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VoxelPanda/VoxelPanda/AAPLSceneViewController.m

/*

 Copyright (C) 2015 Apple Inc. All Rights Reserved.

 See LICENSE.txt for this sample’s licensing information

 Abstract:

 This view controller contains the Model IO code which is the focus of the sample, which is the loading of voxels. The voxels are displayed using SceneKit as an example graphics library.

*/

@import SceneKit;

@import ModelIO;

@import SceneKit.ModelIO;

#import "AAPLSceneViewController.h"

@implementation AAPLSceneViewController

    SCNNode *_character;

    SCNNode *_voxels;

    BOOL _explodeUsingCubes;

#define SCALE_FACTOR 0.1

static float rnd()

    return 0.01 * SCALE_FACTOR * ((rand() / (float)RAND_MAX) - 0.5);

 // Set up scene with character.scn asset and set view properties

- (void) awakeFromNib

#if TARGET_OS_IPHONE

    self.sceneView = (SCNView *)self.view;

    // Set up tap gesture recognizer

    UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTapGesture:)];

    [self.view addGestureRecognizer:tapGesture];

#endif

    // Load scene from file path

    SCNScene *characterScene = [SCNScene sceneNamed:@"character.scnassets/character.scn"];

    // For each static physics body in the scene, set its shape and remove the node's geometry so it doesn't appear in the scene.

    SCNNode *collisionNode = [characterScene.rootNode childNodeWithName:@"collision" recursively:YES];

    [collisionNode enumerateChildNodesUsingBlock:^(SCNNode * __nonnull child, BOOL * __nonnull stop)

        child.physicsBody.physicsShape =[SCNPhysicsShape shapeWithGeometry:child.geometry options:nil];

        child.geometry = nil;

}];

    // Set view properties and defaults

    _character = [characterScene.rootNode childNodeWithName:@"character" recursively:YES];

    self.sceneView.scene = characterScene;

    self.sceneView.jitteringEnabled = YES;

    self.sceneView.allowsCameraControl = NO;

- (IBAction)voxelize:(id)sender

    // Create MDLAsset from scene

    SCNScene *tempScene = [SCNScene scene];

    [tempScene.rootNode addChildNode:_character];

    MDLAsset *asset = [MDLAsset assetWithSCNScene:tempScene];

    // Create voxel grid from MDLAsset

    MDLVoxelArray *grid = [[MDLVoxelArray alloc]  initWithAsset:asset divisions:25 interiorShells:0 exteriorShells:0 patchRadius:0.f];

    NSData *voxelData = [grid voxelIndices];   // retrieve voxel data

    if (voxelData && voxelData.bytes)

        // Create voxel parent node and add to scene

        [_voxels removeFromParentNode];

        _voxels = [SCNNode node];

        [self.sceneView.scene.rootNode addChildNode:_voxels];

        // Create the voxel node geometry

        SCNBox *particle = [SCNBox boxWithWidth:2.f * SCALE_FACTOR height:2.f * SCALE_FACTOR length:2.f * SCALE_FACTOR chamferRadius:0.f];

        // Get the character's texture map and convert to a bitmap

        NSURL *url = _character.childNodes[0].geometry.firstMaterial.diffuse.contents;

        assert([url isKindOfClass:NSURL.class]); // this sample assumes that the `diffuse` material property is an URL to an image

        CGImageRef image;

#if TARGET_OS_IPHONE

        image = [[UIImage imageWithContentsOfFile:[url path]] CGImage];

#else

        image = [[[NSImage alloc] initByReferencingURL:url] CGImageForProposedRect:nil context:nil hints:nil];

#endif

        CFDataRef pixelData = CGDataProviderCopyData(CGImageGetDataProvider(image));

        UInt8 *buf = (UInt8 *)CFDataGetBytePtr(pixelData);

        size_t w = CGImageGetWidth(image);

        size_t h = CGImageGetHeight(image);

        size_t bpr = CGImageGetBytesPerRow(image); // this sample assumes 8 bits per component

        size_t bpp = CGImageGetBitsPerPixel(image) / 8;

        // Traverse the NSData voxel array and for each ijk index, create a voxel node positioned at its spatial location

        MDLVoxelIndex *voxels = (MDLVoxelIndex *)voxelData.bytes;

        size_t count = voxelData.length / sizeof(MDLVoxelIndex);

        for (int i = 0; i < count; ++i)

            vector_float3 position = [grid spatialLocationOfIndex:*voxels++];

#define OFFSET_FACTOR 0.9

            // Determine color of the voxel by performing a hit test and then getting the texture coordinate at the point of intersection

            NSArray *results = [self.sceneView.scene.rootNode

                                hitTestWithSegmentFromPoint:SCNVector3Make(position.x, position.y, position.z + 1.f)

                                toPoint:SCNVector3Make(position.x  * OFFSET_FACTOR , position.y  * OFFSET_FACTOR, position.z - 5.f)

                                options:@{SCNHitTestRootNodeKey : _character, SCNHitTestBackFaceCullingKey : @(NO)}];

#if TARGET_OS_IPHONE

            UIColor *color = [UIColor darkGrayColor]; // default voxel color

#else

            NSColor *color = [NSColor darkGrayColor];

#endif

            if (results.count)

                SCNHitTestResult *result = results[0];

                CGPoint tx = [result textureCoordinatesWithMappingChannel:0];

                // Get the bitmap pixel color at the texture coordinate

                int x = tx.x * w;

                int y = tx.y * h;

                int pixel = bpr * round(y) + bpp * round(x);

                CGFloat r = (CGFloat)buf[pixel] / (CGFloat)255.0; // this sample code assumes that the first 3 components are R, G and B

                CGFloat g = (CGFloat)buf[pixel+1] / (CGFloat)255.0;

                CGFloat b = (CGFloat)buf[pixel+2] / (CGFloat)255.0;

#if TARGET_OS_IPHONE

                color = [UIColor colorWithRed:r green:g blue:b alpha:1];

#else

                color = [NSColor colorWithCalibratedRed:r green:g blue:b alpha:1];

#endif

            // Create the voxel node and set its properties

            SCNNode *voxelNode = [SCNNode nodeWithGeometry:[particle copy]];

            voxelNode.position = SCNVector3Make(position.x + rnd(), position.y, position.z + rnd());

            SCNMaterial *material = [SCNMaterial material];

            material.diffuse.contents = color;

            material.selfIllumination.contents = @"character.scnassets/textures/max_ambiant.png";

            voxelNode.geometry.firstMaterial = material;

            // Add voxel node to the scene

            [_voxels addChildNode:voxelNode];

        _explodeUsingCubes = true;

        CFRelease(pixelData);

- (IBAction)dispalyVoxelsAsCubes:(id)sender

    if (!_explodeUsingCubes)

        SCNBox *cube = [SCNBox boxWithWidth:2.f * SCALE_FACTOR height:2.f * SCALE_FACTOR length:2.f * SCALE_FACTOR chamferRadius:0.f];

        // For each voxel node, change its geometry to a cube

        [_voxels enumerateChildNodesUsingBlock:^(SCNNode * child, BOOL * stop)

             SCNMaterial *material = child.geometry.firstMaterial;

             child.geometry = [cube copy];

             child.geometry.firstMaterial = material;

}];

        _explodeUsingCubes = true;

- (IBAction)dispalyVoxelsAsSpheres:(id)sender

    if (_explodeUsingCubes)

        SCNSphere *sphere = [SCNSphere sphereWithRadius:1.f * SCALE_FACTOR];

        // For each voxel node, change its geometry to a sphere

        [_voxels enumerateChildNodesUsingBlock:^(SCNNode * child, BOOL * stop)

             SCNMaterial *material = child.geometry.firstMaterial;

             child.geometry = [sphere copy];

             child.geometry.firstMaterial = material;

}];

        _explodeUsingCubes = false;

- (IBAction)explode:(id)sender

    // The shape of the physics body varies depending on the geometry of the voxel node

    SCNGeometry *particle;

    if (_explodeUsingCubes)

        particle = [SCNBox boxWithWidth:1.9 * SCALE_FACTOR height:1.9 * SCALE_FACTOR length:1.9 * SCALE_FACTOR chamferRadius:0.f];

    } else

        particle = [SCNSphere sphereWithRadius:0.9 * SCALE_FACTOR];

    // For each voxel node, apply a physics force

    [_voxels enumerateChildNodesUsingBlock:^(SCNNode * child, BOOL * stop)

         child.physicsBody = [SCNPhysicsBody dynamicBody];

         child.physicsBody.physicsShape = [SCNPhysicsShape shapeWithGeometry:particle options:nil];

         [child.physicsBody applyForce:SCNVector3Make(rnd() * 1000.f, 3.f + 100.f * rnd(), rnd() * 1000.f) atPosition:SCNVector3Make(0.f, 0.f, 0.f) impulse:YES];

}];

- (IBAction)reset:(id)sender

    [_voxels removeFromParentNode];

    [self.sceneView.scene.rootNode addChildNode:_character];

#if TARGET_OS_IPHONE

- (void)handleTapGesture:(UITapGestureRecognizer *)gesture

    CGRect targetRectangle = CGRectMake(self.view.bounds.size.width * .5 - 50, self.view.bounds.size.height * .25, 100, 100);

    [[UIMenuController sharedMenuController] setTargetRect:targetRectangle inView:self.view];

    // Create custom menu items

    UIMenuItem *voxelizeMenuItem = [[UIMenuItem alloc] initWithTitle:@"Voxelize" action:@selector(voxelize:)];

    UIMenuItem *cubesMenuItem = [[UIMenuItem alloc] initWithTitle:@"Cubes" action:@selector(dispalyVoxelsAsCubes:)];

    UIMenuItem *spheresMenuItem = [[UIMenuItem alloc] initWithTitle:@"Spheres" action:@selector(dispalyVoxelsAsSpheres:)];

    UIMenuItem *explodeMenuItem = [[UIMenuItem alloc] initWithTitle:@"Explode" action:@selector(explode:)];

    UIMenuItem *resetMenuItem = [[UIMenuItem alloc] initWithTitle:@"Reset" action:@selector(reset:)];

    // Add menu items to shared menu controller

    [[UIMenuController sharedMenuController] setMenuItems:@[voxelizeMenuItem, cubesMenuItem, spheresMenuItem, explodeMenuItem, resetMenuItem]];

    // Make menu controller visible

    [[UIMenuController sharedMenuController] setMenuVisible:YES animated:YES];

- (BOOL)canBecomeFirstResponder {

    return YES;

- (BOOL)canPerformAction:(SEL)action withSender:(id)sender

    if (action == @selector(voxelize:) || action == @selector(dispalyVoxelsAsCubes:) || action == @selector(dispalyVoxelsAsSpheres:) ||

        action == @selector(explode:) || action == @selector(reset:))

        return YES;

    return NO;

#endif

@end

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