// :D

in vec2 aUv;
in vec4 aNorm;
in vec3 aCo;
in vec3 aWorldCo;

#include "common_world.glsl"

float sdLine( vec3 p, vec3 a, vec3 b )
{
  vec3 pa = p - a;
  vec3 ba = b - a;

  float h = clamp( dot(pa,ba)/dot(ba,ba), 0.0, 1.0 );
  return length( pa - ba*h );
}

float compute_board_shadow()
{
   // player shadow
   float dist_to_player = max( 0.0, sdLine( aWorldCo, g_board_0.xyz,
                                                      g_board_1.xyz )-0.1 );
   float player_shadow = max( 1.0-dist_to_player*2.7, 0.0 );
   player_shadow *= player_shadow*player_shadow*player_shadow;

   return 1.0 - player_shadow*0.8;
}

vec3 scene_compute_lighting( vec3 diffuse, vec3 normal, vec3 co )
{
   return world_compute_lighting( diffuse, normal, co, compute_board_shadow() );
}