// viewof module = wgsl` struct Vertex { @builtin(vertex_index) vertex_index : u32, }; struct Point { @builtin(position) position: vec4f, }; struct Uniforms { time: f32, frame: u32, resolution: vec4f, view: mat4x4f, }; struct Pointers { count: u32, positions: array, } struct Ray { origin: vec3f, // assume direction is normalized direction: vec3f, }; @group(0) @binding(0) var uniforms: Uniforms; @group(1) @binding(0) var pointers: Pointers; const bin = vec4f(-1,3,0,1); const points = array( Point( bin.xxzw, ), Point( bin.xyzw, ), Point( bin.yxzw, ), ); const spheres = array( // cube bin.xxxw, bin.xxww, bin.xwxw, bin.xwww, bin.wxxw, bin.wxww, bin.wwxw, bin.wwww, // octahedron bin.zzww, bin.zzxw, bin.zwzw, bin.zxzw, bin.wzzw, bin.xzzw, ); fn set_xyz(point: ptr, value: vec3f) { *point = vec4(value, point.w); } fn ray_point(ray: Ray, t: f32) -> vec3f { return ray.origin + t * ray.direction; } // apply projective transform // in affine space fn rotate(point: vec3f, transform: mat4x4f) -> vec3f { let q = transform * vec4(point, 1); return q.xyz / q.w; } // apply projective function // in tangent space fn rotate_direction(direction: vec3f, transform: mat4x4f) -> vec3f { let q = transform * vec4(direction, 0); return q.xyz; } fn rotate_ray(ray: Ray, transform: mat4x4f) -> Ray { return Ray( rotate(ray.origin, transform), rotate_direction(ray.direction, transform) ); } fn rotate_ray_ref(ray: ptr, transform: mat4x4f) { ray.origin = rotate(ray.origin, transform); ray.direction = rotate(ray.direction, transform); } fn sphere(color: ptr, ray: Ray, center: vec3f, r: f32) { let offset = center - ray.origin; let t_closest = dot(offset, ray.direction); let closest = ray_point(ray, t_closest); let d = distance(closest, center); if (d > r) { return; } let dt = sqrt(r*r - d*d); var t = t_closest - dt; if (t < 0.01) { t = t_closest + dt; if (t < 0.01) { return; } } var z = color.w - 1; if (z == 0) { z = 100; } if (t > z) { return; } color.w = t + 1; let intersection = ray_point(ray, t); let normal = (intersection - center) / r; set_xyz(color, .8*(.5 + .5*normal)); *color += vec4( vec3(.2 * fract(1.5*intersection)), 0); var fresnel = length(cross(normal, ray.direction)); fresnel=saturate(exp(fresnel - 3.)); //set_xyz(color, mix(color.xyz, vec3(1), fresnel); } fn rescale(pixels: vec2f) -> vec2f { return 2 * (pixels - uniforms.resolution.xy / 2) / uniforms.resolution.z; } @vertex fn vertex( vert: Vertex, ) -> Point { return points[vert.vertex_index]; } @fragment fn fragment(point: Point) -> @location(0) vec4f { _ = uniforms; _ = pointers; var pos = rescale(point.position.xy); pos *= 1.25; var d = length(pos); d = smoothstep(1.1, 1.2, d) *exp(-d); var color = vec2(d, 1.0).xxxy; let origin = vec3(pos, -5); var ray = Ray( origin, // ortographic //vec3(0,0,1), normalize(origin + vec3(0,0,10)) ); rotate_ray_ref(&ray, uniforms.view); sphere(&color, ray, vec3(0), 1); for (var i = 0u; i < 8u + 6u; i++) { let s = spheres[i]; sphere(&color, ray, s.xyz, s.w / 10); } for (var i = 0u; i < pointers.count; i++) { let pointer = pointers.positions[i]; var d = 0.03 * length( (point.position.xy - pointer.xy) / vec2(pointer.zw) ); color = mix( color, vec4(1), exp(-d) ); } return color; } `.value