source: data/branches/terrain/shaders/mapped_water.frag @ 3926

varying vec4 refrCoords; 
varying vec4 normCoords; 
varying vec4 viewCoords;
varying vec4 viewTangetSpace;
varying vec4 lightTangetSpace;

uniform sampler2D reflection;
uniform sampler2D refraction;
uniform sampler2D normalMap;
uniform sampler2D dudvMap;
uniform sampler2D depthMap;
uniform vec4 waterColor;

void main()
{
        const float kShine = 128.0;
        const float kDistortion = 0.015;
        const float kRefraction = 0.009;

        vec4 distOffset = texture2D(dudvMap, normCoords.xy) * kDistortion;
        vec4 dudvColor = texture2D(dudvMap, vec2(refrCoords + distOffset));
        dudvColor = normalize(dudvColor * 2.0 - 1.0) * kRefraction;

        vec4 normalVector = texture2D(normalMap, vec2(refrCoords + distOffset));
        normalVector = normalVector * 2.0 - 1.0;
        normalVector.a = 0.0;

        vec4 lightReflection = normalize( reflect(-lightTangetSpace, normalVector) );

        vec4 invertedFresnel = vec4( dot(normalVector, lightReflection ) );
        vec4 fresnelTerm = 1.0 - invertedFresnel;

        vec4 projCoord = viewCoords / viewCoords.q;
        projCoord = (projCoord + 1.0) * 0.5;
        projCoord += dudvColor;
        projCoord = clamp(projCoord, 0.001, 0.999);
        
        vec4 reflectionColor  = texture2D(reflection, projCoord.xy);
        vec4 refractionColor  = texture2D(refraction, projCoord.xy);
        vec4 depthValue = texture2D(depthMap, projCoord.xy);
                
        vec4 invDepth = 1.0 - depthValue;
        refractionColor *= invertedFresnel * invDepth;
        refractionColor +=  waterColor * depthValue * invertedFresnel;

        reflectionColor *= fresnelTerm;

        vec4 localView = normalize(viewTangetSpace);            
        float intensity = max(0.0, dot(lightReflection, localView) );
        vec4 specular = vec4(pow(intensity, kShine));

        gl_FragColor = refractionColor + reflectionColor + specular; 
}