[orx-fx] convert to MPP

orx-fx/src/shaders/glsl/blend/source-in.frag

@@ -0,0 +1,31 @@
+#ifdef OR_IN_OUT
+in vec2 v_texCoord0;
+#else
+varying vec2 v_texCoord0;
+#endif
+
+uniform sampler2D tex0;
+uniform sampler2D tex1;
+
+#ifndef OR_GL_FRAGCOLOR
+out vec4 o_color;
+#endif
+
+void main() {
+    #ifndef OR_GL_TEXTURE2D
+    vec4 src = texture(tex0, v_texCoord0);
+    vec4 dest = texture(tex1, v_texCoord0);
+    #else
+    vec4 src = texture2D(tex0, v_texCoord0);
+    vec4 dest = texture2D(tex1, v_texCoord0);
+    #endif
+
+    float lboth = src.a * dest.a;
+    vec4 result = src * lboth;
+
+    #ifdef OR_GL_FRAGCOLOR
+    gl_FragColor = result;
+    #else
+    o_color = result;
+    #endif
+}