Initial commit

shader/bitmapBlit.frag

@@ -0,0 +1,31 @@
+
+uniform sampler2D source;
+uniform sampler2D destination;
+
+uniform vec4 subRect;
+
+uniform float opacity;
+
+void main()
+{
+	vec2 coor = gl_TexCoord[0].xy;
+	vec2 dstCoor = (coor - subRect.xy) * subRect.zw;
+
+	vec4 srcFrag = texture2D(source, coor);
+	vec4 dstFrag = texture2D(destination, dstCoor);
+
+	vec4 resFrag;
+
+	float ab = opacity;
+	const float as = srcFrag.a;
+	const float ad = dstFrag.a;
+
+	const float at = ab*as;
+	resFrag.a = at + ad - ad*at;
+
+	resFrag.rgb = mix(dstFrag.rgb, srcFrag.rgb, ab*as);
+//	resFrag.rgb /= (resFrag.a);
+	resFrag.rgb = mix(srcFrag.rgb, resFrag.rgb, ad*resFrag.a);
+
+	gl_FragColor = resFrag;
+}