Richard Zink
433d743446
Reduce raymarch iterations from 28 to 18 and fBm octaves from 4 to 3 (with step size 0.55->0.85 to preserve cloud coverage). Per-pixel cost drops by ~55% while visual density stays similar.
271 lines
9.7 KiB
JavaScript
271 lines
9.7 KiB
JavaScript
/* Volumetric 3D cloud renderer.
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* Raymarches a horizontal cloud layer with the camera flying
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* slowly above and through the cloud deck. Density threshold
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* comes from the weather theme, so 'sunny' gives breaks in the
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* deck and 'stormy' puts you inside overcast most of the time.
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*
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* Reads palette + weather + speed from window globals (same
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* contract as clouds2d.js, theme-agnostic).
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*/
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(function() {
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function makeShader(gl, type, src) {
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var s = gl.createShader(type);
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gl.shaderSource(s, src);
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gl.compileShader(s);
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if (!gl.getShaderParameter(s, gl.COMPILE_STATUS)) {
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console.error('clouds3d: Shader compile error:', gl.getShaderInfoLog(s));
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gl.deleteShader(s);
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return null;
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}
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return s;
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}
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function makeProgram(gl, vsSrc, fsSrc) {
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var vs = makeShader(gl, gl.VERTEX_SHADER, vsSrc);
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var fs = makeShader(gl, gl.FRAGMENT_SHADER, fsSrc);
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if (!vs || !fs) return null;
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var p = gl.createProgram();
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gl.attachShader(p, vs);
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gl.attachShader(p, fs);
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gl.linkProgram(p);
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if (!gl.getProgramParameter(p, gl.LINK_STATUS)) {
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console.error('clouds3d: Program link error:', gl.getProgramInfoLog(p));
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gl.deleteProgram(p);
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return null;
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}
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return p;
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}
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var VERT_SRC = [
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'attribute vec2 aPos;',
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'void main() { gl_Position = vec4(aPos, 0.0, 1.0); }'
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].join('\n');
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// Volumetric raymarch through a horizontal cloud layer.
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// Cheap 3D value noise + 3-octave fbm. 18 raymarch steps.
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// Tuned for low-end hardware: fewer steps + fewer noise samples
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// per step keep the frame within budget on integrated GPUs.
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// Camera path is sinusoidal so the view occasionally dips
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// into the cloud deck for the "fly through the edges" feel.
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var FRAG_SRC = [
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'precision highp float;',
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'uniform vec2 uResolution;',
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'uniform float uTime;',
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'uniform vec3 uSky;',
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'uniform vec3 uCloud;',
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'uniform vec3 uCloudShadow;',
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'uniform vec3 uLight;',
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'uniform vec3 uBg;',
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'uniform float uSpeed;',
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'uniform float uDensity;',
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'uniform float uDayProgress;',
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// 3D hash and value noise
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'float hash3(vec3 p) {',
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'p = fract(p * vec3(0.1031, 0.1030, 0.0973));',
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'p += dot(p, p.yxz + 33.33);',
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'return fract((p.x + p.y) * p.z);',
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'}',
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'float noise3(vec3 p) {',
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'vec3 i = floor(p);',
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'vec3 f = fract(p);',
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'f = f * f * (3.0 - 2.0 * f);',
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'return mix(',
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'mix(mix(hash3(i + vec3(0,0,0)), hash3(i + vec3(1,0,0)), f.x),',
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'mix(hash3(i + vec3(0,1,0)), hash3(i + vec3(1,1,0)), f.x), f.y),',
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'mix(mix(hash3(i + vec3(0,0,1)), hash3(i + vec3(1,0,1)), f.x),',
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'mix(hash3(i + vec3(0,1,1)), hash3(i + vec3(1,1,1)), f.x), f.y),',
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'f.z);',
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'}',
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'float fbm3(vec3 p) {',
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'float v = 0.0;',
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'float a = 0.5;',
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'for (int i = 0; i < 3; i++) {',
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'v += a * noise3(p);',
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'p = p * 2.03 + vec3(13.7, 7.1, 19.3);',
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'a *= 0.5;',
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'}',
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'return v;',
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'}',
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// Density at a point in the cloud layer.
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'float cloudDensity(vec3 p, float baseThresh) {',
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'float n = fbm3(p * 0.35 + vec3(0.0, 0.0, uTime * 0.06));',
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// Cloud layer thickness: between y=-0.3 (deck bottom)
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// and y=1.8 (top), densest in the middle.
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'float h = clamp((p.y + 0.3) / 2.1, 0.0, 1.0);',
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'float profile = 4.0 * h * (1.0 - h); // bell curve',
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'profile = max(profile, 0.0);',
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'return smoothstep(baseThresh, baseThresh + 0.18, n) * profile;',
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'}',
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'void main() {',
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'vec2 uv = (gl_FragCoord.xy / uResolution.xy) * 2.0 - 1.0;',
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'uv.x *= uResolution.x / uResolution.y;',
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// Camera path: slow drift in X, sinusoidal altitude.
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// The altitude dip drives the "fly through cloud edges" effect.
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'float drift = uTime * uSpeed * 0.45;',
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'vec3 ro = vec3(',
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'drift,',
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// Altitude oscillates: above (1.5), at cloud-top (0.6), inside (0.1)
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'1.5 - 1.4 * (0.5 + 0.5 * sin(uTime * 0.07)),',
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'drift * 0.7',
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');',
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// Ray direction: gentle downward tilt so we see the cloud deck
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// and the sky horizon at once.
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'vec3 rd = normalize(vec3(uv.x * 0.55, -0.18 + uv.y * 0.25, 1.0));',
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// Sky gradient based on ray Y (background).
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'float skyT = clamp(rd.y * 0.7 + 0.5, 0.0, 1.0);',
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'vec3 col = mix(uBg, uSky, skyT);',
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// Density threshold: weather 'sunny' -> high (sparse clouds),
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// 'stormy' -> low (overcast deck).
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'float baseThresh = mix(0.72, 0.40, uDensity);',
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// March the cloud layer (bounded in Y).
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'float t = 0.0;',
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'float stepSize = 0.85;',
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'float trans = 1.0;',
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// Pre-compute ray entry/exit on cloud layer for early out
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'for (int i = 0; i < 18; i++) {',
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'vec3 p = ro + rd * t;',
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'if (p.y > 2.0 || p.y < -0.4) break;',
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'float d = cloudDensity(p, baseThresh);',
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'if (d > 0.005) {',
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// Cloud shading: bottom = shadow, top = lit
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'float lit = clamp((p.y + 0.3) / 2.1, 0.0, 1.0);',
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'vec3 cloudCol = mix(uCloudShadow, uCloud, lit);',
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// Sun tint on the lit side, fades at night
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'cloudCol = mix(cloudCol, uLight, uDayProgress * 0.35 * lit);',
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'float alpha = clamp(d * stepSize * 0.9, 0.0, 1.0);',
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'col = mix(col, cloudCol, alpha * trans);',
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'trans *= (1.0 - alpha);',
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'if (trans < 0.04) break;',
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'}',
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't += stepSize;',
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'}',
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// Night darkening
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'col = mix(col, mix(uBg, col, 0.4), (1.0 - uDayProgress) * 0.55);',
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'gl_FragColor = vec4(col, 1.0);',
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'}'
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].join('\n');
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function init(canvas) {
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var gl = canvas.getContext('webgl', { antialias: false, alpha: false });
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if (!gl) {
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console.error('clouds3d: WebGL not available');
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return null;
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}
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var prog = makeProgram(gl, VERT_SRC, FRAG_SRC);
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if (!prog) return null;
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var buf = gl.createBuffer();
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gl.bindBuffer(gl.ARRAY_BUFFER, buf);
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gl.bufferData(gl.ARRAY_BUFFER,
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new Float32Array([ -1,-1, 3,-1, -1,3 ]),
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gl.STATIC_DRAW);
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var aPos = gl.getAttribLocation(prog, 'aPos');
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var uRes = gl.getUniformLocation(prog, 'uResolution');
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var uTime = gl.getUniformLocation(prog, 'uTime');
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var uSky = gl.getUniformLocation(prog, 'uSky');
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var uCloud = gl.getUniformLocation(prog, 'uCloud');
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var uCloudShadow = gl.getUniformLocation(prog, 'uCloudShadow');
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var uLight = gl.getUniformLocation(prog, 'uLight');
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var uBg = gl.getUniformLocation(prog, 'uBg');
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var uSpeed = gl.getUniformLocation(prog, 'uSpeed');
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var uDensity = gl.getUniformLocation(prog, 'uDensity');
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var uDayProgress = gl.getUniformLocation(prog, 'uDayProgress');
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return {
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gl: gl, prog: prog, buf: buf, aPos: aPos,
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uRes: uRes, uTime: uTime, uSky: uSky, uCloud: uCloud,
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uCloudShadow: uCloudShadow, uLight: uLight, uBg: uBg,
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uSpeed: uSpeed, uDensity: uDensity, uDayProgress: uDayProgress
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};
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}
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function hex(rgb) {
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return [((rgb >> 16) & 255) / 255,
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((rgb >> 8) & 255) / 255,
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(rgb & 255) / 255];
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}
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// Same density mapping as clouds2d so swapping renderers doesn't
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// change the visual weather.
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var WEATHER_DENSITY = {
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sunny: 0.20,
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cloudy: 0.70,
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stormy: 1.00,
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night: 0.45
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};
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window.clouds3dRender = function(target) {
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if (!target || typeof target !== 'object') {
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console.error('clouds3d: invalid target');
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return;
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}
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var canvas = target.__clouds3dCanvas;
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if (!canvas) {
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canvas = document.createElement('canvas');
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canvas.style.position = 'absolute';
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canvas.style.top = '0';
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canvas.style.left = '0';
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canvas.style.width = '100%';
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canvas.style.height = '100%';
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while (target.firstChild) target.removeChild(target.firstChild);
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target.appendChild(canvas);
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target.style.position = 'relative';
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target.__clouds3dCanvas = canvas;
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}
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if (!canvas.__state) {
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canvas.__state = init(canvas);
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if (!canvas.__state) return;
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}
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var s = canvas.__state;
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var gl = s.gl;
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canvas.width = target.clientWidth || window.innerWidth;
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canvas.height = target.clientHeight || window.innerHeight;
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gl.viewport(0, 0, canvas.width, canvas.height);
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gl.useProgram(s.prog);
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gl.bindBuffer(gl.ARRAY_BUFFER, s.buf);
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gl.enableVertexAttribArray(s.aPos);
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gl.vertexAttribPointer(s.aPos, 2, gl.FLOAT, false, 0, 0);
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gl.uniform2f(s.uRes, canvas.width, canvas.height);
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gl.uniform1f(s.uTime, performance.now() / 1000);
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var pal = window.__currentPalette;
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if (!pal) {
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gl.clearColor(0, 0, 0, 1);
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gl.clear(gl.COLOR_BUFFER_BIT);
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return;
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}
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var weather = window.__currentWeatherName;
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var dayProgress = window.__currentDayProgress;
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var themeSpeed = window.__currentThemeSpeed;
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gl.uniform3fv(s.uSky, hex(pal.sky));
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gl.uniform3fv(s.uCloud, hex(pal.cloud));
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gl.uniform3fv(s.uCloudShadow, hex(
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pal.cloudShadow !== undefined ? pal.cloudShadow : pal.sky));
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gl.uniform3fv(s.uLight, hex(pal.light));
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gl.uniform3fv(s.uBg, hex(pal.bg));
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var density = (weather && WEATHER_DENSITY[weather] !== undefined)
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? WEATHER_DENSITY[weather] : 0.5;
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gl.uniform1f(s.uDensity, density);
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var day = (typeof dayProgress === 'number')
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? Math.max(0, Math.min(1, dayProgress)) : 0.5;
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gl.uniform1f(s.uDayProgress, day);
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var speed = (typeof themeSpeed === 'number')
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? Math.max(0.1, Math.min(3, themeSpeed)) : 1.0;
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gl.uniform1f(s.uSpeed, speed);
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gl.drawArrays(gl.TRIANGLES, 0, 3);
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};
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})(); |