Eevee: Add support for alpha background in viewport

Viewport now displays alpha checkerboard pattern like Cycles does when
film alpha is set to "Transparent".

Some small workarounds were necessary for Depth of Field and correct TAA
support.

1 files changed, 6 insertions, 0 deletions

diff --git a/source/blender/draw/engines/eevee/eevee_private.h b/source/blender/draw/engines/eevee/eevee_private.h
index 8e21c7f389c..b2aeffb0d1a 100644
--- a/source/blender/draw/engines/eevee/eevee_private.h
+++ b/source/blender/draw/engines/eevee/eevee_private.h
@@ -246,6 +246,7 @@ typedef struct EEVEE_PassList {
   struct DRWPass *color_downsample_cube_ps;
   struct DRWPass *velocity_resolve;
   struct DRWPass *taa_resolve;
+  struct DRWPass *alpha_checker;
 
   /* HiZ */
   struct DRWPass *minz_downlevel_ps;
@@ -537,6 +538,7 @@ typedef enum EEVEE_EffectsFlag {
   EFFECT_VELOCITY_BUFFER = (1 << 12),     /* Not really an effect but a feature */
   EFFECT_TAA_REPROJECT = (1 << 13),       /* should be mutually exclusive with EFFECT_TAA */
   EFFECT_DEPTH_DOUBLE_BUFFER = (1 << 14), /* Not really an effect but a feature */
+  EFFECT_ALPHA_CHECKER = (1 << 15),       /* Not really an effect but a feature */
 } EEVEE_EffectsFlag;
 
 typedef struct EEVEE_EffectsInfo {
@@ -598,6 +600,9 @@ typedef struct EEVEE_EffectsInfo {
   struct GPUTexture *dof_coc;
   struct GPUTexture *dof_blur;
   struct GPUTexture *dof_blur_alpha;
+  /* Alpha Checker */
+  float color_checker_dark[4];
+  float color_checker_light[4];
   /* Other */
   float prev_persmat[4][4];
   /* Bloom */
@@ -1073,6 +1078,7 @@ void EEVEE_effects_cache_init(EEVEE_ViewLayerData *sldata, EEVEE_Data *vedata);
 void EEVEE_create_minmax_buffer(EEVEE_Data *vedata, struct GPUTexture *depth_src, int layer);
 void EEVEE_downsample_buffer(EEVEE_Data *vedata, struct GPUTexture *texture_src, int level);
 void EEVEE_downsample_cube_buffer(EEVEE_Data *vedata, struct GPUTexture *texture_src, int level);
+void EEVEE_draw_alpha_checker(EEVEE_Data *vedata);
 void EEVEE_draw_effects(EEVEE_ViewLayerData *sldata, EEVEE_Data *vedata);
 void EEVEE_effects_free(void);