Comment utiliser OpenGL ES sur un thread séparé sur l'iphone?

Merci, Fistman. J'ai fait le travail et a obtenu le gain de performance que j'attendais de l'aide d'un thread séparé. EAGLSharegroup résolu le problème.

J'ai créé le cadre pour le deuxième thread comme décrit ici.

Ici est le code standard:

#import <UIKit/UIKit.h>
#import <OpenGLES/EAGL.h>
#import <OpenGLES/ES1/gl.h>
#import <OpenGLES/ES1/glext.h>
#import <QuartzCore/QuartzCore.h>
#import <OpenGLES/EAGLDrawable.h>
struct OpenGLContext
{
GLint Width;
GLint Height;
GLuint RenderBuffer;
GLuint FrameBuffer;
GLuint DepthBuffer;
UIView* View;
EAGLContext* MainContext;
EAGLContext* WorkingContext;
EAGLSharegroup* Sharegroup; 
//Trivial constructor.
OpenGLContext();
//Call on the main thread before use.
//I call it in layoutSubviews.
//view must not be nil.
void MainInit(UIView* view);
//Call on the rendering thread before use, but
//after MainInit();
void InitOnSecondaryThread();   
//Call before any OpenGL ES calls, at the
//beginning of each frame.
void PrepareBuffers();
//Present frame. Call at the end of each
//frame.
void SwapBuffers();
};
OpenGLContext::OpenGLContext()
{
Width = 0;
Height = 0;
RenderBuffer = 0;
FrameBuffer = 0;
DepthBuffer = 0;
View = 0;
MainContext = 0;
WorkingContext = 0;
Sharegroup = 0; 
}
void OpenGLContext::InitOnSecondaryThread()
{
EAGLSharegroup* group = MainContext.sharegroup;
if (!group)
{
NSLog(@"Could not get sharegroup from the main context");
}
WorkingContext = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES1 sharegroup:group];
if (!WorkingContext || ![EAGLContext setCurrentContext:WorkingContext]) {
NSLog(@"Could not create WorkingContext");
}
}
void OpenGLContext::MainInit(UIView* view)
{
View = view;
MainContext = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES1];
if (!MainContext || ![EAGLContext setCurrentContext:MainContext]) {
NSLog(@"Could not create EAGLContext"); 
return;
}
NSLog(@"Main EAGLContext created");     
glGenFramebuffersOES(1, &FrameBuffer);
glGenRenderbuffersOES(1, &RenderBuffer);
glGenRenderbuffersOES(1, &DepthBuffer);
glBindFramebufferOES(GL_FRAMEBUFFER_OES, FrameBuffer);
glBindRenderbufferOES(GL_RENDERBUFFER_OES, RenderBuffer);
if (![MainContext renderbufferStorage:GL_RENDERBUFFER_OES fromDrawable:(CAEAGLLayer*)View.layer])
{
NSLog(@"error calling MainContext renderbufferStorage");
return;
}
glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_COLOR_ATTACHMENT0_OES, GL_RENDERBUFFER_OES, RenderBuffer);
glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_WIDTH_OES, &Width);
glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_HEIGHT_OES, &Height);
glBindRenderbufferOES(GL_RENDERBUFFER_OES, DepthBuffer);
glRenderbufferStorageOES(GL_RENDERBUFFER_OES, GL_DEPTH_COMPONENT16_OES, Width, Height);
glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_DEPTH_ATTACHMENT_OES, GL_RENDERBUFFER_OES, DepthBuffer);
glFlush();
if(glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES) != GL_FRAMEBUFFER_COMPLETE_OES) {
NSLog(@"failed to make complete framebuffer object %x", glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES));
}
WorkingContext = MainContext;
}
void OpenGLContext::PrepareBuffers()
{   
if (!WorkingContext || [EAGLContext setCurrentContext:WorkingContext] == NO)
{
NSLog(@"PrepareBuffers: [EAGLContext setCurrentContext:WorkingContext] failed");
return;
}
glBindFramebufferOES(GL_FRAMEBUFFER_OES, FrameBuffer);  
}
void OpenGLContext::SwapBuffers()
{
if (!WorkingContext || [EAGLContext setCurrentContext:WorkingContext] == NO)
{
NSLog(@"SwapBuffers: [EAGLContext setCurrentContext:WorkingContext] failed");
return;
}
glBindRenderbufferOES(GL_RENDERBUFFER_OES, RenderBuffer);
if([WorkingContext presentRenderbuffer:GL_RENDERBUFFER_OES] == NO)
{
NSLog(@"SwapBuffers: [WorkingContext presentRenderbuffer:GL_RENDERBUFFER_OES] failed");
}   
}