I'm trying to make a small project using Three.js & the physics plugin physijs; just a little dice roller. My approach is to use setGravity to move the dice around, modelling gravity to move the dice around. The issue I'm running into is that once the dice come to a rest, they no longer respond to gravity. Has anyone run into this before?
Whats happening:
Ammo.js, on which Physijs is based, puts resting or very slow moving objects in a sleep state to save performance. So when you change the worlds gravity the sleeping objects dont care, because Physijs doesnt tell them gravity has changed.
You have the ability to modify the sleeping thresholds, set activation states or just quickly activate the rigid bodys before changing gravity.
Please note this code applys to native Ammo.js, I am not sure how to
do this when using physijs but you get the idea.
Solution 1: Loop over your Bodys and activate them, then change gravity:
// dice is an array with your rigid bodys
for ( var i = 0; i < dice.length; i ++ ) {
// hey wake up
dice[ i ].activate();
}
physicsWorld.setGravity( new Ammo.btVector3( 0, -9.81, 0 ) );
Solution 2: Thou shall get no sleep, do this after creating your dice:
var DISABLE_DEACTIVATION = 4;
for ( var i = 0; i < dice.length; i ++ )
// no sleep for you... ever
dice[ i ].setActivationState( DISABLE_DEACTIVATION );
}
Related
I'm fairly new to three.js and trying to get a better understanding of ray casting. I have used it so far in a game to show when an object collides with another on the page which works perfectly. In the game I'm building this is to take health from the hero as it crashes into walls.
I am now trying to implement a target which when hovered over some objects it will auto shoot. However the target only registers a target hit once the object passes through the target mesh rather than when its ray is cast through it.
to further detail this, the ray is cast from the camera through the target, if the target is on a mesh (stored as an object array) then I want it to trigger a function.
within my update function I have this:
var ray = new THREE.Raycaster();
var crossHairClone = crossHair.position.clone();
var coards = {};
coards.x = crossHairClone.x
coards.y = crossHairClone.y
ray.setFromCamera(coards, camera);
var collisionResults = ray.intersectObjects( collidableMeshList );
if ( collisionResults.length > 0 ) {
console.log('Target Hit!', collisionResults)
}
The console log is only triggered when the collidableMeshList actually touches the target mesh rather than when it is aiming at it.
How do I extend the ray to pass through the target (which I thought it was already doing) so that if anything hits the ray then it triggers my console log.
Edit
I've added a URL to the game in progress. There are other wider issues with the game, my current focus is just the target ray casting.
Game Link
Many thanks to everyone who helped me along the way on this one but I finally solved it, only not through the means that I had expected to. Upon reading into the setFromCamera() function it looks like it is mainly used around mouse coards which in my instance was not what I wanted. I wanted a target on the page and the ray to pass through this. For some reason my Ray was shooting vertically up from the centre of the whole scene.
In the end I tried a different approach and set the Rays position and direction directly rather rely on setting it from the cameras position.
var vector = new THREE.Vector3(crossHair.position.x, crossHair.position.y, crossHair.position.z);
var targetRay = new THREE.Raycaster(camera.position, vector.sub(camera.position).normalize());
var enemyHit = targetRay.intersectObject( enemy );
if ( enemyHit.length > 0 ) {
console.log('Target Hit!', targetRay)
}
I'll leave this up for a while before accepting this answer in case anyone has a better approach than this or has any corrections over what I have said in regards to setFromCamera().
Apologies if my mistake is obvious. Started learning code a few weeks ago. Have searched copiously for an answer.
Attempting to control a variable of a graphical equation animated in three.js using Dat.Gui. By assigning the variable to nothing, I was able to see that the gui is linked because clinking anywhere on the slider immediately calls the intended graphed equation (for simplicity's sake I have replaced my more complicated equation with a simple parabola). The graphed equation also disappears when the gui slider is clicked again, as hoped, to clear the way for the 'redrawn' equation (wider or skinnier parabola as determined by gui slider), however it throws this error:
"[.CommandBufferContext]RENDER WARNING: Render count or primcount is 0."
I've been able to rearrange the code so it doesn't throw this error, but it still does not call the next visible iteration of the equation.... Below is the code that succeeds in drawing the parabola, removes it upon the next .onChange, but then throws the above error...
init function + scene, camera setup, etc....
gui = new DAT.GUI();
gui_a = gui.add(this, 'a').min(0.01).max(5).step(0.01).name('Width');
gui_a.onChange(function(value){createGraph();});
}
function createGraph(){
if(graphLine) scene.remove(graphLine);
var graphGeometry = new THREE.Geometry();
while (x<20){
var y = a*(Math.pow(x,2));
next_x = x+0.05;
next_y = a*(Math.pow(next_x,2));
x=x+0.05;
graphGeometry.vertices.push(
new THREE.Vector3(x, next_y),
new THREE.Vector3(next_x, next_y)
);};
graphLine = new THREE.Line(graphGeometry, material);
scene.add(graphLine);
};
Help would be hugely appreciated.
Figured out my own problem... quite simple as I thought: the value of 'x' is not getting reset in creategraph();. It is defined with variables at the top of the code as "var x = -20" (which is not visible in my post..). Therefore the 'second' rendering of the graph is starting at x = 20, instead of reverting back to the original x=-20.
I have found a tutorial on parallax scrolling in spritekit using objective-C though I have been trying to port it to swift without much success, very little in fact.
Parallax Scrolling
Does anyone have any other tutorials or methods of doing parallax scrolling in swift.
This is a SUPER simple way of starting a parallax background. WITH SKACTIONS! I am hoping it helps you understand the basics before moving to a harder but more effective way of coding this.
So I'll start with the code that get a background moving and then you try duplicating the code for the foreground or objects you want to put in your scene.
//declare ground picture. If Your putting this image over the top of another image (use a png file).
var groundImage = SKTexture(imageNamed: "background.jpg")
//make your SKActions that will move the image across the screen. this one goes from right to left.
var moveBackground = SKAction.moveByX(-groundImage.size().width, y: 0, duration: NSTimeInterval(0.01 * groundImage.size().width))
//This resets the image to begin again on the right side.
var resetBackGround = SKAction.moveByX(groundImage.size().width, y: 0, duration: 0.0)
//this moves the image run forever and put the action in the correct sequence.
var moveBackgoundForever = SKAction.repeatActionForever(SKAction.sequence([moveBackground, resetBackGround]))
//then run a for loop to make the images line up end to end.
for var i:CGFloat = 0; i<2 + self.frame.size.width / (groundImage.size().width); ++i {
var sprite = SKSpriteNode(texture: groundImage)
sprite.position = CGPointMake(i * sprite.size.width, sprite.size.height / 2)
sprite.runAction(moveBackgoundForever)
self.addChild(sprite)
}
}
//once this is done repeat for a forground or other items but them run at a different speed.
/*make sure your pictures line up visually end to end. Just duplicating this code will NOT work as you will see but it is a starting point. hint. if your using items like simple obstructions then using actions to spawns a function that creates that obstruction maybe a good way to go too. If there are more then two separate parallax objects then using an array for those objects would help performance. There are many ways to handle this so my point is simple: If you can't port it from ObjectiveC then rethink it in Swift. Good luck!
I am creating several THREE.Lines using THREE.BufferGeometry. Initially my app had them all starting at the origin and things worked as expected. Now, I would like to be able to start (and end) them at any point.
This fiddle (http://jsfiddle.net/9nVqU/) illustrates (I hope) how changing one end of the line away from the origin causes unexpected results.
I wondered if it was because any given line follows on from the previous one - switching the start/end order didn't change anything though so if that were true, I'd expect it to break.
Maybe I have the arrays set up incorrectly or the attributes that tell THREE.js how to interpret it - I think I need 2 * 3 verts for each line but changes I made to buffer_geometry.attributes = { seemed to make things worse.
FWIW, the actual effect I'm trying to achieve is to selectively turn on and off the lines based on user input. I can do that already by changing the end position but then I lose that value and I don't want to store it elsewhere. I thought that I could move the start point to the end point to switch it off and then move the start point to the origin again to re-enable it. If there is a way to enable/disable lines individually with BufferGeometry, then that would clearly be better.
First of all, you would have to do this:
var line = new THREE.Line( buffer_geometry, material );
line.type = THREE.LinePieces;
Second, this is not supported in r.58 , but should be.
As a work-around, you can hack WebGLRenderer.renderBufferDirect() like so:
// render lines
setLineWidth( material.linewidth );
var position = geometryAttributes[ "position" ];
primitives = ( object.type === THREE.LineStrip ) ? _gl.LINE_STRIP : _gl.LINES;
_gl.drawArrays( primitives, 0, position.numItems / 3 );
_this.info.render.calls ++;
_this.info.render.points += position.numItems;
three.js r.58
I am trying to spin a 3D Gameobject in unity. It is actually a cylinder with just a texture of a poker chip on it. I want to spin it 360 degrees once it has collided with a raycast. It is working just fine in the Unity emulator, however, on the device itself the chip comes to a stop after its spin and then continues to spin in an endless loop. Here is a snippet of the code in question. Thank you for any help in advance.
// Spin the chip
if (Animate) {
if (Speed > 0 && Chip.tag.Contains("Chip")) {
Chip.transform.Rotate(0, Speed*Time.deltaTime, 0);
Speed -= 3;
Debug.Log(Speed);
}
else {
// Reset
Animate = false;
Speed = 360;
Chip.transform.localRotation = Quaternion.Euler(0.0,0.0,0.0);
}
}
To summorize this the best I can the gameobject Chip is assigned when it collides on raycast as such
// Set the chip
Chip = hit.transform;
Everything is done in the update function. Once the raycast hits it calls a betting function then after the betting is calculated it changes the Boolean Animate to true causing the spinning of the chip.
Something is setting Animate = true in some other code, hard to tell whats going on without seeing the rest of it.
Put some debug next to every spot where Animate is set to true, you should see something else setting it, only possible explanation as to why it continues to spin.
Another option is to use the Animation tool and instead of rotating, you just play the animation which performs the rotation for you.
Edit: Chances are its around the touch code, cause when you debug in the editor your using key strokes. A gotcha I've experienced a few times.
James Gramosli is correct in that some other code is triggering the animation again and it is most likely your touch code. It is a common problem when moving between editor and a touch-enabled device. You can determine if this is the case by using the UnityRemote to verify the control flow of your code.
That said, I would change your code to the following which removes the spin code from the Update loop that runs every frame. It is a small optimization, but primarily it cleans up the architecture and makes it more modular and a little neater.
It is not clear from your code snippet, but I will assume you are using UnityScript.
In your script that handles the touch code when you click on the chip, insert this line:
hit.transform.SendMessage("Spin", hit.transform, SendMessageOptions.DontRequireReceiver);
Put this code in a separate script called "SpinChip" and then add the script to your chip object.
var StartSpeed = 360.0;
var Deceleration = 3.0;
function Spin()
{
if (Animating)
{
print("Chip is already spinning, not starting another animation");
return;
}
/*
This code isn't necessary if this exists in a separate script and is only ever attached to the clickable chip
if (!gameObject.tag.Contains("Chip"))
{
print("That wasn't a chip you clicked");
return;
}
*/
print("Chip has been told to spin");
StartCoroutine(SpinningAnimation);
}
function SpinningAnimation()
{
print("Chip spin start");
transform.localRotation = Quaternion.identity;
Speed = StartSpeed;
Animating = true;
while (Speed > 0)
{
transform.Rotate(0, Speed*Time.deltaTime, 0);
Speed -= Deceleration;
yield; // wait one frame
}
print("Chip has completed the spin");
Animating = false;
}
What this code does is create a co-routine that runs once per update loop when activated that will spin the chip for you, and is independent of your actual button clicking code.
var rotSpeed: float = 60; // degrees per second
function Update(){
transform.Rotate(0, rotSpeed * Time.deltaTime, 0, Space.World);
}
Here is a code that rotates your game object, you can use it just with a vector 3 :transform.Rotate(x, y, z); or with Space transform.Rotate(x, y, z, Space.World);
rotSpeed is the rotation speed.
In your update function . The Bool variable Animate may becoming true . This may be reason your cylinder continues to rotate.
Other Solution is : You can create an animation of your cylinder and then take a stopwatch . So that after sometime you can stop you animation using the time of stopwatch