fix color bleeding

data/shaders/texture-blend.glsl

@@ -18,7 +18,6 @@ void main()
 #include "include/blend.glsl"
 
 uniform sampler2D tex;
-uniform sampler2D tex_alpha;
 uniform sampler2D tex_bg;
 uniform highp float alpha;
 uniform int blend_mode;
@@ -41,7 +40,7 @@ void main()
     highp vec4 bg = texture(tex_bg, uv);
 #endif
 
-    highp vec4 fg = vec4(texture(tex, uv).rgb, texture(tex_alpha, uv).a);
+    highp vec4 fg = texture(tex, uv);
     if (fg.a == 0.0)
     {
         frag = bg;