parse abr from PS 2018, restore xmp injection, check uniform hash collision

data/layout.xml

@@ -1024,7 +1024,7 @@ PanoPainter - Copyright 2018 OmixLab Ltd
   In the late 2016 Facebook started to make it possible for users to post 360 content
   captured from the first 360 cameras born after the advent of the VR to the market.
   
-    That's where me and a bounch or artists started to wonder about making art in 360.
+  That's where me and a bunch or artists started to wonder about making art in 360.
   I then started coding in my spare time to create something that would have helped 
   artists in the long process of creating a panoramic painting (panopainting).
   
@@ -1036,6 +1036,7 @@ PanoPainter - Copyright 2018 OmixLab Ltd
   - Instagram: @panopainter
   - Twitter: @panopainter
   - Facebook: fb.me/panopainter
+  - Reddit: reddit.com/r/panopainter
   
                       
 ------------------------------------------------- FREE SOFTWARE LICENSES -------------------------------------------------

data/shaders/comp-draw.glsl

@@ -51,7 +51,8 @@ void main()
 {
     mediump vec4 base = texture(tex, uv);
     mediump vec4 stroke = texture(tex_stroke, uv);
-    if (stroke.a == 0)
+    
+    if (stroke.a == 0.0)
     {
         frag = base;
         return;
@@ -68,13 +69,13 @@ void main()
             patt = brightness1(patt, 1.0 - pattern_bright);
         if (pattern_contr != 0.5)
             patt = contrast1(patt, pattern_contr);
-        stroke.a = blend_stroke(stroke.a, patt, pattern_depth, patt_blend_mode);
+        stroke.a = clamp(blend_stroke(stroke.a, patt, pattern_depth, patt_blend_mode), 0.0, 1.0);
     }
 
     if (use_dual)
     {
         mediump vec4 dual = texture(tex_dual, uv);
-        stroke.a = blend_stroke(stroke.a, dual.a, dual_alpha, dual_blend_mode);
+        stroke.a = clamp(blend_stroke(stroke.a, dual.a, dual_alpha, dual_blend_mode), 0.0, 1.0);
     }
 
     stroke.a = mask ? stroke.a * blur(tex_mask, uv).r : stroke.a;