Fix T66811 Eevee: Flickering in weight paint mode

This was caused by TAA offset being computed as the 2nd sample even if the
sampling was reset afterwards.

The fix is to update the matrices after any potential reset.

2 files changed, 6 insertions, 1 deletions

diff --git a/source/blender/draw/engines/eevee/eevee_effects.c b/source/blender/draw/engines/eevee/eevee_effects.c
index 021afa64fee..1b152afa3bf 100644
--- a/source/blender/draw/engines/eevee/eevee_effects.c
+++ b/source/blender/draw/engines/eevee/eevee_effects.c
@@ -161,6 +161,12 @@ void EEVEE_effects_init(EEVEE_ViewLayerData *sldata,
   effects->enabled_effects |= EEVEE_occlusion_init(sldata, vedata);
   effects->enabled_effects |= EEVEE_screen_raytrace_init(sldata, vedata);
 
+  if ((effects->enabled_effects & EFFECT_TAA) && effects->taa_current_sample > 1) {
+    /* Update matrices here because EEVEE_screen_raytrace_init can have reset the
+     * taa_current_sample. (See T66811) */
+    EEVEE_temporal_sampling_update_matrices(vedata);
+  }
+
   EEVEE_volumes_init(sldata, vedata);
   EEVEE_subsurface_init(sldata, vedata);
 
diff --git a/source/blender/draw/engines/eevee/eevee_temporal_sampling.c b/source/blender/draw/engines/eevee/eevee_temporal_sampling.c
index 099147a82dd..96924efa8bc 100644
--- a/source/blender/draw/engines/eevee/eevee_temporal_sampling.c
+++ b/source/blender/draw/engines/eevee/eevee_temporal_sampling.c
@@ -253,7 +253,6 @@ int EEVEE_temporal_sampling_init(EEVEE_ViewLayerData *UNUSED(sldata), EEVEE_Data
         if (!DRW_state_is_image_render()) {
           effects->taa_current_sample += 1;
           repro_flag = 0;
-          EEVEE_temporal_sampling_update_matrices(vedata);
         }
       }
       else {