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webgl-3d-lighting-directional-world.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>WebGL2 - 3D Directional Lighting</title>
<link type="text/css" href="resources/webgl-tutorials.css" rel="stylesheet" />
</head>
<body>
<div class="description">
Drag slider to rotate F.
</div>
<canvas id="canvas" width="400" height="300"></canvas>
<div id="uiContainer">
<div id="ui">
<div id="fRotation"></div>
</div>
</div>
</body>
<script src="resources/webgl-utils.js"></script>
<script src="resources/webgl-lessons-helper.js"></script>
<script src="resources/3d-math.js"></script>
<script>
"use strict";
var vertexShaderSource = `#version 300 es
// an attribute is an input (in) to a vertex shader.
// It will receive data from a buffer
in vec4 a_position;
in vec3 a_normal;
uniform mat4 u_worldViewProjection;
uniform mat4 u_world;
// varying to pass the normal to the fragment shader
out vec3 v_normal;
// all shaders have a main function
void main() {
// Multiply the position by the matrix.
gl_Position = u_worldViewProjection * a_position;
// orient the normals and pass to the fragment shader
v_normal = mat3(u_world) * a_normal;
}
`;
var fragmentShaderSource = `#version 300 es
precision mediump float;
// Passed in and varied from the vertex shader.
in vec3 v_normal;
uniform vec3 u_reverseLightDirection;
uniform vec4 u_color;
// we need to declare an output for the fragment shader
out vec4 outColor;
void main() {
// because v_normal is a varying it's interpolated
// so it will not be a uint vector. Normalizing it
// will make it a unit vector again
vec3 normal = normalize(v_normal);
// compute the light by taking the dot product
// of the normal to the light's reverse direction
float light = dot(normal, u_reverseLightDirection);
outColor = u_color;
// Lets multiply just the color portion (not the alpha)
// by the light
outColor.rgb *= light;
}
`;
function main() {
// Get A WebGL context
var canvas = document.getElementById("canvas");
webglLessonsHelper.setupLesson(canvas);
/** @type {WebGLRenderingContext} */
var gl = canvas.getContext("webgl2");
if (!gl) {
webglLessonsHelper.showNeedWebGL2(canvas);
return;
}
// Use our boilerplate utils to compile the shaders and link into a program
var program = webglUtils.createProgramFromSources(gl,
[vertexShaderSource, fragmentShaderSource]);
// look up where the vertex data needs to go.
var positionAttributeLocation = gl.getAttribLocation(program, "a_position");
var normalAttributeLocation = gl.getAttribLocation(program, "a_normal");
// look up uniform locations
var worldViewProjectionLocation =
gl.getUniformLocation(program, "u_worldViewProjection");
var worldLocation = gl.getUniformLocation(program, "u_world");
var colorLocation = gl.getUniformLocation(program, "u_color");
var reverseLightDirectionLocation =
gl.getUniformLocation(program, "u_reverseLightDirection");
// Create a buffer
var positionBuffer = gl.createBuffer();
// Create a vertex array object (attribute state)
var vao = gl.createVertexArray();
// and make it the one we're currently working with
gl.bindVertexArray(vao);
// Turn on the attribute
gl.enableVertexAttribArray(positionAttributeLocation);
// Bind it to ARRAY_BUFFER (think of it as ARRAY_BUFFER = positionBuffer)
gl.bindBuffer(gl.ARRAY_BUFFER, positionBuffer);
// Set Geometry.
setGeometry(gl);
// Tell the attribute how to get data out of positionBuffer (ARRAY_BUFFER)
var size = 3; // 3 components per iteration
var type = gl.FLOAT; // the data is 32bit floats
var normalize = false; // don't normalize the data
var stride = 0; // 0 = move forward size * sizeof(type) each iteration to get the next position
var offset = 0; // start at the beginning of the buffer
gl.vertexAttribPointer(
positionAttributeLocation, size, type, normalize, stride, offset);
// create the normalr buffer, make it the current ARRAY_BUFFER
// and copy in the normal values
var normalBuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, normalBuffer);
setNormals(gl);
// Turn on the attribute
gl.enableVertexAttribArray(normalAttributeLocation);
// Tell the attribute how to get data out of colorBuffer (ARRAY_BUFFER)
var size = 3; // 3 components per iteration
var type = gl.FLOAT; // the data is 32bit floats
var normalize = false; // don't normalize the data
var stride = 0; // 0 = move forward size * sizeof(type) each iteration to get the next color
var offset = 0; // start at the beginning of the buffer
gl.vertexAttribPointer(
normalAttributeLocation, size, type, normalize, stride, offset);
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 fieldOfViewRadians = degToRad(60);
var fRotationRadians = 0;
drawScene();
// Setup a ui.
webglLessonsHelper.setupSlider("#fRotation", {value: radToDeg(fRotationRadians), slide: updateRotation, min: -360, max: 360});
function updateRotation(event, ui) {
fRotationRadians = degToRad(ui.value);
drawScene();
}
// Draw the scene.
function drawScene() {
var numFs = 5;
var radius = 200;
// Tell WebGL how to convert from clip space to pixels
gl.viewport(0, 0, gl.canvas.width, gl.canvas.height);
// Clear the canvas
gl.clearColor(0, 0, 0, 0);
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
// turn on depth testing
gl.enable(gl.DEPTH_TEST);
// tell webgl to cull faces
gl.enable(gl.CULL_FACE);
// Tell it to use our program (pair of shaders)
gl.useProgram(program);
// Bind the attribute/buffer set we want.
gl.bindVertexArray(vao);
// Compute the matrix
var aspect = gl.canvas.clientWidth / gl.canvas.clientHeight;
var zNear = 1;
var zFar = 2000;
var projectionMatrix = m4.perspective(fieldOfViewRadians, aspect, zNear, zFar);
// Compute the camera's matrix
var camera = [100, 150, 200];
var target = [0, 35, 0];
var up = [0, 1, 0];
var cameraMatrix = m4.lookAt(camera, target, up);
// Make a view matrix from the camera matrix.
var viewMatrix = m4.inverse(cameraMatrix);
// create a viewProjection matrix. This will both apply perspective
// AND move the world so that the camera is effectively the origin
var viewProjectionMatrix = m4.multiply(projectionMatrix, viewMatrix);
// Draw a F at the origin with rotation
var worldMatrix = m4.yRotation(fRotationRadians);
var worldViewProjectionMatrix = m4.multiply(viewProjectionMatrix, worldMatrix);
// Set the matrices
gl.uniformMatrix4fv(
worldViewProjectionLocation, false,
worldViewProjectionMatrix);
gl.uniformMatrix4fv(worldLocation, false, worldMatrix);
// Set the color to use
gl.uniform4fv(colorLocation, [0.2, 1, 0.2, 1]); // green
// set the light direction.
gl.uniform3fv(reverseLightDirectionLocation, m4.normalize([0.5, 0.7, 1]));
// Draw the geometry.
var primitiveType = gl.TRIANGLES;
var offset = 0;
var count = 16 * 6;
gl.drawArrays(primitiveType, offset, count);
}
}
// Fill the current ARRAY_BUFFER buffer
// with the values that define a letter 'F'.
function setGeometry(gl) {
var positions = 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]);
// Center the F around the origin and Flip it around. We do this because
// we're in 3D now with and +Y is up where as before when we started with 2D
// we had +Y as down.
// We could do by changing all the values above but I'm lazy.
// We could also do it with a matrix at draw time but you should
// never do stuff at draw time if you can do it at init time.
var matrix = m4.xRotation(Math.PI);
matrix = m4.translate(matrix, -50, -75, -15);
for (var ii = 0; ii < positions.length; ii += 3) {
var vector = m4.transformVector([positions[ii + 0], positions[ii + 1], positions[ii + 2], 1], matrix);
positions[ii + 0] = vector[0];
positions[ii + 1] = vector[1];
positions[ii + 2] = vector[2];
}
gl.bufferData(gl.ARRAY_BUFFER, positions, gl.STATIC_DRAW);
}
// Fill the current ARRAY_BUFFER buffer with colors for the 'F'.
function setColors(gl) {
gl.bufferData(
gl.ARRAY_BUFFER,
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]),
gl.STATIC_DRAW);
}
function setNormals(gl) {
var normals = new Float32Array([
// left column front
0, 0, 1,
0, 0, 1,
0, 0, 1,
0, 0, 1,
0, 0, 1,
0, 0, 1,
// top rung front
0, 0, 1,
0, 0, 1,
0, 0, 1,
0, 0, 1,
0, 0, 1,
0, 0, 1,
// middle rung front
0, 0, 1,
0, 0, 1,
0, 0, 1,
0, 0, 1,
0, 0, 1,
0, 0, 1,
// left column back
0, 0, -1,
0, 0, -1,
0, 0, -1,
0, 0, -1,
0, 0, -1,
0, 0, -1,
// top rung back
0, 0, -1,
0, 0, -1,
0, 0, -1,
0, 0, -1,
0, 0, -1,
0, 0, -1,
// middle rung back
0, 0, -1,
0, 0, -1,
0, 0, -1,
0, 0, -1,
0, 0, -1,
0, 0, -1,
// top
0, 1, 0,
0, 1, 0,
0, 1, 0,
0, 1, 0,
0, 1, 0,
0, 1, 0,
// top rung right
1, 0, 0,
1, 0, 0,
1, 0, 0,
1, 0, 0,
1, 0, 0,
1, 0, 0,
// under top rung
0, -1, 0,
0, -1, 0,
0, -1, 0,
0, -1, 0,
0, -1, 0,
0, -1, 0,
// between top rung and middle
1, 0, 0,
1, 0, 0,
1, 0, 0,
1, 0, 0,
1, 0, 0,
1, 0, 0,
// top of middle rung
0, 1, 0,
0, 1, 0,
0, 1, 0,
0, 1, 0,
0, 1, 0,
0, 1, 0,
// right of middle rung
1, 0, 0,
1, 0, 0,
1, 0, 0,
1, 0, 0,
1, 0, 0,
1, 0, 0,
// bottom of middle rung.
0, -1, 0,
0, -1, 0,
0, -1, 0,
0, -1, 0,
0, -1, 0,
0, -1, 0,
// right of bottom
1, 0, 0,
1, 0, 0,
1, 0, 0,
1, 0, 0,
1, 0, 0,
1, 0, 0,
// bottom
0, -1, 0,
0, -1, 0,
0, -1, 0,
0, -1, 0,
0, -1, 0,
0, -1, 0,
// left side
-1, 0, 0,
-1, 0, 0,
-1, 0, 0,
-1, 0, 0,
-1, 0, 0,
-1, 0, 0]);
gl.bufferData(gl.ARRAY_BUFFER, normals, gl.STATIC_DRAW);
}
main();
</script>
</html>