与移动物体碰撞

Question

我曾试图与移动的“花车”发生碰撞，但没有成功。是什么东西可能在“碰撞”代码的错误位置？

//
// FruitsView.m
//

#import "FruitsView.h"
#import "Constants.h"
#import "Utilities.h"

#define kFloat1Speed 0.15
#define kFloat2Speed 0.3
#define kFloat3Speed 0.2

@interface FruitsView (Private)
- (void) stopTimer;
@end

@implementation FruitsView
@synthesize apple, float1, float2, float3, posFloat1, posFloat2, posFloat3;


-(void)onTimer {

float1.center = CGPointMake(float1.center.x+posFloat1.x,float1.cen ter.y+posFloat1.y);

if(float1.center.x > 380 || float1.center.x < -60)
posFloat1.x = -posFloat1.x;
if(float1.center.y > 100 || float1.center.y < -40)
posFloat1.y = -posFloat1.y;

float2.center = CGPointMake(float2.center.x+posFloat2.x,float2.cen ter.y+posFloat2.y);

if(float2.center.x > 380 || float2.center.x < -50)
posFloat2.x = -posFloat2.x;
if(float2.center.y > 150 || float2.center.y < -30)
posFloat2.y = -posFloat2.y;

float3.center = CGPointMake(float3.center.x+posFloat3.x,float3.cen ter.y+posFloat3.y);

if(float3.center.x > 380 || float3.center.x < -70)
posFloat3.x = -posFloat3.x;
if(float3.center.y > 100 || float3.center.y < -20)
posFloat3.y = -posFloat3.y;


if(CGRectIntersectsRect(apple.frame,float1.frame)) {
if(apple.center.y > float1.center.y) {
posApple.y = -posApple.y;
}
}

if(CGRectIntersectsRect(apple.frame,float2.frame)) {
if(apple.center.y > float2.center.y) {
posFloat2.y = -posFloat2.y;
}
}

if(CGRectIntersectsRect(apple.frame,float3.frame)) {
if(apple.center.y > float3.center.y) {
posFloat3.y = -posFloat3.y;
}
}   
}

#pragma mark Initialisation/destruction

- (void)awakeFromNib {

[NSTimer scheduledTimerWithTimeInterval:0.0001 target:self selector:@selector(onTimer) userInfo:nil repeats:YES];

posFloat1 = CGPointMake(kFloat1Speed, 0);
posFloat2 = CGPointMake(kFloat2Speed, 0);
posFloat3 = CGPointMake(kFloat3Speed, 0);

timer = nil;
modeLock = lockNotYetChosen;

defaultSize = self.bounds.size.width;

modal = self.tag;

[[UIAccelerometer sharedAccelerometer] setDelegate:self];

[UIView beginAnimations:nil context:nil];   
[UIView setAnimationRepeatCount:1];
eadbea.transform = CGAffineTransformMakeScale(0.5,0.5);
[UIView commitAnimations];

[UIView beginAnimations:nil context:nil];   
[UIView setAnimationRepeatCount:1];
apple.transform = CGAffineTransformMakeScale(0.5,0.5);
[UIView commitAnimations];
}

#pragma mark Background animation processing

- (void) startTimer {
if (!timer) {
timer = [[NSTimer scheduledTimerWithTimeInterval:1.0/60.0 target:self selector:@selector(timerTick:) userInfo:nil repeats:YES] retain];
}
}


- (void) stopTimer {
[timer invalidate];
[timer release];
timer = nil;
}

- (void) check:(CGPoint*)position delta:(CGSize*)delta halfSize:(CGSize)halfSize forBouncingAgainst:(CGSize)containerSize {

if ((position->x - halfSize.width)<0)
{
delta->width = fabsf(delta->width)*BOUNCE_DAMPING;
position->x = halfSize.width;
}
if ((position->x + halfSize.width)>containerSize.width)
{
delta->width = fabsf(delta->width)*-BOUNCE_DAMPING;
position->x = containerSize.width - halfSize.width;
}
if ((position->y - halfSize.height)<0)
{
delta->height = fabsf(delta->height)*BOUNCE_DAMPING;
position->y = halfSize.height;
}
if ((position->y + halfSize.height)>containerSize.height)
{
delta->height = fabsf(delta->height)*-BOUNCE_DAMPING;
position->y = containerSize.height - halfSize.height;
}
}


- (void) timerTick: (NSTimer*)timer {

dragDelta = CGSizeScale(dragDelta, INERTIAL_DAMPING);

if ((fabsf(dragDelta.width)>DELTA_ZERO_THRESHOLD) || (fabsf(dragDelta.height)>DELTA_ZERO_THRESHOLD))
{
CGPoint ctr = CGPointApplyDelta(self.center, dragDelta);

CGSize halfSize = CGSizeMake(self.bounds.size.width/4, self.bounds.size.height/4);
[self check:&ctr delta:&dragDelta halfSize:halfSize forBouncingAgainst:self.superview.bounds.size];

self.center = ctr;
}
else
{
[self stopTimer];
}
}

#pragma mark Input Handling

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
NSSet* allTouches = [event touchesForView:self];
if ([allTouches count]==1)
{
if (modeLock>lockNotYetChosen) return;

UITouch* anyTouch = [touches anyObject];
lastMove = anyTouch.timestamp;
CGPoint now = [anyTouch locationInView: self.superview];
CGPoint then = [anyTouch previousLocationInView: self.superview];
dragDelta = CGPointDelta(now, then);

self.center = CGPointApplyDelta(self.center, dragDelta);
[self stopTimer];
}
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {

NSSet* allTouches = [event touchesForView:self];
if ([touches count]==[allTouches count])
{
modeLock = lockNotYetChosen;

if ((event.timestamp - lastMove) > MOVEMENT_PAUSE_THRESHOLD)
return;
if ((fabsf(dragDelta.width)>INERTIA_THRESHOLD) || (fabsf(dragDelta.height)>INERTIA_THRESHOLD))
{
[self startTimer];
}
}
}

- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
modeLock = lockNotYetChosen;
[self stopTimer];
}

- (void)dealloc 
{
[float1 release];
[float2 release];
[float3 release];
[apple release];
[bear_head release];
[self stopTimer];
[super dealloc];
}

@end

Answer 1

不要使用所有浮点数，只需使用两个NSRect并使用NSIntersectionRect(rectA, rectB)检查它们是否相交。然后你可以做if(!NSIsEmptyRect(NSIntersectionRect(playerRect, monsterRect))) gameOver();

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的Nik