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Classes/GLLevelMeter.m

/*

<codex>

*/

#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);

    // Clears the view with black

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

    glEnableClientState(GL_VERTEX_ARRAY);

    ///glEnableClientState(GL_TEXTURE_COORD_ARRAY);

- (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;

    eaglLayer.opaque = YES;

    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

    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 *rgba;

    rgba = CGColorGetComponents(bgc);

    glClearColor(rgba[0], rgba[1], rgba[2], 1.);

    //glClearColor(0., 0., 0., 1.);

    glClear(GL_COLOR_BUFFER_BIT);

    glPushMatrix();

    CGRect bds;

    if (_vertical)

        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)

);

            NSLog(@"Drawing rect (%0.2f, %0.2f, %0.2f, %0.2f)", rect.origin.x, rect.origin.y, rect.size.width, rect.size.height);

            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.origin.y * (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),

};

            glVertexPointer(2, GL_FLOAT, 0, vertices);

            glColor4f(1., 0., 0., 1.);

            if (lightIntensity == 1.)

                //[lightColor set];

                CGColorRef clr = lightColor.CGColor;

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

                const CGFloat *rgba;

                rgba = CGColorGetComponents(clr);

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

                glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

            } else if (lightIntensity > 0.) {

                //CGColorRef clr = CGColorCreateCopyWithAlpha([lightColor CGColor], lightIntensity);

                //CGContextSetFillColorWithColor(cxt, clr);

                CGColorRef clr = lightColor.CGColor;

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

                const CGFloat *rgba;

                rgba = CGColorGetComponents(clr);

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

                glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

                //CGColorRelease(clr);

            lightMinVal = lightMaxVal;

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

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