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

1 files changed, 46 insertions, 0 deletions

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) {