xfy
8931904495
Add planets as ray-traced spheres inside the RK4 geodesic loop. A new planets.wgsl shader tests each integrator segment against a storage buffer of SphereData (center/radius/color/emissive) and composites hits front-to-back alongside the accretion disk. Lambert shading with a fixed light direction; emissive flag bypasses shading. - assets/shaders/planets.wgsl: segment-sphere intersection + shading - src/scene/: Planet component, upload_planets system, default planet - black_hole.wgsl: wire planet_hit into the compositing loop - geodesic_schwarzschild.wgsl: replace tuple return with Deriv struct
41 lines
1.3 KiB
WebGPU Shading Language
41 lines
1.3 KiB
WebGPU Shading Language
const R_ESCAPE: f32 = 1000.0;
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struct Deriv {
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dpos: vec3<f32>,
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ddir: vec3<f32>,
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}
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fn deriv(pos: vec3<f32>, dir: vec3<f32>) -> Deriv {
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let r = length(pos);
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let rs = uniforms.rs;
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let h = cross(pos, dir);
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let h2 = dot(h, h);
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let r5 = max(r * r * r * r * r, 1e-6);
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let dpos = dir;
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let accel = -1.5 * rs * h2 / r5 * pos;
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return Deriv(dpos, accel);
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}
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struct RayResult {
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status: u32,
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final_pos: vec3<f32>,
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final_dir: vec3<f32>,
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}
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fn classify_ray(start_pos: vec3<f32>, start_dir: vec3<f32>, steps: u32, dt: f32) -> RayResult {
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var pos = start_pos;
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var dir = start_dir;
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for (var i: u32 = 0u; i < steps; i = i + 1u) {
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let r = length(pos);
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if (r < uniforms.rs) { return RayResult(1u, pos, dir); }
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if (r > R_ESCAPE) { return RayResult(0u, pos, dir); }
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let k1 = deriv(pos, dir);
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let k2 = deriv(pos + k1.dpos * dt * 0.5, normalize(dir + k1.ddir * dt * 0.5));
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let k3 = deriv(pos + k2.dpos * dt * 0.5, normalize(dir + k2.ddir * dt * 0.5));
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let k4 = deriv(pos + k3.dpos * dt, normalize(dir + k3.ddir * dt));
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pos = pos + (k1.dpos + 2.0 * k2.dpos + 2.0 * k3.dpos + k4.dpos) * dt / 6.0;
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dir = normalize(dir + (k1.ddir + 2.0 * k2.ddir + 2.0 * k3.ddir + k4.ddir) * dt / 6.0);
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}
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return RayResult(0u, pos, dir);
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}
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