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webgl-shadows-depth-texture.html
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<!-- Licensed under a BSD license. See license.html for license -->
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes">
<title>WebGL - Shadows - Depth Texture</title>
<link type="text/css" href="resources/webgl-tutorials.css" rel="stylesheet" />
<link href="/webgl/lessons/resources/webglfundamentals-icon.png" rel="shortcut icon" type="image/png">
<link rel="apple-touch-icon" href="/webgl/lessons/resources/webglfundamentals-icon.png">
<link rel="icon" href="/webgl/lessons/resources/webglfundamentals-icon.png">
<style>
.gman-widget-value {
min-width: 5em;
}
</style>
</head>
<body>
<div class="description">
Shadows - Depth Texture
</div>
<canvas id="canvas"></canvas>
<div id="uiContainer">
<div id="ui">
</div>
</div>
</body>
<!--
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://webglfundamentals.org/webgl/lessons/webgl-boilerplate.html
and https://webglfundamentals.org/webgl/lessons/webgl-resizing-the-canvas.html
for webgl-utils, m3, m4, and webgl-lessons-ui.
-->
<script src="resources/webgl-lessons-ui.js"></script>
<script src="resources/webgl-utils.js"></script>
<script src="resources/m4.js"></script>
<script src="resources/primitives.js"></script>
<!-- vertex shader -->
<script id="vertex-shader-3d" type="x-shader/x-vertex">
attribute vec4 a_position;
attribute vec2 a_texcoord;
uniform mat4 u_projection;
uniform mat4 u_view;
uniform mat4 u_world;
uniform mat4 u_textureMatrix;
varying vec2 v_texcoord;
varying vec4 v_projectedTexcoord;
void main() {
// Multiply the position by the matrix.
vec4 worldPosition = u_world * a_position;
gl_Position = u_projection * u_view * worldPosition;
// Pass the texture coord to the fragment shader.
v_texcoord = a_texcoord;
v_projectedTexcoord = u_textureMatrix * worldPosition;
}
</script>
<!-- fragment shader -->
<script id="fragment-shader-3d" type="x-shader/x-fragment">
precision mediump float;
// Passed in from the vertex shader.
varying vec2 v_texcoord;
varying vec4 v_projectedTexcoord;
uniform vec4 u_colorMult;
uniform sampler2D u_texture;
uniform sampler2D u_projectedTexture;
void main() {
vec3 projectedTexcoord = v_projectedTexcoord.xyz / v_projectedTexcoord.w;
bool inRange =
projectedTexcoord.x >= 0.0 &&
projectedTexcoord.x <= 1.0 &&
projectedTexcoord.y >= 0.0 &&
projectedTexcoord.y <= 1.0;
// the 'r' channel has the depth values
vec4 projectedTexColor = vec4(texture2D(u_projectedTexture, projectedTexcoord.xy).rrr, 1);
vec4 texColor = texture2D(u_texture, v_texcoord) * u_colorMult;
float projectedAmount = inRange ? 1.0 : 0.0;
gl_FragColor = mix(texColor, projectedTexColor, projectedAmount);
}
</script>
<!-- vertex shader -->
<script id="color-vertex-shader" type="x-shader/x-vertex">
attribute vec4 a_position;
uniform mat4 u_projection;
uniform mat4 u_view;
uniform mat4 u_world;
void main() {
// Multiply the position by the matrices.
gl_Position = u_projection * u_view * u_world * a_position;
}
</script>
<!-- fragment shader -->
<script id="color-fragment-shader" type="x-shader/x-fragment">
precision mediump float;
uniform vec4 u_color;
void main() {
gl_FragColor = u_color;
}
</script>
<script>
'use strict';
function main() {
// Get A WebGL context
/** @type {HTMLCanvasElement} */
const canvas = document.querySelector('#canvas');
const gl = canvas.getContext('webgl');
if (!gl) {
return;
}
const ext = gl.getExtension('WEBGL_depth_texture');
if (!ext) {
return alert('need WEBGL_depth_texture'); // eslint-disable-line
}
// setup GLSL programs
const textureProgramInfo = webglUtils.createProgramInfo(gl, ['vertex-shader-3d', 'fragment-shader-3d']);
const colorProgramInfo = webglUtils.createProgramInfo(gl, ['color-vertex-shader', 'color-fragment-shader']);
const sphereBufferInfo = primitives.createSphereBufferInfo(
gl,
1, // radius
32, // subdivisions around
24, // subdivisions down
);
const planeBufferInfo = primitives.createPlaneBufferInfo(
gl,
20, // width
20, // height
1, // subdivisions across
1, // subdivisions down
);
const cubeBufferInfo = primitives.createCubeBufferInfo(
gl,
2, // size
);
const cubeLinesBufferInfo = webglUtils.createBufferInfoFromArrays(gl, {
position: [
-1, -1, -1,
1, -1, -1,
-1, 1, -1,
1, 1, -1,
-1, -1, 1,
1, -1, 1,
-1, 1, 1,
1, 1, 1,
],
indices: [
0, 1,
1, 3,
3, 2,
2, 0,
4, 5,
5, 7,
7, 6,
6, 4,
0, 4,
1, 5,
3, 7,
2, 6,
],
});
// make a 8x8 checkerboard texture
const checkerboardTexture = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, checkerboardTexture);
gl.texImage2D(
gl.TEXTURE_2D,
0, // mip level
gl.LUMINANCE, // internal format
8, // width
8, // height
0, // border
gl.LUMINANCE, // format
gl.UNSIGNED_BYTE, // type
new Uint8Array([ // data
0xFF, 0xCC, 0xFF, 0xCC, 0xFF, 0xCC, 0xFF, 0xCC,
0xCC, 0xFF, 0xCC, 0xFF, 0xCC, 0xFF, 0xCC, 0xFF,
0xFF, 0xCC, 0xFF, 0xCC, 0xFF, 0xCC, 0xFF, 0xCC,
0xCC, 0xFF, 0xCC, 0xFF, 0xCC, 0xFF, 0xCC, 0xFF,
0xFF, 0xCC, 0xFF, 0xCC, 0xFF, 0xCC, 0xFF, 0xCC,
0xCC, 0xFF, 0xCC, 0xFF, 0xCC, 0xFF, 0xCC, 0xFF,
0xFF, 0xCC, 0xFF, 0xCC, 0xFF, 0xCC, 0xFF, 0xCC,
0xCC, 0xFF, 0xCC, 0xFF, 0xCC, 0xFF, 0xCC, 0xFF,
]));
gl.generateMipmap(gl.TEXTURE_2D);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
const depthTexture = gl.createTexture();
const depthTextureSize = 512;
gl.bindTexture(gl.TEXTURE_2D, depthTexture);
gl.texImage2D(
gl.TEXTURE_2D, // target
0, // mip level
gl.DEPTH_COMPONENT, // internal format
depthTextureSize, // width
depthTextureSize, // height
0, // border
gl.DEPTH_COMPONENT, // format
gl.UNSIGNED_INT, // type
null); // data
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
const depthFramebuffer = gl.createFramebuffer();
gl.bindFramebuffer(gl.FRAMEBUFFER, depthFramebuffer);
gl.framebufferTexture2D(
gl.FRAMEBUFFER, // target
gl.DEPTH_ATTACHMENT, // attachment point
gl.TEXTURE_2D, // texture target
depthTexture, // texture
0); // mip level
// create a color texture of the same size as the depth texture
// see article why this is needed_
const unusedTexture = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, unusedTexture);
gl.texImage2D(
gl.TEXTURE_2D,
0,
gl.RGBA,
depthTextureSize,
depthTextureSize,
0,
gl.RGBA,
gl.UNSIGNED_BYTE,
null,
);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
// attach it to the framebuffer
gl.framebufferTexture2D(
gl.FRAMEBUFFER, // target
gl.COLOR_ATTACHMENT0, // attachment point
gl.TEXTURE_2D, // texture target
unusedTexture, // texture
0); // mip level
function degToRad(d) {
return d * Math.PI / 180;
}
const settings = {
cameraX: 6,
cameraY: 5,
posX: 2.5,
posY: 4.8,
posZ: 4.3,
targetX: 2.5,
targetY: 0,
targetZ: 3.5,
projWidth: 1,
projHeight: 1,
perspective: true,
fieldOfView: 120,
};
webglLessonsUI.setupUI(document.querySelector('#ui'), settings, [
{ type: 'slider', key: 'cameraX', min: -10, max: 10, change: render, precision: 2, step: 0.001, },
{ type: 'slider', key: 'cameraY', min: 1, max: 20, change: render, precision: 2, step: 0.001, },
{ type: 'slider', key: 'posX', min: -10, max: 10, change: render, precision: 2, step: 0.001, },
{ type: 'slider', key: 'posY', min: 1, max: 20, change: render, precision: 2, step: 0.001, },
{ type: 'slider', key: 'posZ', min: 1, max: 20, change: render, precision: 2, step: 0.001, },
{ type: 'slider', key: 'targetX', min: -10, max: 10, change: render, precision: 2, step: 0.001, },
{ type: 'slider', key: 'targetY', min: 0, max: 20, change: render, precision: 2, step: 0.001, },
{ type: 'slider', key: 'targetZ', min: -10, max: 20, change: render, precision: 2, step: 0.001, },
{ type: 'slider', key: 'projWidth', min: 0, max: 2, change: render, precision: 2, step: 0.001, },
{ type: 'slider', key: 'projHeight', min: 0, max: 2, change: render, precision: 2, step: 0.001, },
{ type: 'checkbox', key: 'perspective', change: render, },
{ type: 'slider', key: 'fieldOfView', min: 1, max: 179, change: render, },
]);
const fieldOfViewRadians = degToRad(60);
// Uniforms for each object.
const planeUniforms = {
u_colorMult: [0.5, 0.5, 1, 1], // lightblue
u_color: [1, 0, 0, 1],
u_texture: checkerboardTexture,
u_world: m4.translation(0, 0, 0),
};
const sphereUniforms = {
u_colorMult: [1, 0.5, 0.5, 1], // pink
u_color: [0, 0, 1, 1],
u_texture: checkerboardTexture,
u_world: m4.translation(2, 3, 4),
};
const cubeUniforms = {
u_colorMult: [0.5, 1, 0.5, 1], // lightgreen
u_color: [0, 0, 1, 1],
u_texture: checkerboardTexture,
u_world: m4.translation(3, 1, 0),
};
function drawScene(projectionMatrix, cameraMatrix, textureMatrix, programInfo) {
// Make a view matrix from the camera matrix.
const viewMatrix = m4.inverse(cameraMatrix);
gl.useProgram(programInfo.program);
// set uniforms that are the same for both the sphere and plane
// note: any values with no corresponding uniform in the shader
// are ignored.
webglUtils.setUniforms(programInfo, {
u_view: viewMatrix,
u_projection: projectionMatrix,
u_textureMatrix: textureMatrix,
u_projectedTexture: depthTexture,
});
// ------ Draw the sphere --------
// Setup all the needed attributes.
webglUtils.setBuffersAndAttributes(gl, programInfo, sphereBufferInfo);
// Set the uniforms unique to the sphere
webglUtils.setUniforms(programInfo, sphereUniforms);
// calls gl.drawArrays or gl.drawElements
webglUtils.drawBufferInfo(gl, sphereBufferInfo);
// ------ Draw the cube --------
// Setup all the needed attributes.
webglUtils.setBuffersAndAttributes(gl, programInfo, cubeBufferInfo);
// Set the uniforms unique to the cube
webglUtils.setUniforms(programInfo, cubeUniforms);
// calls gl.drawArrays or gl.drawElements
webglUtils.drawBufferInfo(gl, cubeBufferInfo);
// ------ Draw the plane --------
// Setup all the needed attributes.
webglUtils.setBuffersAndAttributes(gl, programInfo, planeBufferInfo);
// Set the uniforms unique to the cube
webglUtils.setUniforms(programInfo, planeUniforms);
// calls gl.drawArrays or gl.drawElements
webglUtils.drawBufferInfo(gl, planeBufferInfo);
}
// Draw the scene.
function render() {
webglUtils.resizeCanvasToDisplaySize(gl.canvas);
gl.enable(gl.CULL_FACE);
gl.enable(gl.DEPTH_TEST);
// first draw from the POV of the light
const lightWorldMatrix = m4.lookAt(
[settings.posX, settings.posY, settings.posZ], // position
[settings.targetX, settings.targetY, settings.targetZ], // target
[0, 1, 0], // up
);
const lightProjectionMatrix = settings.perspective
? m4.perspective(
degToRad(settings.fieldOfView),
settings.projWidth / settings.projHeight,
0.5, // near
10) // far
: m4.orthographic(
-settings.projWidth / 2, // left
settings.projWidth / 2, // right
-settings.projHeight / 2, // bottom
settings.projHeight / 2, // top
0.5, // near
10); // far
// draw to the depth texture
gl.bindFramebuffer(gl.FRAMEBUFFER, depthFramebuffer);
gl.viewport(0, 0, depthTextureSize, depthTextureSize);
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
drawScene(lightProjectionMatrix, lightWorldMatrix, m4.identity(), colorProgramInfo);
// now draw scene to the canvas projecting the depth texture into the scene
gl.bindFramebuffer(gl.FRAMEBUFFER, null);
gl.viewport(0, 0, gl.canvas.width, gl.canvas.height);
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
let textureMatrix = m4.identity();
textureMatrix = m4.translate(textureMatrix, 0.5, 0.5, 0.5);
textureMatrix = m4.scale(textureMatrix, 0.5, 0.5, 0.5);
textureMatrix = m4.multiply(textureMatrix, lightProjectionMatrix);
// use the inverse of this world matrix to make
// a matrix that will transform other positions
// to be relative this world space.
textureMatrix = m4.multiply(
textureMatrix,
m4.inverse(lightWorldMatrix));
// Compute the projection matrix
const aspect = gl.canvas.clientWidth / gl.canvas.clientHeight;
const projectionMatrix =
m4.perspective(fieldOfViewRadians, aspect, 1, 2000);
// Compute the camera's matrix using look at.
const cameraPosition = [settings.cameraX, settings.cameraY, 7];
const target = [0, 0, 0];
const up = [0, 1, 0];
const cameraMatrix = m4.lookAt(cameraPosition, target, up);
drawScene(projectionMatrix, cameraMatrix, textureMatrix, textureProgramInfo);
// ------ Draw the frustum ------
{
const viewMatrix = m4.inverse(cameraMatrix);
gl.useProgram(colorProgramInfo.program);
// Setup all the needed attributes.
webglUtils.setBuffersAndAttributes(gl, colorProgramInfo, cubeLinesBufferInfo);
// scale the cube in Z so it's really long
// to represent the texture is being projected to
// infinity
const mat = m4.multiply(
lightWorldMatrix, m4.inverse(lightProjectionMatrix));
// Set the uniforms we just computed
webglUtils.setUniforms(colorProgramInfo, {
u_color: [0, 0, 0, 1],
u_view: viewMatrix,
u_projection: projectionMatrix,
u_world: mat,
});
// calls gl.drawArrays or gl.drawElements
webglUtils.drawBufferInfo(gl, cubeLinesBufferInfo, gl.LINES);
}
}
render();
}
main();
</script>
</html>