1 files changed, 50 insertions, 0 deletions
diff --git a/shaders/moon.frag b/shaders/moon.frag
new file mode 100644
index 0000000..b72005c
--- /dev/null
+++ b/shaders/moon.frag
@@ -0,0 +1,50 @@
+#version 150
+in vec2 texMapping ;
+in vec3 position ;
+in vec3 normal ;
+
+uniform sampler2D texture ;
+uniform vec3 lightPos ;
+uniform float dX ;
+uniform float dY ;
+
+out vec4 frag_color ;
+
+vec4 sample(float xc,float yc) {
+   return texture2D(texture,texMapping + vec2(xc,yc));
+}
+
+
+vec3 calNormChange( vec3 norm, vec3 down, vec3 right ) {
+    float x00 = length(sample(-dX, dY)) ; 
+    float x01 = length(sample(  0, dY)) ; 
+    float x02 = length(sample( dX, dY)) ; 
+
+    float x10 = length(sample(-dX, 0)) ; 
+    float x11 = length(sample(  0, 0)) ; 
+    float x12 = length(sample( dX, 0)) ; 
+
+    float x20 = length(sample(-dX,-dY)) ; 
+    float x21 = length(sample(  0,-dY)) ; 
+    float x22 = length(sample( dX,-dY)) ; 
+
+    down = ((x11 - x00) + (x11 - x01) + (x11 - x02) - (x11 - x20) - (x11 - x21) - (x11 - x22)) * down ;
+    right = ((x11 - x00) + (x11 - x10) + (x11 - x20) - (x11 - x02) - (x11 - x12) - (x11 - x22)) * right ;
+    
+    return (right + down + norm*3.0) / 5.0 ;
+}
+
+void main() {
+    vec3 down = vec3( 0, -1, 0 ) ;
+    vec3 right = normalize(cross( normal, down )) ;
+    down = normalize(cross( normal, right ) );
+
+    vec3 newNorm = calNormChange( normal, down, right ) ;
+    vec3 diff = lightPos - position ;
+    float intensity = max(dot( normalize(diff), normalize(newNorm) ),0.0) ;
+    intensity = sqrt(sqrt( intensity )) ;
+    
+    vec4 tmpcolor = texture2D(texture, texMapping) * intensity ;
+    tmpcolor *= pow(length(tmpcolor),4.0-min(length(position)/4.0,4.0)) ;
+    frag_color = tmpcolor ;
+}