src/video/uikit/SDL_uikitopengles.m

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2011 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/

#include "SDL_uikitopengles.h"
#include "SDL_uikitopenglview.h"
#include "SDL_uikitappdelegate.h"
#include "SDL_uikitwindow.h"
#include "jumphack.h"
#include "SDL_sysvideo.h"
#include "../../events/SDL_keyboard_c.h"
#include "../../events/SDL_mouse_c.h"
#include "SDL_loadso.h"
#include <dlfcn.h>

static int UIKit_GL_Initialize(_THIS);

void *
UIKit_GL_GetProcAddress(_THIS, const char *proc)
{    
    /* Look through all SO's for the proc symbol.  Here's why:
       -Looking for the path to the OpenGL Library seems not to work in the iPhone Simulator.
       -We don't know that the path won't change in the future.
    */
    return dlsym(RTLD_DEFAULT, proc);
}

/*
    note that SDL_GL_Delete context makes it current without passing the window
*/
int UIKit_GL_MakeCurrent(_THIS, SDL_Window * window, SDL_GLContext context)
{
    
    if (context) {
        SDL_WindowData *data = (SDL_WindowData *)window->driverdata;
        [data->view setCurrentContext];
    }
    else {
        [EAGLContext setCurrentContext: nil];
    }
        
    return 0;
}

int
UIKit_GL_LoadLibrary(_THIS, const char *path)
{
    /* 
        shouldn't be passing a path into this function 
        why?  Because we've already loaded the library
        and because the SDK forbids loading an external SO
    */
    if (path != NULL) {
        SDL_SetError("iPhone GL Load Library just here for compatibility");
        return -1;
    }
    return 0;
}

extern void SDL_UIKit_UpdateBatteryMonitoring(void);

void UIKit_GL_SwapWindow(_THIS, SDL_Window * window)
{
    #ifdef SDL_POWER_UIKIT
    // Check once a frame to see if we should turn off the battery monitor.
    SDL_UIKit_UpdateBatteryMonitoring();
    #endif

    SDL_WindowData *data = (SDL_WindowData *)window->driverdata;
    
    if (nil == data->view) {
        return;
    }
    [data->view swapBuffers];
    /* since now we've got something to draw
       make the window visible */
    [data->uiwindow makeKeyAndVisible];

    /* we need to let the event cycle run, or the OS won't update the OpenGL view! */
    SDL_PumpEvents();
    
}

SDL_GLContext UIKit_GL_CreateContext(_THIS, SDL_Window * window)
{
    SDL_uikitopenglview *view;
    SDL_WindowData *data = (SDL_WindowData *) window->driverdata;
    UIScreen *uiscreen = (UIScreen *) SDL_GetDisplayForWindow(window)->driverdata;
    UIWindow *uiwindow = data->uiwindow;

    /* construct our view, passing in SDL's OpenGL configuration data */
    view = [[SDL_uikitopenglview alloc] initWithFrame: [uiwindow bounds] \
                                    retainBacking: _this->gl_config.retained_backing \
                                    rBits: _this->gl_config.red_size \
                                    gBits: _this->gl_config.green_size \
                                    bBits: _this->gl_config.blue_size \
                                    aBits: _this->gl_config.alpha_size \
                                    depthBits: _this->gl_config.depth_size \
                                    majorVersion: _this->gl_config.major_version];
    
    data->view = view;
    view->viewcontroller = data->viewcontroller;
    if (view->viewcontroller != nil) {
        [view->viewcontroller setView:view];
        [view->viewcontroller retain];
    }

    /* add the view to our window */
    [uiwindow addSubview: view ];

    if ( UIKit_GL_MakeCurrent(_this, window, view) < 0 ) {
        UIKit_GL_DeleteContext(_this, view);
        return NULL;
    }

    /* Make this window the current mouse focus for touch input */
    SDL_SetMouseFocus(window);
    SDL_SetKeyboardFocus(window);

    return view;
}

void UIKit_GL_DeleteContext(_THIS, SDL_GLContext context)
{
    /* the delegate has retained the view, this will release him */
    SDL_uikitopenglview *view = (SDL_uikitopenglview *)context;
    if (view->viewcontroller) {
        [view->viewcontroller setView:nil];
        [view->viewcontroller release];
    }
    [view removeFromSuperview];
    [view release];
}

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