OpenSpace/modules/touch/shaders/marker_fs.glsl

/*****************************************************************************************
 *                                                                                       *
 * OpenSpace                                                                             *
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 * Copyright (c) 2014-2024                                                               *
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#include "PowerScaling/powerScaling_fs.hglsl"
#include "fragment.glsl"

in vec2 out_position;

uniform float opacity;
uniform float thickness;
uniform vec3 color;


Fragment getFragment() {
  // Calculate normal from texture coordinates
  vec3 n;
  n.xy = gl_PointCoord.st * vec2(2.0, -2.0) + vec2(-1.0, 1.0);
  float mag = dot(n.xy, n.xy);

  float edgeSmoothing = 1.0;
  float w = 0.1; // wdith for smoothing
  if (mag > 1.0 - w) {
    // Kill pixels outside circle. Do a smoothstep for soft border
    float t = (mag - (1.0-w)) / w;
    edgeSmoothing = smoothstep(1.0, 0.0, t);
    if (edgeSmoothing <= 0.0) {
        discard;
    }
  }
  n.z = sqrt(1.0 - mag);

  // Calculate lighting
  vec3 light_dir = vec3(0.0, 0.0, 1.0);
  float diffuse = max(0.0, dot(light_dir, n));
  float alpha = min(pow(sqrt(mag), thickness), opacity);
  alpha *= edgeSmoothing;

  Fragment frag;
  frag.color = vec4(color * diffuse, alpha);
  frag.depth = 1.0;
  return frag;
}