/*

     File: MusicCubeViewController.m

 Abstract: n/a

  Version: 1.3

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 */

/*

 In our sound stage, the cube represents an omnidirectional sound source, and the teapot represents a sound listener.

 The four modes in the application shows how the sound volume and balance will change based on the position of the omnidirectional sound source

 and the position and rotation of the listener:

 1. Constant sound

 2. Sound variates corresponding to the listener's position changes relative to the source

 3. Sound variates corresponding to the listener's rotation changes relative to the source

 4. Sound variates corresponding to the listener's position and rotation changes relative to the source

 */

#import <QuartzCore/QuartzCore.h>

#import <OpenGLES/EAGLDrawable.h>

#import <OpenGLES/ES2/glext.h>

#import "MusicCubeViewController.h"

#import "teapot.h"

#define kInnerCircleRadius  1.0

#define kOuterCircleRadius  1.1

#define kCircleSegments     36

#define kTeapotScale        1.8

#define kCubeScale          0.12

#define kButtonScale        0.1

#define kButtonLeftSpace    1.1

#define DegreesToRadians(x) ((x) * M_PI / 180.0)

#define BUFFER_OFFSET(i) ((char *)NULL + (i))

typedef struct

{

    GLKBaseEffect *effect;

    GLuint vertexArray;

    GLuint vertexBuffer;

    GLuint normalBuffer;

} BaseEffect;

// A class extension to declare private methods

@interface MusicCubeViewController ()

{

    BaseEffect innerCircle;

    BaseEffect outerCircle;

    BaseEffect teapot;

    BaseEffect cube[6];

    EAGLContext *context;

    GLuint mode;

    // teapot

    GLfloat rot;

    // cube

    GLfloat cubePos[3];

    GLfloat cubeRot;

    GLuint cubeTexture;

}

@end

@implementation MusicCubeViewController

- (void)didReceiveMemoryWarning

{

    [super didReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}

- (void)viewDidLoad

{

    [super viewDidLoad];

    context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];

    if (!context || ![EAGLContext setCurrentContext:context]) {

        NSLog(@"Failed to create ES context");

    }

    GLKView *view = (GLKView *)self.view;

    view.context = context;

    view.drawableDepthFormat = GLKViewDrawableDepthFormat16;

    mode = 1;

    glEnable(GL_DEPTH_TEST);

    // create base effects for our objects

    [self makeCircle:&innerCircle withNumOfSegments:kCircleSegments radius:kInnerCircleRadius];

    [self makeCircle:&outerCircle withNumOfSegments:kCircleSegments radius:kOuterCircleRadius];

    [self makeTeapot];

    [self makeCube];

    [self setupPlayback];

    [self createGestureRecognizers];

}

- (void)setupPlayback

{

    // initialize playback

    // the sound source (cube) starts at the center

    playback.sourcePos[0] = playback.sourcePos[1] = playback.sourcePos[2] = 0;

    // the linster (teapot) starts on the left side (in landscape)

    playback.listenerPos[0] = 0;

    playback.listenerPos[1] = (kInnerCircleRadius + kOuterCircleRadius) / 2.0;

    playback.listenerPos[2] = 0;

    // and points to the source (cube)

    playback.listenerRotation = 0;

    [playback startSound];

}

# pragma mark Create Objects

- (void)makeCircle:(BaseEffect *)circle withNumOfSegments:(GLint)segments radius:(GLfloat)radius

{

    GLfloat vertices[kCircleSegments*3];

    GLint count = 0;

    for (GLfloat i = 0; i < 360.0f; i += 360.0f/segments)

    {

        vertices[count++] = 0;                                  //x

        vertices[count++] = (cos(DegreesToRadians(i))*radius);  //y

        vertices[count++] = (sin(DegreesToRadians(i))*radius);  //z

    }

    GLKBaseEffect *effect = [[GLKBaseEffect alloc] init];

    effect.useConstantColor = YES;

    effect.constantColor = GLKVector4Make(0.2f, 0.7f, 0.2f, 1.0f);

    GLuint vertexArray, vertexBuffer;

    glGenVertexArraysOES(1, &vertexArray);

    glBindVertexArrayOES(vertexArray);

    glGenBuffers(1, &vertexBuffer);

    glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);

    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

    glEnableVertexAttribArray(GLKVertexAttribPosition);

    glVertexAttribPointer(GLKVertexAttribPosition, 3, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));

    glBindVertexArrayOES(0);

    circle->effect = [effect retain];

    circle->vertexArray = vertexArray;

    circle->vertexBuffer = vertexBuffer;

    circle->normalBuffer = 0;

    [effect release];

}

- (void)makeTeapot

{

    GLKBaseEffect *effect = [[GLKBaseEffect alloc] init];

    // material

    effect.material.ambientColor = GLKVector4Make(0.4, 0.8, 0.4, 1.0);

    effect.material.diffuseColor = GLKVector4Make(1.0, 1.0, 1.0, 1.0);

    effect.material.specularColor = GLKVector4Make(1.0, 1.0, 1.0, 1.0);

    effect.material.shininess = 100.0;

    // light0

    effect.light0.enabled = GL_TRUE;

    effect.light0.ambientColor = GLKVector4Make(0.2, 0.2, 0.2, 1.0);

    effect.light0.diffuseColor = GLKVector4Make(0.2, 0.7, 0.2, 1.0);

    effect.light0.position = GLKVector4Make(0.0, 0.0, 1.0, 0.0);

    GLuint vertexArray, vertexBuffer, normalBuffer;

    glGenVertexArraysOES(1, &vertexArray);

    glBindVertexArrayOES(vertexArray);

    // position

    glGenBuffers(1, &vertexBuffer);

    glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);

    glBufferData(GL_ARRAY_BUFFER, sizeof(teapot_vertices), teapot_vertices, GL_STATIC_DRAW);

    glEnableVertexAttribArray(GLKVertexAttribPosition);

    glVertexAttribPointer(GLKVertexAttribPosition, 3, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));

    // normal

    glGenBuffers(1, &normalBuffer);

    glBindBuffer(GL_ARRAY_BUFFER, normalBuffer);

    glBufferData(GL_ARRAY_BUFFER, sizeof(teapot_normals), teapot_normals, GL_STATIC_DRAW);

    glEnableVertexAttribArray(GLKVertexAttribNormal);

    glVertexAttribPointer(GLKVertexAttribNormal, 3, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));

    glBindVertexArrayOES(0);

    teapot.effect = [effect retain];

    teapot.vertexArray = vertexArray;

    teapot.vertexBuffer = vertexBuffer;

    teapot.normalBuffer = normalBuffer;

    [effect release];

}

-(void)makeCube

{

    // simple cube data

    // our sound source is omnidirectional, adjust the vertices

    // so that speakers in the textures point to all different directions

    const GLshort cubeVertices[6][20] = {

        //position3 texcoord2

        { 1,-1, 1, 1, 0,   -1,-1, 1, 1, 1,   1, 1, 1, 0, 0,  -1, 1, 1, 0, 1 },

        { 1, 1, 1, 1, 0,    1,-1, 1, 1, 1,   1, 1,-1, 0, 0,   1,-1,-1, 0, 1 },

        {-1, 1,-1, 1, 0,   -1,-1,-1, 1, 1,  -1, 1, 1, 0, 0,  -1,-1, 1, 0, 1 },

        { 1, 1, 1, 1, 0,   -1, 1, 1, 1, 1,   1, 1,-1, 0, 0,  -1, 1,-1, 0, 1 },

        { 1,-1,-1, 1, 0,   -1,-1,-1, 1, 1,   1, 1,-1, 0, 0,  -1, 1,-1, 0, 1 },

        { 1,-1, 1, 1, 0,   -1,-1, 1, 1, 1,   1,-1,-1, 0, 0,  -1,-1,-1, 0, 1 },

    };

    const GLushort cubeColors[6][4] = {

        {1, 0, 0, 1}, {0, 1, 0, 1}, {0, 0, 1, 1}, {1, 1, 0, 1}, {0, 1, 1, 1}, {1, 0, 1, 1},

    };

    for (int f = 0; f < 6; f++)

    {

        GLKBaseEffect *effect = [[GLKBaseEffect alloc] init];

        // texture

        effect.texture2d0.enabled = GL_TRUE;

        // texture name is set later

        // tint color

        effect.useConstantColor = GL_TRUE;

        effect.constantColor = GLKVector4Make(cubeColors[f][0], cubeColors[f][1], cubeColors[f][2], cubeColors[f][3]);

        GLuint vertexArray, vertexBuffer;

        glGenVertexArraysOES(1, &vertexArray);

        glBindVertexArrayOES(vertexArray);

        glGenBuffers(1, &vertexBuffer);

        glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);

        glBufferData(GL_ARRAY_BUFFER, sizeof(cubeVertices[f]), cubeVertices[f], GL_STATIC_DRAW);

        // position

        glEnableVertexAttribArray(GLKVertexAttribPosition);

        glVertexAttribPointer(GLKVertexAttribPosition, 3, GL_SHORT, GL_FALSE, 10, BUFFER_OFFSET(0));

        // texture cooridnates

        glEnableVertexAttribArray(GLKVertexAttribTexCoord0);

        glVertexAttribPointer(GLKVertexAttribTexCoord0, 2, GL_SHORT, GL_FALSE, 10, BUFFER_OFFSET(6));

        glBindVertexArrayOES(0);

        cube[f].effect = [effect retain];

        cube[f].vertexArray = vertexArray;

        cube[f].vertexBuffer = vertexBuffer;

        cube[f].normalBuffer = 0;

        [effect release];

    }

    UIImage *image = [UIImage imageNamed:@"speaker.png"];

    GLKTextureLoader *textureloader = [[GLKTextureLoader alloc] initWithSharegroup:context.sharegroup];

    [textureloader textureWithCGImage:image.CGImage options:nil queue:nil completionHandler:^(GLKTextureInfo *textureInfo, NSError *error) {

        if(error) {

            NSLog(@"Error loading texture %@",error);

        }

        else {

            for (int f=0; f<6; f++)

                cube[f].effect.texture2d0.name = textureInfo.name;

            cubeTexture = textureInfo.name;

        }

    }];

}

# pragma mark Draw

- (void)drawTeapotAndUpdatePlayback

{

    int start = 0, i = 0;

    rot -= 1.0f;

    GLfloat radius = (kOuterCircleRadius + kInnerCircleRadius) / 2.;

    GLfloat teapotPos[3] = {0.0f, cos(DegreesToRadians(rot))*radius, sin(DegreesToRadians(rot))*radius};

    // move clockwise along the circle

    GLKMatrix4 modelView = GLKMatrix4MakeTranslation(teapotPos[0], teapotPos[1], teapotPos[2]);

    modelView = GLKMatrix4Scale(modelView, kTeapotScale, kTeapotScale, kTeapotScale);

    // add rotation

    GLfloat rotYInRadians;

    if (mode == 2 || mode == 4)

        // in mode 2 and 4, the teapot (listener) always faces to one direction

        rotYInRadians = 0.0f;

    else

        // in mode 1 and 3, the teapot (listener) always faces to the cube (sound source)

        rotYInRadians = atan2(teapotPos[2]-cubePos[2], teapotPos[1]-cubePos[1]);

    modelView = GLKMatrix4Rotate(modelView, -M_PI_2, 0, 0, 1); //we want to display in landscape mode

    modelView = GLKMatrix4Rotate(modelView, rotYInRadians, 0, 1, 0);

    teapot.effect.transform.modelviewMatrix = modelView;

    // draw the teapot

    glBindVertexArrayOES(teapot.vertexArray);

    [teapot.effect prepareToDraw];

    while(i < num_teapot_indices) {

        if(teapot_indices[i] == -1) {

            glDrawElements(GL_TRIANGLE_STRIP, i - start, GL_UNSIGNED_SHORT, &teapot_indices[start]);

            start = i + 1;

        }

        i++;

    }

    if(start < num_teapot_indices)

        glDrawElements(GL_TRIANGLE_STRIP, i - start - 1, GL_UNSIGNED_SHORT, &teapot_indices[start]);

    // update playback

    playback.listenerPos = teapotPos; //listener's position

    playback.listenerRotation = rotYInRadians - M_PI; //listener's rotation in Radians

}

-(void)drawCube

{

    cubeRot += 3;

    GLKMatrix4 modelView = GLKMatrix4MakeTranslation(cubePos[0], cubePos[1], cubePos[2]);

    modelView = GLKMatrix4Scale(modelView, kCubeScale, kCubeScale, kCubeScale);

    if (mode <= 2)

        // origin of the teapot is at its bottom, but

        // origin of the cube is at its center, so move up a unit to put the cube on surface

        // we'll pass the bottom of the cube (cubePos) to the playback

        modelView = GLKMatrix4Translate(modelView, 1.0f, 0.0f, 0.0f);

    else

        // in mode 3 and 4, simply move up the cube a bit more to avoid colliding with the teapot

        modelView = GLKMatrix4Translate(modelView, 4.5f, 0.0f, 0.0f);

    // rotate around to simulate the omnidirectional effect

    modelView = GLKMatrix4Rotate(modelView, DegreesToRadians(cubeRot), 1, 0, 0);

    modelView = GLKMatrix4Rotate(modelView, DegreesToRadians(cubeRot), 0, 1, 1);

    for (int f=0; f<6; f++) {

        cube[f].effect.transform.modelviewMatrix = modelView;

        glBindVertexArrayOES(cube[f].vertexArray);

        [cube[f].effect prepareToDraw];

        glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

    }

}

#pragma mark - GLKView and GLKViewController delegate methods

- (void)glkView:(GLKView *)view drawInRect:(CGRect)rect

{

    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);

    glClearDepthf(1.0f);

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    GLfloat aspectRatio = (GLfloat)(view.drawableWidth) / (GLfloat)(view.drawableHeight);

    GLKMatrix4 projectionMatrix = GLKMatrix4MakeOrtho(-1.0f, 1.0f, -1.0f/aspectRatio, 1.0f/aspectRatio, -10.0f, 10.0f);

    // rotate the camara for a better view

    projectionMatrix = GLKMatrix4Rotate(projectionMatrix, DegreesToRadians(-30.0f), 0.0f, 1.0f, 0.0f);

    // set the projection matrix

    innerCircle.effect.transform.projectionMatrix = projectionMatrix;

    outerCircle.effect.transform.projectionMatrix = projectionMatrix;

    teapot.effect.transform.projectionMatrix = projectionMatrix;

    for (int f=0; f<6; f++)

        cube[f].effect.transform.projectionMatrix = projectionMatrix;

    glBindVertexArrayOES(innerCircle.vertexArray);

    [innerCircle.effect prepareToDraw];

    glDrawArrays (GL_LINE_LOOP, 0, kCircleSegments);

    glBindVertexArrayOES(outerCircle.vertexArray);

    [outerCircle.effect prepareToDraw];

    glDrawArrays (GL_LINE_LOOP, 0, kCircleSegments);

    [self drawTeapotAndUpdatePlayback];

    [self drawCube];

}

- (void)deleteBaseEffect:(BaseEffect)e

{

    if (e.vertexBuffer)

        glDeleteBuffers(1, e.vertexBuffer);

    if (e.normalBuffer)

        glDeleteBuffers(1, e.normalBuffer);

    if (e.vertexArray)

        glDeleteVertexArraysOES(1, &e.vertexArray);

    [e.effect release];

}

- (void)dealloc {

    [playback stopSound];

    [self deleteBaseEffect:innerCircle];

    [self deleteBaseEffect:outerCircle];

    [self deleteBaseEffect:teapot];

    glDeleteTextures(1, &cubeTexture);

    if ([EAGLContext currentContext] == context) {

        [EAGLContext setCurrentContext:nil];

    }

    [context release];

    [super dealloc];

}

#pragma mark - Gesture Recognizers

- (void)createGestureRecognizers

{

    // Create a single tap recognizer and add it to the view

    UITapGestureRecognizer *recognizer;

    recognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleSingleTapFrom:)];

    recognizer.delegate = (id)self;

    [self.view addGestureRecognizer:recognizer];

    [recognizer release];

}

- (IBAction)handleSingleTapFrom:(UIGestureRecognizer *)sender

{

    mode++;

    if (mode > 4) mode = 1;

    // update the position of the cube (sound source)

    // in mode 1 and 2, the teapot (sound source) is at the center of the sound stage

    // in mode 3 and 4, the teapot (sound source) is on the left side

    if (mode <= 2) {

        cubePos[0] = cubePos[1] = cubePos[2] = 0;

    }

    else {

        cubePos[0] = 0;

        cubePos[1] = (kInnerCircleRadius + kOuterCircleRadius) / 2.0;

        cubePos[2] = 0;

    }

    // update playback

    playback.sourcePos = cubePos; //sound source's position

}

@end