/// <summary>
/// Basic lighting vertex shader.
/// </summary>


/// <summary>
/// Material source structure.
/// <summary>
struct MaterialSource
{
    vec3 Ambient;
    vec4 Diffuse;
    vec3 Specular;
    float Shininess;
    vec2 TextureOffset;
    vec2 TextureScale;
};


/// <summary>
/// Attributes.
/// <summary>
attribute vec3 Vertex;
attribute vec2 Uv;
attribute vec3 Normal;


/// <summary>
/// Uniform variables.
/// <summary>
uniform mat4 ProjectionMatrix;
uniform mat4 ViewMatrix;
uniform mat4 ModelMatrix;
uniform vec3 ModelScale;

uniform MaterialSource Material;


/// <summary>
/// Varying variables.
/// <summary>
varying vec4 vWorldVertex;
varying vec3 vWorldNormal;
varying vec2 vUv;
varying vec3 vViewVec;


/// <summary>
/// Vertex shader entry.
/// <summary>
void main ()
{
    // Transform the vertex
    vWorldVertex = ModelMatrix * vec4(Vertex * ModelScale, 1.0);
    vec4 viewVertex = ViewMatrix * vWorldVertex;
    gl_Position = ProjectionMatrix * viewVertex;
    
    // Setup the UV coordinates
    vUv = Material.TextureOffset + (Uv * Material.TextureScale);
    
    // Rotate normal
    vWorldNormal = normalize(mat3(ModelMatrix) * Normal);
    
    // Calculate view vector (for specular lighting)
    vViewVec = normalize(-viewVertex.xyz);
}
                            
                        

                            
/// <summary>
/// Vertex shader for rendering a 2D plane on the screen. The plane should be sized
/// from -1.0 to 1.0 in the x and y axis. This shader can be shared amongst multiple
/// post-processing fragment shaders.
/// </summary>


/// <summary>
/// Attributes.
/// <summary>
attribute vec3 Vertex;
attribute vec2 Uv;


/// <summary>
/// Uniform variables.
/// <summary>
uniform mat4 ProjectionMatrix;
uniform mat4 ViewMatrix;
uniform mat4 ModelMatrix;
uniform vec3 ModelScale;


/// <summary>
/// Varying variables.
/// <summary>
varying vec2 vUv;


/// <summary>
/// Vertex shader entry.
/// <summary>
void main ()
{
    vec4 worldVertex = ModelMatrix * vec4(Vertex * ModelScale, 1.0);
    vec4 viewVertex = ViewMatrix * worldVertex;
    gl_Position = ProjectionMatrix * viewVertex;
    
    vUv = Uv;
}
                            
                        

                            
/// <summary>
/// Vertex shader for rendering a cubemapped skybox.
/// </summary>


/// <summary>
/// Attributes.
/// <summary>
attribute vec3 Vertex;
attribute vec3 Normal;


/// <summary>
/// Uniform variables.
/// <summary>
uniform mat4 ProjectionMatrix;
uniform mat4 ViewMatrix;
uniform mat4 ModelMatrix;
uniform vec3 ModelScale;


/// <summary>
/// Varying variables.
/// <summary>
varying vec3 vNormal;


/// <summary>
/// Vertex shader entry.
/// <summary>
void main ()
{
    gl_Position = ProjectionMatrix * ViewMatrix * ModelMatrix * vec4(Vertex * ModelScale, 1.0);
    vNormal = Normal;
}
                            
                        

                            
/// <summary>
/// Basic lighting fragment shader.
/// </summary>


#ifdef GL_ES
    precision highp float;
#endif


/// <summary>
/// Light source structure.
/// <summary>
struct LightSource
{
    vec3 Position;
    vec3 Attenuation;
    vec3 Direction;
    vec3 Colour;
    float OuterCutoff;
    float InnerCutoff;
    float Exponent;
};


/// <summary>
/// Material source structure.
/// <summary>
struct MaterialSource
{
    vec3 Ambient;
    vec4 Diffuse;
    vec3 Specular;
    float Shininess;
    vec2 TextureOffset;
    vec2 TextureScale;
};


/// <summary>
/// Uniform variables.
/// <summary>
uniform int NumLight;
uniform LightSource Light[4];
uniform MaterialSource Material;
uniform sampler2D Sample0;


/// <summary>
/// Varying variables.
/// <summary>
varying vec4 vWorldVertex;
varying vec3 vWorldNormal;
varying vec2 vUv;
varying vec3 vViewVec;


/// <summary>
/// Fragment shader entry.
/// <summary>
void main ()
{
    // vWorldNormal is interpolated when passed into the fragment shader.
    // We need to renormalize the vector so that it stays at unit length.
    vec3 normal = normalize(vWorldNormal);

    vec3 colour = Material.Ambient;
    for (int i = 0; i < 4; ++i)
    {
        if ( i >= NumLight )
            break;
        
        // Calculate diffuse term
        vec3 lightVec = normalize(Light[i].Position - vWorldVertex.xyz);
        float l = dot(normal, lightVec);
        if ( l > 0.0 )
        {
            // Calculate spotlight effect
            float spotlight = 1.0;
            if ( (Light[i].Direction.x != 0.0) || (Light[i].Direction.y != 0.0) || (Light[i].Direction.z != 0.0) )
            {
                spotlight = max(-dot(lightVec, Light[i].Direction), 0.0);
                float spotlightFade = clamp((Light[i].OuterCutoff - spotlight) / (Light[i].OuterCutoff - Light[i].InnerCutoff), 0.0, 1.0);
                spotlight = pow(spotlight * spotlightFade, Light[i].Exponent);
            }
            
            // Calculate specular term
            vec3 r = -normalize(reflect(lightVec, normal));
            float s = pow(max(dot(r, vViewVec), 0.0), Material.Shininess);
            
            // Calculate attenuation factor
            float d = distance(vWorldVertex.xyz, Light[i].Position);
            float a = 1.0 / (Light[i].Attenuation.x + (Light[i].Attenuation.y * d) + (Light[i].Attenuation.z * d * d));
            
            // Add to colour
            colour += ((Material.Diffuse.xyz * l) + (Material.Specular * s)) * Light[i].Colour * a * spotlight;
        }
    }
    
    gl_FragColor = clamp(vec4(colour, Material.Diffuse.w), 0.0, 1.0) * texture2D(Sample0, vUv);
}
                            
                        

                            
/// <summary>
/// Fragment shader for rendering a cubemapped skybox.
/// </summary>


#ifdef GL_ES
    precision highp float;
#endif


/// <summary>
/// Uniform variables.
/// <summary>
uniform samplerCube Sample0;


/// <summary>
/// Varying variables.
/// <summary>
varying vec3 vNormal;


/// <summary>
/// Fragment shader entry.
/// <summary>
void main ()
{
    gl_FragColor = textureCube(Sample0, vNormal);
}
                            
                        

                            
/// <summary>
/// Shader for tagging pixels that will be affected by the refraction shader.
/// </summary>


#ifdef GL_ES
    precision highp float;
#endif


/// <summary>
/// Fragment shader entry.
/// <summary>
void main ()
{
    // Simply set the alpha value
    gl_FragColor.w = 0.0;
}
                            
                        

                            
/// <summary>
/// Shader to refract all pixels with their alpha channel set to 0.
/// </summary>


#ifdef GL_ES
    precision highp float;
#endif


/// <summary>
/// Uniform variables.
/// <summary>
uniform vec2 ImageSize;
uniform vec2 TexelSize;
uniform sampler2D Sample0;

/// <summary>
/// Size of the refraction.
/// <summary>
uniform float Amplitude;

/// <summary>
/// Frequency of the refraction.
/// <summary>
uniform float Frequency;

/// <summary>
/// Relative speed (period) of the refraction.
/// <summary>
uniform float Period;

/// <summary>
/// Random number to animate or mix up the refracted results.
/// <summary>
uniform float RandomNumber;


/// <summary>
/// Varying variables.
/// <summary>
varying vec2 vUv;


// Description : Array and textureless GLSL 3D simplex noise function.
//      Author : Ian McEwan, Ashima Arts.
//  Maintainer : ijm
//     Lastmod : 20110822 (ijm)
//     License : Copyright (C) 2011 Ashima Arts. All rights reserved.
//               Distributed under the MIT License. See LICENSE file.
//               https://github.com/ashima/webgl-noise
vec3 mod289(vec3 x) { return x - floor(x * (1.0 / 289.0)) * 289.0; }
vec4 mod289(vec4 x) { return x - floor(x * (1.0 / 289.0)) * 289.0; }
vec4 permute(vec4 x) { return mod289(((x*34.0)+1.0)*x); }
vec4 taylorInvSqrt(vec4 r) { return 1.79284291400159 - 0.85373472095314 * r; }
float snoise(vec3 v)
{ 
  const vec2  C = vec2(1.0/6.0, 1.0/3.0) ;
  const vec4  D = vec4(0.0, 0.5, 1.0, 2.0);

  // First corner
  vec3 i  = floor(v + dot(v, C.yyy) );
  vec3 x0 =   v - i + dot(i, C.xxx) ;

  // Other corners
  vec3 g = step(x0.yzx, x0.xyz);
  vec3 l = 1.0 - g;
  vec3 i1 = min( g.xyz, l.zxy );
  vec3 i2 = max( g.xyz, l.zxy );

  //   x0 = x0 - 0.0 + 0.0 * C.xxx;
  //   x1 = x0 - i1  + 1.0 * C.xxx;
  //   x2 = x0 - i2  + 2.0 * C.xxx;
  //   x3 = x0 - 1.0 + 3.0 * C.xxx;
  vec3 x1 = x0 - i1 + C.xxx;
  vec3 x2 = x0 - i2 + C.yyy; // 2.0*C.x = 1/3 = C.y
  vec3 x3 = x0 - D.yyy;      // -1.0+3.0*C.x = -0.5 = -D.y

  // Permutations
  i = mod289(i); 
  vec4 p = permute( permute( permute( 
             i.z + vec4(0.0, i1.z, i2.z, 1.0 ))
           + i.y + vec4(0.0, i1.y, i2.y, 1.0 )) 
           + i.x + vec4(0.0, i1.x, i2.x, 1.0 ));

  // Gradients: 7x7 points over a square, mapped onto an octahedron.
  // The ring size 17*17 = 289 is close to a multiple of 49 (49*6 = 294)
  float n_ = 0.142857142857; // 1.0/7.0
  vec3  ns = n_ * D.wyz - D.xzx;

  vec4 j = p - 49.0 * floor(p * ns.z * ns.z);  //  mod(p,7*7)

  vec4 x_ = floor(j * ns.z);
  vec4 y_ = floor(j - 7.0 * x_ );    // mod(j,N)

  vec4 x = x_ *ns.x + ns.yyyy;
  vec4 y = y_ *ns.x + ns.yyyy;
  vec4 h = 1.0 - abs(x) - abs(y);

  vec4 b0 = vec4( x.xy, y.xy );
  vec4 b1 = vec4( x.zw, y.zw );

  //vec4 s0 = vec4(lessThan(b0,0.0))*2.0 - 1.0;
  //vec4 s1 = vec4(lessThan(b1,0.0))*2.0 - 1.0;
  vec4 s0 = floor(b0)*2.0 + 1.0;
  vec4 s1 = floor(b1)*2.0 + 1.0;
  vec4 sh = -step(h, vec4(0.0));

  vec4 a0 = b0.xzyw + s0.xzyw*sh.xxyy ;
  vec4 a1 = b1.xzyw + s1.xzyw*sh.zzww ;

  vec3 p0 = vec3(a0.xy,h.x);
  vec3 p1 = vec3(a0.zw,h.y);
  vec3 p2 = vec3(a1.xy,h.z);
  vec3 p3 = vec3(a1.zw,h.w);

  //Normalise gradients
  vec4 norm = taylorInvSqrt(vec4(dot(p0,p0), dot(p1,p1), dot(p2, p2), dot(p3,p3)));
  p0 *= norm.x;
  p1 *= norm.y;
  p2 *= norm.z;
  p3 *= norm.w;

  // Mix final noise value
  vec4 m = max(0.6 - vec4(dot(x0,x0), dot(x1,x1), dot(x2,x2), dot(x3,x3)), 0.0);
  m = m * m;
  return 42.0 * dot( m*m, vec4( dot(p0,x0), dot(p1,x1), 
                                dot(p2,x2), dot(p3,x3) ) );
}


/// <summary>
/// Compute the normal using a sobel filter on the adjacent noise pixels.
///
/// Normally you would output the noise to a texture first and then calculate
/// the normals on that texture to improve performance; however everthing is
/// kept in this shader as a single process to help illustrate what's going on.
/// <summary>
/// <returns>A normal vector.</returns>
vec3 GetNormal ()
{
    // Get Sobel values
    vec2 uv = vUv * Frequency;
    float z = RandomNumber * Period;
    
    float tl = snoise(vec3(uv.x - TexelSize.x, uv.y - TexelSize.y, z));
    float t = snoise(vec3(uv.x, uv.y - TexelSize.y, z));
    float tr = snoise(vec3(uv.x + TexelSize.x, uv.y - TexelSize.y, z));
    float l = snoise(vec3(uv.x - TexelSize.x, uv.y, z));
    float r = snoise(vec3(uv.x + TexelSize.x, uv.y, z));
    float bl = snoise(vec3(uv.x - TexelSize.x, uv.y + TexelSize.y, z));
    float b = snoise(vec3(uv.x, uv.y + TexelSize.y, z));
    float br = snoise(vec3(uv.x + TexelSize.x, uv.y + TexelSize.y, z));

    // Sobel filter
    vec3 normal = vec3((-tl - l * 2.0 - bl) + (tr + r * 2.0 + br),
                (-tl - t * 2.0 - tr) + (bl + b * 2.0 + br),
                1.0 / Amplitude);
                        
    // Return normalized vector
    return normalize(normal);
}


/// <summary>
/// Fragment shader entry.
/// <summary>
void main ()
{
    // Refract only tagged pixels (that is, the alpha channel has been set)
    vec2 offset;
    if ( texture2D(Sample0, vUv).w == 0.0 )
    {
        // Method 1: Use noise as the refraction angle.
        // Fast and good results for some scenarios.
        //const float pi = 3.141592;
        //float noise = snoise(vec3((vUv * Frequency), RandomNumber * Period)) * pi;
        //offset = vec2(cos(noise), sin(noise)) * Amplitude * TexelSize;
        
        // Method 2: Get the normal from an animating normalmap to use as the refracted vector.
        // Slower, but better results.
        vec3 normal = GetNormal();
        offset = normal.xy;
    }
    
    // Use the colour at the specified offset into the texture
    gl_FragColor.xyz = texture2D(Sample0, vUv + offset).xyz;
    gl_FragColor.w = 1.0;
}
                            
                        

                            
/// <summary>
/// Fragment shader to modify brightness, contrast, and gamma of an image.
/// </summary>


#ifdef GL_ES
    precision highp float;
#endif


/// <summary>
/// Uniform variables.
/// <summary>
uniform float Brightness;   // 0 is the centre. < 0 = darken, > 1 = brighten
uniform float Contrast;     // 1 is the centre. < 1 = lower contrast, > 1 is raise contrast
uniform float InvGamma;     // Inverse gamma correction applied to the pixel

uniform sampler2D Sample0;  // Colour texture to modify


/// <summary>
/// Varying variables.
/// <summary>
varying vec2 vUv;


/// <summary>
/// Fragment shader entry.
/// <summary>
void main ()
{
    // Get the sample
    vec4 colour = texture2D(Sample0, vUv);
    
    // Adjust the brightness
    colour.xyz = colour.xyz + Brightness;
    
    // Adjust the contrast
    colour.xyz = (colour.xyz - vec3(0.5)) * Contrast + vec3(0.5);
    
    // Clamp result
    colour.xyz = clamp(colour.xyz, 0.0, 1.0);
    
    // Apply gamma correction, except for the alpha channel
    colour.xyz = pow(colour.xyz, vec3(InvGamma));
    
    // Set fragment
    gl_FragColor = colour;
}