Sculpt: Render Face Sets always as flat shading

This removes the smooth shading rendering from the face set overlay when
smooth shading is enabled.

Reviewed By: jbakker

Maniphest Tasks: T74906, T74622, T75331, T76530

Differential Revision: https://developer.blender.org/D7105

7 files changed, 100 insertions, 183 deletions

diff --git a/source/blender/blenkernel/intern/pbvh.c b/source/blender/blenkernel/intern/pbvh.c
index 7d5a0e7fd91..d925a2b4db9 100644
--- a/source/blender/blenkernel/intern/pbvh.c
+++ b/source/blender/blenkernel/intern/pbvh.c
@@ -1274,7 +1274,6 @@ static void pbvh_update_draw_buffer_cb(void *__restrict userdata,
         break;
       case PBVH_FACES:
         node->draw_buffers = GPU_pbvh_mesh_buffers_build(
-            node->face_vert_indices,
             bvh->mpoly,
             bvh->mloop,
             bvh->looptri,
@@ -1310,14 +1309,11 @@ static void pbvh_update_draw_buffer_cb(void *__restrict userdata,
       case PBVH_FACES:
         GPU_pbvh_mesh_buffers_update(node->draw_buffers,
                                      bvh->verts,
-                                     node->vert_indices,
-                                     node->uniq_verts + node->face_verts,
                                      CustomData_get_layer(bvh->vdata, CD_PAINT_MASK),
                                      CustomData_get_layer(bvh->ldata, CD_MLOOPCOL),
                                      CustomData_get_layer(bvh->pdata, CD_SCULPT_FACE_SETS),
                                      bvh->face_sets_color_seed,
                                      bvh->face_sets_color_default,
-                                     node->face_vert_indices,
                                      update_flags);
         break;
       case PBVH_BMESH:
diff --git a/source/blender/draw/CMakeLists.txt b/source/blender/draw/CMakeLists.txt
index 46263f694cb..6f932bf8797 100644
--- a/source/blender/draw/CMakeLists.txt
+++ b/source/blender/draw/CMakeLists.txt
@@ -384,6 +384,7 @@ data_to_c_simple(engines/overlay/shaders/particle_frag.glsl SRC)
 data_to_c_simple(engines/overlay/shaders/pointcloud_vert.glsl SRC)
 data_to_c_simple(engines/overlay/shaders/pointcloud_frag.glsl SRC)
 data_to_c_simple(engines/overlay/shaders/sculpt_mask_vert.glsl SRC)
+data_to_c_simple(engines/overlay/shaders/sculpt_mask_frag.glsl SRC)
 data_to_c_simple(engines/overlay/shaders/volume_velocity_vert.glsl SRC)
 data_to_c_simple(engines/overlay/shaders/wireframe_vert.glsl SRC)
 data_to_c_simple(engines/overlay/shaders/wireframe_frag.glsl SRC)
diff --git a/source/blender/draw/engines/overlay/overlay_shader.c b/source/blender/draw/engines/overlay/overlay_shader.c
index 264791a6661..59f388df4e3 100644
--- a/source/blender/draw/engines/overlay/overlay_shader.c
+++ b/source/blender/draw/engines/overlay/overlay_shader.c
@@ -105,6 +105,7 @@ extern char datatoc_particle_frag_glsl[];
 extern char datatoc_pointcloud_vert_glsl[];
 extern char datatoc_pointcloud_frag_glsl[];
 extern char datatoc_sculpt_mask_vert_glsl[];
+extern char datatoc_sculpt_mask_frag_glsl[];
 extern char datatoc_volume_velocity_vert_glsl[];
 extern char datatoc_wireframe_vert_glsl[];
 extern char datatoc_wireframe_frag_glsl[];
@@ -1307,7 +1308,7 @@ GPUShader *OVERLAY_shader_sculpt_mask(void)
                                  datatoc_common_view_lib_glsl,
                                  datatoc_sculpt_mask_vert_glsl,
                                  NULL},
-        .frag = (const char *[]){datatoc_gpu_shader_3D_smooth_color_frag_glsl, NULL},
+        .frag = (const char *[]){datatoc_sculpt_mask_frag_glsl, NULL},
         .defs = (const char *[]){sh_cfg->def, NULL},
     });
   }
diff --git a/source/blender/draw/engines/overlay/shaders/sculpt_mask_frag.glsl b/source/blender/draw/engines/overlay/shaders/sculpt_mask_frag.glsl
new file mode 100644
index 00000000000..a778e518392
--- /dev/null
+++ b/source/blender/draw/engines/overlay/shaders/sculpt_mask_frag.glsl
@@ -0,0 +1,10 @@
+
+flat in vec3 faceset_color;
+in float mask_color;
+
+out vec4 fragColor;
+
+void main()
+{
+  fragColor = vec4(faceset_color * vec3(mask_color), 1.0);
+}
diff --git a/source/blender/draw/engines/overlay/shaders/sculpt_mask_vert.glsl b/source/blender/draw/engines/overlay/shaders/sculpt_mask_vert.glsl
index 5d79195a40b..f2b827738ac 100644
--- a/source/blender/draw/engines/overlay/shaders/sculpt_mask_vert.glsl
+++ b/source/blender/draw/engines/overlay/shaders/sculpt_mask_vert.glsl
@@ -8,13 +8,16 @@ in float msk;
 
 out vec4 finalColor;
 
+flat out vec3 faceset_color;
+out float mask_color;
+
 void main()
 {
   vec3 world_pos = point_object_to_world(pos);
   gl_Position = point_world_to_ndc(world_pos);
 
-  finalColor = vec4(mix(vec3(1.0), fset, faceSetsOpacity), 1.0);
-  finalColor.rgb *= (1.0 - (msk * maskOpacity));
+  faceset_color = mix(vec3(1.0), fset, faceSetsOpacity);
+  mask_color = 1.0 - (msk * maskOpacity);
 
 #ifdef USE_WORLD_CLIP_PLANES
   world_clip_planes_calc_clip_distance(world_pos);
diff --git a/source/blender/gpu/GPU_buffers.h b/source/blender/gpu/GPU_buffers.h
index 22086b8a9d6..ab16bfc43c4 100644
--- a/source/blender/gpu/GPU_buffers.h
+++ b/source/blender/gpu/GPU_buffers.h
@@ -49,8 +49,7 @@ typedef struct GPU_PBVH_Buffers GPU_PBVH_Buffers;
 
 /* Build must be called once before using the other functions, used every time
  * mesh topology changes. Threaded. */
-GPU_PBVH_Buffers *GPU_pbvh_mesh_buffers_build(const int (*face_vert_indices)[3],
-                                              const struct MPoly *mpoly,
+GPU_PBVH_Buffers *GPU_pbvh_mesh_buffers_build(const struct MPoly *mpoly,
                                               const struct MLoop *mloop,
                                               const struct MLoopTri *looptri,
                                               const struct MVert *verts,
@@ -78,14 +77,11 @@ enum {
 
 void GPU_pbvh_mesh_buffers_update(GPU_PBVH_Buffers *buffers,
                                   const struct MVert *mvert,
-                                  const int *vert_indices,
-                                  int totvert,
                                   const float *vmask,
                                   const struct MLoopCol *vcol,
                                   const int *sculpt_face_sets,
                                   const int face_sets_color_seed,
                                   const int face_sets_color_default,
-                                  const int (*face_vert_indices)[3],
                                   const int update_flags);
 
 void GPU_pbvh_bmesh_buffers_update(GPU_PBVH_Buffers *buffers,
diff --git a/source/blender/gpu/intern/gpu_buffers.c b/source/blender/gpu/intern/gpu_buffers.c
index 03e0d1829c5..e9061f1a029 100644
--- a/source/blender/gpu/intern/gpu_buffers.c
+++ b/source/blender/gpu/intern/gpu_buffers.c
@@ -219,14 +219,11 @@ static bool gpu_pbvh_is_looptri_visible(const MLoopTri *lt,
 /* Threaded - do not call any functions that use OpenGL calls! */
 void GPU_pbvh_mesh_buffers_update(GPU_PBVH_Buffers *buffers,
                                   const MVert *mvert,
-                                  const int *vert_indices,
-                                  int totvert,
                                   const float *vmask,
                                   const MLoopCol *vcol,
                                   const int *sculpt_face_sets,
                                   const int face_sets_color_seed,
                                   const int face_sets_color_default,
-                                  const int (*face_vert_indices)[3],
                                   const int update_flags)
 {
   const bool show_mask = vmask && (update_flags & GPU_PBVH_BUFFERS_SHOW_MASK) != 0;
@@ -237,7 +234,7 @@ void GPU_pbvh_mesh_buffers_update(GPU_PBVH_Buffers *buffers,
   bool default_face_set = true;
 
   {
-    int totelem = (buffers->smooth ? totvert : (buffers->tot_tri * 3));
+    const int totelem = buffers->tot_tri * 3;
 
     /* Build VBO */
     if (gpu_pbvh_vert_buf_data_set(buffers, totelem)) {
@@ -255,127 +252,77 @@ void GPU_pbvh_mesh_buffers_update(GPU_PBVH_Buffers *buffers,
         GPU_vertbuf_attr_get_raw_data(buffers->vert_buf, g_vbo_id.col, &col_step);
       }
 
-      /* Vertex data is shared if smooth-shaded, but separate
-       * copies are made for flat shading because normals
-       * shouldn't be shared. */
-      if (buffers->smooth) {
-        for (uint i = 0; i < totvert; i++) {
-          const int vidx = vert_indices[i];
-          const MVert *v = &mvert[vidx];
-          copy_v3_v3(GPU_vertbuf_raw_step(&pos_step), v->co);
-          copy_v3_v3_short(GPU_vertbuf_raw_step(&nor_step), v->no);
+      /* calculate normal for each polygon only once */
+      uint mpoly_prev = UINT_MAX;
+      short no[3] = {0, 0, 0};
 
-          uchar mask;
-          if (show_mask) {
-            mask = (uchar)(vmask[vidx] * 255);
-          }
-          else {
-            mask = 0.0f;
-          }
-          *(uchar *)GPU_vertbuf_raw_step(&msk_step) = mask;
-          empty_mask = empty_mask && (mask == 0);
+      for (uint i = 0; i < buffers->face_indices_len; i++) {
+        const MLoopTri *lt = &buffers->looptri[buffers->face_indices[i]];
+        const uint vtri[3] = {
+            buffers->mloop[lt->tri[0]].v,
+            buffers->mloop[lt->tri[1]].v,
+            buffers->mloop[lt->tri[2]].v,
+        };
+
+        if (!gpu_pbvh_is_looptri_visible(lt, mvert, buffers->mloop, sculpt_face_sets)) {
+          continue;
         }
 
-        /* Face Sets. */
-        for (uint i = 0; i < buffers->face_indices_len; i++) {
-          uchar face_set_color[4] = {UCHAR_MAX, UCHAR_MAX, UCHAR_MAX, UCHAR_MAX};
-          if (show_face_sets) {
-            const MLoopTri *lt = &buffers->looptri[buffers->face_indices[i]];
-            const int fset = abs(sculpt_face_sets[lt->poly]);
-
-            /* Skip for the default color Face Set to render it white. */
-            if (fset != face_sets_color_default) {
-              face_set_overlay_color_get(fset, face_sets_color_seed, face_set_color);
-              default_face_set = false;
-            }
-          }
-          for (int j = 0; j < 3; j++) {
-            const int vidx = face_vert_indices[i][j];
-            GPU_vertbuf_attr_set(buffers->vert_buf, g_vbo_id.fset, vidx, &face_set_color);
-          }
+        /* Face normal and mask */
+        if (lt->poly != mpoly_prev && !buffers->smooth) {
+          const MPoly *mp = &buffers->mpoly[lt->poly];
+          float fno[3];
+          BKE_mesh_calc_poly_normal(mp, &buffers->mloop[mp->loopstart], mvert, fno);
+          normal_float_to_short_v3(no, fno);
+          mpoly_prev = lt->poly;
         }
 
-        if (show_vcol) {
-          for (uint i = 0; i < buffers->face_indices_len; i++) {
-            const MLoopTri *lt = &buffers->looptri[buffers->face_indices[i]];
-            for (int j = 0; j < 3; j++) {
-              const int loop_index = lt->tri[j];
-              const int vidx = face_vert_indices[i][j];
-              const MLoopCol *mcol = &vcol[loop_index];
-              ushort scol[4];
-              scol[0] = unit_float_to_ushort_clamp(BLI_color_from_srgb_table[mcol->r]);
-              scol[1] = unit_float_to_ushort_clamp(BLI_color_from_srgb_table[mcol->g]);
-              scol[2] = unit_float_to_ushort_clamp(BLI_color_from_srgb_table[mcol->b]);
-              scol[3] = unit_float_to_ushort_clamp(mcol->a * (1.0f / 255.0f));
-              GPU_vertbuf_attr_set(buffers->vert_buf, g_vbo_id.col, vidx, scol);
-            }
+        uchar face_set_color[4] = {UCHAR_MAX, UCHAR_MAX, UCHAR_MAX, UCHAR_MAX};
+        if (show_face_sets) {
+          const int fset = abs(sculpt_face_sets[lt->poly]);
+          /* Skip for the default color Face Set to render it white. */
+          if (fset != face_sets_color_default) {
+            face_set_overlay_color_get(fset, face_sets_color_seed, face_set_color);
+            default_face_set = false;
           }
         }
-      }
-      else {
-        /* calculate normal for each polygon only once */
-        uint mpoly_prev = UINT_MAX;
-        short no[3] = {0, 0, 0};
-
-        for (uint i = 0; i < buffers->face_indices_len; i++) {
-          const MLoopTri *lt = &buffers->looptri[buffers->face_indices[i]];
-          const uint vtri[3] = {
-              buffers->mloop[lt->tri[0]].v,
-              buffers->mloop[lt->tri[1]].v,
-              buffers->mloop[lt->tri[2]].v,
-          };
-
-          if (!gpu_pbvh_is_looptri_visible(lt, mvert, buffers->mloop, sculpt_face_sets)) {
-            continue;
-          }
 
-          /* Face normal and mask */
-          if (lt->poly != mpoly_prev) {
-            const MPoly *mp = &buffers->mpoly[lt->poly];
-            float fno[3];
-            BKE_mesh_calc_poly_normal(mp, &buffers->mloop[mp->loopstart], mvert, fno);
-            normal_float_to_short_v3(no, fno);
-            mpoly_prev = lt->poly;
-          }
+        float fmask = 0.0f;
+        uchar cmask = 0;
+        if (show_mask && !buffers->smooth) {
+          fmask = (vmask[vtri[0]] + vmask[vtri[1]] + vmask[vtri[2]]) / 3.0f;
+          cmask = (uchar)(fmask * 255);
+        }
 
-          uchar face_set_color[4] = {UCHAR_MAX, UCHAR_MAX, UCHAR_MAX, UCHAR_MAX};
-          if (show_face_sets) {
-            const int fset = abs(sculpt_face_sets[lt->poly]);
-            /* Skip for the default color Face Set to render it white. */
-            if (fset != face_sets_color_default) {
-              face_set_overlay_color_get(fset, face_sets_color_seed, face_set_color);
-              default_face_set = false;
-            }
-          }
+        for (uint j = 0; j < 3; j++) {
+          const MVert *v = &mvert[vtri[j]];
+          copy_v3_v3(GPU_vertbuf_raw_step(&pos_step), v->co);
 
-          float fmask = 0.0f;
-          uchar cmask = 0;
-          if (show_mask) {
-            fmask = (vmask[vtri[0]] + vmask[vtri[1]] + vmask[vtri[2]]) / 3.0f;
-            cmask = (uchar)(fmask * 255);
+          if (buffers->smooth) {
+            copy_v3_v3_short(no, v->no);
           }
+          copy_v3_v3_short(GPU_vertbuf_raw_step(&nor_step), no);
 
-          for (uint j = 0; j < 3; j++) {
-            const MVert *v = &mvert[vtri[j]];
-
-            copy_v3_v3(GPU_vertbuf_raw_step(&pos_step), v->co);
-            copy_v3_v3_short(GPU_vertbuf_raw_step(&nor_step), no);
-            *(uchar *)GPU_vertbuf_raw_step(&msk_step) = cmask;
-            empty_mask = empty_mask && (cmask == 0);
-            /* Face Sets. */
-            memcpy(GPU_vertbuf_raw_step(&fset_step), face_set_color, sizeof(uchar) * 3);
+          if (show_mask && buffers->smooth) {
+            cmask = (uchar)(vmask[vtri[j]] * 255);
+          }
 
-            if (show_vcol) {
-              const uint loop_index = lt->tri[j];
-              const MLoopCol *mcol = &vcol[loop_index];
-              ushort scol[4];
-              scol[0] = unit_float_to_ushort_clamp(BLI_color_from_srgb_table[mcol->r]);
-              scol[1] = unit_float_to_ushort_clamp(BLI_color_from_srgb_table[mcol->g]);
-              scol[2] = unit_float_to_ushort_clamp(BLI_color_from_srgb_table[mcol->b]);
-              scol[3] = unit_float_to_ushort_clamp(mcol->a * (1.0f / 255.0f));
-              memcpy(GPU_vertbuf_raw_step(&col_step), scol, sizeof(scol));
-            }
+          *(uchar *)GPU_vertbuf_raw_step(&msk_step) = cmask;
+          empty_mask = empty_mask && (cmask == 0);
+
+          if (show_vcol) {
+            const uint loop_index = lt->tri[j];
+            const MLoopCol *mcol = &vcol[loop_index];
+            ushort scol[4];
+            scol[0] = unit_float_to_ushort_clamp(BLI_color_from_srgb_table[mcol->r]);
+            scol[1] = unit_float_to_ushort_clamp(BLI_color_from_srgb_table[mcol->g]);
+            scol[2] = unit_float_to_ushort_clamp(BLI_color_from_srgb_table[mcol->b]);
+            scol[3] = unit_float_to_ushort_clamp(mcol->a * (1.0f / 255.0f));
+            memcpy(GPU_vertbuf_raw_step(&col_step), scol, sizeof(scol));
           }
+
+          /* Face Sets. */
+          memcpy(GPU_vertbuf_raw_step(&fset_step), face_set_color, sizeof(uchar) * 3);
         }
       }
 
@@ -393,8 +340,7 @@ void GPU_pbvh_mesh_buffers_update(GPU_PBVH_Buffers *buffers,
 }
 
 /* Threaded - do not call any functions that use OpenGL calls! */
-GPU_PBVH_Buffers *GPU_pbvh_mesh_buffers_build(const int (*face_vert_indices)[3],
-                                              const MPoly *mpoly,
+GPU_PBVH_Buffers *GPU_pbvh_mesh_buffers_build(const MPoly *mpoly,
                                               const MLoop *mloop,
                                               const MLoopTri *looptri,
                                               const MVert *mvert,
@@ -441,70 +387,34 @@ GPU_PBVH_Buffers *GPU_pbvh_mesh_buffers_build(const int (*face_vert_indices)[3],
     return buffers;
   }
 
-  /* An element index buffer is used for smooth shading, but flat
-   * shading requires separate vertex normals so an index buffer
-   * can't be used there. */
-  if (buffers->smooth) {
-    /* Fill the triangle and line buffers. */
-    GPUIndexBufBuilder elb, elb_lines;
-    GPU_indexbuf_init(&elb, GPU_PRIM_TRIS, tottri, INT_MAX);
-    GPU_indexbuf_init(&elb_lines, GPU_PRIM_LINES, tot_real_edges, INT_MAX);
+  /* Fill the only the line buffer. */
+  GPUIndexBufBuilder elb_lines;
+  GPU_indexbuf_init(&elb_lines, GPU_PRIM_LINES, tot_real_edges, INT_MAX);
+  int vert_idx = 0;
 
-    for (i = 0; i < face_indices_len; i++) {
-      const MLoopTri *lt = &looptri[face_indices[i]];
-
-      /* Skip hidden faces */
-      if (!gpu_pbvh_is_looptri_visible(lt, mvert, mloop, sculpt_face_sets)) {
-        continue;
-      }
-
-      GPU_indexbuf_add_tri_verts(&elb, UNPACK3(face_vert_indices[i]));
-      int r_edges[3];
-      BKE_mesh_looptri_get_real_edges(mesh, lt, r_edges);
+  for (i = 0; i < face_indices_len; i++) {
+    const MLoopTri *lt = &looptri[face_indices[i]];
 
-      if (r_edges[0] != -1) {
-        GPU_indexbuf_add_line_verts(&elb_lines, face_vert_indices[i][0], face_vert_indices[i][1]);
-      }
-      if (r_edges[1] != -1) {
-        GPU_indexbuf_add_line_verts(&elb_lines, face_vert_indices[i][1], face_vert_indices[i][2]);
-      }
-      if (r_edges[2] != -1) {
-        GPU_indexbuf_add_line_verts(&elb_lines, face_vert_indices[i][2], face_vert_indices[i][0]);
-      }
+    /* Skip hidden faces */
+    if (!gpu_pbvh_is_looptri_visible(lt, mvert, mloop, sculpt_face_sets)) {
+      continue;
     }
-    buffers->index_buf = GPU_indexbuf_build(&elb);
-    buffers->index_lines_buf = GPU_indexbuf_build(&elb_lines);
-  }
-  else {
-    /* Fill the only the line buffer. */
-    GPUIndexBufBuilder elb_lines;
-    GPU_indexbuf_init(&elb_lines, GPU_PRIM_LINES, tot_real_edges, INT_MAX);
-    int vert_idx = 0;
-
-    for (i = 0; i < face_indices_len; i++) {
-      const MLoopTri *lt = &looptri[face_indices[i]];
 
-      /* Skip hidden faces */
-      if (!gpu_pbvh_is_looptri_visible(lt, mvert, mloop, sculpt_face_sets)) {
-        continue;
-      }
-
-      int r_edges[3];
-      BKE_mesh_looptri_get_real_edges(mesh, lt, r_edges);
-      if (r_edges[0] != -1) {
-        GPU_indexbuf_add_line_verts(&elb_lines, vert_idx * 3 + 0, vert_idx * 3 + 1);
-      }
-      if (r_edges[1] != -1) {
-        GPU_indexbuf_add_line_verts(&elb_lines, vert_idx * 3 + 1, vert_idx * 3 + 2);
-      }
-      if (r_edges[2] != -1) {
-        GPU_indexbuf_add_line_verts(&elb_lines, vert_idx * 3 + 2, vert_idx * 3 + 0);
-      }
-
-      vert_idx++;
+    int r_edges[3];
+    BKE_mesh_looptri_get_real_edges(mesh, lt, r_edges);
+    if (r_edges[0] != -1) {
+      GPU_indexbuf_add_line_verts(&elb_lines, vert_idx * 3 + 0, vert_idx * 3 + 1);
     }
-    buffers->index_lines_buf = GPU_indexbuf_build(&elb_lines);
+    if (r_edges[1] != -1) {
+      GPU_indexbuf_add_line_verts(&elb_lines, vert_idx * 3 + 1, vert_idx * 3 + 2);
+    }
+    if (r_edges[2] != -1) {
+      GPU_indexbuf_add_line_verts(&elb_lines, vert_idx * 3 + 2, vert_idx * 3 + 0);
+    }
+
+    vert_idx++;
   }
+  buffers->index_lines_buf = GPU_indexbuf_build(&elb_lines);
 
   buffers->tot_tri = tottri;