Fix T74923: Weight Painting Overlay Invisible for In Front Objects

For In Front Objects we need to use the in front depth buffer.

This patch will use the in front depth buffer and also makes sure that
it is filled with the center pixel depth.

Reviewed By: fclem

Differential Revision: https://developer.blender.org/D7216

5 files changed, 66 insertions, 1 deletions

diff --git a/source/blender/draw/engines/overlay/overlay_engine.c b/source/blender/draw/engines/overlay/overlay_engine.c
index 9b900a53d8d..9788d38478c 100644
--- a/source/blender/draw/engines/overlay/overlay_engine.c
+++ b/source/blender/draw/engines/overlay/overlay_engine.c
@@ -98,6 +98,7 @@ static void OVERLAY_engine_init(void *vedata)
   OVERLAY_image_init(vedata);
   OVERLAY_outline_init(vedata);
   OVERLAY_wireframe_init(vedata);
+  OVERLAY_paint_init(vedata);
 }
 
 static void OVERLAY_cache_init(void *vedata)
diff --git a/source/blender/draw/engines/overlay/overlay_paint.c b/source/blender/draw/engines/overlay/overlay_paint.c
index e88a69b695e..bb0b124f2ae 100644
--- a/source/blender/draw/engines/overlay/overlay_paint.c
+++ b/source/blender/draw/engines/overlay/overlay_paint.c
@@ -28,6 +28,15 @@
 
 #include "overlay_private.h"
 
+void OVERLAY_paint_init(OVERLAY_Data *vedata)
+{
+  OVERLAY_StorageList *stl = vedata->stl;
+  OVERLAY_PrivateData *pd = stl->pd;
+  const DRWContextState *draw_ctx = DRW_context_state_get();
+
+  pd->painting.in_front = draw_ctx->obact && (draw_ctx->obact->dtx & OB_DRAWXRAY);
+}
+
 void OVERLAY_paint_cache_init(OVERLAY_Data *vedata)
 {
   const DRWContextState *draw_ctx = DRW_context_state_get();
@@ -194,12 +203,15 @@ void OVERLAY_paint_weight_cache_populate(OVERLAY_Data *vedata, Object *ob)
 
 void OVERLAY_paint_draw(OVERLAY_Data *vedata)
 {
+  OVERLAY_StorageList *stl = vedata->stl;
+  OVERLAY_PrivateData *pd = stl->pd;
+
   OVERLAY_PassList *psl = vedata->psl;
   DefaultFramebufferList *dfbl = DRW_viewport_framebuffer_list_get();
 
   if (DRW_state_is_fbo()) {
     /* Pain overlay needs final color because of multiply blend mode. */
-    GPU_framebuffer_bind(dfbl->default_fb);
+    GPU_framebuffer_bind(pd->painting.in_front ? dfbl->in_front_fb : dfbl->default_fb);
   }
 
   if (psl->paint_color_ps) {
diff --git a/source/blender/draw/engines/overlay/overlay_private.h b/source/blender/draw/engines/overlay/overlay_private.h
index de35d4f760e..47c52c885b2 100644
--- a/source/blender/draw/engines/overlay/overlay_private.h
+++ b/source/blender/draw/engines/overlay/overlay_private.h
@@ -317,6 +317,9 @@ typedef struct OVERLAY_PrivateData {
     bool do_pose_fade_geom;
   } armature;
   struct {
+    bool in_front;
+  } painting;
+  struct {
     DRWCallBuffer *handle[2];
   } mball;
 } OVERLAY_PrivateData; /* Transient data */
@@ -524,6 +527,7 @@ void OVERLAY_outline_cache_populate(OVERLAY_Data *vedata,
                                     bool init_dupli);
 void OVERLAY_outline_draw(OVERLAY_Data *vedata);
 
+void OVERLAY_paint_init(OVERLAY_Data *vedata);
 void OVERLAY_paint_cache_init(OVERLAY_Data *vedata);
 void OVERLAY_paint_texture_cache_populate(OVERLAY_Data *vedata, Object *ob);
 void OVERLAY_paint_vertex_cache_populate(OVERLAY_Data *vedata, Object *ob);
diff --git a/source/blender/draw/engines/workbench/workbench_effect_antialiasing.c b/source/blender/draw/engines/workbench/workbench_effect_antialiasing.c
index 3cd21dfeace..3050093062f 100644
--- a/source/blender/draw/engines/workbench/workbench_effect_antialiasing.c
+++ b/source/blender/draw/engines/workbench/workbench_effect_antialiasing.c
@@ -133,6 +133,32 @@ void workbench_antialiasing_view_updated(WORKBENCH_Data *vedata)
   }
 }
 
+/* This function checks if the overlay engine should need center in front depth's.
+ * When that is the case the in front depth are stored and restored. Otherwise it
+ * will be filled with the current sample data. */
+static bool workbench_in_front_history_needed(WORKBENCH_Data *vedata)
+{
+  WORKBENCH_StorageList *stl = vedata->stl;
+  const DRWContextState *draw_ctx = DRW_context_state_get();
+  const View3D *v3d = draw_ctx->v3d;
+  const Object *obact = draw_ctx->obact;
+
+  if (!v3d || (v3d->flag2 & V3D_HIDE_OVERLAYS)) {
+    return false;
+  }
+
+  if (stl->wpd->is_playback) {
+    return false;
+  }
+
+  if (!obact || draw_ctx->object_mode != OB_MODE_WEIGHT_PAINT ||
+      v3d->overlay.weight_paint_mode_opacity == 0.0) {
+    return false;
+  }
+
+  return true;
+}
+
 void workbench_antialiasing_engine_init(WORKBENCH_Data *vedata)
 {
   WORKBENCH_FramebufferList *fbl = vedata->fbl;
@@ -168,6 +194,13 @@ void workbench_antialiasing_engine_init(WORKBENCH_Data *vedata)
 
     DRW_texture_ensure_fullscreen_2d(&txl->history_buffer_tx, GPU_RGBA16F, DRW_TEX_FILTER);
     DRW_texture_ensure_fullscreen_2d(&txl->depth_buffer_tx, GPU_DEPTH24_STENCIL8, 0);
+    const bool in_front_history = workbench_in_front_history_needed(vedata);
+    if (in_front_history) {
+      DRW_texture_ensure_fullscreen_2d(&txl->depth_buffer_in_front_tx, GPU_DEPTH24_STENCIL8, 0);
+    }
+    else {
+      DRW_TEXTURE_FREE_SAFE(txl->depth_buffer_in_front_tx);
+    }
 
     wpd->smaa_edge_tx = DRW_texture_pool_query_fullscreen(GPU_RG8, owner);
     wpd->smaa_weight_tx = DRW_texture_pool_query_fullscreen(GPU_RGBA8, owner);
@@ -177,6 +210,12 @@ void workbench_antialiasing_engine_init(WORKBENCH_Data *vedata)
                                       GPU_ATTACHMENT_TEXTURE(txl->depth_buffer_tx),
                                       GPU_ATTACHMENT_TEXTURE(txl->history_buffer_tx),
                                   });
+    if (in_front_history) {
+      GPU_framebuffer_ensure_config(&fbl->antialiasing_in_front_fb,
+                                    {
+                                        GPU_ATTACHMENT_TEXTURE(txl->depth_buffer_in_front_tx),
+                                    });
+    }
 
     GPU_framebuffer_ensure_config(&fbl->smaa_edge_fb,
                                   {
@@ -227,6 +266,7 @@ void workbench_antialiasing_engine_init(WORKBENCH_Data *vedata)
     /* Cleanup */
     DRW_TEXTURE_FREE_SAFE(txl->history_buffer_tx);
     DRW_TEXTURE_FREE_SAFE(txl->depth_buffer_tx);
+    DRW_TEXTURE_FREE_SAFE(txl->depth_buffer_in_front_tx);
     DRW_TEXTURE_FREE_SAFE(txl->smaa_search_tx);
     DRW_TEXTURE_FREE_SAFE(txl->smaa_area_tx);
   }
@@ -387,6 +427,9 @@ void workbench_antialiasing_draw_pass(WORKBENCH_Data *vedata)
      * In this case no need to save the depth buffer. */
     eGPUFrameBufferBits bits = GPU_COLOR_BIT | (!wpd->is_playback ? GPU_DEPTH_BIT : 0);
     GPU_framebuffer_blit(dfbl->default_fb, 0, fbl->antialiasing_fb, 0, bits);
+    if (workbench_in_front_history_needed(vedata)) {
+      GPU_framebuffer_blit(dfbl->in_front_fb, 0, fbl->antialiasing_in_front_fb, 0, GPU_DEPTH_BIT);
+    }
   }
   else {
     /* Accumulate result to the TAA buffer. */
@@ -394,6 +437,9 @@ void workbench_antialiasing_draw_pass(WORKBENCH_Data *vedata)
     DRW_draw_pass(psl->aa_accum_ps);
     /* Copy back the saved depth buffer for correct overlays. */
     GPU_framebuffer_blit(fbl->antialiasing_fb, 0, dfbl->default_fb, 0, GPU_DEPTH_BIT);
+    if (workbench_in_front_history_needed(vedata)) {
+      GPU_framebuffer_blit(fbl->antialiasing_in_front_fb, 0, dfbl->in_front_fb, 0, GPU_DEPTH_BIT);
+    }
   }
 
   if (!DRW_state_is_image_render() || wpd->taa_sample + 1 == wpd->taa_sample_len) {
diff --git a/source/blender/draw/engines/workbench/workbench_private.h b/source/blender/draw/engines/workbench/workbench_private.h
index 1fa49c8f818..87b1c82ce94 100644
--- a/source/blender/draw/engines/workbench/workbench_private.h
+++ b/source/blender/draw/engines/workbench/workbench_private.h
@@ -88,6 +88,7 @@ typedef struct WORKBENCH_FramebufferList {
   struct GPUFrameBuffer *dof_blur2_fb;
 
   struct GPUFrameBuffer *antialiasing_fb;
+  struct GPUFrameBuffer *antialiasing_in_front_fb;
   struct GPUFrameBuffer *smaa_edge_fb;
   struct GPUFrameBuffer *smaa_weight_fb;
 } WORKBENCH_FramebufferList;
@@ -97,6 +98,7 @@ typedef struct WORKBENCH_TextureList {
   struct GPUTexture *coc_halfres_tx;
   struct GPUTexture *history_buffer_tx;
   struct GPUTexture *depth_buffer_tx;
+  struct GPUTexture *depth_buffer_in_front_tx;
   struct GPUTexture *smaa_search_tx;
   struct GPUTexture *smaa_area_tx;
   struct GPUTexture *dummy_image_tx;