/* ******************************************************************* */
/* Resolve GLOW pass                                                   */
/* ******************************************************************* */
uniform sampler2D strokeColor;
uniform sampler2D strokeDepth;
uniform sampler2D glowColor;
uniform sampler2D glowDepth;
uniform int alpha_mode;

out vec4 FragColor;

void main()
{
  vec4 outcolor;
  ivec2 uv = ivec2(gl_FragCoord.xy);

  float stroke_depth = texelFetch(strokeDepth, uv.xy, 0).r;
  vec4 src_pixel = texelFetch(strokeColor, uv.xy, 0);
  vec4 glow_pixel = texelFetch(glowColor, uv.xy, 0);
  float glow_depth = texelFetch(glowDepth, uv.xy, 0).r;

  if (alpha_mode == 0) {
    outcolor = src_pixel + glow_pixel;
  }
  else {
    if ((src_pixel.a < 0.1) || (glow_pixel.a < 0.1)) {
      outcolor = src_pixel + glow_pixel;
    }
    else {
      outcolor = src_pixel;
    }
  }

  if (src_pixel.a < glow_pixel.a) {
    gl_FragDepth = glow_depth;
  }
  else {
    gl_FragDepth = stroke_depth;
  }

  if (outcolor.a < 0.001) {
    discard;
  }

  FragColor = outcolor;
}