source: data/branches/Shader_HS18/programs/GLSL120/OffsetMapping_specular.glsl @ 12115

#version 120

uniform vec4 lightDiffuse;
uniform vec4 lightSpecular;
uniform vec4 scaleBias;
uniform float exponent;
uniform sampler2D normalHeightMap;

varying vec3 tangentEyeDir;
varying vec3 tangentLightDir[2];
varying vec4 shadowUV[2];
varying vec4 oUv0;

vec4 lit(float NdotL, float NdotH, float m) {

  float ambient = 1.0;
  float diffuse = max(NdotL, 0.0);
  float specular = step(0.0, NdotL) * max(NdotH * m, 0.0);

  return vec4(ambient, diffuse, specular, 1.0);
}

vec3 expand(vec3 v)
{
        return (v - 0.5) * 2.0;
}

/*
  Pixel Shader for doing bump mapping with parallax plus diffuse and specular lighting by masterfalcon
*/
void main()
{
        float height = texture2D(normalHeightMap, oUv0.xy).a;
        float displacement = (height * scaleBias.x) + scaleBias.y;
        vec2 newTexCoord = ((tangentEyeDir * displacement) + oUv0.xyz).xy;
        vec3 bumpVec = expand(texture2D(normalHeightMap, newTexCoord).xyz);
        vec3 N = normalize(bumpVec);

        vec3 halfAngle = normalize(tangentEyeDir + tangentLightDir[0]); 
        float NdotL = dot(normalize(tangentLightDir[0]), N);
        float NdotH = dot(normalize(halfAngle), N); 

        vec4 Lit = lit(NdotL, NdotH, exponent);
        
        gl_FragColor = lightDiffuse * Lit.y + lightSpecular * Lit.z;
}