/* <copyright>
Copyright (c) 2012, Motorola Mobility LLC.
All Rights Reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice,
  this list of conditions and the following disclaimer.

* Redistributions in binary form must reproduce the above copyright notice,
  this list of conditions and the following disclaimer in the documentation
  and/or other materials provided with the distribution.

* Neither the name of Motorola Mobility LLC nor the names of its
  contributors may be used to endorse or promote products derived from this
  software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
</copyright> */


#ifdef GL_ES
precision highp float;
#endif

// lighting uniforms
uniform vec3 u_lightPos;
uniform vec4 u_lightDiff;
uniform vec4 u_lightAmb;

// diffuse map
uniform sampler2D colMap;

// environment map
uniform sampler2D envMap;

// normal map
uniform sampler2D normalMap;

//material uniforms
uniform vec4   u_matAmbient;
uniform vec4   u_matDiffuse;
uniform vec4   u_matSpecular;
uniform float  u_matShininess;
uniform vec4   u_matEmission;
uniform float  u_renderGlow;

// varyings
varying vec4 vNormal; // w = texcoord.x
varying vec4 vECPos;  // w = texcoord.y
varying vec3 vEyePos;

void main()
{
  vec4 colMapTexel = vec4(texture2D(colMap, vec2(vNormal.w, 1.0 - vECPos.w)).rgb, 1.0);

  // normal mapping
  vec3 normal = normalize(vNormal.xyz);
  vec3 mapNormal = texture2D(normalMap, vec2(vNormal.w, vECPos.w)).xyz * 2.0 - 1.0;
  mapNormal = normalize(mapNormal.x*vec3(normal.z, 0.0, -normal.x) + vec3(0.0, mapNormal.y, 0.0) + mapNormal.z*normal);

  // create envmap coordinates
  vec3 r = reflect( normalize(vec3(vECPos.xyz - vEyePos.xyz)), mapNormal);
  float m = 2.0 * sqrt( r.x*r.x + r.y*r.y + r.z*r.z );

  // calculate environment map texel
  vec4 envMapTexel = vec4(texture2D(envMap, vec2(r.x/m + 0.5, r.y/m + 0.5)).rgb, 0.0);

  // lighting
  vec3 lightDirection = u_lightPos - vECPos.xyz;
  float lightDist = length(lightDirection);
  lightDirection /= lightDist;

  float attenuation = clamp(1.0 - lightDist * 0.01, 0.0, 1.0);

  vec3 halfVec = normalize(lightDirection + vEyePos);

  float diffuseIntensity = max(0.0, dot(mapNormal, lightDirection));
  float specularModifier = max(0.0, dot(mapNormal, halfVec));

  float pf;
  if(diffuseIntensity == 0.0)
    pf = 0.0;
  else
    pf = pow(specularModifier, 76.0);

  vec4 ambient = u_matAmbient * u_lightAmb;
  vec4 diffuse = u_matDiffuse * (colMapTexel + envMapTexel);

  if (u_renderGlow <= 0.5)
    diffuse *= u_lightDiff * diffuseIntensity * attenuation;

  vec4 specular = 2.0 * pf * envMapTexel;

  gl_FragColor = (colMapTexel*(ambient + diffuse)) + specular + vec4(0.0,0.0,0.0,1.0);
}