move shaders into .glsl files and add #include feature

data/shaders/lightmap.glsl

@@ -0,0 +1,27 @@
+[[vertex]]
+uniform mat4 mvp;
+in vec4 pos;
+in vec3 nor;
+in vec2 uvs;
+out vec3 n;
+out vec2 uv;
+void main()
+{
+   n = nor;
+   uv = uvs;
+   gl_Position = mvp * pos;
+}
+
+[[fragment]]
+uniform mediump sampler2D tex;
+uniform mediump vec3 light_dir;
+uniform mediump float ambient;
+in mediump vec3 n;
+in mediump vec2 uv;
+out mediump vec4 frag;
+void main()
+{
+   mediump float d = max(0.0, dot(normalize(n), normalize(light_dir)));
+   mediump vec4 c = texture(tex, uv);
+   frag = vec4(c.rgb * d + ambient, 1.0);
+}