[Bf-blender-cvs] [d4744d120e4] greasepencil-object: Fix T74477: Onion opacity not working

[Antonio Vazquez]

Commit: d4744d120e407f0e60dfa601063401dcbe254f75
Author: Antonio Vazquez
Date:   Sat Mar 7 11:12:33 2020 +0100
Branches: greasepencil-object
https://developer.blender.org/rBd4744d120e407f0e60dfa601063401dcbe254f75

Fix T74477: Onion opacity not working

Also adjust the low limit when opacity is > 0. This allows to see all frames when the opacity is very low.

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M	source/blender/draw/engines/gpencil/gpencil_cache_utils.c

===================================================================

diff --git a/source/blender/draw/engines/gpencil/gpencil_cache_utils.c b/source/blender/draw/engines/gpencil/gpencil_cache_utils.c
index 9ae273adcd0..743171b09fb 100644
--- a/source/blender/draw/engines/gpencil/gpencil_cache_utils.c
+++ b/source/blender/draw/engines/gpencil/gpencil_cache_utils.c
@@ -219,8 +219,9 @@ static void gpencil_layer_final_tint_and_alpha_get(const GPENCIL_PrivateData *pd
     copy_v4_fl4(r_tint, UNPACK3(onion_col_custom), 1.0f);
 
     *r_alpha = use_onion_fade ? (1.0f / abs(gpf->runtime.onion_id)) : 0.5f;
-    *r_alpha += (gpd->onion_factor * 2.0f - 1.0f);
-    *r_alpha = clamp_f(*r_alpha, 0.01f, 1.0f);
+    *r_alpha *= gpd->onion_factor;
+    *r_alpha = (gpd->onion_factor > 0.0f) ? clamp_f(*r_alpha, 0.1f, 1.0f) :
+                                            clamp_f(*r_alpha, 0.01f, 1.0f);
   }
   else {
     copy_v4_v4(r_tint, gpl->tintcolor);