From 676a795d6eae1f01eb34234abed209b01b7251a6 Mon Sep 17 00:00:00 2001
From: itsmattkc <itsmattkc@gmail.com>
Date: Thu, 31 Jan 2019 03:30:26 +1100
Subject: [PATCH] more accurate opacity fix

---
 effects/internal/blending.frag | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/effects/internal/blending.frag b/effects/internal/blending.frag
index b211aa801..c8d14d593 100644
--- a/effects/internal/blending.frag
+++ b/effects/internal/blending.frag
@@ -180,7 +180,7 @@ void main(void) {
 	vec3 composite = blend(bg_color.rgb, fg_color.rgb);	
 
 	// add foreground and background alpha's together
-	float alpha_opac = fg_color.a*opacity;
+	// float alpha_opac = fg_color.a*opacity;
 
 	if (blendmode == BLEND_MODE_OVERLAY
 			|| blendmode == BLEND_MODE_LIGHTEN 
@@ -194,13 +194,13 @@ void main(void) {
 			|| blendmode == BLEND_MODE_REFLECT 
 			|| blendmode == BLEND_MODE_EXCLUSION 
 			|| blendmode == BLEND_MODE_DIFFERENCE) {
-		composite *= alpha_opac;
+		composite *= fg_color.a;
 	}
 
-	vec4 full_composite = vec4(composite + bg_color.rgb*(1.0-alpha_opac), bg_color.a + fg_color.a);
+	vec4 full_composite = vec4(composite + bg_color.rgb*(1.0-fg_color.a), bg_color.a + fg_color.a);
 	// vec4 full_composite = vec4(mix(bg_color.rgb, composite, alpha_opac), bg_color.a + alpha_opac);
 
-	full_composite = mix(bg_color, full_composite, alpha_opac);
+	full_composite = mix(bg_color, full_composite, opacity);
 
 	// output to color
 	gl_FragColor = full_composite;