/*

    File: EAGLView.m

Abstract: The EAGLView class is responsible for rendering the GL view.

 Version: 1.6

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*/

#import <QuartzCore/QuartzCore.h>

#import <OpenGLES/EAGLDrawable.h>

#import "EAGLView.h"

#import "PVRTexture.h"

#define USE_DEPTH_BUFFER    0

// A class extension to declare private methods

@interface EAGLView ()

@property (nonatomic, retain) EAGLContext *context;

- (BOOL)createFramebuffer;

- (void)destroyFramebuffer;

- (void)updateSettings;

@end

@implementation EAGLView

@synthesize compressionSupported = _compressionSupported;

@synthesize anisotropySupported = _anisotropySupported;

@dynamic compressionSetting;

@dynamic mipmapFilterSetting;

@dynamic filterSetting;

@synthesize context = _context;

- (void)loadImageFile:(NSString *)name ofType:(NSString *)extension mipmap:(BOOL)mipmap texture:(uint32_t)texture

{

    UIImage *image;

    size_t width, height;

    CGImageRef cgImage;

    GLubyte *data;

    CGContextRef cgContext;

    CGColorSpaceRef colorSpace;

    GLenum err;

    image = [UIImage imageWithContentsOfFile:[[NSBundle mainBundle] pathForResource:name ofType:extension]];

    if (image == nil)

    {

        NSLog(@"Failed to load %@.%@", name, extension);

        return;

    }

    cgImage = [image CGImage];

    width = CGImageGetWidth(cgImage);

    height = CGImageGetHeight(cgImage);

    colorSpace = CGColorSpaceCreateDeviceRGB();

    // Malloc may be used instead of calloc if your cg image has dimensions equal to the dimensions of the cg bitmap context

    data = (GLubyte *)calloc(width * height * 4, sizeof(GLubyte));

    cgContext = CGBitmapContextCreate(data, width, height, 8, width * 4, colorSpace, kCGImageAlphaPremultipliedLast);

    if (cgContext != NULL)

    {

        // Set the blend mode to copy. We don't care about the previous contents.

        CGContextSetBlendMode(cgContext, kCGBlendModeCopy);

        CGContextDrawImage(cgContext, CGRectMake(0.0f, 0.0f, width, height), cgImage);

        glGenTextures(1, &(_textures[texture]));

        glBindTexture(GL_TEXTURE_2D, _textures[texture]);

        if (mipmap)

            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);

        else

            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, (int)width, (int)height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);

        if (mipmap)

            glGenerateMipmapOES(GL_TEXTURE_2D);

        err = glGetError();

        if (err != GL_NO_ERROR)

            NSLog(@"Error uploading texture. glError: 0x%04X", err);

        CGContextRelease(cgContext);

    }

    free(data);

    CGColorSpaceRelease(colorSpace);

}

- (void)loadTextures

{

    if (_compressionSupported)

    {

        PVRTexture *pvrTexture;

        NSArray *names = [NSArray arrayWithObjects:@"Brick_mipmap_4", @"Brick_mipmap_2", @"Brick_4", @"Brick_2", nil];

        [EAGLContext setCurrentContext:_context];

        [_pvrTextures removeAllObjects];

        for (int i=0; i < [names count]; i++)

        {

            pvrTexture = [PVRTexture pvrTextureWithContentsOfFile:[[NSBundle mainBundle] pathForResource:[names objectAtIndex:i] ofType:@"pvr"]];

            if (pvrTexture == nil)

                NSLog(@"Failed to load %@.pvr", [names objectAtIndex:i]);

            else {

                _textures[i] = [pvrTexture name];

                [_pvrTextures addObject:pvrTexture];

            }

        }

    }

    [self loadImageFile:@"Brick" ofType:@"png" mipmap:TRUE texture:kTextureMipmap];

    [self loadImageFile:@"Brick" ofType:@"png" mipmap:FALSE texture:kTexture];

}

// You must implement this method

+ (Class)layerClass

{

    return [CAEAGLLayer class];

}

- (Compression)compressionSetting

{

    return _compressionSetting;

}

- (MipmipFilter)mipmapFilterSetting

{

    return _mipmapFilterSetting;

}

- (Filter)filterSetting

{

    return _filterSetting;

}

- (void)setCompressionSetting:(Compression)setting

{

    _compressionSetting = setting;

    [self updateSettings];

    [self drawView];

}

- (void)setMipmapFilterSetting:(MipmipFilter)setting

{

    _mipmapFilterSetting = setting;

    [self updateSettings];

    [self drawView];

}

- (void)setFilterSetting:(Filter)setting

{

    _filterSetting = setting;

    [self updateSettings];

    [self drawView];

}

- (void)updateSettings

{

    // choose texture name

    if (_mipmapFilterSetting == kMipmapFilterOff)

    {

        if (_compressionSetting == kCompressionFourBPP)

            _texSelection = kTexturePvrtc4;

        else if (_compressionSetting == kCompressionTwoBPP)

            _texSelection = kTexturePvrtc2;

        else if (_compressionSetting == kCompressionOff)

            _texSelection = kTexture;

    }

    else

    {

        if (_compressionSetting == kCompressionFourBPP)

            _texSelection = kTexturePvrtcMipmap4;

        else if (_compressionSetting == kCompressionTwoBPP)

            _texSelection = kTexturePvrtcMipmap2;

        else if (_compressionSetting == kCompressionOff)

            _texSelection = kTextureMipmap;

    }

    // choose filter settings

    if (_mipmapFilterSetting == kMipmapFilterOff)

    {

        if (_filterSetting == kFilterNearest)

        {

            _minTexParam = GL_NEAREST;

            _magTexParam = GL_NEAREST;

        }

        else if (_filterSetting == kFilterLinear || _filterSetting == kFilterSuper)

        {

            _minTexParam = GL_LINEAR;

            _magTexParam = GL_LINEAR;

        }

    }

    else if (_mipmapFilterSetting == kMipmapFilterNearest)

    {

        if (_filterSetting == kFilterNearest)

        {

            _minTexParam = GL_NEAREST_MIPMAP_NEAREST;

            _magTexParam = GL_NEAREST;

        }

        else if (_filterSetting == kFilterLinear || _filterSetting == kFilterSuper)

        {

            _minTexParam = GL_LINEAR_MIPMAP_NEAREST;

            _magTexParam = GL_LINEAR;

        }

    }

    else if (_mipmapFilterSetting == kMipmapFilterLinear)

    {

        if (_filterSetting == kFilterNearest)

        {

            _minTexParam = GL_NEAREST_MIPMAP_LINEAR;

            _magTexParam = GL_NEAREST;

        }

        else if (_filterSetting == kFilterLinear || _filterSetting == kFilterSuper)

        {

            _minTexParam = GL_LINEAR_MIPMAP_LINEAR;

            _magTexParam = GL_LINEAR;

        }

    }

    if (_filterSetting == kFilterSuper)

        _anisotropyTexParam = 2.0f;

    else

        _anisotropyTexParam = 1.0f;

}

- (BOOL)extensionSupported:(NSString *)name

{

    NSString *extensionsString = [NSString stringWithCString:(char *)glGetString(GL_EXTENSIONS) encoding:NSUTF8StringEncoding];

    NSArray *extensionsNames = [extensionsString componentsSeparatedByString:@" "];

    return [extensionsNames containsObject:name];

}

// The GL view is stored in the nib file. When it's unarchived it's sent -initWithCoder:

- (id)initWithCoder:(NSCoder*)coder

{    

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

    {

        // Get the layer

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

        eaglLayer.opaque = YES;

        eaglLayer.drawableProperties = [NSDictionary dictionaryWithObjectsAndKeys:

                                        [NSNumber numberWithBool:NO], kEAGLDrawablePropertyRetainedBacking, kEAGLColorFormatRGBA8, kEAGLDrawablePropertyColorFormat, nil];

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

        if (!_context || ![EAGLContext setCurrentContext:_context])

        {

            [self release];

            return nil;

        }

        _scale = 1.5f;

        _rotate = 0.0f;

        _compressionSetting = kCompressionOff;

        _mipmapFilterSetting = kMipmapFilterOff;

        _filterSetting = kFilterNearest;

        _texSelection = kTexture;

        _minTexParam = GL_NEAREST;

        _magTexParam = GL_NEAREST;

        _anisotropyTexParam = 1.0f;

        // PVRTC textures will not be loaded if the PVRTC extension is not supported.

        // UI selection for compression levels will also be disabled.

        _compressionSupported = [self extensionSupported:@"GL_IMG_texture_compression_pvrtc"];

        // The use of GL_TEXTURE_MAX_ANISOTROPY_EXT will be avoided if anisotropic filtering is not supported.

        // UI selection for anisotropic filtering will also be disabled.

        _anisotropySupported = [self extensionSupported:@"GL_EXT_texture_filter_anisotropic"];

        _pvrTextures = [[NSMutableArray alloc] initWithCapacity:10];

        [self loadTextures];

        [self setMultipleTouchEnabled:YES];

    }

    return self;

}

- (void)drawView

{

    const GLfloat squareVertices[] = {

        -1.0f, -1.0f,

         1.0f, -1.0f,

        -1.0f,  1.0f,

         1.0f,  1.0f

    };

    const GLfloat squareTexCoords[] = {

        0.0, 1.0,

        1.0, 1.0,

        0.0, 0.0,

        1.0, 0.0

    };

    GLenum err;

    [EAGLContext setCurrentContext:_context];

    glBindFramebufferOES(GL_FRAMEBUFFER_OES, _viewFramebuffer);

    glViewport(0, 0, _backingWidth, _backingHeight);

    GLfloat aspectRatio = (GLfloat)(_backingWidth)/(GLfloat)(_backingHeight);

    glMatrixMode(GL_PROJECTION);

    glLoadIdentity();

    glFrustumf(-1.0f, 1.0f, -1.0/aspectRatio, 1.0/aspectRatio, 1.0f, 10.0f);

    glMatrixMode(GL_MODELVIEW);

    glLoadIdentity();

    glScalef(_scale, _scale, 1.0f);

    glTranslatef(0.0f, 0.0f, -2.0f);

    glRotatef(_rotate, 1.0f, 0.0f, 0.0f);

    glClearColor(0.5f, 0.5f, 0.5f, 1.0f);

    glClear(GL_COLOR_BUFFER_BIT);

    glVertexPointer(2, GL_FLOAT, 0, squareVertices);

    glEnableClientState(GL_VERTEX_ARRAY);

    glTexCoordPointer(2, GL_FLOAT, 0, squareTexCoords);

    glEnableClientState(GL_TEXTURE_COORD_ARRAY);

    glEnable(GL_TEXTURE_2D);

    glBindTexture(GL_TEXTURE_2D, _textures[_texSelection]);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, _minTexParam);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, _magTexParam);

    if (_anisotropySupported)

        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT, _anisotropyTexParam);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

    glDisable(GL_TEXTURE_2D);

    glBindRenderbufferOES(GL_RENDERBUFFER_OES, _viewRenderbuffer);

    [_context presentRenderbuffer:GL_RENDERBUFFER_OES];

    err = glGetError();

    if (err != GL_NO_ERROR)

        NSLog(@"Error in frame. glError: 0x%04X", err);

}

- (void)layoutSubviews

{

    [EAGLContext setCurrentContext:_context];

    [self destroyFramebuffer];

    [self createFramebuffer];

    [self drawView];

}

- (BOOL)createFramebuffer

{

    glGenFramebuffersOES(1, &_viewFramebuffer);

    glGenRenderbuffersOES(1, &_viewRenderbuffer);

    glBindFramebufferOES(GL_FRAMEBUFFER_OES, _viewFramebuffer);

    glBindRenderbufferOES(GL_RENDERBUFFER_OES, _viewRenderbuffer);

    [_context renderbufferStorage:GL_RENDERBUFFER_OES fromDrawable:(CAEAGLLayer*)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);

    if (USE_DEPTH_BUFFER)

    {

        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;

}

- (void)destroyFramebuffer

{    

    glDeleteFramebuffersOES(1, &_viewFramebuffer);

    _viewFramebuffer = 0;

    glDeleteRenderbuffersOES(1, &_viewRenderbuffer);

    _viewRenderbuffer = 0;

    if(_depthRenderbuffer)

    {

        glDeleteRenderbuffersOES(1, &_depthRenderbuffer);

        _depthRenderbuffer = 0;

    }

}

- (void)dealloc

{

    if ([EAGLContext currentContext] == _context)

        [EAGLContext setCurrentContext:nil];

    if (_textures[kTexture] != 0)

        glDeleteTextures(1, &_textures[kTexture]);

    if (_textures[kTextureMipmap] != 0)

        glDeleteTextures(1, &_textures[kTextureMipmap]);

    [_pvrTextures release];

    [_context release];

    [super dealloc];

}

- (float)distanceFromPoint:(CGPoint)pointA toPoint:(CGPoint)pointB

{

    float xD = fabs(pointA.x - pointB.x);

    float yD = fabs(pointA.y - pointB.y);

    return sqrt(xD*xD + yD*yD);

}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event

{

    UITouch *touchA, *touchB;

    CGPoint pointA, pointB;

    if ([touches count] == 1)

    {

        touchA = [[touches allObjects] objectAtIndex:0];

        pointA = [touchA locationInView:self];

        pointB = [touchA previousLocationInView:self];

        float yDistance = pointA.y - pointB.y;

        _rotate += 0.5 * yDistance;

        [self drawView];

    }

    else if ([touches count] == 2)

    {

        touchA = [[touches allObjects] objectAtIndex:0];

        touchB = [[touches allObjects] objectAtIndex:1];

        pointA = [touchA locationInView:self];

        pointB = [touchB locationInView:self];

        float currDistance = [self distanceFromPoint:pointA toPoint:pointB];

        pointA = [touchA previousLocationInView:self];

        pointB = [touchB previousLocationInView:self];

        float prevDistance = [self distanceFromPoint:pointA toPoint:pointB];

        _scale += 0.005 * (currDistance - prevDistance);

        if (_scale > 10.0f)

            _scale = 10.0f;

        else if (_scale < 0.025f)

            _scale = 0.025f;

        [self drawView];

    }

}

@end