I've imported a GLTF file with two different meshes. My goal is to give each mesh a material with a unique custom fragment shader using onBeforeCompile. Each mesh has the same type of material (MeshNormalMaterial).
When I try to apply one fragment shader to one material and the other fragment shader to the other material, both materials wind up with the same fragment shader. The fragment shader each material has depends on which material I setup first.
Here's a few pictures showing what I'm talking about:
Below is all the relevant code.
Main code: This is the general structure of my code. I've enclosed the important part between "PRIMARY AREA OF INTEREST" comments. For simplicity, I've replaced my shader code with "..." or a comment describing what it does. They do work as shown in the pictures above.
// Three.JS Canvas
const threeDisplay = document.getElementById("threeDisplay");
// Globals
var displayDimensions = getElemDimensions(threeDisplay); // Uniform
var currentTime = 0; // Uniform
var helix = null; // Mesh
var innerHelix = null; // Mesh
var horseshoe = null; // Mesh
// Set the scene and camera up
const scene = new THREE.Scene();
const camera = initCamera();
// Setup a directional light
const light = new THREE.DirectionalLight( 0xffffff, 1.0 );
light.position.set(-0.2, 1, -0.6);
scene.add(light);
// Setup WebGL renderer
const renderer = initRenderer();
threeDisplay.appendChild( renderer.domElement );
// Load the gltf model
new GLTFLoader().load( "./spiral_pillar_hq_horseshoe.glb", function (object) {
const helixFragmentShaderReplacements = [
{
from: ' ... ',
to: ' // rainbow '
}
];
const horseshoeFragmentShaderReplacements = [
{
from: ' ... ',
to: ' // white '
}
];
//////////////////////////////////////
// PRIMARY AREA OF INTEREST - START //
//////////////////////////////////////
// Turn the horseshoe into a shader.
horseshoe = object.scene.children[1];
var horseshoeGeometry = horseshoe.geometry;
var horseshoeMaterial = shaderMeshMaterial(new THREE.MeshNormalMaterial(), horseshoeGeometry, horseshoeFragmentShaderReplacements);
var horseshoeMesh = new THREE.Mesh(horseshoeGeometry, horseshoeMaterial);
horseshoe = horseshoeMesh;
horseshoe.rotation.z = deg2rad(180); // Re-orient the horseshoe to the correct position and rotation.
horseshoe.position.y = 13;
scene.add(horseshoe);
// Turn the inner helix into a colorful, wiggly shader.
helix = object.scene.children[0];
var helixGeometry = helix.geometry;
var helixMaterial = shaderMeshMaterial(new THREE.MeshNormalMaterial(), helixGeometry, helixFragmentShaderReplacements);
var helixMesh = new THREE.Mesh(helixGeometry, helixMaterial);
helix = helixMesh;
scene.add(innerHelix);
animate();
////////////////////////////////////
// PRIMARY AREA OF INTEREST - END //
////////////////////////////////////
}, undefined, function (error) {
console.error(error);
});
Below are functions which are relevant.
shaderMeshMaterial: Constructs a new material based on the supplied materialType that supports editing the default shader. If it's not initProcessing, then the problem may stem from this function.
// Globals used: displayDimensions
function shaderMeshMaterial(materialType, geometry, fragmentShaderReplacements) {
var material = materialType;
material.onBeforeCompile = function ( shader ) {
// Uniforms
shader.uniforms.time = { value: 0 };
shader.uniforms.resolution = { value: new THREE.Vector2(displayDimensions.width, displayDimensions.height) };
shader.uniforms.bboxMin = { value: geometry.boundingBox.min };
shader.uniforms.bboxMax = { value: geometry.boundingBox.max };
fragmentShaderReplacements.forEach((rep) => {
shader.fragmentShader = shader.fragmentShader.replace(rep.from, rep.to);
});
console.log(shader);
material.userData.shader = shader;
}
return material;
}
initRenderer: Sets up the renderer. Just showing you guys the renderer setup I have in case that's important.
// Globals used: displayDimensions
function initRenderer() {
var renderer = new THREE.WebGLRenderer({
alpha: true,
antialias: true,
precision: "mediump"
});
renderer.setClearColor( 0x000000, 0);
renderer.setPixelRatio( window.devicePixelRatio );
renderer.setSize( displayDimensions.width, displayDimensions.height );
renderer.shadowMap.enabled = true;
renderer.outputEncoding = THREE.sRGBEncoding;
renderer.toneMapping = THREE.ACESFilmicToneMapping;
renderer.toneMappingExposure = 1.25;
return renderer;
}
animate: Handles the animation frames.
// Globals used: renderer, currentTime, postprocessing
function animate (timestamp = 0) {
requestAnimationFrame(animate);
resizeRendererToDisplaySize(renderer);
currentTime = timestamp/1000; // Current time in seconds.
scene.traverse( function ( child ) {
if ( child.isMesh ) {
const shader = child.material.userData.shader;
if ( shader ) {
shader.uniforms.time.value = currentTime;
}
}
} );
renderer.render( scene, camera );
postprocessing.composer.render( 0.1 );
};
One last thing to note is that when I inspected the console log of shader from the shaderMeshMaterial function, I can see that the fragment shaders are indeed different as they should be for each material. Also not sure why there are 4 console logs when there should only be 2.
Sorry for all the code, but I did condense it to where all irrelevant code was stripped out. I'm fairly new to Three.JS, so any possible explanations as to why this is happening are much appreciated!
EDIT: Removed vertex shader parameter from shaderMeshMaterial function to keep this question focused on just the fragment shaders. Though this problem does apply to both the vertex and fragment shaders, I figure if you fix one then you'll fix the other.
EDIT 2: Added language identifiers to code snippets. Also I removed the postprocessing function and the problem still persists, so I know the problem isn't caused by that. I've updated the code above to reflect this change. As a happy side effect of removing the postprocessing function, the console.log of the shader variable from shaderMeshMaterial new appears twice in the log (as it should).
EDIT 3: (Implementing WestLangley's suggestion) I tweaked the shaderMeshMaterial function by adding the customProgramCacheKey function. I had to condense the four parameters of shaderMeshMaterial into one for the sake of the customProgramCacheKey function. I believe I implemented the function correctly, but I'm still getting the same result as before where both materials display the same fragment shader.
New "PRIMARY AREA OF INTEREST" code:
horseshoe = object.scene.children[1];
var horseshoeGeometry = horseshoe.geometry;
var meshData = {
materialType: new THREE.MeshNormalMaterial(),
geometry: horseshoeGeometry,
fragmentShaderReplacements: horseshoeFragmentShaderReplacements
}
var horseshoeMaterial = shaderMeshMaterial(meshData);
var horseshoeMesh = new THREE.Mesh(horseshoeGeometry, horseshoeMaterial);
horseshoe = horseshoeMesh;
horseshoe.rotation.z = deg2rad(180); // Re-orient the horseshoe to the correct position and rotation.
horseshoe.position.y = 13;
scene.add(horseshoe);
// Turn the inner helix into a colorful, wiggly shader.
helix = object.scene.children[0];
var helixGeometry = helix.geometry;
var meshData2 = {
materialType: new THREE.MeshNormalMaterial(),
geometry: helixGeometry,
fragmentShaderReplacements: helixFragmentShaderReplacements
}
var helixMaterial = shaderMeshMaterial(meshData2);
var helixMesh = new THREE.Mesh(helixGeometry, helixMaterial);
helix = helixMesh;
scene.add(innerHelix);
animate();
New shaderMeshMaterial code:
// Globals used: displayDimensions
function shaderMeshMaterial(meshData) {
var material = meshData.materialType;
material.onBeforeCompile = function ( shader ) {
// Uniforms
shader.uniforms.time = { value: 0 };
shader.uniforms.resolution = { value: new THREE.Vector2(displayDimensions.width, displayDimensions.height) };
shader.uniforms.bboxMin = { value: meshData.geometry.boundingBox.min };
shader.uniforms.bboxMax = { value: meshData.geometry.boundingBox.max };
meshData.fragmentShaderReplacements.forEach((rep) => {
shader.fragmentShader = shader.fragmentShader.replace(rep.from, rep.to);
});
material.customProgramCacheKey = function () {
return meshData;
};
console.log(shader);
material.userData.shader = shader;
}
return material;
}
WestLangley suggestion worked for me!
material.onBeforeCompile = ...
// Make sure WebGLRenderer doesnt reuse a single program
material.customProgramCacheKey = function () {
return UNIQUE_PER_MATERIAL_ID;
};
I believe your mistake is returning meshData from customProgramCacheKey.
I think customProgramCacheKey need concrete identifier like a number or string.
It would be nice to understand what exactly happening and why do we need to specify customProgramCacheKey.
EDIT: I discover that default value for customProgramCacheKey calculated as follow in Threejs source.
customProgramCacheKey() {
return this.onBeforeCompile.toString();
}
Perhaps this is explains this default caching behavior because calling toString on function returns that function body literally as string.
For example consider function const myFunc = () => { return 1 }. Calling myFunc.toString() returns "() => { return 1 }"
So if your calling onBeforeCompile in a for loop you function body as string never change.
I am trying to add a simple countdown timer to a Phaser game. When the timer ends I want the game to restart. After adding the relevant code there are no errors in the console but I can't get the timer to appear on the screen. I am new to Phaser and am still learning Javascript. Where I am going wrong please? I have posted only the relevant code below, and the code used for already existing text in the game that is working fine (text to count coins collected).
PlayState = {};
PlayState.init = function () {
//....
};
PlayState.preload = function () {
this.game.load.image('font:numbers', 'images/numbers.png'); //for the
//HUD coin count - not the timer
};
PlayState.create = function () {
//TIMER CODE:
this.timeInSeconds = 120;
this.timeText = this.game.add.text(this.game.world.centerX,
this.game.world.centerY, "0:00",{font: '15px Arial', fill: '#FFFFFF', align:
'center'});
this.timeText.anchor.set(0.5, 0.5);
this.timer = this.game.time.events.loop(Phaser.Timer.SECOND,
this.updateTimer, this);
};
PlayState.update = function () {
this.coinFont.text = `x${this.coinPickupCount}`; //for HUD coin count not
//the timer
};
//TIMER CODE:
PlayState.updateTimer = function() {
this.timeInSeconds--;
var minutes = Math.floor(this.timeInSeconds / 60);
var seconds = this.timeInSeconds - (minutes * 60);
var timeString = this.addZeros(minutes) + ":" + this.addZeros(seconds);
this.timeText.text = timeString;
if (this.timeInSeconds == 0) {
this.game.state.restart();
}
};
//add leading zeros to any number less than 10
//for example turn 1 to 01
PlayState.addZeros = function(num) {
if (num < 10) {
num = "0" + num;
}
return num;
};
//BELOW IS CODE FOR THE COIN COUNT NOT THE TIMER
PlayState._createHud = function () {
this.keyIcon = this.game.make.image(0, 30, 'icon:key');
this.keyIcon.anchor.set(0, 0.5);
const NUMBERS_STR = '0123456789X ';
this.coinFont = this.game.add.retroFont('font:numbers', 20,
26,NUMBERS_STR, 6);
let coinIcon = this.game.make.image(this.keyIcon.width + 7,
0, 'icon:coin');
let coinScoreImg = this.game.make.image(coinIcon.x +
coinIcon.width, coinIcon.height / 2, this.coinFont);
coinScoreImg.anchor.set(0, 0.5);
this.hud = this.game.add.group();
this.hud.add(coinIcon);
this.hud.position.set(10, 10);
this.hud.add(coinScoreImg);
this.hud.add(this.keyIcon);
this.hud.fixedToCamera = true;
};
window.onload = function () {
let game = new Phaser.Game(1280, 800, Phaser.CANVAS, 'game');
game.state.add('play', PlayState);
game.state.start('play');
};
I have finally solved the issue. The text was not showing because it was being rendered AFTER the background image in create. So it was there but being hidden by the background image. I simply moved the timer code to the end of create and it now works.
PlayState.create = function () {
this.game.world.setBounds(0, 0, 2560, 800);
background1 = this.game.add.sprite(0, 0, 'background');
background2 = this.game.add.sprite(1280, 0, 'background2');
this.game.scale.scaleMode = Phaser.ScaleManager.SHOW_ALL;
this.game.scale.setMinMax(480,320,1280,800);
this.game.scale.windowConstraints.bottom = 'visual';
this.game.add.image(0, 0, 'background');
this._loadLevel(this.game.cache.getJSON('level:1'));
this._createHud();
//TIMER CODE SHOULD GO HERE AND NOT AT THE BEGINNING OF CREATE
this.timeInSeconds = 120;
this.timeText = this.game.add.text(220, 30, "0:00",{font: '30px Arial', fill:
'#FFFFFF', align: 'center'});
this.timeText.anchor.set(0.5, 0.5);
this.timer = this.game.time.events.loop(Phaser.Timer.SECOND, this.updateTimer,
this);
};
You set the initial text to "0:00" and even that doesn't show on screen? First thing I would do is look at the coordinates where the text is located, maybe it's not visible off screen. Instead of this.game.world.centerX, this.game.world.centerY try something like 100,100, does it show up then? Also try to set very long initial text, so something like "blah test ABC 123" instead of "0:00" maybe makes some difference.
Secondly, maybe the Arial font is not available for some reason. If you leave out the {font: '15px..'center'} part it will use a default font, does that change anything?
Thirdly, you say you didn't post all your code here, but maybe you accidentally overwrite the variable this.timeText somewhere in you code? So check that you don't set that variable to be something else.
Finally, I would add a console.log to the updateTimer function, just to see if it is being called. so:
PlayState.updateTimer = function() {
console.log('updateTimer was called: ' + this.timeInSeconds);
this.timeInSeconds--;
// etc.
I can’t seem to be able to clone an FBX model (FBX downloaded from Mixamo) while retaining animation keyframes.
Have attempted a number of approaches including using the cloneFbx gist (included in the example below); all to no avail. Even placing the entire FBXLoader() function inside a loop does not work as expected since only one of the models will animate at a time.
This issue has been partially addressed here, but I cannot seem to ‘copy’ the animation sequence as answer suggests.
Can anyone point out where I’m going wrong?
Here's a rough example of one of my tests:
Load fbx model and store animation:
var loader = new THREE.FBXLoader();
loader.load( 'models/Walking.fbx', function ( fbx ) {
clip = fbx.animations[ 0 ];
// createVehicle(fbx); // Works! Creates one animated model via FBX
// cloneFbx via: https://gist.github.com/kevincharm/bf12a2c673b43a3988f0f171a05794c1
for (var i = 0; i < 2; i++) {
const model = cloneFbx(fbx);
createVehicle(model);
}
});
Add mixers and actions based on stored clip, add model to scene:
function createVehicle(model){
model.mixer = new THREE.AnimationMixer( model );
mixers.push( model.mixer );
var action = model.mixer.clipAction( clip );
action.play();
model.traverse( function ( child ) {
if ( child.isMesh ) {
child.castShadow = true;
child.receiveShadow = true;
}
});
const x = Math.random() * groundSize - groundSize/2;
const z = Math.random() * groundSize - groundSize/2;
model.position.set(x, 0, z);
const vehicle = new Vehicle(model, x, z);
vehicles.push(vehicle);
scene.add( model );
}
Animation cycle:
if ( mixers.length > 0 ) {
for ( var i = 0; i < mixers.length; i ++ ) {
mixers[ 0 ].update( clock.getDelta() );
}
}
Couldn’t figure out an elegant solution to this. Best I could come up with is creating a loop with the loading sequence inside of it; this is very slow (since the FBX has to be parsed each time).
The key here was having an animation mixer controlling the animated objects as a group as opposed to creating a mixer per animated object.
If anyone can figure out a better solution, I would be super keen to hear it (perhaps using the cloneFbx script properly).
Create mixer, load FBX:
// Create mixer to run animations
mixer = new THREE.AnimationMixer( scene );
// Load fbx
var loader = new THREE.FBXLoader();
for (var i = 0; i < 5; i++) {
loader.load( 'models/Walking.fbx', function ( fbx ) {
mixer.clipAction( fbx.animations[ 0 ], fbx )
.startAt( - Math.random() )
.play();
createVehicle(fbx);
});
}
Create class instances, add to scene:
function createVehicle(model){
const x = Math.random() * groundSize - groundSize/2;
const z = Math.random() * groundSize - groundSize/2;
model.position.set(x, 0, z);
const vehicle = new Vehicle(model, x, z);
vehicles.push(vehicle);
scene.add( model );
}
Draw cycle:
mixer.update( clock.getDelta() );
I found out that SkeletonUtils.clone() works good for me.
https://threejs.org/docs/index.html#examples/en/utils/SkeletonUtils.clone
I need to have multiple identical, animated models on a scene. If possible, I would like them to have a shared geometry and material, but if it is impossible, having them instanced per model will suffice too.
Unfortunately, the only way to achieve this result I found is to go through JSONLoader for every model instance.
SkinnedMesh does have a clone() method, but it seems not to be fully implemented yet. If used and both original and cloned mesh are present on the scene, only one will appear, and cloned one will be without animation.
I have attempted to use this example with shared skeletons:
https://github.com/mrdoob/three.js/pull/11666
...and indeed it works, but I need to be able to play different animations for every model instance, having them all play the same one is not sufficient, sadly. I hoped I could do similar hax and insert my own skeleton (made out of bones from the JSON file), but it behaves very much like if I just used clone() from SkinnedMesh.
I am using this code:
https://github.com/arturitu/threejs-animation-workflow/blob/master/js/main.js
Basically what I'd like to achieve is
var onLoad = function (geometry, materials) {
window.geometry = geometry;
character = new THREE.SkinnedMesh(
geometry,
new THREE.MeshFaceMaterial(materials)
);
character2 = character.someMagicalClone();
scene.add(character);
scene.add(character2);
(...)
I need any clue... and while I wait for help, I am busily deconstructing constructor for SkinnedMesh and JSONLoader for clues ;)
Thanks in advance!
I found a solution in this pull request:
https://github.com/mrdoob/three.js/pull/14494
in short, there are two functions added:
function cloneAnimated( source ) {
var cloneLookup = new Map();
var clone = source.clone();
parallelTraverse( source, clone, function ( sourceNode, clonedNode ) {
cloneLookup.set( sourceNode, clonedNode );
} );
source.traverse( function ( sourceMesh ) {
if ( ! sourceMesh.isSkinnedMesh ) return;
var sourceBones = sourceMesh.skeleton.bones;
var clonedMesh = cloneLookup.get( sourceMesh );
clonedMesh.skeleton = sourceMesh.skeleton.clone();
clonedMesh.skeleton.bones = sourceBones.map( function ( sourceBone ) {
if ( ! cloneLookup.has( sourceBone ) ) {
throw new Error( 'THREE.AnimationUtils: Required bones are not descendants of the given object.' );
}
return cloneLookup.get( sourceBone );
} );
clonedMesh.bind( clonedMesh.skeleton, sourceMesh.bindMatrix );
} );
return clone;
}
function parallelTraverse( a, b, callback ) {
callback( a, b );
for ( var i = 0; i < a.children.length; i ++ ) {
parallelTraverse( a.children[ i ], b.children[ i ], callback );
}
}
As I understand it rebinds cloned skeleton to the cloned mesh.
so topic example could look like:
var onLoad = function (geometry, materials) {
window.geometry = geometry;
character = new THREE.SkinnedMesh(
geometry,
new THREE.MeshFaceMaterial(materials)
);
character2 = cloneAnimated(character); // <-- used that new function
scene.add(character);
scene.add(character2);
(...)
EDIT
OK, I've tried a camera using quaternions:
qyaw = [Math.cos(rot[0]/2), 0, Math.sin(rot[0]/2), 0];
qpitch = [Math.cos(rot[1]/2), 0, 0, Math.sin(rot[1]/2)];
rotQuat = quat4.multiply (qpitch, qyaw);
camRot = quat4.toMat4(rotQuat);
camMat = mat4.multiply(camMat,camRot);
and I get exactly the same problem. So I'm guessing it's not gimbal lock. I've tried changing the order I multiply my matrices, but it just goes camera matrix * model view matrix, then object matrix * model view. That's right isn't it?
I'm trying to build a 3d camera in webGL that can move about the world and be rotated around the x and y (right and up) axes.
I'm getting the familiar problem (possibly gimbal lock?) that once one of the axes is rotated, the rotation around the other is screwed up; for example, when you rotate around the Y axis 90degrees, rotation around the x becomes a spin around z.
I appreciate this is a common problem, and there are copious guides to building a camera that avoid this problem, but as far as I can tell, I've implemented two different solutions and I'm still getting the same problem. Frankly, it's doing my head in...
One solution I'm using is this (adapted from http://www.toymaker.info/Games/html/camera.html):
function updateCam(){
yAx = [0,1,0];
xAx = [1,0,0];
zAx = [0,0,1];
mat4.identity(camMat);
xRotMat = mat4.create();
mat4.identity(xRotMat)
mat4.rotate(xRotMat,rot[0],xAx);
mat4.multiplyVec3(xRotMat,zAx);
mat4.multiplyVec3(xRotMat,yAx);
yRotMat = mat4.create();
mat4.identity(yRotMat)
mat4.rotate(yRotMat,rot[1],yAx);
mat4.multiplyVec3(yRotMat,zAx);
mat4.multiplyVec3(yRotMat,xAx);
zRotMat = mat4.create();
mat4.identity(zRotMat)
mat4.rotate(zRotMat,rot[2],zAx);
mat4.multiplyVec3(zRotMat,yAx);
mat4.multiplyVec3(zRotMat,xAx);
camMat[0] = xAx[0];
camMat[1] = yAx[0];
camMat[2] = zAx[0];
//camMat[3] =
camMat[4] = xAx[1]
camMat[5] = yAx[1];
camMat[6] = zAx[1];
//camMat[7] =
camMat[8] = xAx[2]
camMat[9] = yAx[2];
camMat[10]= zAx[2];
//camMat[11]=
camMat[12]= -1* vec3.dot(camPos, xAx);
camMat[13]= -1* vec3.dot(camPos, yAx);
camMat[14]= -1* vec3.dot(camPos, zAx);
//camMat[15]=
var movSpeed = 1.5 * forward;
var movVec= vec3.create(zAx);
vec3.scale(movVec, movSpeed);
vec3.add(camPos, movVec);
movVec= vec3.create(xAx);
movSpeed = 1.5 * strafe;
vec3.scale(movVec, movSpeed);
vec3.add(camPos, movVec);
}
I also tried using this method using
mat4.rotate(camMat, rot[1], yAx);
instead of explicitly building the camera matrix - same result.
My second (actually first...) method looks like this (rot is an array containing the current rotations around x, y and z (z is always zero):
function updateCam(){
mat4.identity(camRot);
mat4.identity(camMat);
camRot = fullRotate(rot);
mat4.set(camRot,camMat);
mat4.translate(camMat, camPos);
}
function fullRotate(angles){
var cosX = Math.cos(angles[0]);
var sinX = Math.sin(angles[0]);
var cosY = Math.cos(angles[1]);
var sinY = Math.sin(angles[1]);
var cosZ = Math.cos(angles[2]);
var sinZ = Math.sin(angles[2]);
rotMatrix = mat4.create([cosZ*cosY, -1*sinZ*cosX + cosZ*sinY*sinX, sinZ*sinX+cosZ*sinY*cosX, 0,
sinZ*cosY, cosZ*cosX + sinZ*sinY*sinX, -1*cosZ*sinX + sinZ*sinY*cosX, 0,
-1*sinY, cosY*sinX, cosY*cosX, 0,
0,0,0,1 ] );
mat4.transpose(rotMatrix);
return (rotMatrix);
}
The code (I've taken out most of the boilerplate gl lighting stuff etc and just left the transformations) to actually draw the scene is:
function drawScene() {
gl.viewport(0, 0, gl.viewportWidth, gl.viewportHeight);
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
mat4.perspective(45, gl.viewportWidth / gl.viewportHeight, 0.1, 2000.0, pMatrix);
mat4.identity(mvMatrix);
for(var i=0; i<planets.length; i++){
if (planets[i].type =="sun"){
currentProgram = perVertexSunProgram;
} else {
currentProgram = perVertexNormalProgram;
}
alpha = planets[i].alphaFlag;
mat4.identity(planets[i].rotMat);
mvPushMatrix();
//all the following puts planets in orbit around a central sun, but it's not really relevant to my current problem
var rot = [0,rotCount*planets[i].orbitSpeed,0];
var planetMat;
planetMat = mat4.create(fullRotate(rot));
mat4.multiply(planets[i].rotMat, planetMat);
mat4.translate(planets[i].rotMat, planets[i].position);
if (planets[i].type == "moon"){
var rot = [0,rotCount*planets[i].moonOrbitSpeed,0];
moonMat = mat4.create(fullRotate(rot));
mat4.multiply(planets[i].rotMat, moonMat);
mat4.translate(planets[i].rotMat, planets[i].moonPosition);
mat4.multiply(planets[i].rotMat, mat4.inverse(moonMat));
}
mat4.multiply(planets[i].rotMat, mat4.inverse(planetMat));
mat4.rotate(planets[i].rotMat, rotCount*planets[i].spinSpd, [0, 1, 0]);
//this bit does the work - multiplying the model view by the camera matrix, then by the matrix of the object we want to render
mat4.multiply(mvMatrix, camMat);
mat4.multiply(mvMatrix, planets[i].rotMat);
gl.useProgram(currentProgram);
setMatrixUniforms();
gl.drawElements(gl.TRIANGLES, planets[i].VertexIndexBuffer.numItems, gl.UNSIGNED_SHORT, 0);
mvPopMatrix();
}
}
However, most of the transformations can be ignored, the same effect cab be seen simply displaying a sphere at world coords 0,0,0.
I thought my two methods - either rotating the axes one at a time as you go, or building up the rotation matrix in one go avoided the problem of doing two rotations one after the other. Any ideas where I'm going wrong?
PS - I'm still very much starting to learn WebGL and 3d maths, so be gentle and talk to me like someone who hadn't heard of a matrix til a couple of months ago... Also, I know quaternions are a good solution to 3d rotation, and that would be my next attempt, however, I think I need to understand why these two methods don't work first...
For the sake of clarification, think about gimbal lock this way: You've played Quake/Unreal/Call of Duty/Any First Person Shooter, right? You know how when you are looking forward and move the mouse side to side your view swings around in a nice wide arc, but if you look straight up or down and move your mouse side to side you basically just spin tightly around a single point? That's gimbal lock. It's something that pretty much any FPS game uses because it happens to mimic what we would do in real life, and thus most people don't usually think of it as a problem.
For something like a space flight sim, however, or (more commonly) skeletal animation that type of effect is undesirable, and so we use things like quaternions to help us get around it. Wether or not you care about gimbal lock for your camera depends on the effect that you are looking to achieve.
I don't think you're experiencing that, however. What it sounds like is that your order of matrix multiplication is messed up, and as a result your view is rotating in a way that you don't expect. I would try playing with the order that you do your X/Y/Z rotations in and see if you can find an order than gives you the desired results.
Now, I hate doing code dumps, but this may be useful to you so here we go: This is the code that I use in most of my newer WebGL projects to manage a free-floating camera. It is gimbal locked, but as I mentioned earlier it doesn't really matter in this case. Basically it just gives you FPS style controls that you can use to fly around your scene.
/**
* A Flying Camera allows free motion around the scene using FPS style controls (WASD + mouselook)
* This type of camera is good for displaying large scenes
*/
var FlyingCamera = Object.create(Object, {
_angles: {
value: null
},
angles: {
get: function() {
return this._angles;
},
set: function(value) {
this._angles = value;
this._dirty = true;
}
},
_position: {
value: null
},
position: {
get: function() {
return this._position;
},
set: function(value) {
this._position = value;
this._dirty = true;
}
},
speed: {
value: 100
},
_dirty: {
value: true
},
_cameraMat: {
value: null
},
_pressedKeys: {
value: null
},
_viewMat: {
value: null
},
viewMat: {
get: function() {
if(this._dirty) {
var mv = this._viewMat;
mat4.identity(mv);
mat4.rotateX(mv, this.angles[0]-Math.PI/2.0);
mat4.rotateZ(mv, this.angles[1]);
mat4.rotateY(mv, this.angles[2]);
mat4.translate(mv, [-this.position[0], -this.position[1], - this.position[2]]);
this._dirty = false;
}
return this._viewMat;
}
},
init: {
value: function(canvas) {
this.angles = vec3.create();
this.position = vec3.create();
this.pressedKeys = new Array(128);
// Initialize the matricies
this.projectionMat = mat4.create();
this._viewMat = mat4.create();
this._cameraMat = mat4.create();
// Set up the appropriate event hooks
var moving = false;
var lastX, lastY;
var self = this;
window.addEventListener("keydown", function(event) {
self.pressedKeys[event.keyCode] = true;
}, false);
window.addEventListener("keyup", function(event) {
self.pressedKeys[event.keyCode] = false;
}, false);
canvas.addEventListener('mousedown', function(event) {
if(event.which == 1) {
moving = true;
}
lastX = event.pageX;
lastY = event.pageY;
}, false);
canvas.addEventListener('mousemove', function(event) {
if (moving) {
var xDelta = event.pageX - lastX;
var yDelta = event.pageY - lastY;
lastX = event.pageX;
lastY = event.pageY;
self.angles[1] += xDelta*0.025;
while (self.angles[1] < 0)
self.angles[1] += Math.PI*2;
while (self.angles[1] >= Math.PI*2)
self.angles[1] -= Math.PI*2;
self.angles[0] += yDelta*0.025;
while (self.angles[0] < -Math.PI*0.5)
self.angles[0] = -Math.PI*0.5;
while (self.angles[0] > Math.PI*0.5)
self.angles[0] = Math.PI*0.5;
self._dirty = true;
}
}, false);
canvas.addEventListener('mouseup', function(event) {
moving = false;
}, false);
return this;
}
},
update: {
value: function(frameTime) {
var dir = [0, 0, 0];
var speed = (this.speed / 1000) * frameTime;
// This is our first person movement code. It's not really pretty, but it works
if(this.pressedKeys['W'.charCodeAt(0)]) {
dir[1] += speed;
}
if(this.pressedKeys['S'.charCodeAt(0)]) {
dir[1] -= speed;
}
if(this.pressedKeys['A'.charCodeAt(0)]) {
dir[0] -= speed;
}
if(this.pressedKeys['D'.charCodeAt(0)]) {
dir[0] += speed;
}
if(this.pressedKeys[32]) { // Space, moves up
dir[2] += speed;
}
if(this.pressedKeys[17]) { // Ctrl, moves down
dir[2] -= speed;
}
if(dir[0] != 0 || dir[1] != 0 || dir[2] != 0) {
var cam = this._cameraMat;
mat4.identity(cam);
mat4.rotateX(cam, this.angles[0]);
mat4.rotateZ(cam, this.angles[1]);
mat4.inverse(cam);
mat4.multiplyVec3(cam, dir);
// Move the camera in the direction we are facing
vec3.add(this.position, dir);
this._dirty = true;
}
}
}
});
This camera assumes that Z is your "Up" axis, which may or may not be true for you. It's also using ECMAScript 5 style objects, but that shouldn't be an issue for any WebGL-enabled browser, and it utilizes my glMatrix library but it looks like you're already using that anyway. Basic usage is pretty simple:
// During your init code
var camera = Object.create(FlyingCamera).init(canvasElement);
// During your draw loop
camera.update(16); // 16ms per-frame == 60 FPS
// Bind a shader, etc, etc...
gl.uniformMatrix4fv(shaderUniformModelViewMat, false, camera.viewMat);
Everything else is handled internally for you, including keyboard and mouse controls. May not fit your needs exactly, but hopefully you can glean what you need to from there. (Note: This is essentially the same as the camera used in my Quake 3 demo, so that should give you an idea of how it works.)
Okay, that's enough babbling from me for one post! Good luck!
It doesn't matter how you build your matrices, using euler angle rotations (like both of your code snippets do) will always result in a transformation that shows the gimble lock problem.
You may want to have a look at https://en.wikipedia.org/wiki/Quaternions_and_spatial_rotation as a starting point for creating transformations that avoid gimble locks.
Try my new project (webGL2 part of visual-js game engine) based on glmatrix 2.0 .
Activate events for camera use : App.camera.FirstPersonController = true;
live examples
For camera important functions :
Camera interaction
App.operation.CameraPerspective = function() {
this.GL.gl.viewport(0, 0, wd, ht);
this.GL.gl.clear(this.GL.gl.COLOR_BUFFER_BIT | this.GL.gl.DEPTH_BUFFER_BIT);
// mat4.identity( world.mvMatrix )
// mat4.translate(world.mvMatrix , world.mvMatrix, [ 10 , 10 , 10] );
/* Field of view, Width height ratio, min distance of viewpoint, max distance of viewpoint, */
mat4.perspective(this.pMatrix, degToRad( App.camera.viewAngle ), (this.GL.gl.viewportWidth / this.GL.gl.viewportHeight), App.camera.nearViewpoint , App.camera.farViewpoint );
};
manifest.js :
var App = {
name : "webgl2 experimental",
version : 0.3,
events : true,
logs : false ,
draw_interval : 10 ,
antialias : false ,
camera : { viewAngle : 45 ,
nearViewpoint : 0.1 ,
farViewpoint : 1000 ,
edgeMarginValue : 100 ,
FirstPersonController : false },
textures : [] , //readOnly in manifest
tools : {}, //readOnly in manifest
download source from :
webGL 2 part of visual-js GE project
Old :
opengles 1.1
https://stackoverflow.com/a/17261523/1513187
Very fast first person controler with glmatrix 0.9 based on http://learningwebgl.com/ examples.