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Pulse effect in SceneKit - Objective C
//
// GameViewController.h
// pulseeffectobjectivec
//
// Created by Lachlan Hurst on 10/3/17.
// Copyright © 2017 Lachlan Hurst. All rights reserved.
//
#import <UIKit/UIKit.h>
#import <SceneKit/SceneKit.h>
@interface GameViewController : UIViewController
@end
//
// GameViewController.m
// pulseeffectobjectivec
//
// Created by Lachlan Hurst on 10/3/17.
// Copyright © 2017 Lachlan Hurst. All rights reserved.
//
#import "GameViewController.h"
@implementation GameViewController
- (void)viewDidLoad
{
[super viewDidLoad];
// create a new scene
SCNScene *scene = [SCNScene scene];
// create and add a camera to the scene
SCNNode *cameraNode = [SCNNode node];
cameraNode.camera = [SCNCamera camera];
[scene.rootNode addChildNode:cameraNode];
// place the camera
cameraNode.position = SCNVector3Make(0, 0, 15);
// create and add a light to the scene
SCNNode *lightNode = [SCNNode node];
lightNode.light = [SCNLight light];
lightNode.light.type = SCNLightTypeOmni;
lightNode.position = SCNVector3Make(0, 10, 10);
[scene.rootNode addChildNode:lightNode];
// create and add an ambient light to the scene
SCNNode *ambientLightNode = [SCNNode node];
ambientLightNode.light = [SCNLight light];
ambientLightNode.light.type = SCNLightTypeAmbient;
ambientLightNode.light.color = [UIColor darkGrayColor];
[scene.rootNode addChildNode:ambientLightNode];
SCNNode *boxNode = [SCNNode nodeWithGeometry:[SCNBox boxWithWidth:1.0 height:1.0 length:1.0 chamferRadius:0.0]];
boxNode.geometry.firstMaterial.diffuse.contents = [UIColor redColor];
[scene.rootNode addChildNode:boxNode];
CGFloat pulseSize = 5.0;
SCNPlane *pulsePlane = [SCNPlane planeWithWidth:pulseSize height:pulseSize];
[pulsePlane.firstMaterial setDoubleSided:true];
pulsePlane.firstMaterial.diffuse.contents = [UIColor blueColor];
SCNNode *pulseNode = [SCNNode nodeWithGeometry:pulsePlane];
NSString *pulseShaderModifier = [NSString stringWithFormat:
@"#pragma transparent; \n"
"vec4 originalColour = _surface.diffuse; \n"
"vec4 transformed_position = u_inverseModelTransform * u_inverseViewTransform * vec4(_surface.position, 1.0); \n"
"vec2 xy = vec2(transformed_position.x, transformed_position.y); \n"
"float xyLength = length(xy); \n"
"float xyLengthNormalised = xyLength/%f; \n"
"float speedFactor = 1.5; \n"
"float maxDist = fmod(u_time, speedFactor) / speedFactor; \n"
"float distbasedalpha = step(maxDist, xyLengthNormalised); \n"
"distbasedalpha = max(distbasedalpha, maxDist); \n"
"_surface.diffuse = mix(originalColour, vec4(0.0), distbasedalpha);", pulseSize/2.0];
NSDictionary *smdict = [NSDictionary dictionaryWithObject:pulseShaderModifier forKey:SCNShaderModifierEntryPointSurface];
[pulsePlane.firstMaterial setShaderModifiers:smdict];
[boxNode addChildNode:pulseNode];
SCNLookAtConstraint *pulseNodeConstraint = [SCNLookAtConstraint lookAtConstraintWithTarget:cameraNode];
NSArray *constraints = [NSArray arrayWithObject:pulseNodeConstraint];
[pulseNode setConstraints:constraints];
// animate the 3d object
[boxNode runAction:[SCNAction repeatActionForever:[SCNAction rotateByX:0 y:2 z:0 duration:1]]];
// retrieve the SCNView
SCNView *scnView = (SCNView *)self.view;
// set the scene to the view
scnView.scene = scene;
// allows the user to manipulate the camera
scnView.allowsCameraControl = YES;
// show statistics such as fps and timing information
scnView.showsStatistics = YES;
// configure the view
scnView.backgroundColor = [UIColor lightGrayColor];
// add a tap gesture recognizer
UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTap:)];
NSMutableArray *gestureRecognizers = [NSMutableArray array];
[gestureRecognizers addObject:tapGesture];
[gestureRecognizers addObjectsFromArray:scnView.gestureRecognizers];
scnView.gestureRecognizers = gestureRecognizers;
}
- (void) handleTap:(UIGestureRecognizer*)gestureRecognize
{
// retrieve the SCNView
SCNView *scnView = (SCNView *)self.view;
// check what nodes are tapped
CGPoint p = [gestureRecognize locationInView:scnView];
NSArray *hitResults = [scnView hitTest:p options:nil];
// check that we clicked on at least one object
if([hitResults count] > 0){
// retrieved the first clicked object
SCNHitTestResult *result = [hitResults objectAtIndex:0];
// get its material
SCNMaterial *material = result.node.geometry.firstMaterial;
// highlight it
[SCNTransaction begin];
[SCNTransaction setAnimationDuration:0.5];
// on completion - unhighlight
[SCNTransaction setCompletionBlock:^{
[SCNTransaction begin];
[SCNTransaction setAnimationDuration:0.5];
material.emission.contents = [UIColor blackColor];
[SCNTransaction commit];
}];
material.emission.contents = [UIColor redColor];
[SCNTransaction commit];
}
}
- (BOOL)shouldAutorotate
{
return YES;
}
- (BOOL)prefersStatusBarHidden {
return YES;
}
- (UIInterfaceOrientationMask)supportedInterfaceOrientations
{
if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) {
return UIInterfaceOrientationMaskAllButUpsideDown;
} else {
return UIInterfaceOrientationMaskAll;
}
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Release any cached data, images, etc that aren't in use.
}
@end
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