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webgl-3d-lighting-spot-using-step.html
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<!-- Licensed under a BSD license. See license.html for license -->
<!DOCTYPE html>
<html>
<head>
<metacharset="utf-8">
<metaname="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes">
<title>WebGL - 3D Spot Lighting using step</title>
<linktype="text/css" href="resources/webgl-tutorials.css" rel="stylesheet" />
</head>
<body>
<divclass="description">
Drag slider to rotate F.
</div>
<canvasid="canvas"></canvas>
<divid="uiContainer">
<divid="ui">
<divid="fRotation"></div>
<divid="lightRotationX"></div>
<divid="lightRotationY"></div>
<divid="limit"></div>
</div>
</div>
</body>
<!-- vertex shader -->
<scriptid="vertex-shader-3d" type="x-shader/x-vertex">
attributevec4a_position;
attributevec3a_normal;
uniformvec3u_lightWorldPosition;
uniformvec3u_viewWorldPosition;
uniformmat4u_world;
uniformmat4u_worldViewProjection;
uniformmat4u_worldInverseTranspose;
varyingvec3v_normal;
varyingvec3v_surfaceToLight;
varyingvec3v_surfaceToView;
voidmain(){
// 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_worldInverseTranspose)*a_normal;
// compute the world position of the surfoace
vec3surfaceWorldPosition=(u_world*a_position).xyz;
// compute the vector of the surface to the light
// and pass it to the fragment shader
v_surfaceToLight=u_lightWorldPosition-surfaceWorldPosition;
// compute the vector of the surface to the view/camera
// and pass it to the fragment shader
v_surfaceToView=u_viewWorldPosition-surfaceWorldPosition;
}
</script>
<!-- fragment shader -->
<scriptid="fragment-shader-3d" type="x-shader/x-fragment">
precisionmediumpfloat;
// Passed in from the vertex shader.
varyingvec3v_normal;
varyingvec3v_surfaceToLight;
varyingvec3v_surfaceToView;
uniformvec4u_color;
uniformfloatu_shininess;
uniformvec3u_lightDirection;
uniformfloatu_limit;// in dot space
voidmain(){
// because v_normal is a varying it's interpolated
// so it will not be a unit vector. Normalizing it
// will make it a unit vector again
vec3 normal =normalize(v_normal);
vec3surfaceToLightDirection=normalize(v_surfaceToLight);
vec3surfaceToViewDirection=normalize(v_surfaceToView);
vec3halfVector=normalize(surfaceToLightDirection+surfaceToViewDirection);
floatdotFromDirection=dot(surfaceToLightDirection,
-u_lightDirection);
floatinLight=step(u_limit,dotFromDirection);
floatlight=inLight*dot(normal,surfaceToLightDirection);
floatspecular=inLight*pow(dot(normal,halfVector),u_shininess);
gl_FragColor=u_color;
// Lets multiply just the color portion (not the alpha)
// by the light
gl_FragColor.rgb*=light;
// Just add in the specular
gl_FragColor.rgb+=specular;
}
</script>
<!--
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.
-->
<scriptsrc="resources/webgl-utils.js"></script>
<scriptsrc="resources/webgl-lessons-ui.js"></script>
<scriptsrc="resources/m4.js"></script>
<script>
"use strict";
functionmain(){
// Get A WebGL context
/** @type {HTMLCanvasElement} */
varcanvas=document.querySelector("#canvas");
vargl=canvas.getContext("webgl");
if(!gl){
return;
}
// setup GLSL program
varprogram=webglUtils.createProgramFromScripts(gl,["vertex-shader-3d","fragment-shader-3d"]);
// look up where the vertex data needs to go.
varpositionLocation=gl.getAttribLocation(program,"a_position");
varnormalLocation=gl.getAttribLocation(program,"a_normal");
// lookup uniforms
varworldViewProjectionLocation=gl.getUniformLocation(program,"u_worldViewProjection");
varworldInverseTransposeLocation=gl.getUniformLocation(program,"u_worldInverseTranspose");
varcolorLocation=gl.getUniformLocation(program,"u_color");
varshininessLocation=gl.getUniformLocation(program,"u_shininess");
varlightDirectionLocation=gl.getUniformLocation(program,"u_lightDirection");
varlimitLocation=gl.getUniformLocation(program,"u_limit");
varlightWorldPositionLocation=
gl.getUniformLocation(program,"u_lightWorldPosition");
varviewWorldPositionLocation=
gl.getUniformLocation(program,"u_viewWorldPosition");
varworldLocation=
gl.getUniformLocation(program,"u_world");
// Create a buffer to put positions in
varpositionBuffer=gl.createBuffer();
// Bind it to ARRAY_BUFFER (think of it as ARRAY_BUFFER = positionBuffer)
gl.bindBuffer(gl.ARRAY_BUFFER,positionBuffer);
// Put geometry data into buffer
setGeometry(gl);
// Create a buffer to put normals in
varnormalBuffer=gl.createBuffer();
// Bind it to ARRAY_BUFFER (think of it as ARRAY_BUFFER = normalBuffer)
gl.bindBuffer(gl.ARRAY_BUFFER,normalBuffer);
// Put normals data into buffer
setNormals(gl);
functionradToDeg(r){
returnr*180/Math.PI;
}
functiondegToRad(d){
returnd*Math.PI/180;
}
varfieldOfViewRadians=degToRad(60);
varfRotationRadians=0;
varshininess=150;
varlightRotationX=0;
varlightRotationY=0;
varlightDirection=[0,0,1];// this is computed in updateScene
varlimit=degToRad(10);
drawScene();
// Setup a ui.
webglLessonsUI.setupSlider("#fRotation",{value: radToDeg(fRotationRadians),slide: updateRotation,min: -360,max: 360});
webglLessonsUI.setupSlider("#lightRotationX",{value: lightRotationX,slide: updatelightRotationX,min: -2,max: 2,precision: 2,step: 0.001});
webglLessonsUI.setupSlider("#lightRotationY",{value: lightRotationY,slide: updatelightRotationY,min: -2,max: 2,precision: 2,step: 0.001});
webglLessonsUI.setupSlider("#limit",{value: radToDeg(limit),slide: updateLimit,min: 0,max: 180});
functionupdateRotation(event,ui){
fRotationRadians=degToRad(ui.value);
drawScene();
}
functionupdatelightRotationX(event,ui){
lightRotationX=ui.value;
drawScene();
}
functionupdatelightRotationY(event,ui){
lightRotationY=ui.value;
drawScene();
}
functionupdateLimit(event,ui){
limit=degToRad(ui.value);
drawScene();
}
// Draw the scene.
functiondrawScene(){
webglUtils.resizeCanvasToDisplaySize(gl.canvas);
// Tell WebGL how to convert from clip space to pixels
gl.viewport(0,0,gl.canvas.width,gl.canvas.height);
// Clear the canvas AND the depth buffer.
gl.clear(gl.COLOR_BUFFER_BIT|gl.DEPTH_BUFFER_BIT);
// Turn on culling. By default backfacing triangles
// will be culled.
gl.enable(gl.CULL_FACE);
// Enable the depth buffer
gl.enable(gl.DEPTH_TEST);
// Tell it to use our program (pair of shaders)
gl.useProgram(program);
// Turn on the position attribute
gl.enableVertexAttribArray(positionLocation);
// Bind the position buffer.
gl.bindBuffer(gl.ARRAY_BUFFER,positionBuffer);
// Tell the position attribute how to get data out of positionBuffer (ARRAY_BUFFER)
varsize=3;// 3 components per iteration
vartype=gl.FLOAT;// the data is 32bit floats
varnormalize=false;// don't normalize the data
varstride=0;// 0 = move forward size * sizeof(type) each iteration to get the next position
varoffset=0;// start at the beginning of the buffer
gl.vertexAttribPointer(
positionLocation,size,type,normalize,stride,offset);
// Turn on the normal attribute
gl.enableVertexAttribArray(normalLocation);
// Bind the normal buffer.
gl.bindBuffer(gl.ARRAY_BUFFER,normalBuffer);
// Tell the attribute how to get data out of normalBuffer (ARRAY_BUFFER)
varsize=3;// 3 components per iteration
vartype=gl.FLOAT;// the data is 32bit floating point values
varnormalize=false;// normalize the data (convert from 0-255 to 0-1)
varstride=0;// 0 = move forward size * sizeof(type) each iteration to get the next position
varoffset=0;// start at the beginning of the buffer
gl.vertexAttribPointer(
normalLocation,size,type,normalize,stride,offset);
// Compute the projection matrix
varaspect=gl.canvas.clientWidth/gl.canvas.clientHeight;
varzNear=1;
varzFar=2000;
varprojectionMatrix=m4.perspective(fieldOfViewRadians,aspect,zNear,zFar);
// Compute the camera's matrix
varcamera=[100,150,200];
vartarget=[0,35,0];
varup=[0,1,0];
varcameraMatrix=m4.lookAt(camera,target,up);
// Make a view matrix from the camera matrix.
varviewMatrix=m4.inverse(cameraMatrix);
// Compute a view projection matrix
varviewProjectionMatrix=m4.multiply(projectionMatrix,viewMatrix);
// Draw a F at the origin
varworldMatrix=m4.yRotation(fRotationRadians);
// Multiply the matrices.
varworldViewProjectionMatrix=m4.multiply(viewProjectionMatrix,worldMatrix);
varworldInverseMatrix=m4.inverse(worldMatrix);
varworldInverseTransposeMatrix=m4.transpose(worldInverseMatrix);
// Set the matrices
gl.uniformMatrix4fv(worldViewProjectionLocation,false,worldViewProjectionMatrix);
gl.uniformMatrix4fv(worldInverseTransposeLocation,false,worldInverseTransposeMatrix);
gl.uniformMatrix4fv(worldLocation,false,worldMatrix);
// Set the color to use
gl.uniform4fv(colorLocation,[0.2,1,0.2,1]);// green
// set the light position
constlightPosition=[40,60,120];
gl.uniform3fv(lightWorldPositionLocation,lightPosition);
// set the camera/view position
gl.uniform3fv(viewWorldPositionLocation,camera);
// set the shininess
gl.uniform1f(shininessLocation,shininess);
// set the spotlight uniforms
// since we don't have a plane like most spotlight examples
// let's point the spot light at the F
{
varlmat=m4.lookAt(lightPosition,target,up);
lmat=m4.multiply(m4.xRotation(lightRotationX),lmat);
lmat=m4.multiply(m4.yRotation(lightRotationY),lmat);
// get the zAxis from the matrix
// negate it because lookAt looks down the -Z axis
lightDirection=[-lmat[8],-lmat[9],-lmat[10]];
}
gl.uniform3fv(lightDirectionLocation,lightDirection);
gl.uniform1f(limitLocation,Math.cos(limit));
// Draw the geometry.
varprimitiveType=gl.TRIANGLES;
varoffset=0;
varcount=16*6;
gl.drawArrays(primitiveType,offset,count);
}
}
// Fill the buffer with the values that define a letter 'F'.
functionsetGeometry(gl){
varpositions=newFloat32Array([
// 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.
varmatrix=m4.xRotation(Math.PI);
matrix=m4.translate(matrix,-50,-75,-15);
for(varii=0;ii<positions.length;ii+=3){
varvector=m4.transformPoint(matrix,[positions[ii+0],positions[ii+1],positions[ii+2],1]);
positions[ii+0]=vector[0];
positions[ii+1]=vector[1];
positions[ii+2]=vector[2];
}
gl.bufferData(gl.ARRAY_BUFFER,positions,gl.STATIC_DRAW);
}
functionsetNormals(gl){
varnormals=newFloat32Array([
// 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>
