void main()

in src/renderers/webgl/programs/VideoRenderProgram.ts [25:97]

• 58 lines of code
• 5 McCabe index (conditional complexity)

void main () {
    gl_Position = vec4(0.0, 0.0, 2.0, 1.0);

    uvec4 motion1 = texelFetch(u_texture, ivec2(((uint(index) & 0x3ffu) << 2) | 3u, uint(index) >> 10), 0);
    vec2 trbf = unpackHalf2x16(motion1.w);
    float dt = time - trbf.x;

    float topacity = exp(-1.0 * pow(dt / trbf.y, 2.0));
    if(topacity < 0.02) return;

    uvec4 motion0 = texelFetch(u_texture, ivec2(((uint(index) & 0x3ffu) << 2) | 2u, uint(index) >> 10), 0);
    uvec4 static0 = texelFetch(u_texture, ivec2(((uint(index) & 0x3ffu) << 2), uint(index) >> 10), 0);

    vec2 m0 = unpackHalf2x16(motion0.x), m1 = unpackHalf2x16(motion0.y), m2 = unpackHalf2x16(motion0.z), 
         m3 = unpackHalf2x16(motion0.w), m4 = unpackHalf2x16(motion1.x); 
      
    vec4 trot = vec4(unpackHalf2x16(motion1.y).xy, unpackHalf2x16(motion1.z).xy) * dt;
    vec3 tpos = (vec3(m0.xy, m1.x) * dt + vec3(m1.y, m2.xy) * dt*dt + vec3(m3.xy, m4.x) * dt*dt*dt);
      
    vec4 cam = view * vec4(uintBitsToFloat(static0.xyz) + tpos, 1);
    vec4 pos = projection * cam;
  
    float clip = 1.2 * pos.w;
    if (pos.z < -clip || pos.x < -clip || pos.x > clip || pos.y < -clip || pos.y > clip) return;
    uvec4 static1 = texelFetch(u_texture, ivec2(((uint(index) & 0x3ffu) << 2) | 1u, uint(index) >> 10), 0);

    vec4 rot = vec4(unpackHalf2x16(static0.w).xy, unpackHalf2x16(static1.x).xy) + trot;
    vec3 scale = vec3(unpackHalf2x16(static1.y).xy, unpackHalf2x16(static1.z).x);
    rot /= sqrt(dot(rot, rot));
  
    mat3 S = mat3(scale.x, 0.0, 0.0, 0.0, scale.y, 0.0, 0.0, 0.0, scale.z);
    mat3 R = mat3(
        1.0 - 2.0 * (rot.z * rot.z + rot.w * rot.w), 2.0 * (rot.y * rot.z - rot.x * rot.w), 2.0 * (rot.y * rot.w + rot.x * rot.z),
        2.0 * (rot.y * rot.z + rot.x * rot.w), 1.0 - 2.0 * (rot.y * rot.y + rot.w * rot.w), 2.0 * (rot.z * rot.w - rot.x * rot.y),
        2.0 * (rot.y * rot.w - rot.x * rot.z), 2.0 * (rot.z * rot.w + rot.x * rot.y), 1.0 - 2.0 * (rot.y * rot.y + rot.z * rot.z));
    mat3 M = S * R;
    mat3 Vrk = 4.0 * transpose(M) * M;
    mat3 J = mat3(
        focal.x / cam.z, 0., -(focal.x * cam.x) / (cam.z * cam.z), 
        0., -focal.y / cam.z, (focal.y * cam.y) / (cam.z * cam.z), 
        0., 0., 0.
    );
  
    mat3 T = transpose(mat3(view)) * J;
    mat3 cov2d = transpose(T) * Vrk * T;
  
    float mid = (cov2d[0][0] + cov2d[1][1]) / 2.0;
    float radius = length(vec2((cov2d[0][0] - cov2d[1][1]) / 2.0, cov2d[0][1]));
    float lambda1 = mid + radius, lambda2 = mid - radius;
  
    if(lambda2 < 0.0) return;
    vec2 diagonalVector = normalize(vec2(cov2d[0][1], lambda1 - cov2d[0][0]));
    vec2 majorAxis = min(sqrt(2.0 * lambda1), 1024.0) * diagonalVector;
    vec2 minorAxis = min(sqrt(2.0 * lambda2), 1024.0) * vec2(diagonalVector.y, -diagonalVector.x);
      
    uint rgba = static1.w;
    vColor = 
        clamp(pos.z/pos.w+1.0, 0.0, 1.0) * 
        vec4(1.0, 1.0, 1.0, topacity) *
        vec4(
            (rgba) & 0xffu, 
            (rgba >> 8) & 0xffu, 
            (rgba >> 16) & 0xffu, 
            (rgba >> 24) & 0xffu) / 255.0;

    vec2 vCenter = vec2(pos) / pos.w;
    gl_Position = vec4(
        vCenter 
        + position.x * majorAxis / viewport 
        + position.y * minorAxis / viewport, 0.0, 1.0);

    vPosition = position;
}