, 3, GPU_FETCH_FLOAT);
+			tangent_id[i] = GPU_vertformat_attr_add(format, attrib_name, GPU_COMP_F32, 4, GPU_FETCH_FLOAT);
 #endif
 
 			if (i == rdata->cd.layers.tangent_active) {
@@ -2576,7 +2575,11 @@ static GPUVertBuf *mesh_batch_cache_get_tri_shading_data(MeshRenderData *rdata,
 					float (*layer_data)[4] = rdata->cd.layers.tangent[j];
 					for (uint t = 0; t < 3; t++) {
 						const float *elem = layer_data[BM_elem_index_get(bm_looptri[t])];
-						normal_float_to_short_v3(GPU_vertbuf_raw_step(&tangent_step[j]), elem);
+#ifdef USE_COMP_MESH_DATA
+						normal_float_to_short_v4(GPU_vertbuf_raw_step(&tangent_step[j]), elem);
+#else
+						copy_v4_v4(GPU_vertbuf_raw_step(&tangent_step[j]), elem);
+#endif
 					}
 				}
 				/* VCOLs */
@@ -2607,9 +2610,9 @@ static GPUVertBuf *mesh_batch_cache_get_tri_shading_data(MeshRenderData *rdata,
 					for (uint t = 0; t < 3; t++) {
 						const float *elem = layer_data[mlt->tri[t]];
 #ifdef USE_COMP_MESH_DATA
-						normal_float_to_short_v3(GPU_vertbuf_raw_step(&tangent_step[j]), elem);
+						normal_float_to_short_v4(GPU_vertbuf_raw_step(&tangent_step[j]), elem);
 #else
-						copy_v3_v3(GPU_vertbuf_raw_step(&tangent_step[j]), elem);
+						copy_v4_v4(GPU_vertbuf_raw_step(&tangent_step[j]), elem);
 #endif
 					}
 				}