PaintingModes: Facemask Wireframe Drawing

The wireframe drawing for face masks is intrusive as selected wires
were solid white and always drawn. This made it hard for users to see
the exact color near edges.

This patch draws only the border of the selected faces,
edges between two selected faces are not drawn at all.

Reviewed By: brecht, fclem

Differential Revision: https://developer.blender.org/D5147

1 files changed, 74 insertions, 5 deletions

diff --git a/source/blender/draw/intern/draw_cache_impl_mesh.c b/source/blender/draw/intern/draw_cache_impl_mesh.c
index f4acb586c5e..2490a2c8529 100644
--- a/source/blender/draw/intern/draw_cache_impl_mesh.c
+++ b/source/blender/draw/intern/draw_cache_impl_mesh.c
@@ -1985,6 +1985,7 @@ typedef struct MeshBatchCache {
     /* Indices to vloops. */
     GPUIndexBuf *loops_tris;
     GPUIndexBuf *loops_lines;
+    GPUIndexBuf *loops_lines_paint_mask;
     GPUIndexBuf *loops_line_strips;
     /* Edit mode. */
     GPUIndexBuf *edit_loops_points; /* verts */
@@ -2025,7 +2026,7 @@ typedef struct MeshBatchCache {
     GPUBatch *loose_edges;
     GPUBatch *edge_detection;
     GPUBatch *wire_edges;     /* Individual edges with face normals. */
-    GPUBatch *wire_loops;     /* Loops around faces. */
+    GPUBatch *wire_loops;     /* Loops around faces. no edges between selected faces */
     GPUBatch *wire_loops_uvs; /* Same as wire_loops but only has uvs. */
   } batch;
 
@@ -2227,6 +2228,7 @@ void DRW_mesh_batch_cache_dirty_tag(Mesh *me, int mode)
     case BKE_MESH_BATCH_DIRTY_SELECT_PAINT:
       /* Paint mode selection flag is packed inside the nor attrib.
        * Note that it can be slow if auto smooth is enabled. (see T63946) */
+      GPU_INDEXBUF_DISCARD_SAFE(cache->ibo.loops_lines_paint_mask);
       GPU_VERTBUF_DISCARD_SAFE(cache->ordered.loop_pos_nor);
       GPU_BATCH_DISCARD_SAFE(cache->batch.surface);
       GPU_BATCH_DISCARD_SAFE(cache->batch.wire_loops);
@@ -3788,10 +3790,71 @@ static void mesh_create_loops_lines(MeshRenderData *rdata, GPUIndexBuf *ibo, con
       }
     }
   }
-  else {
-    /* Implement ... eventually if needed. */
+
+  GPU_indexbuf_build_in_place(&elb, ibo);
+}
+
+static void mesh_create_loops_lines_paint_mask(MeshRenderData *rdata, GPUIndexBuf *ibo)
+{
+  const int loop_len = mesh_render_data_loops_len_get(rdata);
+  const int poly_len = mesh_render_data_polys_len_get(rdata);
+
+  GPUIndexBufBuilder elb;
+  GPU_indexbuf_init(&elb, GPU_PRIM_LINES, loop_len, loop_len);
+
+  if (rdata->edit_bmesh) {
+    /* painting does not use the edit_bmesh */
     BLI_assert(0);
   }
+  else {
+    /* contains all edges where at least one face has been selected */
+    EdgeHash *edge_hash = BLI_edgehash_new(__func__);
+
+    /* Fill the EdgeHash tables. */
+    for (int poly = 0; poly < poly_len; poly++) {
+      const MPoly *mpoly = &rdata->mpoly[poly];
+
+      /* Do not check faces that are hidden and faces that aren't selected */
+      if (mpoly->flag & ME_HIDE || ((mpoly->flag & ME_FACE_SEL) == 0)) {
+        continue;
+      }
+
+      for (int loop_index = 0; loop_index < mpoly->totloop; loop_index++) {
+        const MLoop *mloop = &rdata->mloop[mpoly->loopstart + loop_index];
+        const MEdge *edge = (MEdge *)rdata->medge + mloop->e;
+        const int v1 = edge->v1;
+        const int v2 = edge->v2;
+
+        void **edge_value;
+
+        if (BLI_edgehash_ensure_p(edge_hash, v1, v2, &edge_value)) {
+          *edge_value = POINTER_FROM_INT(POINTER_AS_INT(*edge_value) + 1);
+        }
+        else {
+          *edge_value = POINTER_FROM_INT(1);
+        }
+      }
+    }
+
+    for (int poly = 0; poly < poly_len; poly++) {
+      const MPoly *mpoly = &rdata->mpoly[poly];
+      if (!(mpoly->flag & ME_HIDE)) {
+        for (int loop_index = 0; loop_index < mpoly->totloop; loop_index++) {
+          const MLoop *mloop = &rdata->mloop[mpoly->loopstart + loop_index];
+          const MEdge *edge = (MEdge *)rdata->medge + mloop->e;
+          int v1 = mpoly->loopstart + loop_index;
+          int v2 = mpoly->loopstart + (loop_index + 1) % mpoly->totloop;
+
+          void *edge_value = BLI_edgehash_lookup(edge_hash, edge->v1, edge->v2);
+          if (edge_value == NULL || POINTER_AS_INT(edge_value) == 1) {
+            GPU_indexbuf_add_line_verts(&elb, v1, v2);
+          }
+        }
+      }
+    }
+
+    BLI_edgehash_free(edge_hash, NULL);
+  }
 
   GPU_indexbuf_build_in_place(&elb, ibo);
 }
@@ -5053,8 +5116,8 @@ void DRW_mesh_batch_cache_create_requested(
     DRW_vbo_request(cache->batch.surface_weights, &cache->ordered.pos_nor);
     DRW_vbo_request(cache->batch.surface_weights, &cache->ordered.weights);
   }
-  if (DRW_batch_requested(cache->batch.wire_loops, GPU_PRIM_LINE_STRIP)) {
-    DRW_ibo_request(cache->batch.wire_loops, &cache->ibo.loops_line_strips);
+  if (DRW_batch_requested(cache->batch.wire_loops, GPU_PRIM_LINES)) {
+    DRW_ibo_request(cache->batch.wire_loops, &cache->ibo.loops_lines_paint_mask);
     DRW_vbo_request(cache->batch.wire_loops, &cache->ordered.loop_pos_nor);
   }
   if (DRW_batch_requested(cache->batch.wire_edges, GPU_PRIM_LINES)) {
@@ -5207,6 +5270,9 @@ void DRW_mesh_batch_cache_create_requested(
       mr_flag, cache->ibo.loops_tris, MR_DATATYPE_LOOP | MR_DATATYPE_POLY | MR_DATATYPE_LOOPTRI);
   DRW_ADD_FLAG_FROM_IBO_REQUEST(
       mr_flag, cache->ibo.loops_lines, MR_DATATYPE_LOOP | MR_DATATYPE_EDGE | MR_DATATYPE_POLY);
+  DRW_ADD_FLAG_FROM_IBO_REQUEST(mr_flag,
+                                cache->ibo.loops_lines_paint_mask,
+                                MR_DATATYPE_LOOP | MR_DATATYPE_EDGE | MR_DATATYPE_POLY);
   DRW_ADD_FLAG_FROM_IBO_REQUEST(
       mr_flag, cache->ibo.loops_line_strips, MR_DATATYPE_LOOP | MR_DATATYPE_POLY);
   DRW_ADD_FLAG_FROM_IBO_REQUEST(
@@ -5323,6 +5389,9 @@ void DRW_mesh_batch_cache_create_requested(
   if (DRW_ibo_requested(cache->ibo.loops_lines)) {
     mesh_create_loops_lines(rdata, cache->ibo.loops_lines, use_hide);
   }
+  if (DRW_ibo_requested(cache->ibo.loops_lines_paint_mask)) {
+    mesh_create_loops_lines_paint_mask(rdata, cache->ibo.loops_lines_paint_mask);
+  }
   if (DRW_ibo_requested(cache->ibo.loops_line_strips)) {
     mesh_create_loops_line_strips(rdata, cache->ibo.loops_line_strips, use_hide);
   }