I'm using accelerometer in my first Cocos2D game and it work fine, i'm able to move the sprite using the below code however, when i change the orientation from landscapeLeft to landscapeRight, the sprite stops responding to Y coordination, and the sprite goes to the top of the screen and doesn't properly respond... I believe it's because of changing the device orientation, but i'm not sure since i'm pretty new to App Development, any help will be appreciated.
Here is the sample code i'm using...
- (void)accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration
{
//this determines how sensitive the accelerometer reacts (higher = more sensitive)
NSUserDefaults *defaulObj = [NSUserDefaults standardUserDefaults];
float sensitivity = [defaulObj floatForKey:#"Sensitivity"]; //10.0f
if (!sensitivity) {
sensitivity = 6;
}
// this controls how quickly the velocity decelerates (lower = quicker to change direction)
float deceleration = 0.4f;
static float xVal = 0;
if (!self.isFlag) {
xVal = -acceleration.x;
self.isFlag = TRUE;
}
playerVelocity.x = playerVelocity.x * deceleration + (xVal + acceleration.x) * sensitivity;
playerVelocity.y = playerVelocity.y * deceleration + acceleration.y * sensitivity;
playerVelocity.y = playerVelocity.y*-1;
}
Perhaps this helps out, flips Y along your current device orientation.
float rotatedY = acceleration.y;
if ([UIApplication sharedApplication].statusBarOrientation==UIInterfaceOrientationLandscapeLeft) {
rotatedY *= -1;
}
then use rotatedY insteat of acceleration.y
Related
i am working on game in which i want to move CCSprite in direction of accelerometer tilt.i have referred this tutorial http://www.raywenderlich.com/457/intro-to-box2d-with-cocos2d-tutorial-bouncing-balls but i am not clear with it. Please can any one help me.
Thanks in Advance.
Refer this solution. I used same for moving sprite from left to right in landscape game.: See answer here
Only change for landscape mode is use accelerometer y in place of x.
-(void) accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration
{
if(self.isGamePaused || self.isGameOver)
return;
float deceleration = 1.0f, sensitivity = 15.0f, maxVelocity = 450;
if(sGame.IsIpad)
{
sensitivity = 14.0f;
maxVelocity = 850;
deceleration = 1.5f;
}
// adjust velocity based on current accelerometer acceleration
// vel.x = vel.x * deceleration + acceleration.x * sensitivity;
AppController *app = (AppController*)[UIApplication sharedApplication].delegate;
float velocity_x = self.gameActor.velocity.x ;
self.gameActor.accelVal = ABS(acceleration.y);
if(app.orient == UIInterfaceOrientationLandscapeLeft)
{
velocity_x = velocity_x * deceleration + acceleration.y * sensitivity;
}
else
{
velocity_x = velocity_x * deceleration + (-acceleration.y) * sensitivity;
}
//limit the maximum velocity of the player sprite, in both directions (positive & negative values)
velocity_x = fmaxf(fminf(velocity_x, maxVelocity), -maxVelocity);
self.gameActor.velocity = ccp(velocity_x, self.gameActor.velocity.y);
}
I m start learning game development. As a beginner i create one demo game in which one cannon hit bullets to the enemies (coming toward cannon from different direction).
Now i stuck on cannon sprite image rotation anywhere user touch on the screen or enemies. How i do that, My initial code as following,
void HelloWorld:: ccTouchesBegan(CCSet *touches, CCEvent * event)
{
CCSize winSize = CCDirector::sharedDirector()->getWinSize();
CCTouch* touch = (CCTouch*)( touches->anyObject() );
CCPoint location = touch->locationInView(touch->view());
location = CCDirector::sharedDirector()->convertToGL(location);
//Rotate cannon direction toward touch point
CCPoint diffPoint = ccpSub(_cannonImage->getPosition(), location);
float angleRadians = atanf((float)diffPoint.y/(float)diffPoint.x);
float angleOffset = CC_DEGREES_TO_RADIANS(180);
if(diffPoint.x < 0){
angleRadians += angleOffset;
}else{
angleRadians -= angleOffset;
}
CCLog("angle to be rotate = %f", angleRadians);
_cannonImage->runAction(CCRotateBy::actionWithDuration(0.1, angleRadians));
}
The code is written in cocos2d-x . I also accepting answer by someone who written in plain cocos2d.
Thanks
iHungry
The perfect answer as follows,
float HelloWorld::changingAngleAccordingToCoordinateSystem(CCPoint imageCenter, CCPoint touchLocation, float calculatedAngle){
//Consideration :- all Angles is in Degree
if((calculatedAngle >= 0 && calculatedAngle <= 90) || (calculatedAngle >= 90 && calculatedAngle <= 180)){
//Ist quardant
calculatedAngle = calculatedAngle;
}
else if(calculatedAngle < 0 && calculatedAngle >= -90){
//IInd quardant
calculatedAngle = 270 + (90 + calculatedAngle);
}
else if(calculatedAngle < -90 && calculatedAngle >= -180){
calculatedAngle = 180 + (180 + calculatedAngle);
}
return calculatedAngle;
}
//Rotate cannon direction toward touch point
float diff_X = touchLocation.x - myImage->getPosition().x;
float diff_Y = touchLocation.y - myImage->getPosition().y;
CCPoint diffPoint = CCPoint(diff_X, diff_Y);
float angleRadians = atan2f(diffPoint.y,diffPoint.x);
angleRadians = CC_RADIANS_TO_DEGREES(angleRadians);
angleRadians = HelloWorld::changingAngleAccordingToCoordinateSystem(myImage->getPosition(), touchLocation, angleRadians);
myImage->setRotation(-angleRadians);
i used this code to rotate my sprite. i Was moving the sprite according to my accelerometer reading.
float angleRadians =-accelX;
float angleDegrees = CC_RADIANS_TO_DEGREES(angleRadians);
objGlider->sprite_Glider.rotation = cocosAngle;
Check it. The reason of slow may be that you may be using CClog or NSLog in the code.
Here goes the complete code.
if(!boolPlayerDied)
{
static float prevX=0, prevY=0;
#define kFilterFactor 1.0f// don't use filter. the code is here just as an example
float accelX = (float) acceleration.x * kFilterFactor + (1- kFilterFactor)*prevX;
float accelY = (float) acceleration.y * kFilterFactor + (1- kFilterFactor)*prevY;
prevX = accelX;
prevY = accelY;
accelX = accelX-0.5;// Angle check fot tgfor the player to play
float angleRadians =-accelX;
float angleDegrees = CC_RADIANS_TO_DEGREES(angleRadians);
if(accelX>0)
{
cocosAngle = 1.1 * angleDegrees;
}
else
{
if(accelX<-0.5)
accelX=-0.5;
cocosAngle = 1.1 * angleDegrees;
}
objGlider->sprite_Glider.rotation = cocosAngle;
}
objGlider is the object of the class which creates glider sprite and sprite_Glider is the sprite used in glider class.
you can use rotation property with your sprite to be rotated. In cocos2Dx it might be setRotation.
First of all, replace
float angleRadians = atanf((float)diffPoint.y/(float)diffPoint.x);
float angleOffset = CC_DEGREES_TO_RADIANS(180);
if(diffPoint.x < 0){
angleRadians += angleOffset;
}else{
angleRadians -= angleOffset;
}
by
float angleRadians = atan2f(diffPoint.y, diffPoint.x);
Then it would be better to set rotation immediately (without actions) to process multiple frequent touches.
_cannonImage->setRotation(angleRadians);
Maybe you will need to adjust rotation like setRotation(-angleRadians) or setRotation(angleRadians+90) - it depends on your coordinate system.
I've got a subclass of CCSprite that knows how to move itself based on two float properties, velX and velY. I call the subclass's - (void)update:(ccTime)dt method from the method of the same name in my game layer.
I use dt to scale how much I move the player and it works great. I'd like to use dt to scale a deceleration factor to make how the player slows down consistent regardless of how often it's updated.
But it just makes my CCSprite not even show up.
Here's the CCSprite class...
#import "Player.h"
#define kDeceleration 0.95
#implementation Player
#synthesize velX, velY;
# pragma mark
+ (id)player
{
Player *player = nil;
if ((player = [[[super alloc] initWithFile:#"rocket.png"] autorelease])) {
player.velX = 0.0;
player.velY = 0.0;
}
return player;
}
- (void)update:(ccTime)dt
{
CGSize winSize = [[CCDirector sharedDirector] winSize];
// move
self.position = ccp(self.position.x + self.velX * dt, self.position.y + self.velY * dt);
if (self.position.x < -self.contentSize.width/2) self.position = ccp(winSize.width + self.contentSize.width/2, self.position.y);
if (self.position.x > winSize.width + self.contentSize.width/2) self.position = ccp(-self.contentSize.width/2, self.position.y);
if (self.position.y < -self.contentSize.width/2) self.position = ccp(self.position.x, winSize.height + self.contentSize.width/2);
if (self.position.y > winSize.height + self.contentSize.width/2) self.position = ccp(self.position.x, -self.contentSize.width/2);
// decelerate
self.velX *= kDeceleration * 0.0165 / dt; // works if the line is: self.velX *= kDeceleration;
if (fabs(self.velX) < 1.0) self.velX = 0.0;
self.velY *= kDeceleration * 0.0165 / dt; // works if the line is: self.velY *= kDeceleration;
if (fabs(self.velY) < 1.0) self.velY = 0.0;
}
- (void)draw
{
[super draw];
glLineWidth(1);
ccDrawCircle(ccp(self.contentSize.width/2, self.contentSize.height/2), 3*self.contentSize.width/4, CC_DEGREES_TO_RADIANS(360), 60, NO);
}
#end
The problem is in the // decelerate section. If I leave out the * 0.0165 / dt part of the two lines that decelerate the player, it works, but it's way faster on the phone than the simulator due to framerate differences. This should scale it, but it just screws it up.
I've tried all kinds of NSLogging and if I use dt at all, I get nan for the value of my velX and velY properties.
Could it have something to do with using the method name -update?
Try using this formula instead:
float decelerator = pow(kDeceleration, 60 * dt);
self.velX *= decelerator;
self.velY *= decelerator;
The logic behind the math:
Suppose the framerate on simulator is at 30fps compared to the normal 60fps on device. Thus, for every frame on simulator, the device already shows 2 frames. Thus every call on the update on simulator should give the same result for 2 calls on device. After two calls on device, self.velX has been multiplied by kDeceleration two times, meaning the new value is equal to self.velX * kDeceleration * kDeceleration. By same logic, if the framerate on simulator is 1/3 of that on device, the new value is self.velX * kDeceleration * kDeceleration * kDeceleration. Thus, we can generalize it as self.velX * pow(kDeceleration, n) where n is the number of times the update method to be called to catch up with framerate of 60fps, which is 60 * dt.
I am making an iphone app where a ball will roll around the screen based on how the user tilts the device. If the device is lies flat on the table theoretically the ball would not move. If the device is tilted standing completely upward the I want the ball to roll straight down at maximum speed. The speed depends on how far from the flat position the device is tilted. Also, it also works for if the user tilts right or left or up or combinations of the four. I am using the accelerometer right now and the ball moves and it works okay, I am just not real familiar with physics. If someone has any suggestions on how to get this to work smoothly please let me know.
Thanks!
- (void)accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration
{
float xx = -[acceleration x];
float yy = [acceleration y];
float z = -[acceleration z];
z = 1 - z;
NSString * zaxis = [NSString stringWithFormat:#"%f", z];
lblz.text = zaxis;
lbly.text = [NSString stringWithFormat:#"%f", yy];
lblx.text = [NSString stringWithFormat:#"%f", xx];
CGFloat newx;
CGFloat newy;
if (yy > 0)
{
newy = ball.center.y - ((1 - yy) * z);
}
else
{
newy = ball.center.y + ((1 - yy) * z);
}
if (xx > 0)
{
newx = ball.center.x - ((1 - xx) * z);
}
else
{
newx = ball.center.x + ((1 - xx) * z);
}
CGPoint newPoint = CGPointMake(newx, newy);
ball.center = newPoint;
If you want to make it look more realistic and leverage existing stuff, look at some of the existing physics engines and 2d frameworks, Box2d and Cocos2d, but there are many others.
I think the key thing you are messing here is the difference between acceleration and velocity. You want the 'amount of tilt' to work as an acceleration. Each frame the balls Velocity should change by the acceleration, then the balls position should change by the balls velocity.
So just in X it should be something like:
float accelX = acceleration.x;
mVel.x += accelX; \\mVel is a member variable you have to store
ball.center.x += mVel.x;
---More Complex version
Now the more I think about it, it might not be the 'amount of tilt' you want to be the acceleration. You might want the amount of tilt to be the 'Target Velocity.' But you still want to use an acceleration to get there.
mTargetVel.x = acceleration.x;
//Now apply an acceleration to the velocity to move towards the Target Velocity
if(mVel.x < mTargetVel.x) {
mVel.x += ACCEL_X; //ACCEL_X is just a constant value that works well for you
}
else if(mVel.x > mTargetVel.x) {
mVel.x -= ACCEL_X;
}
//Now update the position based on the new velocity
ball.center.x += mVel.x;
i use following code to move my Box2D object into screen, but because gravity of my world or something else i dont know why my objects is forced to move down, i am new to box2d.
i want to move my object in entire world without gravity.
-(void) tick:(NSTimer *)timer {
int32 velocityIterations = 8;
int32 positionIterations = 1;
world->Step(1.0f/60.0f, velocityIterations, positionIterations);
for (b2Body* b = world->GetBodyList(); b; b = b->GetNext())
{
if (b->GetUserData() != NULL)
{
UIView *oneView = (UIView *)b->GetUserData();
CGPoint newCenter = CGPointMake(b->GetPosition().x * PTM_RATIO,self.view.bounds.size.height - b->GetPosition().y * PTM_RATIO);
oneView.center = newCenter;
CGAffineTransform transform = CGAffineTransformMakeRotation(- b->GetAngle());
oneView.transform = transform;
}
}
}
my accelerometer code is as follow.
- (void)accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration {
b2Vec2 gravity;
gravity.Set( acceleration.x * 1.81, acceleration.y * 1.81 );
world->SetGravity(gravity);
}
pleas if any one work around.
Thanks.
As i understand you want to move your object setting it's position. It's a bad idea because it will provide non-physical behavior of the bodies colliding with your object. That's because if you will only change the position of your body it's velocity for physics engine will be still zero and collision will be processed according to zero speed of your object.
A better solution is to use b2_kinematicBody type for your object. Then you will be able to control it's motion specifying it's velocity vector and physics will behave as expected. Also the gravity (and no other forces) will not be applied to your object because of it's type.
EDIT
//creation
b2BodyDef bDef;
bDef.type = b2_kinematicBody;
bDef.position.Set(5, 6);
b2Body *body = physWorld->CreateBody(&bDef);
//control
body->SetLinearVelocity(b2Vec2(3, 4));