/*

     File: ASCSlideGeometry.m

 Abstract: Explains how geometries are made.

  Version: 1.1

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#import <GLKit/GLKMath.h>

#import "ASCPresentationViewController.h"

#import "ASCSlideTextManager.h"

#import "ASCSlide.h"

#import "Utils.h"

@interface ASCSlideGeometry : ASCSlide

@end

@implementation ASCSlideGeometry {

    SCNNode *_teapotNodeForPositionsAndNormals;

    SCNNode *_teapotNodeForUVs;

    SCNNode *_teapotNodeForMaterials;

    SCNNode *_positionsVisualizationNode;

    SCNNode *_normalsVisualizationNode;

}

- (NSUInteger)numberOfSteps {

    return 6;

}

- (void)setupSlideWithPresentationViewController:(ASCPresentationViewController *)presentationViewController {

    // Set the slide's title and subtile and add some text

    self.textManager.title = @"Node Attributes";

    self.textManager.subtitle = @"Geometry";

    [self.textManager addBullet:@"Triangles" atLevel:0];

    [self.textManager addBullet:@"Vertices" atLevel:0];

    [self.textManager addBullet:@"Normals" atLevel:0];

    [self.textManager addBullet:@"UVs" atLevel:0];

    [self.textManager addBullet:@"Materials" atLevel:0];

    // We create a container for several versions of the teapot model

    // - one teapot to show positions and normals

    // - one teapot to show texture coordinates

    // - one teapot to show materials

    SCNNode *allTeapotsNode = [SCNNode node];

    allTeapotsNode.rotation = SCNVector4Make(1, 0, 0, -M_PI_2);

    [self.groundNode addChildNode:allTeapotsNode];

    _teapotNodeForPositionsAndNormals = [allTeapotsNode asc_addChildNodeNamed:@"TeapotLowRes" fromSceneNamed:@"teapotLowRes" withScale:17];

    _teapotNodeForUVs = [allTeapotsNode asc_addChildNodeNamed:@"Teapot" fromSceneNamed:@"teapot" withScale:17];

    _teapotNodeForMaterials = [allTeapotsNode asc_addChildNodeNamed:@"teapotMaterials" fromSceneNamed:@"teapotMaterial" withScale:17];

    _teapotNodeForPositionsAndNormals.position = SCNVector3Make(4, 0, 0);

    _teapotNodeForUVs.position = SCNVector3Make(4, 0, 0);

    _teapotNodeForMaterials.position = SCNVector3Make(4, 0, 0);

    [_teapotNodeForMaterials childNodesPassingTest:^BOOL(SCNNode *child, BOOL *stop) {

        for (SCNMaterial *material in child.geometry.materials) {

            material.normal.intensity = 0.3;

            material.reflective.contents = [NSColor whiteColor];

            material.reflective.intensity = 3.0;

            material.fresnelExponent = 3.0;

        }

        return NO;

    }];

    // Animate the teapots (rotate forever)

    CABasicAnimation *rotationAnimation = [CABasicAnimation animationWithKeyPath:@"rotation"];

    rotationAnimation.duration = 40.0;

    rotationAnimation.repeatCount = FLT_MAX;

    rotationAnimation.toValue = [NSValue valueWithSCNVector4:SCNVector4Make(0, 0, 1, M_PI * 2)];

    [_teapotNodeForPositionsAndNormals addAnimation:rotationAnimation forKey:nil];

    [_teapotNodeForUVs addAnimation:rotationAnimation forKey:nil];

    [_teapotNodeForMaterials addAnimation:rotationAnimation forKey:nil];

    // Load the "explode" shader modifier and add it to the geometry

    NSString *explodeShaderPath = [[NSBundle mainBundle] pathForResource:@"explode" ofType:@"shader"];

    NSString *explodeShaderSource = [NSString stringWithContentsOfFile:explodeShaderPath encoding:NSUTF8StringEncoding error:nil];

    _teapotNodeForPositionsAndNormals.geometry.shaderModifiers = @{ SCNShaderModifierEntryPointGeometry : explodeShaderSource};

    // Build nodes that will help visualize the vertices (position and normal)

    [self buildVisualizationsOfNode:_teapotNodeForPositionsAndNormals

                      positionsNode:&_positionsVisualizationNode

                        normalsNode:&_normalsVisualizationNode];

    [_teapotNodeForPositionsAndNormals addChildNode:_positionsVisualizationNode];

    [_teapotNodeForPositionsAndNormals addChildNode:_normalsVisualizationNode];

}

- (void)presentStepIndex:(NSUInteger)index withPresentionViewController:(ASCPresentationViewController *)presentationViewController {

    switch (index) {

        case 0:

        {

            // Adjust the near clipping plane of the spotlight to maximize the precision of the dynamic drop shadows

            [presentationViewController.spotLight.light setAttribute:@(30) forKey:SCNLightShadowNearClippingKey];

            // Show what needs to be shown, hide what needs to be hidden

            _positionsVisualizationNode.opacity = 0.0;

            _normalsVisualizationNode.opacity = 0.0;

            _teapotNodeForUVs.opacity = 0.0;

            _teapotNodeForMaterials.opacity = 0.0;

            _teapotNodeForPositionsAndNormals.opacity = 1.0;

            // Don't highlight bullets (this is useful when we go back from the next slide)

            [self.textManager highlightBulletAtIndex:NSNotFound];

            break;

        }

        case 1:

        {

            [self.textManager highlightBulletAtIndex:0];

            // Animate the "explodeValue" parameter (uniform) of the shader modifier

            CABasicAnimation *explodeAnimation = [CABasicAnimation animationWithKeyPath:@"explodeValue"];

            explodeAnimation.duration = 2.0;

            explodeAnimation.repeatCount = FLT_MAX;

            explodeAnimation.autoreverses = YES;

            explodeAnimation.toValue = @20.0;

            explodeAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];

            [_teapotNodeForPositionsAndNormals.geometry addAnimation:explodeAnimation forKey:@"explode"];

            break;

        }

        case 2:

        {

            [self.textManager highlightBulletAtIndex:1];

            // Remove the "explode" animation and freeze the "explodeValue" parameter to the current value

            [SCNTransaction begin];

            [SCNTransaction setAnimationDuration:0.0];

            {

                NSNumber *explodeValue = [_teapotNodeForPositionsAndNormals.presentationNode.geometry valueForKey:@"explodeValue"];

                [_teapotNodeForPositionsAndNormals.geometry setValue:explodeValue forKey:@"explodeValue"];

                [_teapotNodeForPositionsAndNormals.geometry removeAnimationForKey:@"explode"];

            }

            [SCNTransaction commit];

            // Animate to a "no explosion" state and show the positions on completion

            void (^showPositions)(void) = ^{

                [SCNTransaction begin];

                [SCNTransaction setAnimationDuration:1.0];

                {

                    _positionsVisualizationNode.opacity = 1.0;

                }

                [SCNTransaction commit];

            };

            [SCNTransaction begin];

            [SCNTransaction setAnimationDuration:1.0];

            [SCNTransaction setCompletionBlock:showPositions];

            {

                [_teapotNodeForPositionsAndNormals.geometry setValue:@0.0 forKey:@"explodeValue"];

            }

            [SCNTransaction commit];

            break;

        }

        case 3:

        {

            [self.textManager highlightBulletAtIndex:2];

            [SCNTransaction begin];

            [SCNTransaction setAnimationDuration:1.0];

            {

                _positionsVisualizationNode.opacity = 0.0;

                _normalsVisualizationNode.opacity = 1.0;

            }

            [SCNTransaction commit];

            break;

        }

        case 4:

        {

            [self.textManager highlightBulletAtIndex:3];

            [SCNTransaction begin];

            [SCNTransaction setAnimationDuration:0];

            {

                _normalsVisualizationNode.hidden = YES;

                _teapotNodeForUVs.opacity = 1.0;

                _teapotNodeForPositionsAndNormals.opacity = 0.0;

            }

            [SCNTransaction commit];

            break;

        }

        case 5:

        {

            [self.textManager highlightBulletAtIndex:4];

            [SCNTransaction begin];

            [SCNTransaction setAnimationDuration:0];

            {

                _teapotNodeForUVs.hidden = YES;

                _teapotNodeForMaterials.opacity = 1.0;

            }

            [SCNTransaction commit];

            break;

        }

    }

}

- (void)buildVisualizationsOfNode:(SCNNode *)node positionsNode:(SCNNode * __strong *)verticesNode normalsNode:(SCNNode * __strong *)normalsNode {

    // A material that will prevent the nodes from being lit

    SCNMaterial *noLightingMaterial = [SCNMaterial material];

    noLightingMaterial.lightingModelName = SCNLightingModelConstant;

    // Create nodes to represent the vertex and normals

    SCNNode *positionVisualizationNode = [SCNNode node];

    SCNNode *normalsVisualizationNode = [SCNNode node];

    // Retrieve the vertices and normals from the model

    SCNGeometrySource *positionSource = [node.geometry geometrySourcesForSemantic:SCNGeometrySourceSemanticVertex][0];

    SCNGeometrySource *normalSource = [node.geometry geometrySourcesForSemantic:SCNGeometrySourceSemanticNormal][0];

    // Get vertex and normal bytes

    float *vertexBuffer = (float *)positionSource.data.bytes;

    float *normalBuffer = (float *)normalSource.data.bytes;

    // Iterate and create geometries to represent the positions and normals

    for (NSUInteger i = 0; i < positionSource.vectorCount; i++) {

        // One new node per normal/vertex

        SCNNode *vertexNode = [SCNNode node];

        SCNNode *normalNode = [SCNNode node];

        // Attach one sphere per vertex

        SCNSphere *sphere = [SCNSphere sphereWithRadius:0.5];

        sphere.segmentCount = 4; // use a small segment count for better performances

        sphere.firstMaterial = noLightingMaterial;

        vertexNode.geometry = sphere;

        // And one pyramid per normal

        SCNPyramid *pyramid = [SCNPyramid pyramidWithWidth:0.1 height:0.1 length:8];

        pyramid.firstMaterial = noLightingMaterial;

        normalNode.geometry = pyramid;

        // Place the position node

        NSInteger componentsPerVector = positionSource.componentsPerVector;

        vertexNode.position = SCNVector3Make(vertexBuffer[i * componentsPerVector], vertexBuffer[i * componentsPerVector + 1], vertexBuffer[i * componentsPerVector + 2]);

        // Place the normal node

        normalNode.position = vertexNode.position;

        // Orientate the normal

        GLKVector3 up = GLKVector3Make(0, 0, 1);

        GLKVector3 normalVec = GLKVector3Make(normalBuffer[i * 3], normalBuffer[i * 3 + 1], normalBuffer[i * 3 + 2]);

        GLKVector3 axis = GLKVector3Normalize(GLKVector3CrossProduct(up, normalVec));

        float dotProduct = GLKVector3DotProduct(up, normalVec);

        normalNode.rotation = SCNVector4Make(axis.x, axis.y, axis.z, acos(dotProduct));

        // Add the nodes to their parent

        [positionVisualizationNode addChildNode:vertexNode];

        [normalsVisualizationNode addChildNode:normalNode];

    }

    // We must flush the transaction in order to make sure that the parametric geometries (sphere and pyramid)

    // are up-to-date before flattening the nodes

    [SCNTransaction flush];

    // Flatten the visualization nodes so that they can be rendered with 1 draw call

    *verticesNode = [positionVisualizationNode flattenedClone];

    *normalsNode = [normalsVisualizationNode flattenedClone];

}

@end