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Extract the uniform helper to its own module
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@TristanCacqueray
TristanCacqueray committed Oct 19, 2024
1 parent 735d531 commit 5c983ce
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236 changes: 2 additions & 234 deletions packages/shader/index.mjs
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/*
shader.mjs - implements the `loadShader` helper and `shader` pattern function
Copyright (C) 2024 Strudel contributors
This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details. You should have received a copy of the GNU Affero General Public License along with this program. If not, see <https://www.gnu.org/licenses/>.
*/

import { PicoGL } from 'picogl';
import { register, logger } from '@strudel/core';

// The standard fullscreen vertex shader.
const vertexShader = `#version 300 es
precision highp float;
layout(location=0) in vec2 position;
void main() {
gl_Position = vec4(position, 1, 1);
}
`;

// Make the fragment source, similar to the one from shadertoy.
function mkFragmentShader(code) {
return `#version 300 es
precision highp float;
out vec4 oColor;
uniform float iTime;
uniform vec2 iResolution;
${code}
void main(void) {
mainImage(oColor, gl_FragCoord.xy);
}
`;
}

// Modulation helpers.
const hardModulation = () => {
let val = 0;
return {
get: () => val,
set: (v) => {
val = v;
},
};
};

const decayModulation = (decay) => {
let val = 0;
let desired = 0;
return {
get: (ts) => {
val += (desired - val) / decay;
return val;
},
set: (v) => {
desired = val + v;
},
};
};

// Set an uniform value (from a pattern).
function setUniform(instance, name, value, position) {
const uniform = instance.uniforms[name];
if (uniform) {
if (uniform.count == 0) {
// This is a single value
uniform.mod.set(value);
} else {
// This is an array
const idx = position % uniform.mod.length;
uniform.mod[idx].set(value);
}
} else {
logger('[shader] unknown uniform: ' + name);
}

// Ensure the instance is drawn
instance.age = 0;
if (!instance.drawing) {
instance.drawing = requestAnimationFrame(instance.update);
}
}

// Update the uniforms for a given drawFrame call.
function updateUniforms(drawFrame, elapsed, uniforms) {
Object.values(uniforms).forEach((uniform) => {
const value =
uniform.count == 0 ? uniform.mod.get(elapsed) : uniform.value.map((_, i) => uniform.mod[i].get(elapsed));
// Send the value to the GPU
drawFrame.uniform(uniform.name, value);
});
}

// Setup the instance's uniform after shader compilation.
function setupUniforms(uniforms, program) {
Object.entries(program.uniforms).forEach(([name, uniform]) => {
if (name != 'iTime' && name != 'iResolution') {
// remove array suffix
const uname = name.replace('[0]', '');
const count = uniform.count | 0;
if (!uniforms[uname] || uniforms[uname].count != count) {
// TODO: keep the previous value when the count change...
uniforms[uname] = {
name,
count,
value: count == 0 ? 0 : new Float32Array(count),
mod: count == 0 ? decayModulation(50) : new Array(count).fill().map(() => decayModulation(50)),
};
}
}
});
// TODO: remove previous uniform that are no longer used...
return uniforms;
}

// Setup the canvas and return the WebGL context.
function setupCanvas(name) {
// TODO: support custom size
const width = 400;
const height = 300;
const canvas = document.createElement('canvas');
canvas.id = 'cnv-' + name;
canvas.width = width;
canvas.height = height;
const top = 60 + Object.keys(_instances).length * height;
canvas.style = `pointer-events:none;width:${width}px;height:${height}px;position:fixed;top:${top}px;right:23px`;
document.body.append(canvas);
return canvas.getContext('webgl2');
}

// Setup the shader instance
async function initializeShaderInstance(name, code) {
// Setup PicoGL app
const ctx = setupCanvas(name);
console.log(ctx);
const app = PicoGL.createApp(ctx);
app.resize(400, 300);

// Setup buffers
const resolution = new Float32Array([ctx.canvas.width, ctx.canvas.height]);

// Two triangle to cover the whole canvas
const positionBuffer = app.createVertexBuffer(
PicoGL.FLOAT,
2,
new Float32Array([-1, -1, -1, 1, 1, 1, 1, 1, 1, -1, -1, -1]),
);

// Setup the arrays
const arrays = app.createVertexArray().vertexAttributeBuffer(0, positionBuffer);

return app
.createPrograms([vertexShader, code])
.then(([program]) => {
const drawFrame = app.createDrawCall(program, arrays);
const instance = { app, code, program, arrays, drawFrame, uniforms: setupUniforms({}, program) };

// Render frame logic
let prev = performance.now() / 1000;
instance.age = 0;
instance.update = () => {
const now = performance.now() / 1000;
const elapsed = now - prev;
prev = now;
// console.log("drawing!")
app.clear();
instance.drawFrame.uniform('iResolution', resolution).uniform('iTime', now);

updateUniforms(instance.drawFrame, elapsed, instance.uniforms);

instance.drawFrame.draw();
if (instance.age++ < 100) requestAnimationFrame(instance.update);
else instance.drawing = false;
};
return instance;
})
.catch((err) => {
ctx.canvas.remove();
throw err;
});
}

// Update the instance program
async function reloadShaderInstanceCode(instance, code) {
return instance.app.createPrograms([vertexShader, code]).then(([program]) => {
instance.program.delete();
instance.program = program;
instance.uniforms = setupUniforms(instance.uniforms, program);
instance.drawFrame = instance.app.createDrawCall(program, instance.arrays);
});
}

// Keep track of the running shader instances
let _instances = {};
export async function loadShader(code = '', name = 'default') {
if (code) {
code = mkFragmentShader(code);
}
if (!_instances[name]) {
_instances[name] = await initializeShaderInstance(name, code);
logger('[shader] ready');
} else if (_instances[name].code != code) {
await reloadShaderInstanceCode(_instances[name], code);
logger('[shader] reloaded');
}
}

export const shader = register('shader', (options, pat) => {
// Keep track of the pitches value: Map String Int
const pitches = { _count: 0 };

return pat.onTrigger((time_deprecate, hap, currentTime, cps, targetTime) => {
const instance = _instances[options.instance || 'default'];
if (!instance) {
logger('[shader] not loaded yet', 'warning');
return;
}

const value = options.gain || 1.0;
if (options.pitch !== undefined) {
const note = hap.value.note || hap.value.s;
if (pitches[note] === undefined) {
// Assign new value, the first note gets 0, then 1, then 2, ...
pitches[note] = Object.keys(pitches).length;
}
setUniform(instance, options.pitch, value, pitches[note]);
} else if (options.seq !== undefined) {
setUniform(instance, options.seq, value, pitches._count++);
} else if (options.uniform !== undefined) {
setUniform(instance, options.uniform, value);
} else {
console.error('Unknown shader options, need either pitch or uniform', options);
}
}, false);
});
export {loadShader} from './shader.mjs';
export * from './uniform.mjs';
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