/**
 * Downsample pass: CoC aware downsample to quarter resolution.
 *
 * Pretty much identical to the setup pass but get CoC from buffer. Also does not
 * weight luma for the bilateral weights.
 */

#pragma BLENDER_REQUIRE(effect_dof_lib.glsl)

/* Half resolution. */
uniform sampler2D colorBuffer;
uniform sampler2D cocBuffer;

/* Quarter resolution. */
layout(location = 0) out vec4 outColor;

void main()
{
  vec2 halfres_texel_size = 1.0 / vec2(textureSize(colorBuffer, 0).xy);
  /* Center uv around the 4 halfres pixels. */
  vec2 quad_center = (floor(gl_FragCoord.xy) * 2.0 + 1.0) * halfres_texel_size;

  vec4 colors[4];
  vec4 cocs;
  for (int i = 0; i < 4; i++) {
    vec2 sample_uv = quad_center + quad_offsets[i] * halfres_texel_size;
    colors[i] = textureLod(colorBuffer, sample_uv, 0.0);
    cocs[i] = textureLod(cocBuffer, sample_uv, 0.0).r;
  }

  vec4 weights = dof_downsample_bilateral_coc_weights(cocs);
  /* Normalize so that the sum is 1. */
  weights *= safe_rcp(sum(weights));

  outColor = weighted_sum_array(colors, weights);
}