Fix T77130: Visually broken/stepped wireframe in object mode (regression)

Create a new shader for the selection fix.

Differential Revision: https://developer.blender.org/D7873

5 files changed, 28 insertions, 14 deletions

diff --git a/source/blender/draw/engines/overlay/overlay_extra.c b/source/blender/draw/engines/overlay/overlay_extra.c
index 32085890f20..653fd22769e 100644
--- a/source/blender/draw/engines/overlay/overlay_extra.c
+++ b/source/blender/draw/engines/overlay/overlay_extra.c
@@ -65,6 +65,7 @@ void OVERLAY_extra_cache_init(OVERLAY_Data *vedata)
   OVERLAY_PassList *psl = vedata->psl;
   OVERLAY_TextureList *txl = vedata->txl;
   OVERLAY_PrivateData *pd = vedata->stl->pd;
+  const bool is_select = DRW_state_is_select();
 
   DRWState state_blend = DRW_STATE_WRITE_COLOR | DRW_STATE_BLEND_ALPHA;
   DRW_PASS_CREATE(psl->extra_blend_ps, state_blend | pd->clipping_state);
@@ -108,7 +109,7 @@ void OVERLAY_extra_cache_init(OVERLAY_Data *vedata)
     /* Sorted by shader to avoid state changes during render. */
     {
       format = formats->instance_extra;
-      sh = OVERLAY_shader_extra();
+      sh = OVERLAY_shader_extra(is_select);
 
       grp = DRW_shgroup_create(sh, extra_ps);
       DRW_shgroup_uniform_block_persistent(grp, "globalsBlock", G_draw.block_ubo);
@@ -179,7 +180,7 @@ void OVERLAY_extra_cache_init(OVERLAY_Data *vedata)
       cb->groundline = BUF_INSTANCE(grp, format, DRW_cache_groundline_get());
     }
     {
-      sh = OVERLAY_shader_extra_wire(false);
+      sh = OVERLAY_shader_extra_wire(false, is_select);
 
       grp = DRW_shgroup_create(sh, extra_ps);
       DRW_shgroup_uniform_block_persistent(grp, "globalsBlock", G_draw.block_ubo);
@@ -188,7 +189,7 @@ void OVERLAY_extra_cache_init(OVERLAY_Data *vedata)
       cb->extra_lines = BUF_LINE(grp, formats->wire_extra);
     }
     {
-      sh = OVERLAY_shader_extra_wire(true);
+      sh = OVERLAY_shader_extra_wire(true, is_select);
 
       cb->extra_wire = grp = DRW_shgroup_create(sh, extra_ps);
       DRW_shgroup_uniform_block_persistent(grp, "globalsBlock", G_draw.block_ubo);
diff --git a/source/blender/draw/engines/overlay/overlay_private.h b/source/blender/draw/engines/overlay/overlay_private.h
index fa7c7f6d090..fdc421b29fb 100644
--- a/source/blender/draw/engines/overlay/overlay_private.h
+++ b/source/blender/draw/engines/overlay/overlay_private.h
@@ -589,9 +589,9 @@ GPUShader *OVERLAY_shader_edit_mesh_skin_root(void);
 GPUShader *OVERLAY_shader_edit_mesh_vert(void);
 GPUShader *OVERLAY_shader_edit_particle_strand(void);
 GPUShader *OVERLAY_shader_edit_particle_point(void);
-GPUShader *OVERLAY_shader_extra(void);
+GPUShader *OVERLAY_shader_extra(bool is_select);
 GPUShader *OVERLAY_shader_extra_groundline(void);
-GPUShader *OVERLAY_shader_extra_wire(bool use_object);
+GPUShader *OVERLAY_shader_extra_wire(bool use_object, bool is_select);
 GPUShader *OVERLAY_shader_extra_loose_point(void);
 GPUShader *OVERLAY_shader_extra_point(void);
 GPUShader *OVERLAY_shader_facing(void);
diff --git a/source/blender/draw/engines/overlay/overlay_shader.c b/source/blender/draw/engines/overlay/overlay_shader.c
index 59f388df4e3..0610b8397a1 100644
--- a/source/blender/draw/engines/overlay/overlay_shader.c
+++ b/source/blender/draw/engines/overlay/overlay_shader.c
@@ -164,8 +164,10 @@ typedef struct OVERLAY_Shaders {
   GPUShader *edit_particle_strand;
   GPUShader *edit_particle_point;
   GPUShader *extra;
+  GPUShader *extra_select;
   GPUShader *extra_groundline;
   GPUShader *extra_wire[2];
+  GPUShader *extra_wire_select;
   GPUShader *extra_point;
   GPUShader *extra_lightprobe_grid;
   GPUShader *extra_loose_point;
@@ -797,23 +799,24 @@ GPUShader *OVERLAY_shader_edit_particle_point(void)
   return sh_data->edit_particle_point;
 }
 
-GPUShader *OVERLAY_shader_extra(void)
+GPUShader *OVERLAY_shader_extra(bool is_select)
 {
   const DRWContextState *draw_ctx = DRW_context_state_get();
   const GPUShaderConfigData *sh_cfg = &GPU_shader_cfg_data[draw_ctx->sh_cfg];
   OVERLAY_Shaders *sh_data = &e_data.sh_data[draw_ctx->sh_cfg];
-  if (!sh_data->extra) {
-    sh_data->extra = GPU_shader_create_from_arrays({
+  GPUShader **sh = (is_select) ? &sh_data->extra_select : &sh_data->extra;
+  if (!*sh) {
+    *sh = GPU_shader_create_from_arrays({
         .vert = (const char *[]){sh_cfg->lib,
                                  datatoc_common_globals_lib_glsl,
                                  datatoc_common_view_lib_glsl,
                                  datatoc_extra_vert_glsl,
                                  NULL},
         .frag = (const char *[]){datatoc_common_view_lib_glsl, datatoc_extra_frag_glsl, NULL},
-        .defs = (const char *[]){sh_cfg->def, NULL},
+        .defs = (const char *[]){sh_cfg->def, (is_select) ? "#define SELECT_EDGES\n" : NULL, NULL},
     });
   }
-  return sh_data->extra;
+  return *sh;
 }
 
 GPUShader *OVERLAY_shader_extra_grid(void)
@@ -855,12 +858,13 @@ GPUShader *OVERLAY_shader_extra_groundline(void)
   return sh_data->extra_groundline;
 }
 
-GPUShader *OVERLAY_shader_extra_wire(bool use_object)
+GPUShader *OVERLAY_shader_extra_wire(bool use_object, bool is_select)
 {
   const DRWContextState *draw_ctx = DRW_context_state_get();
   const GPUShaderConfigData *sh_cfg = &GPU_shader_cfg_data[draw_ctx->sh_cfg];
   OVERLAY_Shaders *sh_data = &e_data.sh_data[draw_ctx->sh_cfg];
-  if (!sh_data->extra_wire[use_object]) {
+  GPUShader **sh = (is_select) ? &sh_data->extra_wire_select : &sh_data->extra_wire[use_object];
+  if (!*sh) {
     char colorids[1024];
     /* NOTE: define all ids we need here. */
     BLI_snprintf(colorids,
@@ -875,7 +879,7 @@ GPUShader *OVERLAY_shader_extra_wire(bool use_object)
                  TH_TRANSFORM,
                  TH_WIRE,
                  TH_CAMERA_PATH);
-    sh_data->extra_wire[use_object] = GPU_shader_create_from_arrays({
+    *sh = GPU_shader_create_from_arrays({
         .vert = (const char *[]){sh_cfg->lib,
                                  datatoc_common_globals_lib_glsl,
                                  datatoc_common_view_lib_glsl,
@@ -884,11 +888,12 @@ GPUShader *OVERLAY_shader_extra_wire(bool use_object)
         .frag = (const char *[]){datatoc_common_view_lib_glsl, datatoc_extra_wire_frag_glsl, NULL},
         .defs = (const char *[]){sh_cfg->def,
                                  colorids,
+                                 (is_select) ? "#define SELECT_EDGES\n" : "",
                                  (use_object) ? "#define OBJECT_WIRE \n" : NULL,
                                  NULL},
     });
   }
-  return sh_data->extra_wire[use_object];
+  return *sh;
 }
 
 GPUShader *OVERLAY_shader_extra_loose_point(void)
diff --git a/source/blender/draw/engines/overlay/shaders/extra_vert.glsl b/source/blender/draw/engines/overlay/shaders/extra_vert.glsl
index 1662e6519c7..2168d8065fc 100644
--- a/source/blender/draw/engines/overlay/shaders/extra_vert.glsl
+++ b/source/blender/draw/engines/overlay/shaders/extra_vert.glsl
@@ -221,10 +221,12 @@ void main()
   /* Convert to screen position [0..sizeVp]. */
   edgePos = edgeStart = ((gl_Position.xy / gl_Position.w) * 0.5 + 0.5) * sizeViewport.xy;
 
+#ifdef SELECT_EDGES
   /* HACK: to avoid loosing sub pixel object in selections, we add a bit of randomness to the
    * wire to at least create one fragment that will pass the occlusion query. */
   /* TODO(fclem) Limit this workaround to selection. It's not very noticeable but still... */
   gl_Position.xy += sizeViewportInv.xy * gl_Position.w * ((gl_VertexID % 2 == 0) ? -1.0 : 1.0);
+#endif
 
 #ifdef USE_WORLD_CLIP_PLANES
   world_clip_planes_calc_clip_distance(world_pos);
diff --git a/source/blender/draw/engines/overlay/shaders/extra_wire_vert.glsl b/source/blender/draw/engines/overlay/shaders/extra_wire_vert.glsl
index 9598f8b2814..0fbf9ba8137 100644
--- a/source/blender/draw/engines/overlay/shaders/extra_wire_vert.glsl
+++ b/source/blender/draw/engines/overlay/shaders/extra_wire_vert.glsl
@@ -17,10 +17,12 @@ void main()
   vec3 world_pos = point_object_to_world(pos);
   gl_Position = point_world_to_ndc(world_pos);
 
+#ifdef SELECT_EDGES
   /* HACK: to avoid loosing sub pixel object in selections, we add a bit of randomness to the
    * wire to at least create one fragment that will pass the occlusion query. */
   /* TODO(fclem) Limit this workaround to selection. It's not very noticeable but still... */
   gl_Position.xy += sizeViewportInv.xy * gl_Position.w * ((gl_VertexID % 2 == 0) ? -1.0 : 1.0);
+#endif
 
   stipple_coord = stipple_start = screen_position(gl_Position);
 
@@ -39,6 +41,10 @@ void main()
   }
 #endif
 
+#ifdef SELECT_EDGES
+  finalColor.a = 0.0; /* No Stipple */
+#endif
+
 #ifdef USE_WORLD_CLIP_PLANES
   world_clip_planes_calc_clip_distance(world_pos);
 #endif