Remove duplication between world/chrome shaders.

glsl/shp.vert

@@ -0,0 +1,18 @@
+uniform vec2 Scroll;
+uniform vec2 r1,r2;		// matrix elements
+
+vec4 DecodeChannelMask( float x )
+{
+	if (x > 0.0)
+		return (x > 0.5) ? vec4(1,0,0,0) : vec4(0,1,0,0);
+	else
+		return (x < -0.5) ? vec4(0,0,0,1) : vec4(0,0,1,0);
+}
+
+void main()
+{
+	vec2 p = (gl_Vertex.xy - Scroll.xy)*r1 + r2;
+	gl_Position = vec4(p.x,p.y,0,1);
+	gl_TexCoord[0] = gl_MultiTexCoord0;
+	gl_TexCoord[1] = DecodeChannelMask(gl_MultiTexCoord0.w);
+}