Simple Lighting Model

Developer
Omar Shehata
Size
3,365 Kb
Views
32,384
  1. Simple Lighting Model Previews
  2. Simple Lighting Model HTML Codes
  3. Simple Lighting Model CSS Codes
  4. Simple Lighting Model JS Codes

How do I make an simple lighting model?

This is the final result of part 3 of TutsPlus tutorial on writing graphics shaders.. What is a simple lighting model? How do you make a simple lighting model? This script and codes were developed by Omar Shehata on 13 August 2022, Saturday.

Simple Lighting Model Previews
IQ Test

Simple Lighting Model - Script Codes HTML Codes

<!DOCTYPE html>
<html >
<head> <meta charset="UTF-8"> <title>Simple Lighting Model</title> <link rel="stylesheet" href="css/style.css">
</head>
<body> <script id="fragShader" type="shader-code">	uniform sampler2D tex;//The main texture	uniform sampler2D norm;//The normal texture	uniform vec2 res;//Our screen dimensions	uniform vec4 light;//Our light source information	void main() { vec2 pixel = gl_FragCoord.xy / res.xy; vec4 color = texture2D(tex,pixel); vec4 normalVector = texture2D(norm,pixel);//We get the normal value of this pixel vec2 lightPosition = light.xy / res.xy;//We normalize the light source lightPosition.y = 1.0 - lightPosition.y; //We calculate the direction from the light to this pixel vec3 LightVector = vec3(lightPosition.x - pixel.x,lightPosition.y - pixel.y,light.z); //By "up" direction of our normal map has the value (0.5,0.5,1.0) in terms of rgb //So we offset by that amount normalVector.x -= 0.5; normalVector.y -= 0.5; //We normalize our vectors to compute the direction vec3 NormalVector = normalize(normalVector.xyz); LightVector = normalize(LightVector); // Compute the diffuse term for the Phong equation float diffuse = 1.5 * max(dot( NormalVector, LightVector ),0.0); //Toggle light system on or off if(light.w == 0.0){ gl_FragColor = color; } else { gl_FragColor = color * diffuse; } }	</script> <script src='https://cdnjs.cloudflare.com/ajax/libs/three.js/r71/three.min.js'></script> <script src="js/index.js"></script>
</body>
</html>

Simple Lighting Model - Script Codes CSS Codes

/* We want our scene to span the entire window */
body { margin: 0; }

Simple Lighting Model - Script Codes JS Codes

//@author Omar Shehata. 2015.
//We are loading the Three.js library from the cdn here: http://cdnjs.com/libraries/three.js/
var scene;
var camera;
var renderer;
function scene_setup(){ //This is all code needed to set up a basic ThreeJS scene //First we initialize the scene and our camera scene = new THREE.Scene(); camera = new THREE.PerspectiveCamera( 75, window.innerWidth / window.innerHeight, 0.1, 1000 ); //We create the WebGL renderer and add it to the document renderer = new THREE.WebGLRenderer(); renderer.setSize( window.innerWidth, window.innerHeight ); document.body.appendChild( renderer.domElement );
}
//Initialize the Threejs scene
scene_setup();
//Pull the shader code from the html
var shaderCode = document.getElementById("fragShader").innerHTML;
//Our textures are up on github
var textureURL = "https://raw.githubusercontent.com/tutsplus/Beginners-Guide-to-Shaders/master/Part3/images/blocks.JPG"
var normalURL = "https://raw.githubusercontent.com/tutsplus/Beginners-Guide-to-Shaders/master/Part3/normal_maps/blocks_normal.JPG"
THREE.ImageUtils.crossOrigin = '';//Allows us to load an external image
//Load in the texture and the normal
var texture = THREE.ImageUtils.loadTexture(textureURL);
var normal = THREE.ImageUtils.loadTexture(normalURL);
//Set up the uniforms we'll send to our share
//More info on uniform types: http://threejs.org/docs/#Reference/Materials/ShaderMaterial
var uniforms = { tex : {type:'t',value:texture},//The texture norm: {type:'t',value:normal},//Normal res : {type: 'v2',value:new THREE.Vector2(window.innerWidth,window.innerHeight)},//Keeps the resolution light: {type: 'v4',value:new THREE.Vector4()}//Our light source, we will use the 3 numbers as have x,y and height away from the screen. 4th value is whether the light is on or not
}
//We stick our shader onto a 2d plane big enough to fill the screen
var material = new THREE.ShaderMaterial({uniforms:uniforms,fragmentShader:shaderCode})
var geometry = new THREE.PlaneGeometry( 10, 10 );
var sprite = new THREE.Mesh( geometry,material );
//Add it to the scene
scene.add( sprite );
//Move the camera back so we can see it
camera.position.z = 2;
uniforms.light.value.z = 0.3;//How high up our light source should be
uniforms.light.value.w = 1.0;//Turn light on
//Render everything!
function render() { requestAnimationFrame( render ); renderer.render( scene, camera );
}
render();
document.onmousemove = function(event){ //Update the light source to follow our mouse uniforms.light.value.x = event.clientX; uniforms.light.value.y = event.clientY;
}
document.onmousedown = function(event){ //Toggle lighting system if( uniforms.light.value.w) uniforms.light.value.w = 0.0; else uniforms.light.value.w = 1.0;
}
Simple Lighting Model - Script Codes
Simple Lighting Model - Script Codes
Home Page Home
Developer Omar Shehata
Username omarshe7ta
Uploaded August 13, 2022
Rating 3
Size 3,365 Kb
Views 32,384
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