SHADER模块整理，初始化代码移至main

parts/shaders/grad2.glsl

@@ -0,0 +1,10 @@
+extern float t,h;
+vec4 effect(vec4 color,Image text,vec2 pos,vec2 scr_pos){
+	float y=scr_pos.y/h;
+	return vec4(
+		.8-y*.6,
+		.2+y*.4,
+		.3+.1*sin(t),
+		1.
+	);
+}