// #define TEST
#define X	100
#define Y	100

//#define USE_DBL
#ifdef USE_DBL
#define TYPE_FLT  double
#define TYPE_INT  long
#define MASK      0xFFFF
#define SHIFT     16
#define EPSILSON  4.94065645841247E-324
#else
#define TYPE_FLT  float
#define TYPE_INT  int
#define MASK      0x00FF
#define SHIFT     8
#define EPSILSON  1.401298E-45
#endif

constant sampler_t sampler = CLK_NORMALIZED_COORDS_FALSE |
                                CLK_ADDRESS_CLAMP_TO_EDGE |
                                CLK_FILTER_LINEAR;


struct input {
  int tint_map_selector;
};


kernel void TintMap(read_only image2d_t input_frame, read_write image2d_t output_frame, struct input params) 
{
  int2 gid = (int2)(get_global_id(0), get_global_id(1));
  uint4 pixel = read_imageui(input_frame, sampler, gid);

  private float r_step, g_step, b_step;
  private int r_base, g_base, b_base;

  switch(params.tint_map_selector)
  {
    //gray
    case 0:
      r_base = g_base = b_base = 0;
      r_step = g_step = b_step = 1.0;
    break;
    //blue
    case 1:
      r_base = g_base = b_base = 0;
      r_step = g_step = 0 ;
      b_step = 1.0f;
    break;
    //cool blue
    case 2:
      r_base = 0; 
      g_base = b_base = 255;
      r_step = 1.0f;
      g_step = -1.0f;
      b_step = 0;
    break;
    //copper
    case 3:
      r_base = g_base = b_base = 0;
      r_step = 1.0f;
      g_step = 0.7812f;
      b_step = 0.4975f;
    break;
    //otherwise
    case 4:
      r_base = g_base = b_base = 0;
      r_step = g_step = b_step = 1.0f;
    break;
  }

  uchar data = pixel.x;
  if(data > 0) 
  {
    float r = r_base + data * r_step;
    if(r < 0) r = 0;
    if(r > 255) r = 255; 

    float g = g_base + data * g_step;
    if(g < 0) g = 0;
    if(g > 255) g = 255;

    float b = b_base + data * b_step;
    if(b < 0) b = 0;
    if(b > 255) b = 255;

  #ifdef TEST
    if(gid.x == X && gid.y == Y)
      printf("%u ---", out);
  #endif

    pixel.x = (uchar)b;
    pixel.y = (uchar)g;
    pixel.z = (uchar)r;
    pixel.w = 255;
  }

  write_imageui(output_frame, gid, pixel);
}