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webgl-3d-lathe-step-03.html
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<html>
<head>
<metacharset="utf8">
<metaname="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes">
<title>WebGL 3D Lathe Compute Normals</title>
<linktype="text/css" href="resources/webgl-tutorials.css" rel="stylesheet" />
</head>
<body>
<canvas></canvas>
<divid="uiContainer">
<divid="ui">
</div>
</div>
</body>
<!-- vertex shader -->
<scriptid="simple-vertex-shader" type="notjs">
attributevec4a_position;
attributevec2a_texcoord;
attributevec3a_normal;
uniformmat4u_matrix;
varyingvec2v_texcoord;
varyingvec3v_normal;
voidmain(){
// Multiply the position by the matrix.
gl_Position=u_matrix*a_position;
// Pass the texcoord to the fragment shader.
v_texcoord=a_texcoord;
v_normal=a_normal;
}
</script>
<scriptid="specular-vertex-shader" type="notjs">
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="normal-shader" type="notjs">
precisionmediumpfloat;
// Passed in from the vertex shader.
varyingvec2v_texcoord;
varyingvec3v_normal;
uniformsampler2Du_texture;
voidmain(){
gl_FragColor=vec4(v_normal*.5+.5,1);
}
</script>
<scriptid="texture-shader" type="notjs">
precisionmediumpfloat;
// Passed in from the vertex shader.
varyingvec2v_texcoord;
varyingvec3v_normal;
uniformsampler2Du_texture;
voidmain(){
gl_FragColor=texture2D(u_texture,v_texcoord);
}
</script>
<scriptid="specular-shader" type="notjs">
#if GL_FRAGMENT_PRECISION_HIGH
precisionhighpfloat;
#else
precisionmediumpfloat;
#endif
// Passed in from the vertex shader.
varyingvec3v_normal;
varyingvec3v_surfaceToLight;
varyingvec3v_surfaceToView;
uniformvec4u_color;
uniformfloatu_shininess;
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);
floatlight=dot(normal,surfaceToLightDirection);
floatspecular=0.0;
if(light>0.0){
specular =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>
<!-- this is included only for iframe and requestAnimationFrame support -->
<!--
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-lessons-ui.js"></script>
<scriptsrc="resources/webgl-utils.js"></script>
<scriptsrc="resources/3d-math.js"></script>
<scriptsrc="resources/2d-math.js"></script>
<script>
"use strict";
//const svg = "m44,434c18,-33 19,-66 15,-111c-4,-45 -37,-104 -39,-132c-2,-28 11,-51 16,-81c5,-30 3,-63 -36,-63";
constsvg=
"M236,124L197,112L197,34C197,34 184.859,31.871 165,33C186.997,66.892 161.894,89.627 173,109C184.106,128.373 186.493,137.68 205,144C219.37,148.907 222,154 222,154L220,175L202,174L191,194L204,209L222,208C222,208 226.476,278.566 218,295C209.524,311.434 191.013,324.945 201,354C210.987,383.055 213,399 213,399L191,403L191,417L212,422C212,422 233.283,437.511 211,444C188.717,450.489 111,472 111,472L111,485L236,484L236,124Z";
functionmain(){
constopt=getQueryParams();
constcurvePoints=parseSVGPath(svg,{xFlip: true});
// Get A WebGL context
/** @type {HTMLCanvasElement} */
constcanvas=document.querySelector("canvas");
constgl=canvas.getContext("webgl");
if(!gl){
return;
}
constdata={
tolerance: 0.15,
distance: .4,
divisions: 16,
startAngle: 0,
endAngle: Math.PI*2,
capStart: true,
capEnd: true,
triangles: true,
maxAngle: degToRad(30),
mode: 0,
};
functiongenerateMesh(bufferInfo){
consttempPoints=getPointsOnBezierCurves(curvePoints,data.tolerance);
constpoints=simplifyPoints(tempPoints,0,tempPoints.length,data.distance);
consttempArrays=lathePoints(points,data.startAngle,data.endAngle,data.divisions,data.capStart,data.capEnd);
constarrays=generateNormals(tempArrays,data.maxAngle);
constextents=getExtents(arrays.position);
if(!bufferInfo){
// calls gl.createBuffer, gl.bindBuffer, and gl.bufferData for each array
bufferInfo=webglUtils.createBufferInfoFromArrays(gl,arrays);
}else{
gl.bindBuffer(gl.ARRAY_BUFFER,bufferInfo.attribs.a_position.buffer);
gl.bufferData(gl.ARRAY_BUFFER,newFloat32Array(arrays.position),gl.STATIC_DRAW);
gl.bindBuffer(gl.ARRAY_BUFFER,bufferInfo.attribs.a_texcoord.buffer);
gl.bufferData(gl.ARRAY_BUFFER,newFloat32Array(arrays.texcoord),gl.STATIC_DRAW);
gl.bindBuffer(gl.ARRAY_BUFFER,bufferInfo.attribs.a_normal.buffer);
gl.bufferData(gl.ARRAY_BUFFER,newFloat32Array(arrays.normal),gl.STATIC_DRAW);
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER,bufferInfo.indices);
gl.bufferData(gl.ELEMENT_ARRAY_BUFFER,newUint16Array(arrays.indices),gl.STATIC_DRAW);
bufferInfo.numElements=arrays.indices.length;
}
return{
bufferInfo: bufferInfo,
extents: extents,
};
}
// used to force the locations of attributes so they are
// the same across programs
constattributes=['a_position','a_texcoord','a_normal'];
// setup GLSL program
constprogramInfos=[
// compiles shaders, links program and looks up locations
webglUtils.createProgramInfo(gl,["simple-vertex-shader","normal-shader"],attributes),
webglUtils.createProgramInfo(gl,["specular-vertex-shader","specular-shader"],attributes),
webglUtils.createProgramInfo(gl,["simple-vertex-shader","texture-shader"],attributes),
];
consttexInfo=loadImageAndCreateTextureInfo("resources/uv-grid.png",render);
letworldMatrix=m4.identity();
letprojectionMatrix;
letextents;
letbufferInfo;
functionupdate(){
constinfo=generateMesh(bufferInfo);
extents=info.extents;
bufferInfo=info.bufferInfo;
render();
}
update();
functionrender(){
webglUtils.resizeCanvasToDisplaySize(gl.canvas,window.devicePixelRatio);
// Tell WebGL how to convert from clip space to pixels
gl.viewport(0,0,gl.canvas.width,gl.canvas.height);
gl.enable(gl.DEPTH_TEST);
// Clear the canvas AND the depth buffer.
gl.clear(gl.COLOR_BUFFER_BIT|gl.DEPTH_BUFFER_BIT);
// Compute the projection matrix
constfieldOfViewRadians=Math.PI*.25;
constaspect=gl.canvas.clientWidth/gl.canvas.clientHeight;
projectionMatrix=
m4.perspective(fieldOfViewRadians,aspect,1,2000);
// Compute the camera's matrix using look at.
constmidY=lerp(extents.min[1],extents.max[1],.5);
constsizeToFitOnScreen=(extents.max[1]-extents.min[1])*.6;
constdistance=sizeToFitOnScreen/Math.tan(fieldOfViewRadians*.5);
constcameraPosition=[0,midY,distance];
consttarget=[0,midY,0];
constup=[0,-1,0];// we used 2d points as input which means orientation is flipped
constcameraMatrix=m4.lookAt(cameraPosition,target,up);
// Make a view matrix from the camera matrix.
constviewMatrix=m4.inverse(cameraMatrix);
constviewProjectionMatrix=m4.multiply(projectionMatrix,viewMatrix);
constprogramInfo=programInfos[data.mode];
gl.useProgram(programInfo.program);
// Setup all the needed attributes.
// calls gl.bindBuffer, gl.enableVertexAttribArray, gl.vertexAttribPointer for each attribute
webglUtils.setBuffersAndAttributes(gl,programInfo,bufferInfo);
constworldViewProjection=m4.multiply(viewProjectionMatrix,worldMatrix);
// Set the uniforms
// calls gl.uniformXXX, gl.activeTexture, gl.bindTexture
webglUtils.setUniforms(programInfo,{
u_matrix: worldViewProjection,
u_worldViewProjection: worldViewProjection,
u_world: worldMatrix,
u_worldInverseTranspose: m4.transpose(m4.inverse(worldMatrix)),
u_lightWorldPosition: [midY*1.5,midY*2,distance*1.5],
u_viewWorldPosition: cameraMatrix.slice(12,15),
u_color: [1,0.8,0.2,1],
u_shininess: 50,
u_texture: texInfo.texture,
});
// calls gl.drawArrays or gl.drawElements.
webglUtils.drawBufferInfo(gl,bufferInfo,data.triangles ? gl.TRIANGLE : gl.LINES);
}
functiongetExtents(positions){
constmin=positions.slice(0,3);
constmax=positions.slice(0,3);
for(leti=3;i<positions.length;i+=3){
min[0]=Math.min(positions[i+0],min[0]);
min[1]=Math.min(positions[i+1],min[1]);
min[2]=Math.min(positions[i+2],min[2]);
max[0]=Math.max(positions[i+0],max[0]);
max[1]=Math.max(positions[i+1],max[1]);
max[2]=Math.max(positions[i+2],max[2]);
}
return{
min: min,
max: max,
};
}
// get the points from an SVG path. assumes a continous line
functionparseSVGPath(svg,opt){
constpoints=[];
letdelta=false;
letkeepNext=false;
letneed=0;
letvalue='';
letvalues=[];
letlastValues=[0,0];
letnextLastValues=[0,0];
letmode;
functionaddValue(){
if(value.length>0){
constv=parseFloat(value);
if(v>1000){
debugger;// eslint-disable-line
}
values.push(v);
if(values.length===2){
if(delta){
values[0]+=lastValues[0];
values[1]+=lastValues[1];
}
points.push(values);
if(keepNext){
nextLastValues=values.slice();
}
--need;
if(!need){
if(mode==='l'){
constm4=points.pop();
constm1=points.pop();
constm2=v2.lerp(m1,m4,0.25);
constm3=v2.lerp(m1,m4,0.75);
points.push(m1,m2,m3,m4);
}
lastValues=nextLastValues;
}
values=[];
}
value='';
}
}
svg.split('').forEach((c,ndx)=>{
if((c>='0'&&c<='9')||c==='.'){
value+=c;
}elseif(c==='-'){
addValue();
value='-';
}elseif(c==='m'){
addValue();
keepNext=true;
need=1;
delta=true;
mode='m';
}elseif(c==='c'){
addValue();
keepNext=true;
need=3;
delta=true;
mode='c';
}elseif(c==='l'){
addValue();
keepNext=true;
need=1;
delta=false;
mode='l';
}elseif(c==='M'){
addValue();
keepNext=true;
need=1;
delta=false;
mode='m';
}elseif(c==='C'){
addValue();
keepNext=true;
need=3;
delta=false;
mode='c';
}elseif(c==='L'){
addValue();
keepNext=true;
need=1;
delta=false;
mode='l';
}elseif(c==='Z'){
// close the loop
}elseif(c===','){
addValue();
}elseif(c===' '){
addValue();
}else{
debugger;// eslint-disable-line
}
});
addValue();
letmin=points[0].slice();
letmax=points[0].slice();
for(leti=1;i<points.length;++i){
min=v2.min(min,points[i]);
max=v2.max(max,points[i]);
}
letrange=v2.sub(max,min);
lethalfRange=v2.mult(range,.5);
for(leti=0;i<points.length;++i){
constp=points[i];
if(opt.xFlip){
p[0]=max[0]-p[0];
}else{
p[0]=p[0]-min[0];
}
p[1]=(p[1]-min[0])-halfRange[1];
}
returnpoints;
}
functiongetPointOnBezierCurve(points,offset,t){
constinvT=(1-t);
returnv2.add(v2.mult(points[offset+0],invT*invT*invT),
v2.mult(points[offset+1],3*t*invT*invT),
v2.mult(points[offset+2],3*invT*t*t),
v2.mult(points[offset+3],t*t*t));
}
functiongetPointsOnBezierCurve(points,offset,numPoints){
constcpoints=[];
for(leti=0;i<numPoints;++i){
constt=i/(numPoints-1);
cpoints.push(getPointOnBezierCurve(points,offset,t));
}
returncpoints;
}
functionflatness(points,offset){
constp1=points[offset+0];
constp2=points[offset+1];
constp3=points[offset+2];
constp4=points[offset+3];
letux=3*p2[0]-2*p1[0]-p4[0];ux*=ux;
letuy=3*p2[1]-2*p1[1]-p4[1];uy*=uy;
letvx=3*p3[0]-2*p4[0]-p1[0];vx*=vx;
letvy=3*p3[1]-2*p4[1]-p1[1];vy*=vy;
if(ux<vx){
ux=vx;
}
if(uy<vy){
uy=vy;
}
returnux+uy;
}
functiongetPointsOnBezierCurveWithSplitting(points,offset,tolerance,newPoints){
constoutPoints=newPoints||[];
if(flatness(points,offset)<tolerance){
// just add the end points of this curve
outPoints.push(points[offset+0]);
outPoints.push(points[offset+3]);
}else{
// subdivide
constt=.5;
constp1=points[offset+0];
constp2=points[offset+1];
constp3=points[offset+2];
constp4=points[offset+3];
constq1=v2.lerp(p1,p2,t);
constq2=v2.lerp(p2,p3,t);
constq3=v2.lerp(p3,p4,t);
constr1=v2.lerp(q1,q2,t);
constr2=v2.lerp(q2,q3,t);
constred=v2.lerp(r1,r2,t);
// do 1st half
getPointsOnBezierCurveWithSplitting([p1,q1,r1,red],0,tolerance,outPoints);
// do 2nd half
getPointsOnBezierCurveWithSplitting([red,r2,q3,p4],0,tolerance,outPoints);
}
returnoutPoints;
}
// gets points across all segments
functiongetPointsOnBezierCurves(points,tolerance){
constnewPoints=[];
constnumSegments=(points.length-1)/3;
for(leti=0;i<numSegments;++i){
constoffset=i*3;
getPointsOnBezierCurveWithSplitting(points,offset,tolerance,newPoints);
}
returnnewPoints;
}
// Ramer Douglas Peucker algorithm
functionsimplifyPoints(points,start,end,epsilon,newPoints){
constoutPoints=newPoints||[];
// find the most distant point from the line formed by the endpoints
consts=points[start];
conste=points[end-1];
letmaxDistSq=0;
letmaxNdx=1;
for(leti=start+1;i<end-1;++i){
constdistSq=v2.distanceToSegmentSq(points[i],s,e);
if(distSq>maxDistSq){
maxDistSq=distSq;
maxNdx=i;
}
}
// if that point is too far
if(Math.sqrt(maxDistSq)>epsilon){
// split
simplifyPoints(points,start,maxNdx+1,epsilon,outPoints);
simplifyPoints(points,maxNdx,end,epsilon,outPoints);
}else{
// add the 2 end points
outPoints.push(s,e);
}
returnoutPoints;
}
// rotates around Y axis.
functionlathePoints(points,
startAngle,// angle to start at (ie 0)
endAngle,// angle to end at (ie Math.PI * 2)
numDivisions,// how many quads to make around
capStart,// true to cap the top
capEnd){// true to cap the bottom
constpositions=[];
consttexcoords=[];
constindices=[];
constvOffset=capStart ? 1 : 0;
constpointsPerColumn=points.length+vOffset+(capEnd ? 1 : 0);
constquadsDown=pointsPerColumn-1;
// generate v coordniates
letvcoords=[];
// first compute the length of the points
letlength=0;
for(leti=0;i<points.length-1;++i){
vcoords.push(length);
length+=v2.distance(points[i],points[i+1]);
}
vcoords.push(length);// the last point
// now divide each by the total length;
vcoords=vcoords.map(v=>v/length);
// generate points
for(letdivision=0;division<=numDivisions;++division){
constu=division/numDivisions;
constangle=lerp(startAngle,endAngle,u)%(Math.PI*2);
constmat=m4.yRotation(angle);
if(capStart){
// add point on Y access at start
positions.push(0,points[0][1],0);
texcoords.push(u,0);
}
points.forEach((p,ndx)=>{
consttp=m4.transformPoint(mat,[...p,0]);
positions.push(tp[0],tp[1],tp[2]);
texcoords.push(u,vcoords[ndx]);
});
if(capEnd){
// add point on Y access at end
positions.push(0,points[points.length-1][1],0);
texcoords.push(u,1);
}
}
// generate indices
for(letdivision=0;division<numDivisions;++division){
constcolumn1Offset=division*pointsPerColumn;
constcolumn2Offset=column1Offset+pointsPerColumn;
for(letquad=0;quad<quadsDown;++quad){
indices.push(column1Offset+quad,column1Offset+quad+1,column2Offset+quad);
indices.push(column1Offset+quad+1,column2Offset+quad+1,column2Offset+quad);
}
}
return{
position: positions,
texcoord: texcoords,
indices: indices,
};
}
functionmakeIndexedIndicesFn(arrays){
constindices=arrays.indices;
letndx=0;
constfn=function(){
returnindices[ndx++];
};
fn.reset=function(){
ndx=0;
};
fn.numElements=indices.length;
returnfn;
}
functionmakeUnindexedIndicesFn(arrays){
letndx=0;
constfn=function(){
returnndx++;
};
fn.reset=function(){
ndx=0;
};
fn.numElements=arrays.positions.length/3;
returnfn;
}
functionmakeIndiceIterator(arrays){
returnarrays.indices
? makeIndexedIndicesFn(arrays)
: makeUnindexedIndicesFn(arrays);
}
functiongenerateNormals(arrays,maxAngle){
constpositions=arrays.position;
consttexcoords=arrays.texcoord;
// first compute the normal of each face
letgetNextIndex=makeIndiceIterator(arrays);
constnumFaceVerts=getNextIndex.numElements;
constnumVerts=arrays.position.length;
constnumFaces=numFaceVerts/3;
constfaceNormals=[];
// Compute the normal for every face.
// While doing that, create a new vertex for every face vertex
for(leti=0;i<numFaces;++i){
constn1=getNextIndex()*3;
constn2=getNextIndex()*3;
constn3=getNextIndex()*3;
constv1=positions.slice(n1,n1+3);
constv2=positions.slice(n2,n2+3);
constv3=positions.slice(n3,n3+3);
faceNormals.push(m4.normalize(m4.cross(m4.subtractVectors(v1,v2),m4.subtractVectors(v3,v2))));
}
lettempVerts={};
lettempVertNdx=0;
// this assumes vertex positions are an exact match
functiongetVertIndex(x,y,z){
constvertId=x+","+y+","+z;
constndx=tempVerts[vertId];
if(ndx!==undefined){
returnndx;
}
constnewNdx=tempVertNdx++;
tempVerts[vertId]=newNdx;
returnnewNdx;
}
// We need to figure out the shared vertices.
// It's not as simple as looking at the faces (triangles)
// because for example if we have a standard cylinder
//
//
// 3-4
// / \
// 2 5 Looking down a cylinder starting at S
// | | and going around to E, E and S are not
// 1 6 the same vertex in the data we have
// \ / as they don't share UV coords.
// S/E
//
// the vertices at the start and end do not share vertices
// since they have different UVs but if you don't consider
// them to share vertices they will get the wrong normals
constvertIndices=[];
for(leti=0;i<numVerts;++i){
constoffset=i*3;
constvert=positions.slice(offset,offset+3);
vertIndices.push(getVertIndex(vert));
}
// go through every vertex and record which faces it's on
constvertFaces=[];
getNextIndex.reset();
for(leti=0;i<numFaces;++i){
for(letj=0;j<3;++j){
constndx=getNextIndex();
constsharedNdx=vertIndices[ndx];
letfaces=vertFaces[sharedNdx];
if(!faces){
faces=[];
vertFaces[sharedNdx]=faces;
}
faces.push(i);
}
}
// now go through every face and compute the normals for each
// vertex of the face. Only include faces that aren't more than
// maxAngle different. Add the result to arrays of newPositions,
// newTexcoords and newNormals, discarding any vertices that
// are the same.
tempVerts={};
tempVertNdx=0;
constnewPositions=[];
constnewTexcoords=[];
constnewNormals=[];
functiongetNewVertIndex(x,y,z,nx,ny,nz,u,v){
constvertId=
x+","+y+","+z+","+
nx+","+ny+","+nz+","+
u+","+v;
constndx=tempVerts[vertId];
if(ndx!==undefined){
returnndx;
}
constnewNdx=tempVertNdx++;
tempVerts[vertId]=newNdx;
newPositions.push(x,y,z);
newNormals.push(nx,ny,nz);
newTexcoords.push(u,v);
returnnewNdx;
}
constnewVertIndices=[];
getNextIndex.reset();
constmaxAngleCos=Math.cos(maxAngle);
// for each face
for(leti=0;i<numFaces;++i){
constthisFaceVertexNormals=[];
// get the normal for this face
constthisFaceNormal=faceNormals[i];
// for each vertex on the face
for(letj=0;j<3;++j){
constndx=getNextIndex();
constsharedNdx=vertIndices[ndx];
constfaces=vertFaces[sharedNdx];
constnorm=[0,0,0];
faces.forEach(faceNdx=>{
// is this face facing the same way
constotherFaceNormal=faceNormals[faceNdx];
constdot=m4.dot(thisFaceNormal,otherFaceNormal);
if(dot>maxAngleCos){
m4.addVectors(norm,otherFaceNormal,norm);
}
});
m4.normalize(norm,norm);
constpoffset=ndx*3;
consttoffset=ndx*2;
newVertIndices.push(getNewVertIndex(
positions[poffset+0],positions[poffset+1],positions[poffset+2],
norm[0],norm[1],norm[2],
texcoords[toffset+0],texcoords[toffset+1]));
}
}
return{
position: newPositions,
texcoord: newTexcoords,
normal: newNormals,
indices: newVertIndices,
};
}
webglLessonsUI.setupUI(document.querySelector("#ui"),data,[
{type: "slider",key: "distance",change: update,min: 0.001,max: 5,precision: 3,step: 0.001,},
{type: "slider",key: "divisions",change: update,min: 1,max: 60,},
{type: "slider",key: "startAngle",change: update,min: 0,max: Math.PI*2,precision: 3,step: 0.001,uiMult: 180/Math.PI,uiPrecision: 0},
{type: "slider",key: "endAngle",change: update,min: 0,max: Math.PI*2,precision: 3,step: 0.001,uiMult: 180/Math.PI,uiPrecision: 0},
{type: "slider",key: "maxAngle",change: update,min: 0.001,max: Math.PI,precision: 3,step: 0.001,uiMult: 180/Math.PI,uiPrecision: 1},
{type: "checkbox",key: "capStart",change: update},
{type: "checkbox",key: "capEnd",change: update},
{type: "checkbox",key: "triangles",change: render},
{type: "option",key: "mode",change: render,options: ["normals","lit","texcoords"],},
]);
/* eslint brace-style: 0 */
gl.canvas.addEventListener('mousedown',(e)=>{e.preventDefault();startRotateCamera(e);});
window.addEventListener('mouseup',stopRotateCamera);
window.addEventListener('mousemove',rotateCamera);
gl.canvas.addEventListener('touchstart',(e)=>{e.preventDefault();startRotateCamera(e.touches[0]);});
window.addEventListener('touchend',(e)=>{stopRotateCamera(e.touches[0]);});
window.addEventListener('touchmove',(e)=>{rotateCamera(e.touches[0]);});
letlastPos;
letmoving;
functionstartRotateCamera(e){
lastPos=getRelativeMousePosition(gl.canvas,e);
moving=true;
}
functionrotateCamera(e){
if(moving){
constpos=getRelativeMousePosition(gl.canvas,e);
constsize=[4/gl.canvas.width,4/gl.canvas.height];
constdelta=v2.mult(v2.sub(lastPos,pos),size);
// this is bad but it works for a basic case so phffttt
worldMatrix=m4.multiply(m4.xRotation(delta[1]*5),worldMatrix);
worldMatrix=m4.multiply(m4.yRotation(delta[0]*5),worldMatrix);
lastPos=pos;
render();
}
}
functionstopRotateCamera(e){
moving=false;
}
functiondegToRad(deg){
returndeg*Math.PI/180;
}
functionclamp(v,min,max){
returnMath.max(Math.min(v,max),min);
}
functionlerp(a,b,t){
returna+(b-a)*t;
}
functiongetQueryParams(){
varparams={};
if(window.location.search){
window.location.search.substring(1).split("&").forEach(function(pair){
varkeyValue=pair.split("=").map(function(kv){
returndecodeURIComponent(kv);
});
params[keyValue[0]]=keyValue[1];
});
}
returnparams;
}
functiongetRelativeMousePosition(canvas,e){
constrect=canvas.getBoundingClientRect();
constx=(e.clientX-rect.left)/(rect.right-rect.left)*canvas.width;
consty=(e.clientY-rect.top)/(rect.bottom-rect.top)*canvas.height;
return[
(x-canvas.width/2)/window.devicePixelRatio,
(y-canvas.height/2)/window.devicePixelRatio,
];
}
// creates a texture info { width: w, height: h, texture: tex }
// The texture will start with 1x1 pixels and be updated
// when the image has loaded
functionloadImageAndCreateTextureInfo(url,callback){
vartex=gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D,tex);
// Fill the texture with a 1x1 blue pixel.
gl.texImage2D(gl.TEXTURE_2D,0,gl.RGBA,1,1,0,gl.RGBA,gl.UNSIGNED_BYTE,
newUint8Array([0,0,255,255]));
vartextureInfo={
width: 1,// we don't know the size until it loads
height: 1,
texture: tex,
};
varimg=newImage();
img.addEventListener('load',function(){
textureInfo.width=img.width;
textureInfo.height=img.height;
gl.bindTexture(gl.TEXTURE_2D,textureInfo.texture);
gl.texImage2D(gl.TEXTURE_2D,0,gl.RGBA,gl.RGBA,gl.UNSIGNED_BYTE,img);
// Check if the image is a power of 2 in both dimensions.
if(isPowerOf2(img.width)&&isPowerOf2(img.height)){
// Yes, it's a power of 2. Generate mips.
gl.generateMipmap(gl.TEXTURE_2D);
}else{
// No, it's not a power of 2. Turn of mips and set wrapping to clamp to edge
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);
gl.texParameteri(gl.TEXTURE_2D,gl.TEXTURE_MIN_FILTER,gl.LINEAR);
}
if(callback){
callback();
}
});
img.src=url;
returntextureInfo;
}
functionisPowerOf2(value){
return(value&(value-1))===0;
}
}
constv2=(function(){
// adds 1 or more v2s
functionadd(a, ...args){
constn=a.slice();
[...args].forEach(p=>{
n[0]+=p[0];
n[1]+=p[1];
});
returnn;
}
functionsub(a, ...args){
constn=a.slice();
[...args].forEach(p=>{
n[0]-=p[0];
n[1]-=p[1];
});
returnn;
}
functionmult(a,s){
if(Array.isArray(s)){
lett=s;
s=a;
a=t;
}
if(Array.isArray(s)){
return[
a[0]*s[0],
a[1]*s[1],
];
}else{
return[a[0]*s,a[1]*s];
}
}
functionlerp(a,b,t){
return[
a[0]+(b[0]-a[0])*t,
a[1]+(b[1]-a[1])*t,
];
}
functionmin(a,b){
return[
Math.min(a[0],b[0]),
Math.min(a[1],b[1]),
];
}
functionmax(a,b){
return[
Math.max(a[0],b[0]),
Math.max(a[1],b[1]),
];
}
// compute the distance squared between a and b
functiondistanceSq(a,b){
constdx=a[0]-b[0];
constdy=a[1]-b[1];
returndx*dx+dy*dy;
}
// compute the distance between a and b
functiondistance(a,b){
returnMath.sqrt(distanceSq(a,b));
}
// compute the distance squared from p to the line segment
// formed by v and w
functiondistanceToSegmentSq(p,v,w){
constl2=distanceSq(v,w);
if(l2===0){
returndistanceSq(p,v);
}
lett=((p[0]-v[0])*(w[0]-v[0])+(p[1]-v[1])*(w[1]-v[1]))/l2;
