在iPhone上绘制屏幕缓冲区的最快方法

我有一个“软件渲染器”,我正在从PC移植到iPhone。在iPhone上用像素缓冲区手动更新屏幕的最快方法是什么?例如,在Windows中,我找到的最快的函数是setdibitstodevice。

我不太了解iPhone或库,而且似乎有很多层和不同类型的UI元素,所以我可能需要很多解释…

现在我只需要不断更新OpenGL中的纹理并将其呈现到屏幕上,我非常怀疑这是否是最好的方法。

更新:

我尝试过OpenGL屏幕大小的纹理方法:

我得了17FPS…

我用的是512x512纹理(因为它需要2的力量)

只是…的召唤

glTexSubImage2D(GL_TEXTURE_2D,0,0,0,512,512,GL_RGBA,GL_UNSIGNED_BYTE, baseWindowGUI->GetBuffer());

似乎对所有的减速都有很大的责任。

把它注释掉,然后把所有的图形用户界面代码和现在未更新的纹理的渲染留在我的软件中,结果是60帧每秒,30%的渲染器使用率,CPU没有显著的峰值。

注意,getbuffer()只是返回一个指向GUI系统的软件backbuffer的指针,缓冲区不需要重新编译或调整大小,它的大小和格式适合纹理,所以我可以肯定,速度的减慢与软件渲染器无关,这是个好消息,如果我能找到一种方法在60时更新屏幕,软件渲染暂时可以工作。

我尝试用512320而不是512512进行更新纹理调用,这是奇怪的,甚至更慢…它以10fps的速度运行,并且说渲染利用率只有5%,所有的时间都浪费在调用OpenGles中的untWiddle32bpp上。

我可以将我的软件渲染改为本地渲染为任何像素格式,如果它会导致更直接的blit。

仅供参考,在2.2.1 iPod touch G2上测试(就像在类固醇上测试iPhone 3G一样)

更新2:

我刚写完coreanimation/graphics方法,看起来不错,但我有点担心它如何更新屏幕的每一帧,基本上放弃了旧的cgimage,创建了一个全新的cgimage…在下面的“someRandomFunction”中查看: 这是更新图像的最快方法吗?任何帮助都将不胜感激。

//
//  catestAppDelegate.m
//  catest
//
//  Created by User on 3/14/10.
//  Copyright __MyCompanyName__ 2010. All rights reserved.
//




#import "catestAppDelegate.h"
#import "catestViewController.h"
#import "QuartzCore/QuartzCore.h"

const void* GetBytePointer(void* info)
{
    // this is currently only called once
    return info; // info is a pointer to the buffer
}

void ReleaseBytePointer(void*info, const void* pointer)
{
    // don't care, just using the one static buffer at the moment
}


size_t GetBytesAtPosition(void* info, void* buffer, off_t position, size_t count)
{
    // I don't think this ever gets called
    memcpy(buffer, ((char*)info) + position, count);
    return count;
}

CGDataProviderDirectCallbacks providerCallbacks =
{ 0, GetBytePointer, ReleaseBytePointer, GetBytesAtPosition, 0 };


static CGImageRef cgIm;

static CGDataProviderRef dataProvider;
unsigned char* imageData;
 const size_t imageDataSize = 320 * 480 * 4;
NSTimer *animationTimer;
NSTimeInterval animationInterval= 1.0f/60.0f;


@implementation catestAppDelegate

@synthesize window;
@synthesize viewController;


- (void)applicationDidFinishLaunching:(UIApplication *)application {    


    [window makeKeyAndVisible];


    const size_t byteRowSize = 320 * 4;
    imageData = malloc(imageDataSize);

    for(int i=0;i<imageDataSize/4;i++)
            ((unsigned int*)imageData)[i] = 0xFFFF00FF; // just set it to some random init color, currently yellow


    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    dataProvider =
    CGDataProviderCreateDirect(imageData, imageDataSize,
                               &providerCallbacks);  // currently global

    cgIm = CGImageCreate
    (320, 480,
     8, 32, 320*4, colorSpace,
     kCGImageAlphaNone | kCGBitmapByteOrder32Little,
     dataProvider, 0, false, kCGRenderingIntentDefault);  // also global, probably doesn't need to be

    self.window.layer.contents = cgIm; // set the UIWindow's CALayer's contents to the image, yay works!

   // CGImageRelease(cgIm);  // we should do this at some stage...
   // CGDataProviderRelease(dataProvider);

    animationTimer = [NSTimer scheduledTimerWithTimeInterval:animationInterval target:self selector:@selector(someRandomFunction) userInfo:nil repeats:YES];
    // set up a timer in the attempt to update the image

}
float col = 0;

-(void)someRandomFunction
{
    // update the original buffer
    for(int i=0;i<imageDataSize;i++)
        imageData[i] = (unsigned char)(int)col;

    col+=256.0f/60.0f;

    // and currently the only way I know how to apply that buffer update to the screen is to
    // create a new image and bind it to the layer...???
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

    cgIm = CGImageCreate
    (320, 480,
     8, 32, 320*4, colorSpace,
     kCGImageAlphaNone | kCGBitmapByteOrder32Little,
     dataProvider, 0, false, kCGRenderingIntentDefault);

    CGColorSpaceRelease(colorSpace);

    self.window.layer.contents = cgIm;

    // and that currently works, updating the screen, but i don't know how well it runs...
}


- (void)dealloc {
    [viewController release];
    [window release];
    [super dealloc];
}


@end