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@greggman
Created Sep 26, 2022
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WebGL2 with twgl, no scaling as the user resizes, orthographic projection

WebGL2 with twgl, no scaling as the user resizes, orthographic projection

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@import url("https://webgl2fundamentals.org/webgl/resources/webgl-tutorials.css");
body {
margin: 0;
}
canvas {
width: 100vw;
height: 100vh;
display: block;
}
<canvas id="canvas"></canvas>
<div id="uiContainer">
<div id="ui">
<div id="x"></div>
<div id="y"></div>
<div id="z"></div>
<div id="angleX"></div>
<div id="angleY"></div>
<div id="angleZ"></div>
<div id="scaleX"></div>
<div id="scaleY"></div>
<div id="scaleZ"></div>
</div>
</div>
<!--
for most samples webgl-utils only provides shader compiling/linking and
canvas resizing because why clutter the examples with code that's the same in every sample.
See https://webgl2fundamentals.org/webgl/lessons/webgl-boilerplate.html
and https://webgl2fundamentals.org/webgl/lessons/webgl-resizing-the-canvas.html
for webgl-utils, m3, m4, and webgl-lessons-ui.
-->
<script src="https://webgl2fundamentals.org/webgl/resources/webgl-lessons-ui.js"></script>
// WebGL2 - 3D Step 6 - Use Depth Buffer
// from https://webgl2fundamentals.org/webgl/webgl-3d-step6.html
import 'https://greggman.github.io/webgl-lint/webgl-lint.js';
import * as twgl from 'https://twgljs.org/dist/5.x/twgl-full.module.js';
const m4 = twgl.m4;
const vertexShaderSource = `#version 300 es
in vec4 position;
in vec4 color;
uniform mat4 u_matrix;
out vec4 v_color;
void main() {
gl_Position = u_matrix * position;
v_color = color;
}
`;
const fragmentShaderSource = `#version 300 es
precision highp float;
in vec4 v_color;
out vec4 outColor;
void main() {
outColor = v_color;
}
`;
function main() {
// Get A WebGL context
/** @type {HTMLCanvasElement} */
const canvas = document.querySelector("#canvas");
const gl = canvas.getContext("webgl2");
if (!gl) {
return;
}
const programInfo = twgl.createProgramInfo(gl, [vertexShaderSource, fragmentShaderSource]);
const bufferInfo = twgl.createBufferInfoFromArrays(gl, {
position: getPositions(),
color: { data: getColors(), numComponents: 3, },
});
function radToDeg(r) {
return r * 180 / Math.PI;
}
function degToRad(d) {
return d * Math.PI / 180;
}
// First let's make some variables
// to hold the translation,
var translation = [45, 100, 0];
var rotation = [degToRad(28), degToRad(25), degToRad(325)];
var scale = [1, 1, 1];
// Setup a ui.
webglLessonsUI.setupSlider("#x", {value: translation[0], slide: updatePosition(0), max: gl.canvas.width });
webglLessonsUI.setupSlider("#y", {value: translation[1], slide: updatePosition(1), max: gl.canvas.height});
webglLessonsUI.setupSlider("#z", {value: translation[2], slide: updatePosition(2), max: gl.canvas.height});
webglLessonsUI.setupSlider("#angleX", {value: radToDeg(rotation[0]), slide: updateRotation(0), max: 360});
webglLessonsUI.setupSlider("#angleY", {value: radToDeg(rotation[1]), slide: updateRotation(1), max: 360});
webglLessonsUI.setupSlider("#angleZ", {value: radToDeg(rotation[2]), slide: updateRotation(2), max: 360});
webglLessonsUI.setupSlider("#scaleX", {value: scale[0], slide: updateScale(0), min: -5, max: 5, step: 0.01, precision: 2});
webglLessonsUI.setupSlider("#scaleY", {value: scale[1], slide: updateScale(1), min: -5, max: 5, step: 0.01, precision: 2});
webglLessonsUI.setupSlider("#scaleZ", {value: scale[2], slide: updateScale(2), min: -5, max: 5, step: 0.01, precision: 2});
function updatePosition(index) {
return function(event, ui) {
translation[index] = ui.value;
};
}
function updateRotation(index) {
return function(event, ui) {
var angleInDegrees = ui.value;
var angleInRadians = degToRad(angleInDegrees);
rotation[index] = angleInRadians;
};
}
function updateScale(index) {
return function(event, ui) {
scale[index] = ui.value;
};
}
// Draw the scene.
function drawScene() {
twgl.resizeCanvasToDisplaySize(gl.canvas);
gl.viewport(0, 0, gl.canvas.width, gl.canvas.height);
gl.clearColor(0, 0, 0, 0);
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
gl.enable(gl.DEPTH_TEST);
gl.enable(gl.CULL_FACE);
gl.cullFace(gl.FRONT); // becase we're flipping the Y axis
let matrix = m4.ortho(0, gl.canvas.clientWidth, gl.canvas.clientHeight, 0, -400, 400);
matrix = m4.translate(matrix, translation);
matrix = m4.rotateX(matrix, rotation[0]);
matrix = m4.rotateY(matrix, rotation[1]);
matrix = m4.rotateZ(matrix, rotation[2]);
matrix = m4.scale(matrix, scale);
gl.useProgram(programInfo.program);
twgl.setBuffersAndAttributes(gl, programInfo, bufferInfo);
twgl.setUniforms(programInfo, {u_matrix: matrix});
twgl.drawBufferInfo(gl, bufferInfo);
requestAnimationFrame(drawScene);
}
requestAnimationFrame(drawScene);
}
function getPositions(gl) {
return new Float32Array([
// left column front
0, 0, 0,
0, 150, 0,
30, 0, 0,
0, 150, 0,
30, 150, 0,
30, 0, 0,
// top rung front
30, 0, 0,
30, 30, 0,
100, 0, 0,
30, 30, 0,
100, 30, 0,
100, 0, 0,
// middle rung front
30, 60, 0,
30, 90, 0,
67, 60, 0,
30, 90, 0,
67, 90, 0,
67, 60, 0,
// left column back
0, 0, 30,
30, 0, 30,
0, 150, 30,
0, 150, 30,
30, 0, 30,
30, 150, 30,
// top rung back
30, 0, 30,
100, 0, 30,
30, 30, 30,
30, 30, 30,
100, 0, 30,
100, 30, 30,
// middle rung back
30, 60, 30,
67, 60, 30,
30, 90, 30,
30, 90, 30,
67, 60, 30,
67, 90, 30,
// top
0, 0, 0,
100, 0, 0,
100, 0, 30,
0, 0, 0,
100, 0, 30,
0, 0, 30,
// top rung right
100, 0, 0,
100, 30, 0,
100, 30, 30,
100, 0, 0,
100, 30, 30,
100, 0, 30,
// under top rung
30, 30, 0,
30, 30, 30,
100, 30, 30,
30, 30, 0,
100, 30, 30,
100, 30, 0,
// between top rung and middle
30, 30, 0,
30, 60, 30,
30, 30, 30,
30, 30, 0,
30, 60, 0,
30, 60, 30,
// top of middle rung
30, 60, 0,
67, 60, 30,
30, 60, 30,
30, 60, 0,
67, 60, 0,
67, 60, 30,
// right of middle rung
67, 60, 0,
67, 90, 30,
67, 60, 30,
67, 60, 0,
67, 90, 0,
67, 90, 30,
// bottom of middle rung.
30, 90, 0,
30, 90, 30,
67, 90, 30,
30, 90, 0,
67, 90, 30,
67, 90, 0,
// right of bottom
30, 90, 0,
30, 150, 30,
30, 90, 30,
30, 90, 0,
30, 150, 0,
30, 150, 30,
// bottom
0, 150, 0,
0, 150, 30,
30, 150, 30,
0, 150, 0,
30, 150, 30,
30, 150, 0,
// left side
0, 0, 0,
0, 0, 30,
0, 150, 30,
0, 0, 0,
0, 150, 30,
0, 150, 0,
]);
}
// Fill the current ARRAY_BUFFER buffer with colors for the 'F'.
function getColors(gl) {
return new Uint8Array([
// left column front
200, 70, 120,
200, 70, 120,
200, 70, 120,
200, 70, 120,
200, 70, 120,
200, 70, 120,
// top rung front
200, 70, 120,
200, 70, 120,
200, 70, 120,
200, 70, 120,
200, 70, 120,
200, 70, 120,
// middle rung front
200, 70, 120,
200, 70, 120,
200, 70, 120,
200, 70, 120,
200, 70, 120,
200, 70, 120,
// left column back
80, 70, 200,
80, 70, 200,
80, 70, 200,
80, 70, 200,
80, 70, 200,
80, 70, 200,
// top rung back
80, 70, 200,
80, 70, 200,
80, 70, 200,
80, 70, 200,
80, 70, 200,
80, 70, 200,
// middle rung back
80, 70, 200,
80, 70, 200,
80, 70, 200,
80, 70, 200,
80, 70, 200,
80, 70, 200,
// top
70, 200, 210,
70, 200, 210,
70, 200, 210,
70, 200, 210,
70, 200, 210,
70, 200, 210,
// top rung right
200, 200, 70,
200, 200, 70,
200, 200, 70,
200, 200, 70,
200, 200, 70,
200, 200, 70,
// under top rung
210, 100, 70,
210, 100, 70,
210, 100, 70,
210, 100, 70,
210, 100, 70,
210, 100, 70,
// between top rung and middle
210, 160, 70,
210, 160, 70,
210, 160, 70,
210, 160, 70,
210, 160, 70,
210, 160, 70,
// top of middle rung
70, 180, 210,
70, 180, 210,
70, 180, 210,
70, 180, 210,
70, 180, 210,
70, 180, 210,
// right of middle rung
100, 70, 210,
100, 70, 210,
100, 70, 210,
100, 70, 210,
100, 70, 210,
100, 70, 210,
// bottom of middle rung.
76, 210, 100,
76, 210, 100,
76, 210, 100,
76, 210, 100,
76, 210, 100,
76, 210, 100,
// right of bottom
140, 210, 80,
140, 210, 80,
140, 210, 80,
140, 210, 80,
140, 210, 80,
140, 210, 80,
// bottom
90, 130, 110,
90, 130, 110,
90, 130, 110,
90, 130, 110,
90, 130, 110,
90, 130, 110,
// left side
160, 160, 220,
160, 160, 220,
160, 160, 220,
160, 160, 220,
160, 160, 220,
160, 160, 220,
]);
}
main();
{"name":"WebGL2 with twgl, no scaling as the user resizes, orthographic projection","settings":{},"filenames":["index.html","index.css","index.js"]}
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