1 files changed, 39 insertions, 1 deletions
diff --git a/shaders/water.frag b/shaders/water.frag
index 8a0dd0b..9298d15 100644
--- a/shaders/water.frag
+++ b/shaders/water.frag
@@ -3,7 +3,45 @@
 #extension GL_ARB_explicit_uniform_location : enable
 
 layout(location = 0) out vec4 frag_color ;
+layout(location = 8) uniform vec4 lightPos ;
+ uniform sampler2D texture ;
+
+in vec3 normal ;
+in vec4 position ;
+in vec2 texpos ;
+
+float dX = 1 / 512.0 ;
+float dY = 1 / 512.0 ;
+vec4 sample(float xc,float yc) {
+   return texture2D(texture,texpos + vec2(xc,yc));
+}
+
+vec3 calNormChange( vec3 norm, vec3 down, vec3 right ) {
+    float x00 = 1 - length(sample(-dX, dY)) ; 
+    float x01 = 1 - length(sample(  0, dY)) ; 
+    float x02 = 1 - length(sample( dX, dY)) ; 
+
+    float x10 = 1 - length(sample(-dX, 0)) ; 
+    float x11 = 1 - length(sample(  0, 0)) ; 
+    float x12 = 1 - length(sample( dX, 0)) ; 
+
+    float x20 = 1 - length(sample(-dX,-dY)) ; 
+    float x21 = 1 - length(sample(  0,-dY)) ; 
+    float x22 = 1 - 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*2 + down*2 + norm) / 5.0 ;
+}
 
 void main() {
-    frag_color = vec4(0.0,0.3,0.7,0.5) ;
+    vec3 down = vec3( 0, -1, 0 ) ;
+    vec3 right = normalize(cross( normal, down )) ;
+    down = normalize(cross( normal, right ) );
+    vec3 newNorm = calNormChange( normal, down, right ) ;
+
+    float coef = dot( normalize(vec3(lightPos) - vec3(position)), normalize(newNorm) ) ;
+    vec4 color = texture2D(texture,texpos) ;
+    frag_color = vec4(color.xyz * vec3(0.0,0.4,0.7) * coef,0.8);
 }