/*
     File: PaintingView.m
 Abstract: The class responsible for the finger painting. The class wraps the
 CAEAGLLayer from CoreAnimation into a convenient UIView subclass. The view
 content is basically an EAGL surface you render your OpenGL scene into.
  Version: 1.11

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 MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION
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 FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND
 OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS.

 IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL
 OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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*/

#import <QuartzCore/QuartzCore.h>
#import <OpenGLES/EAGLDrawable.h>

#import "PaintingView.h"

//CLASS IMPLEMENTATIONS:

// A class extension to declare private methods
@interface PaintingView (private)

- (BOOL)createFramebuffer;
- (void)destroyFramebuffer;

@end

@implementation PaintingView

@synthesize  location;
@synthesize  previousLocation;

// Implement this to override the default layer class (which is [CALayer class]).
// We do this so that our view will be backed by a layer that is capable of OpenGL ES rendering.
+ (Class) layerClass
{
    return [CAEAGLLayer class];
}

// The GL view is stored in the nib file. When it's unarchived it's sent -initWithCoder:
- (id)initWithCoder:(NSCoder*)coder {

    NSMutableArray* recordedPaths;
    CGImageRef      brushImage;
    CGContextRef    brushContext;
    GLubyte         *brushData;

    if ((self = [super initWithCoder:coder])) {

        brushScale = kBrushScale;

        CAEAGLLayer *eaglLayer = (CAEAGLLayer *)self.layer;

        eaglLayer.opaque = NO;
        // In this application, we want to retain the EAGLDrawable contents after a call to presentRenderbuffer.
        eaglLayer.drawableProperties = [NSDictionary dictionaryWithObjectsAndKeys:
                                        [NSNumber numberWithBool:YES], kEAGLDrawablePropertyRetainedBacking, kEAGLColorFormatRGBA8, kEAGLDrawablePropertyColorFormat, nil];

        context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES1];

        if (!context || ![EAGLContext setCurrentContext:context]) {
            [self release];
            return nil;
        }

        // Create a texture from an image
        // First create a UIImage object from the data in a image file, and then extract the Core Graphics image
        brushImage = [UIImage imageNamed:@"Particle.png"].CGImage;

        // Get the width and height of the image
        width = CGImageGetWidth(brushImage);
        height = CGImageGetHeight(brushImage);

        // Texture dimensions must be a power of 2. If you write an application that allows users to supply an image,
        // you'll want to add code that checks the dimensions and takes appropriate action if they are not a power of 2.

        // Make sure the image exists
        if(brushImage) {
            // Allocate  memory needed for the bitmap context
            brushData = (GLubyte *) calloc(width * height * 4, sizeof(GLubyte));
            // Use  the bitmatp creation function provided by the Core Graphics framework.
            brushContext = CGBitmapContextCreate(brushData, width, height, 8, width * 4, CGImageGetColorSpace(brushImage), kCGImageAlphaPremultipliedLast);
            // After you create the context, you can draw the  image to the context.
            CGContextDrawImage(brushContext, CGRectMake(0.0, 0.0, (CGFloat)width, (CGFloat)height), brushImage);
            // You don't need the context at this point, so you need to release it to avoid memory leaks.
            CGContextRelease(brushContext);
            // Use OpenGL ES to generate a name for the texture.
            glGenTextures(1, &brushTexture);
            // Bind the texture name.
            glBindTexture(GL_TEXTURE_2D, brushTexture);
            // Set the texture parameters to use a minifying filter and a linear filer (weighted average)
            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
            // Specify a 2D texture image, providing the a pointer to the image data in memory
            glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, brushData);
            // Release  the image data; it's no longer needed
            free(brushData);
        }

        // Set the view's scale factor
        self.contentScaleFactor = 1.0;

        // Setup OpenGL states
        glMatrixMode(GL_PROJECTION);
        CGRect frame = self.bounds;
        CGFloat scale = self.contentScaleFactor;
        // Setup the view port in Pixels
        glOrthof(0, frame.size.width * scale, 0, frame.size.height * scale, -1, 1);
        glViewport(0, 0, frame.size.width * scale, frame.size.height * scale);
        glMatrixMode(GL_MODELVIEW);

        glDisable(GL_DITHER);
        glEnable(GL_TEXTURE_2D);
        glEnableClientState(GL_VERTEX_ARRAY);

        glEnable(GL_BLEND);
        // Set a blending function appropriate for premultiplied alpha pixel data
        glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);

        glEnable(GL_POINT_SPRITE_OES);
        glTexEnvf(GL_POINT_SPRITE_OES, GL_COORD_REPLACE_OES, GL_TRUE);
        glPointSize(width / brushScale);

        // Make sure to start with a cleared buffer
        needsErase = YES;

        // Playback recorded path, which is "Shake Me"
        //recordedPaths = [NSMutableArray arrayWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"Recording" ofType:@"data"]];
        //if([recordedPaths count])
        //  [self performSelector:@selector(playback:) withObject:recordedPaths afterDelay:0.2];

    }

    return self;
}

// If our view is resized, we'll be asked to layout subviews.
// This is the perfect opportunity to also update the framebuffer so that it is
// the same size as our display area.
-(void)layoutSubviews
{
    [EAGLContext setCurrentContext:context];
    [self destroyFramebuffer];
    [self createFramebuffer];

    // Clear the framebuffer the first time it is allocated
    if (needsErase) {
        [self erase];
        needsErase = NO;
        [self renderRect];
    }
}

- (BOOL)createFramebuffer
{
    // Generate IDs for a framebuffer object and a color renderbuffer
    glGenFramebuffersOES(1, &viewFramebuffer);
    glGenRenderbuffersOES(1, &viewRenderbuffer);

    glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);
    glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
    // This call associates the storage for the current render buffer with the EAGLDrawable (our CAEAGLLayer)
    // allowing us to draw into a buffer that will later be rendered to screen wherever the layer is (which corresponds with our view).
    [context renderbufferStorage:GL_RENDERBUFFER_OES fromDrawable:(id<EAGLDrawable>)self.layer];
    glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_COLOR_ATTACHMENT0_OES, GL_RENDERBUFFER_OES, viewRenderbuffer);

    glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_WIDTH_OES, &backingWidth);
    glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_HEIGHT_OES, &backingHeight);

    // For this sample, we also need a depth buffer, so we'll create and attach one via another renderbuffer.
    glGenRenderbuffersOES(1, &depthRenderbuffer);
    glBindRenderbufferOES(GL_RENDERBUFFER_OES, depthRenderbuffer);
    glRenderbufferStorageOES(GL_RENDERBUFFER_OES, GL_DEPTH_COMPONENT16_OES, backingWidth, backingHeight);
    glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_DEPTH_ATTACHMENT_OES, GL_RENDERBUFFER_OES, depthRenderbuffer);

    if(glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES) != GL_FRAMEBUFFER_COMPLETE_OES)
    {
        NSLog(@"failed to make complete framebuffer object %x", glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES));
        return NO;
    }

    return YES;
}

// Clean up any buffers we have allocated.
- (void)destroyFramebuffer
{
    glDeleteFramebuffersOES(1, &viewFramebuffer);
    viewFramebuffer = 0;
    glDeleteRenderbuffersOES(1, &viewRenderbuffer);
    viewRenderbuffer = 0;

    if(depthRenderbuffer)
    {
        glDeleteRenderbuffersOES(1, &depthRenderbuffer);
        depthRenderbuffer = 0;
    }
}

// Releases resources when they are not longer needed.
- (void) dealloc
{
    if (brushTexture)
    {
        glDeleteTextures(1, &brushTexture);
        brushTexture = 0;
    }

    if([EAGLContext currentContext] == context)
    {
        [EAGLContext setCurrentContext:nil];
    }

    [context release];
    [super dealloc];
}

// Erases the screen
- (void) erase
{
    [EAGLContext setCurrentContext:context];

    // Clear the buffer
    glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);
    glClearColor(0.0, 0.0, 0.0, 0.0);
    glClear(GL_COLOR_BUFFER_BIT);

    // Display the buffer
    glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
    [context presentRenderbuffer:GL_RENDERBUFFER_OES];
}

// Drawings a line onscreen based on where the user touches
- (void)renderLineFromPoint:(CGPoint)start toPoint:(CGPoint)end
{
    static GLfloat*     vertexBuffer = NULL;
    static NSUInteger   vertexMax = 64;
    NSUInteger          vertexCount = 0,
                        count,
                        i;

    [EAGLContext setCurrentContext:context];
    glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);

    // Convert locations from Points to Pixels
    CGFloat scale = self.contentScaleFactor;
    start.x *= scale;
    start.y *= scale;
    end.x *= scale;
    end.y *= scale;

    // Allocate vertex array buffer
    if(vertexBuffer == NULL)
        vertexBuffer = malloc(vertexMax * 2 * sizeof(GLfloat));

    // Add points to the buffer so there are drawing points every X pixels
    count = MAX(ceilf(sqrtf((end.x - start.x) * (end.x - start.x) + (end.y - start.y) * (end.y - start.y)) / kBrushPixelStep), 1);
    for(i = 0; i < count; ++i) {
        if(vertexCount == vertexMax) {
            vertexMax = 2 * vertexMax;
            vertexBuffer = realloc(vertexBuffer, vertexMax * 2 * sizeof(GLfloat));
        }

        vertexBuffer[2 * vertexCount + 0] = start.x + (end.x - start.x) * ((GLfloat)i / (GLfloat)count);
        vertexBuffer[2 * vertexCount + 1] = start.y + (end.y - start.y) * ((GLfloat)i / (GLfloat)count);
        vertexCount += 1;
    }

    if (isEraserBrushType) {
        brushScale = 5;
        glPointSize(width / brushScale);
        glBlendFunc(GL_ZERO, GL_ONE_MINUS_SRC_ALPHA);
        glColor4f(0, 0, 0, 0.9);
    } else {
        brushScale = kBrushScale;
        glPointSize(width / brushScale);
        glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
        [self setBrushColorWithRed:brushColorRed green:brushColorGreen blue:brushColorBlue];
    }

    // Render the vertex array
    glVertexPointer(2, GL_FLOAT, 0, vertexBuffer);
    glDrawArrays(GL_POINTS, 0, vertexCount);

    // Display the buffer
    glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
    [context presentRenderbuffer:GL_RENDERBUFFER_OES];
}

- (void)renderRect {

    [EAGLContext setCurrentContext:context];
    glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);

    glLoadIdentity();

    // Replace the implementation of this method to do your own custom drawing.
    static const GLfloat squareVertices[] = {
        -15.0f, -13.0f,//-0.5f, -0.33f,
        15.0f, -13.0f,//0.5f, -0.33f,
        -15.0f, 13.0f,//-0.5f,  0.33f,
        15.0f, 13.0f,//0.5f,  0.33f,
    };

    /*static const GLubyte squareColors[] = {
        0, 0, 0, 0,
        0, 0, 0, 0,
        0, 0, 0, 0,
        0, 0, 0, 0,
    };*/

    static float transY = 0.0f;

    glTranslatef(0.0f, (GLfloat)(sinf(transY)/2.0f), 0.0f);


    // Render the color array
    //glColorPointer(4, GL_UNSIGNED_BYTE, 0, squareColors);
    //glEnableClientState(GL_COLOR_ARRAY);

    // Render the vertex array
    glVertexPointer(2, GL_FLOAT, 0, squareVertices);
    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);


    // Display the buffer
    glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
    [context presentRenderbuffer:GL_RENDERBUFFER_OES];
}

/**
 Draw a portion of a Texture2D at a point
 @param rect a CGRect bounding the portion of the texture to draw
 @param point the point to draw the texture at

-(void) drawFromRect:(CGRect)rect atPoint:(CGPoint) point {

    GLfloat  coordinates[] = {
        rect.origin.x/_width,             (rect.origin.y + rect.size.height)/_width,
        (rect.size.width+rect.origin.x)/_width,
        (rect.origin.y + rect.size.height)/_width,
        rect.origin.x/_width,       rect.origin.y/_width,
        (rect.size.width+rect.origin.x)/_width,
        rect.origin.y/_width  };


    GLfloat vertices[] = {
        -rect.size.width / 2 + point.x, -rect.size.height / 2 + point.y, 0.0,
        rect.size.width / 2 + point.x, -rect.size.height / 2 + point.y, 0.0,
        -rect.size.width / 2 + point.x, rect.size.height / 2 + point.y, 0.0,
        rect.size.width / 2 + point.x, rect.size.height / 2 + point.y, 0.0
    };


    glBindTexture(GL_TEXTURE_2D, _name);
    glVertexPointer(3, GL_FLOAT, 0, vertices);
    glTexCoordPointer(2, GL_FLOAT, 0, coordinates);
    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

}*/

// Handles the start of a touch
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    CGRect              bounds = [self bounds];
    UITouch*    touch = [[event touchesForView:self] anyObject];
    firstTouch = YES;
    // Convert touch point from UIView referential to OpenGL one (upside-down flip)
    location = [touch locationInView:self];
    location.y = bounds.size.height - location.y;
}

// Handles the continuation of a touch.
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{

    CGRect              bounds = [self bounds];
    UITouch*            touch = [[event touchesForView:self] anyObject];

    // Convert touch point from UIView referential to OpenGL one (upside-down flip)
    if (firstTouch) {
        firstTouch = NO;
        previousLocation = [touch previousLocationInView:self];
        previousLocation.y = bounds.size.height - previousLocation.y;
    } else {
        location = [touch locationInView:self];
        location.y = bounds.size.height - location.y;
        previousLocation = [touch previousLocationInView:self];
        previousLocation.y = bounds.size.height - previousLocation.y;
    }

    // Render the stroke
    [self renderLineFromPoint:previousLocation toPoint:location];
}

// Handles the end of a touch event when the touch is a tap.
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    CGRect              bounds = [self bounds];
    UITouch*    touch = [[event touchesForView:self] anyObject];
    if (firstTouch) {
        firstTouch = NO;
        previousLocation = [touch previousLocationInView:self];
        previousLocation.y = bounds.size.height - previousLocation.y;
        [self renderLineFromPoint:previousLocation toPoint:location];
    }
}

// Handles the end of a touch event.
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
{
    // If appropriate, add code necessary to save the state of the application.
    // This application is not saving state.
}

- (void)setBrushToEraser:(Boolean)value {
    isEraserBrushType = value;
}

- (void)setBrushColorWithRed:(CGFloat)red green:(CGFloat)green blue:(CGFloat)blue
{
    // Set the brush color using premultiplied alpha values
    brushColorRed = red;
    brushColorGreen = green;
    brushColorBlue = blue;

    glColor4f(red   * kBrushOpacity,
              green * kBrushOpacity,
              blue  * kBrushOpacity,
              kBrushOpacity);
}

@end