太陽と地球と月

太陽の周りを地球、その周りを月がくるっとする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) SCNScene *scene;

@end

@implementation ViewController

– (void)viewDidLoad {

    [super viewDidLoad];

    self.view.backgroundColor = [UIColor lightGrayColor];

    [self setupScene];

    [self createPlanets];

    [self createCameraAndLight];

    [self createButton];

}

– (void)setupScene {

    float w = CGRectGetMaxX(self.view.bounds);

    SCNView *sceneView = [[SCNView alloc] initWithFrame:CGRectMake(0, 0, w, w)];

    sceneView.backgroundColor = [UIColor colorWithHue:0.7 saturation:0.2 brightness:0.2 alpha:1];

    sceneView.scene = [SCNScene scene];

    [self.view addSubview:sceneView];

    

    self.scene = sceneView.scene;

}

– (void)createPlanets {

    SCNSphere *sun = [SCNSphere sphereWithRadius:10];

    sun.firstMaterial.diffuse.contents = [UIColor colorWithHue:0.01 saturation:0.9 brightness:1 alpha:1];

    sun.firstMaterial.reflective.contents = [UIColor yellowColor];

    SCNNode *sunNode = [SCNNode nodeWithGeometry:sun];

    sunNode.name = @”sun”;

    [self.scene.rootNode addChildNode:sunNode];

    

    SCNSphere *earth = [SCNSphere sphereWithRadius:3];

    earth.firstMaterial.diffuse.contents = [UIColor colorWithHue:0.6 saturation:0.9 brightness:1 alpha:1];

    SCNNode *earthNode = [SCNNode nodeWithGeometry:earth];

    earthNode.name = @”earth”;

    earthNode.position = SCNVector3Make(0, 0, 20);

    [sunNode addChildNode:earthNode];

    

    SCNSphere *moon = [SCNSphere sphereWithRadius:1];

    moon.firstMaterial.diffuse.contents = [UIColor colorWithHue:0.13 saturation:0.1 brightness:1 alpha:1];

    moon.firstMaterial.reflective.contents = [UIColor whiteColor];

    SCNNode *moonNode = [SCNNode nodeWithGeometry:moon];

    moonNode.name = @”moon”;

    moonNode.position = SCNVector3Make(0, 0, 5);

    [earthNode addChildNode:moonNode];

}

– (void)createCameraAndLight {

    SCNNode *camera = [SCNNode node];

    camera.camera = [SCNCamera camera];

    camera.position = SCNVector3Make(-5, 10, 50);

    [self.scene.rootNode addChildNode:camera];

    camera.constraints = @[[SCNLookAtConstraint lookAtConstraintWithTarget:[self.scene.rootNode childNodeWithName:@”sun” recursively:NO]]];

    

    SCNLight *light = [SCNLight light];

    light.type = SCNLightTypeSpot;

    SCNNode *lightNode = [SCNNode node];

    lightNode.light = light;

    lightNode.position = SCNVector3Make(0, 10, 80);

    [self.scene.rootNode addChildNode:lightNode];

}

– (void)createButton {

    UIButton *btn = [UIButton buttonWithType:UIButtonTypeSystem];

    [btn setTitle:@”START” forState:UIControlStateNormal];

    btn.titleLabel.font = [UIFont systemFontOfSize:50];

    [btn sizeToFit];

    btn.center = CGPointMake(CGRectGetMidX(self.view.bounds), CGRectGetMidY(self.view.bounds) + 80);

    [self.view addSubview:btn];

    

    [btn addTarget:self action:@selector(start) forControlEvents:UIControlEventTouchUpInside];

}

– (void)start {

    // rotate earth

    SCNNode *sun = [self.scene.rootNode childNodeWithName:@”sun” recursively:NO];

    CABasicAnimation *rotateS = [CABasicAnimation animationWithKeyPath:@”rotation”];

    rotateS.toValue = [NSValue valueWithSCNVector4:SCNVector4Make(-0.2, 1, 0, 2.0 * M_PI)];

    rotateS.repeatCount = HUGE_VAL;

    rotateS.duration = 5.0;

    [sun addAnimation:rotateS forKey:nil];

    

    

    // rotate moon

    SCNNode *earth = [sun childNodeWithName:@”earth” recursively:NO];

    CABasicAnimation *rotate = [CABasicAnimation animationWithKeyPath:@”rotation”];

    rotate.toValue = [NSValue valueWithSCNVector4:SCNVector4Make(0.2, 1, 0, 2.0 * M_PI)];

    rotate.repeatCount = HUGE_VAL;

    rotate.duration = 3.0;

    [earth addAnimation:rotate forKey:nil];

    

}

@end