shaders/light_clearskies.glsl

   1 //const vec3  DAYSKY_COLOUR   = vec3( 0.37, 0.54, 0.97 );
   2 //const vec3  NIGHTSKY_COLOUR = vec3( 0.03, 0.05, 0.20 );
   3 //const vec3  SUNSET_COLOUR   = vec3( 1.00, 0.32, 0.01 );
   4 //const vec3  AMBIENT_COLOUR  = vec3( 0.13, 0.17, 0.35 );
   5 //const vec3  SUNSET_AMBIENT  = vec3( 0.25, 0.17, 0.51 );
   6 //const vec3  SUN_COLOUR      = vec3( 1.10, 0.89, 0.35 );
   7
   8 const float SUN_ANGLE       = 0.0001;
   9 const float PI              = 3.14159265;
  10
  11 //struct world_info
  12 //{
  13 //   float time,
  14 //         time_of_day,
  15 //         day_phase,
  16 //         sunset_phase;
  17 //
  18 //   vec3 sun_dir;
  19 //};
  20
  21 float luminance( vec3 v )
  22 {
  23    return dot( v, vec3(0.2126, 0.7152, 0.0722) );
  24 }
  25
  26 vec3 clearskies_ambient( vec3 dir )
  27 {
  28    float sun_azimuth  = g_sunset_phase * (dot( dir.xz, g_sun_dir.xz )*0.4+0.6);
  29    float sky_gradient = dir.y;
  30
  31    /* Blend phase colours */
  32    vec3 ambient  = g_daysky_colour.rgb   * (g_day_phase-g_sunset_phase*0.1);
  33         ambient += g_sunset_colour.rgb   * (1.0-dir.y*0.5)*sun_azimuth;
  34         ambient += g_nightsky_colour.rgb * (1.0-g_day_phase);
  35
  36    /* Add gradient */
  37         ambient -= sky_gradient * luminance(ambient);
  38
  39    return ambient;
  40 }
  41
  42 vec3 clearskies_sky( vec3 ray_dir )
  43 {
  44    ray_dir.y = abs( ray_dir.y );
  45    vec3 sky_colour  = clearskies_ambient( ray_dir );
  46
  47    /* Sun */
  48    float sun_theta  = dot( ray_dir, g_sun_dir.xyz );
  49    float sun_size   = max( 0.0, sun_theta * 0.5 + 0.5 + SUN_ANGLE );
  50    float sun_shape  = pow( sun_size, 2000.0 );
  51          sun_shape += sun_size * max(g_sun_dir.y,0.0) * 0.5;
  52
  53    vec3 sun_colour  = mix( vec3(1.0), g_sunset_colour.rgb, g_sunset_phase*0.5 );
  54         sun_colour *= sun_shape;
  55
  56    vec3 composite   = sky_colour + sun_colour;
  57    return composite;
  58 }
  59
  60 vec3 clearskies_lighting( vec3 normal, float shadow, vec3 halfview )
  61 {
  62    float fresnel = 1.0 - abs(dot(normal,halfview));
  63
  64    vec3  reflect_colour = mix( g_daysky_colour.rgb, g_sunset_colour.rgb,
  65                                g_sunset_phase );
  66
  67    vec3  sky_reflection = 0.5 * fresnel * reflect_colour;
  68    vec3  light_sun      = max(0.0,dot(normal,g_sun_dir.xyz)*0.75+0.25)
  69                            * g_sun_colour.rgb * g_day_phase;
  70
  71    float scaled_shadow = max( shadow, 1.0 - max(g_sun_dir.y,0.0) );
  72    vec3 ambient = mix( g_ambient_colour.rgb, g_sunset_ambient.rgb,
  73                        g_sunset_phase );
  74
  75    return ambient + (light_sun + sky_reflection) * shadow;
  76 }