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MyOpenGLView.m

/*

 File: MyOpenGLView.m

 Abstract: An NSOpenGLView subclass that demonstrates fundamental techniques

 to obtain optimal textuture upload performance.

 Version: 1.0

 Disclaimer: IMPORTANT:  This Apple software is supplied to you by

 Apple Inc. ("Apple") in consideration of your agreement to the

 following terms, and your use, installation, modification or

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 install, modify or redistribute this Apple software.

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 "Apple Software"), to use, reproduce, modify and redistribute the Apple

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 may be used to endorse or promote products derived from the Apple

 Software without specific prior written permission from Apple.  Except

 as expressly stated in this notice, no other rights or licenses, express

 or implied, are granted by Apple herein, including but not limited to

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 The Apple Software is provided by Apple on an "AS IS" basis.  APPLE

 MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION

 THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS

 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

 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

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 Copyright (C) 2010 Apple Inc. All Rights Reserved.

*/

#import "MyOpenGLView.h"

#import <OpenGL/glu.h>

@interface MyOpenGLView (PrivateMethods)

- (void) initGL;

- (BOOL) initImageData;

- (void) loadTexturesWithClientStorage;

- (void) drawView;

@end

@implementation MyOpenGLView

- (CVReturn) getFrameForTime:(const CVTimeStamp*)outputTime

    // There is no autorelease pool when this method is called because it will be called from a background thread

    // It's important to create one or you will leak objects

    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

    [self drawView];

    [pool release];

    return kCVReturnSuccess;

// This is the renderer output callback function

static CVReturn MyDisplayLinkCallback(CVDisplayLinkRef displayLink, const CVTimeStamp* now, const CVTimeStamp* outputTime, CVOptionFlags flagsIn, CVOptionFlags* flagsOut, void* displayLinkContext)

    CVReturn result = [(MyOpenGLView*)displayLinkContext getFrameForTime:outputTime];

    return result;

- (id) initWithFrame:(NSRect)frameRect

    NSOpenGLPixelFormatAttribute attrs[] =

        NSOpenGLPFAAccelerated,

        NSOpenGLPFANoRecovery,

        NSOpenGLPFADoubleBuffer,

        NSOpenGLPFADepthSize, 24,

};

    NSOpenGLPixelFormat *pf = [[NSOpenGLPixelFormat alloc] initWithAttributes:attrs];

    if (!pf)

        NSLog(@"No OpenGL pixel format");

    if (self = [super initWithFrame:frameRect pixelFormat:[pf autorelease]])

        [self initGL];

        // Create a display link capable of being used with all active displays

        CVDisplayLinkCreateWithActiveCGDisplays(&displayLink);

        // Set the renderer output callback function

        CVDisplayLinkSetOutputCallback(displayLink, &MyDisplayLinkCallback, self);

        // Set the display link for the current renderer

        CGLContextObj cglContext = [[self openGLContext] CGLContextObj];

        CGLPixelFormatObj cglPixelFormat = [[self pixelFormat] CGLPixelFormatObj];

        CVDisplayLinkSetCurrentCGDisplayFromOpenGLContext(displayLink, cglContext, cglPixelFormat);

        // Activate the display link

        CVDisplayLinkStart(displayLink);

        data = nil;

    return self;

- (void) initGL

    [[self openGLContext] makeCurrentContext];

    // Synchronize buffer swaps with vertical refresh rate

    GLint swapInt = 1;

    [[self openGLContext] setValues:&swapInt forParameter:NSOpenGLCPSwapInterval];

    // Create OpenGL textures

    if ([self initImageData])

        [self loadTexturesWithClientStorage];

    glEnable(GL_DEPTH_TEST);

    glEnableClientState(GL_VERTEX_ARRAY);

    glEnableClientState(GL_TEXTURE_COORD_ARRAY);

- (void) loadTexturesWithClientStorage

    int i;

    glGenTextures(TEXTURE_COUNT, texIds);

    // Enable the rectangle texture extenstion

    glEnable(GL_TEXTURE_RECTANGLE_EXT);

    // Eliminate a data copy by the OpenGL driver using the Apple texture range extension along with the rectangle texture extension

    // This specifies an area of memory to be mapped for all the textures. It is useful for tiled or multiple textures in contiguous memory.

    glTextureRangeAPPLE(GL_TEXTURE_RECTANGLE_EXT, TEXTURE_WIDTH * TEXTURE_HEIGHT * 4 * TEXTURE_COUNT, data);

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

        // Bind the rectange texture

        glBindTexture(GL_TEXTURE_RECTANGLE_EXT, texIds[i]);

        // Set a CACHED or SHARED storage hint for requesting VRAM or AGP texturing respectively

        // GL_STORAGE_PRIVATE_APPLE is the default and specifies normal texturing path

        glTexParameteri(GL_TEXTURE_RECTANGLE_EXT, GL_TEXTURE_STORAGE_HINT_APPLE , GL_STORAGE_CACHED_APPLE);

        // Eliminate a data copy by the OpenGL framework using the Apple client storage extension

        glPixelStorei(GL_UNPACK_CLIENT_STORAGE_APPLE, GL_TRUE);

        // Rectangle textures has its limitations compared to using POT textures, for example,

        // Rectangle textures can't use mipmap filtering

        glTexParameteri(GL_TEXTURE_RECTANGLE_EXT, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

        glTexParameteri(GL_TEXTURE_RECTANGLE_EXT, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

        // Rectangle textures can't use the GL_REPEAT warp mode

        glTexParameteri(GL_TEXTURE_RECTANGLE_EXT, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);

        glTexParameteri(GL_TEXTURE_RECTANGLE_EXT, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

        glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);

        // OpenGL likes the GL_BGRA + GL_UNSIGNED_INT_8_8_8_8_REV combination

        glTexImage2D(GL_TEXTURE_RECTANGLE_EXT, 0, GL_RGBA, TEXTURE_WIDTH, TEXTURE_HEIGHT, 0,

                     GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, &data[TEXTURE_WIDTH * TEXTURE_HEIGHT * 4 * i]);

    glBindTexture(GL_TEXTURE_RECTANGLE_EXT, 0);

- (BOOL) getImageData:(GLubyte*)imageData fromPath:(NSString*)path

    NSUInteger              width, height;

    NSURL                   *url = nil;

    CGImageSourceRef        src;

    CGImageRef              image;

    CGContextRef            context = nil;

    CGColorSpaceRef         colorSpace;

    url = [NSURL fileURLWithPath: path];

    src = CGImageSourceCreateWithURL((CFURLRef)url, NULL);

    if (!src) {

        NSLog(@"No image");

        return NO;

    image = CGImageSourceCreateImageAtIndex(src, 0, NULL);

    CFRelease(src);

    width = CGImageGetWidth(image);

    height = CGImageGetHeight(image);

    colorSpace = CGColorSpaceCreateDeviceRGB();

    context = CGBitmapContextCreate(imageData, width, height, 8, 4 * width, colorSpace, kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Host);

    CGColorSpaceRelease(colorSpace);

    // Core Graphics referential is upside-down compared to OpenGL referential

    // Flip the Core Graphics context here

    // An alternative is to use flipped OpenGL texture coordinates when drawing textures

    CGContextTranslateCTM(context, 0.0, height);

    CGContextScaleCTM(context, 1.0, -1.0);

    // Set the blend mode to copy before drawing since the previous contents of memory aren't used. This avoids unnecessary blending.

    CGContextSetBlendMode(context, kCGBlendModeCopy);

    CGContextDrawImage(context, CGRectMake(0, 0, width, height), image);

    CGContextRelease(context);

    CGImageRelease(image);

    return YES;

- (BOOL) initImageData

    int i;

    // This holds the data of all textures

    data = (GLubyte*) calloc(TEXTURE_WIDTH * TEXTURE_HEIGHT * 4 * TEXTURE_COUNT, sizeof(GLubyte));

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

        NSString *path = [[NSBundle mainBundle] pathForResource:[NSString stringWithFormat:@"%d", i] ofType:@"jpg"];

        if (!path) {

            NSLog(@"No valid path");

            return NO;

        // Point to the current texture

        GLubyte *imageData = &data[TEXTURE_WIDTH * TEXTURE_HEIGHT * 4 * i];

        if (![self getImageData:imageData fromPath:path])

            return NO;

    return YES;

- (void) reshape

    // We draw on a secondary thread through the display link

    // When resizing the view, -reshape is called automatically on the main thread

    // Add a mutex around to avoid the threads accessing the context simultaneously when resizing

    CGLLockContext([[self openGLContext] CGLContextObj]);

    NSRect rect = [self bounds];

    glViewport(0, 0, rect.size.width, rect.size.height);

    glMatrixMode(GL_PROJECTION);

    glLoadIdentity();

    glOrtho(-1.0f, 1.0f, -1.0f, 1.0f, -10.0f, 10.0f);

    glMatrixMode(GL_MODELVIEW);

    CGLUnlockContext([[self openGLContext] CGLContextObj]);

- (void) drawView

    // Cube data

    const GLfloat vertices[6][12] = {

        {-1, 1,-1,  -1, 1, 1,  -1,-1, 1,  -1,-1,-1 }, //-x

        { 1,-1,-1,   1,-1, 1,   1, 1, 1,   1, 1,-1 }, //+x

        {-1,-1,-1,  -1,-1, 1,   1,-1, 1,   1,-1,-1 }, //-y

        { 1, 1,-1,   1, 1, 1,  -1, 1, 1,  -1, 1,-1 }, //+y

        { 1,-1,-1,   1, 1,-1,  -1, 1,-1,  -1,-1,-1 }, //-z

        {-1,-1, 1,  -1, 1, 1,   1, 1, 1,   1,-1, 1 }, //+z

};

    // Rectangle textures require non-normalized texture coordinates

    const GLfloat texcoords[] = {

        0,              0,

        0,              TEXTURE_HEIGHT,

        TEXTURE_WIDTH,  TEXTURE_HEIGHT,

        TEXTURE_WIDTH,  0,

};

    int f, t;

    // We draw on a secondary thread through the display link

    // When resizing the view, -reshape is called automatically on the main thread

    // Add a mutex around to avoid the threads accessing the context simultaneously when resizing

    CGLLockContext([[self openGLContext] CGLContextObj]);

    [[self openGLContext] makeCurrentContext];

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

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glPushMatrix();

    glScalef(0.5f, 0.5f, 0.5f);

    glRotatef(rot, 1, 1, 0);

    glRotatef(rot, 0, 1, 0);

    rot += 0.8;

    glTexCoordPointer(2, GL_FLOAT, 0, texcoords);

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

        t = f % TEXTURE_COUNT;

        glBindTexture(GL_TEXTURE_RECTANGLE_EXT, texIds[t]);

        glVertexPointer(3, GL_FLOAT, 0, vertices[f]);

        glDrawArrays(GL_QUADS, 0, 4);

    glPopMatrix();

    glBindTexture(GL_TEXTURE_RECTANGLE_EXT, 0);

    [[self openGLContext] flushBuffer];

    CGLUnlockContext([[self openGLContext] CGLContextObj]);

- (void) dealloc

    glDeleteTextures(TEXTURE_COUNT, texIds);

    if (usePBO)

        glDeleteBuffers(TEXTURE_COUNT, pboIds);

    // When using client storage, we should keep the data around until the textures are deleted

    if (data) {

        free(data);

        data = nil;

    // Release the display link

    CVDisplayLinkRelease(displayLink);

    [super dealloc];

@end

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