/*

    File: GLLevelMeter.m

Abstract: dB meter class for displaying audio power levels using OpenGL

 Version: 2.5

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*/

#import <QuartzCore/QuartzCore.h>

#import <OpenGLES/EAGLDrawable.h>

#import "GLLevelMeter.h"

@implementation GLLevelMeter

+ (Class) layerClass

{

    return [CAEAGLLayer class];

}

- (BOOL)_createFramebuffer

{

    glGenFramebuffersOES(1, &_viewFramebuffer);

    glGenRenderbuffersOES(1, &_viewRenderbuffer);

    glBindFramebufferOES(GL_FRAMEBUFFER_OES, _viewFramebuffer);

    glBindRenderbufferOES(GL_RENDERBUFFER_OES, _viewRenderbuffer);

    [_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);

    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;

}

- (void)_setupView

{

    // Sets up matrices and transforms for OpenGL ES

    glViewport(0, 0, _backingWidth, _backingHeight);

    glMatrixMode(GL_PROJECTION);

    glLoadIdentity();

    glOrthof(0, _backingWidth, 0, _backingHeight, -1.0f, 1.0f);

    glMatrixMode(GL_MODELVIEW);

    glEnableClientState(GL_VERTEX_ARRAY);

    glEnable(GL_BLEND);

    glDisable(GL_LINE_SMOOTH);

    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

}

- (void)_performInit

{

    _level = 0.;

    _numLights = 0;

    _numColorThresholds = 3;

    _variableLightIntensity = YES;

    _bgColor = [[UIColor alloc] initWithRed:0. green:0. blue:0. alpha:0.6];

    _borderColor = [[UIColor alloc] initWithRed:0. green:0. blue:0. alpha:1.];

    _colorThresholds = (LevelMeterColorThreshold*)malloc(3 * sizeof(LevelMeterColorThreshold));

    _colorThresholds[0].maxValue = 0.6;

    _colorThresholds[0].color = [[UIColor alloc] initWithRed:0. green:1. blue:0. alpha:1.];

    _colorThresholds[1].maxValue = 0.9;

    _colorThresholds[1].color = [[UIColor alloc] initWithRed:1. green:1. blue:0. alpha:1.];

    _colorThresholds[2].maxValue = 1.;

    _colorThresholds[2].color = [[UIColor alloc] initWithRed:1. green:0. blue:0. alpha:1.];

    _vertical = ([self frame].size.width < [self frame].size.height) ? YES : NO;

    if ([self respondsToSelector:@selector(setContentScaleFactor:)]){

        _scaleFactor = self.contentScaleFactor = [[UIScreen mainScreen] scale];

    } else {

        _scaleFactor = 1.0;

    }

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

    self.opaque = NO;

    eaglLayer.opaque = NO;

    eaglLayer.drawableProperties = [NSDictionary dictionaryWithObjectsAndKeys:

                                    [NSNumber numberWithBool:FALSE], kEAGLDrawablePropertyRetainedBacking, kEAGLColorFormatRGBA8, kEAGLDrawablePropertyColorFormat, nil];

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

    if(!_context || ![EAGLContext setCurrentContext:_context] || ![self _createFramebuffer]) {

        [self release];

        return;

    }

    [self _setupView];

}

- (void)_drawView

{

    //BOOL success = NO;

    if (!_viewFramebuffer) return;

    // Make sure that you are drawing to the current context

    [EAGLContext setCurrentContext:_context];

    glBindFramebufferOES(GL_FRAMEBUFFER_OES, _viewFramebuffer);

    CGColorRef bgc = self.bgColor.CGColor;

    if (CGColorGetNumberOfComponents(bgc) != 4) goto bail;

    const CGFloat *bg_rgba;

    bg_rgba = CGColorGetComponents(bgc);

    glClearColor(0., 0., 0., 0.);

    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);

    glPushMatrix();

    CGRect bds;

    if (_vertical)

    {

        glTranslatef(0., [self bounds].size.height, 0.);

        glScalef(1., -1., 1.);

        bds = CGRectMake(0., -1., [self bounds].size.width * _scaleFactor, [self bounds].size.height * _scaleFactor);

    } else {

        glTranslatef(0., [self bounds].size.height * _scaleFactor, 0.);

        glRotatef(-90., 0., 0., 1.);

        bds = CGRectMake(0., 1., [self bounds].size.height * _scaleFactor, [self bounds].size.width * _scaleFactor);

    }

    if (_numLights == 0)

    {

        int i;

        CGFloat currentTop = 0.;

        for (i=0; i<_numColorThresholds; i++)

        {

            LevelMeterColorThreshold thisThresh = _colorThresholds[i];

            CGFloat val = MIN(thisThresh.maxValue, _level);

            CGRect rect = CGRectMake(

                                     0, 

                                     (bds.size.height) * currentTop, 

                                     bds.size.width, 

                                     (bds.size.height) * (val - currentTop)

                                     );

            GLfloat vertices[] = {

                CGRectGetMinX(rect), CGRectGetMinY(rect),  

                CGRectGetMaxX(rect), CGRectGetMinY(rect),  

                CGRectGetMinX(rect), CGRectGetMaxY(rect),  

                CGRectGetMaxX(rect), CGRectGetMaxY(rect),  

            };

            CGColorRef clr = thisThresh.color.CGColor;

            if (CGColorGetNumberOfComponents(clr) != 4) goto bail;

            const CGFloat *rgba;

            rgba = CGColorGetComponents(clr);

            glColor4f(rgba[0], rgba[1], rgba[2], rgba[3]);

            glVertexPointer(2, GL_FLOAT, 0, vertices);

            glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

            if (_level < thisThresh.maxValue) break;

            currentTop = val;

        }

    }

    else

    {

        int light_i;

        CGFloat lightMinVal = 0.;

        CGFloat insetAmount, lightVSpace;

        lightVSpace = bds.size.height / (CGFloat)_numLights;

        if (lightVSpace < 4.) insetAmount = 0.;

        else if (lightVSpace < 8.) insetAmount = 0.5;

        else insetAmount = 1.;

        int peakLight = -1;

        if (_peakLevel > 0.)

        {

            peakLight = _peakLevel * _numLights;

            if (peakLight >= _numLights) peakLight = _numLights - 1;

        }

        for (light_i=0; light_i<_numLights; light_i++)

        {

            CGFloat lightMaxVal = (CGFloat)(light_i + 1) / (CGFloat)_numLights;

            CGFloat lightIntensity;

            CGRect lightRect;

            UIColor *lightColor;

            if (light_i == peakLight)

            {

                lightIntensity = 1.;

            } else {

                lightIntensity = (_level - lightMinVal) / (lightMaxVal - lightMinVal);

                lightIntensity = LEVELMETER_CLAMP(0., lightIntensity, 1.);

                if ((!_variableLightIntensity) && (lightIntensity > 0.)) lightIntensity = 1.;

            }

            lightColor = _colorThresholds[0].color;

            int color_i;

            for (color_i=0; color_i<(_numColorThresholds-1); color_i++)

            {

                LevelMeterColorThreshold thisThresh = _colorThresholds[color_i];

                LevelMeterColorThreshold nextThresh = _colorThresholds[color_i + 1];

                if (thisThresh.maxValue <= lightMaxVal) lightColor = nextThresh.color;

            }

            lightRect = CGRectMake(

                                   0., 

                                   bds.size.height * ((CGFloat)(light_i) / (CGFloat)_numLights), 

                                   bds.size.width,

                                   bds.size.height * (1. / (CGFloat)_numLights)

                                   );

            lightRect = CGRectInset(lightRect, insetAmount, insetAmount);

            GLfloat vertices[] = {

                CGRectGetMinX(lightRect), CGRectGetMinY(lightRect),  

                CGRectGetMaxX(lightRect), CGRectGetMinY(lightRect),  

                CGRectGetMinX(lightRect), CGRectGetMaxY(lightRect),  

                CGRectGetMaxX(lightRect), CGRectGetMaxY(lightRect),  

            };

            CGColorRef clr = lightColor.CGColor;

            if (CGColorGetNumberOfComponents(clr) != 4) goto bail;

            const CGFloat *rgba;

            rgba = CGColorGetComponents(clr);

            glVertexPointer(2, GL_FLOAT, 0, vertices);

            glColor4f(bg_rgba[0], bg_rgba[1], bg_rgba[2], bg_rgba[3]);

            glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

            GLfloat lightAlpha = rgba[3] * lightIntensity;

            if ((lightIntensity < 1.) && (lightIntensity > 0.) && (lightAlpha > .8)) lightAlpha = .8;

            glColor4f(rgba[0], rgba[1], rgba[2], lightAlpha);

            glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

            lightMinVal = lightMaxVal;

        }

    }

    //success = YES;

bail:   

    glPopMatrix();

    glFlush();

    glBindRenderbufferOES(GL_RENDERBUFFER_OES, _viewRenderbuffer);

    [_context presentRenderbuffer:GL_RENDERBUFFER_OES];

}   

- (void)layoutSubviews

{

    [EAGLContext setCurrentContext:_context];

    [self _destroyFramebuffer];

    [self _createFramebuffer];

    [self _drawView];

}

- (void)drawRect:(CGRect)rect

{

    [self _drawView];

}

- (void)setNeedsDisplay

{

    [self _drawView];

}

- (void)dealloc

{

    if([EAGLContext currentContext] == _context) {

        [EAGLContext setCurrentContext:nil];

    }

    [_context release];

    _context = nil;

    [super dealloc];

}

@end