ボールを坂に転がして一回転させるiPhoneアプリのサンプルコードを描いてみます。
#import “ViewController.h”
@import SceneKit;
@interface ViewController ()
@property (nonatomic, weak) SCNView *sceneView;
@end
@implementation ViewController
– (void)viewDidLoad {
[super viewDidLoad];
[self setupScene];
[self createSlider];
}
– (void)setupScene {
SCNView *sv = [[SCNView alloc] initWithFrame:self.view.bounds];
sv.backgroundColor = [self color:3];
sv.scene = [SCNScene scene];
sv.allowsCameraControl = YES;
[self.view addSubview:sv];
self.sceneView = sv;
}
– (void)createSlider {
float d = 0.1;
float l = d / sqrt(2.0);
SCNBox *s = [SCNBox boxWithWidth:d height:d length:d chamferRadius:0];
s.firstMaterial.diffuse.contents = [self color:4];
// straight
for (int i=0; i<100; i++) {
for (int j=0; j<2; j++) {
SCNNode *node = [SCNNode nodeWithGeometry:s];
node.rotation = SCNVector4Make(1, 0, 0, – M_PI * 0.25);
node.position = SCNVector3Make(j==0 ? –5 : –4, – i * l, i * l);
node.physicsBody = [SCNPhysicsBody staticBody];
node.physicsBody.restitution = 0;
[self.sceneView.scene.rootNode addChildNode:node];
}
}
// loop 1/2
float dw = M_PI/75.0;
float r = 25.0 * l;
for (int i=0; i<200; i++) {
for (int j=0; j<2; j++) {
float z = r * cos(dw * i – M_PI * 0.75) + 100.0 * l + r / sqrt(2.0);
float y = r * sin(dw * i – M_PI * 0.75) – 100.0 * l + r / sqrt(2.0);
SCNNode *node = [SCNNode nodeWithGeometry:s];
node.position = SCNVector3Make((j==0 ? –5 : –4) + 0.0001 * pow(i, 2), y, z);
node.rotation = SCNVector4Make(1, 0, 0, -dw * i + 0.25 * M_PI);
node.physicsBody = [SCNPhysicsBody staticBody];
node.physicsBody.restitution = 0;
[self.sceneView.scene.rootNode addChildNode:node];
}
}
}
– (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
SCNSphere *ball = [SCNSphere sphereWithRadius:0.51];
ball.firstMaterial.diffuse.contents = [self color:1];
SCNNode *ballNode = [SCNNode nodeWithGeometry:ball];
ballNode.position = SCNVector3Make(-4.5, 0.48, 0);
ballNode.physicsBody = [SCNPhysicsBody dynamicBody];
ballNode.physicsBody.restitution = 0;
[self.sceneView.scene.rootNode addChildNode:ballNode];
[ballNode.physicsBody applyTorque:SCNVector4Make(1, 0, 0, 20) impulse:YES];
[ballNode.physicsBody applyForce:SCNVector3Make(0, –5, 5) impulse:YES];
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(6.0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
[ballNode removeFromParentNode];
});
}
#define ColorHex(rgb) [UIColor colorWithRed:((rgb & 0xFF0000) >> 16)/255.0 green:((rgb & 0xFF00) >> 8)/255.0 blue:(rgb & 0xFF)/255.0 alpha:1.0]
– (UIColor *)color:(int)i {
if (i > 4) return nil;
int colorCode[] = {0xC194A7, 0xFF92B9, 0xFFC6EB, 0xE9FFFF, 0xCAEE9F};
return ColorHex(colorCode[i]);
}
@end