用锥形射击子弹答案

【问题标题】：Shoot bullets in a cone用锥形射击子弹
【发布时间】：2014-07-22 23:54:36
【问题描述】：

我想知道如何使用 SpriteKit 物理原理根据起点在锥形发射弹丸？目前我只使用以下循环（它不以初始滑动为中心）：

float distance = DistanceBetweenTwoPoints(_startSwipe, _endSwipe);
float cballDx = (_endSwipe.x - _startSwipe.x) / distance;
float cballDy = (_endSwipe.y - _startSwipe.y) / distance;    

for (int i = 0; i < playerShip.cannons; i++) {
    SKSpriteNode *cannon = [SKSpriteNode spriteNodeWithImageNamed:@"cball"];
    cannon.name = @"cball";
    cannon.position = _touchedShip.position;
    cannon.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:cannon.size.width * 0.5];
    cannon.physicsBody.dynamic = YES;
    cannon.physicsBody.allowsRotation = NO;
    cannon.physicsBody.friction = 0.0;
    cannon.physicsBody.linearDamping = 0.0;
    cannon.physicsBody.categoryBitMask = cannonCategory;

    cannon.physicsBody.velocity = CGVectorMake(cballDx * 150 + i * 5, cballDy * 150);
    [self addChild:cannon];
}

非常感谢任何帮助！

【问题讨论】：

标签： sprite-kit game-physics projectile

【解决方案1】：

看看这个，你可以根据你的游戏调整 dx 和 dy 冲动

#import "GameScene.h"

@implementation GameScene
{
    CGPoint startTouchPosition;
    CGPoint currentTouchPosition;
    SKSpriteNode *mysprite;
}
-(void)didMoveToView:(SKView *)view {
    /* Setup your scene here */
    self.physicsBody.affectedByGravity=NO;
    self.physicsWorld.gravity=CGVectorMake(0.0,-9.8);
    self.physicsWorld.contactDelegate=self;
    self.physicsWorld.speed=1.5;
    self.speed=1.5;
    [self createObject];
}
-(void)createObject
{
    mysprite=[SKSpriteNode spriteNodeWithImageNamed:@"bottle1.png"];
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{



}

-(void)addspriteandjump:(CGVector)jumpPoint position:(CGPoint)point
{
    SKSpriteNode *clone=mysprite.copy;
    [self addChild:clone];
    clone.position=point;
    clone.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:clone.size];
    clone.physicsBody.dynamic=YES;
    clone.physicsBody.affectedByGravity=YES;
    clone.name=@"gameHero";
    clone.physicsBody.allowsRotation=YES;
    [clone.physicsBody applyImpulse:jumpPoint];
}
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    CGVector jumpPoint;
    UITouch *aTouch = [touches anyObject];
    currentTouchPosition= [aTouch locationInNode:self];
    SKNode *node = [self nodeAtPoint:startTouchPosition];
    jumpPoint.dy=100;
    jumpPoint.dx=abs(currentTouchPosition.x-startTouchPosition.x)/16;
    [self addspriteandjump:jumpPoint position:startTouchPosition];

    startTouchPosition = CGPointZero;
    currentTouchPosition = CGPointZero;

}

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

    UITouch *aTouch = [touches anyObject];
    startTouchPosition= [aTouch locationInNode:self];

    SKNode *node = [self nodeAtPoint:startTouchPosition];
   }

-(void)update:(CFTimeInterval)currentTime {
    /* Called before each frame is rendered */
}

@end

【讨论】：