BFCM Globe 2023: GPU Arcs

gpu_arcs_example.glsl

vec3 cubicBezier(vec3 startPoint, vec3 midCoord1, vec3 midCoord2, vec3 endPoint, float t) {
  float u = 1.0 - t;
  float tt = t * t;
  float uu = u * u;
  float uuu = uu * u;
  float ttt = tt * t;

  vec3 p = uuu * startPoint;
  p += 3.0 * uu * t * midCoord1;
  p += 3.0 * u * tt * midCoord2;
  p += ttt * endPoint;

  return p;
}

vec3 cubicBezierTangent(vec3 startPoint, vec3 midCoord1, vec3 midCoord2, vec3 endPoint, float t) {
// ... tangent calculation used for making arcs always face the viewer
}

vec3 curvePosition = cubicBezier(startPos, midCoord1, midCoord2, endPos, uv.y);