#version 450
#extension GL_EXT_buffer_reference : require

#include "hex_common.glsl"

layout(location = 0) flat out vec4 color;

void main() {
  int hex_index;
  Region region;
  float raise;
  if(gl_InstanceIndex == 0) {
    hex_index = pc.context.clicked_hex;
    region = pc.context.regions[pc.context.clicked_region];
    color = vec4(0.5, 0.5, 0.5, 0.3);
    raise = 0.015;
  } else {
    hex_index = pc.context.hovered_hex;
    region = pc.context.regions[pc.context.hovered_region];
    color = vec4(0.25, 0.25, 0.25, 0.3);
    raise = 0.01;
  }

  vec2 region_qr = vec2(region.q, region.r);

  vec4 region_pos = vec4(0, 0, 0, 0);
  region_pos.x = (region_qr.x+region_qr.y/2)*region_width - region_qr.y*x/2;
  region_pos.z = 0.75*region_qr.y*region_height + 0.25*region_qr.y*z + 0.5*region_qr.x*z;

  float radius = 0;
  float ring = 0;
  int side = 0;
  if(hex_index != 0) {
    radius = floor(0.5 + sqrt(12*hex_index-3)/6);
    ring = hex_index - (3*radius*radius - 3*radius + 1);
    side = int(floor(ring/radius));
  } 

  vec4 position = vertices[indices[gl_VertexIndex]]
                + (starts[side]*radius)
                + (direction[side]*(ring-(radius*side)))
                + region_pos;

  if(gl_VertexIndex % 3 == 0) {
    position.y = (region.hexes[hex_index].heights[0] +
                  region.hexes[hex_index].heights[1] +
                  region.hexes[hex_index].heights[2] +
                  region.hexes[hex_index].heights[3] +
                  region.hexes[hex_index].heights[4] +
                  region.hexes[hex_index].heights[5])/6 + region.y;
  } else {
    position.y = region.hexes[hex_index].heights[indices[gl_VertexIndex]-1] + region.y;
  }

  position.y += raise;

  gl_Position = pc.context.proj * pc.context.view * position;
}