1/*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2020 Sam Lantinga <slouken@libsdl.org>
4
5  This software is provided 'as-is', without any express or implied
6  warranty.  In no event will the authors be held liable for any damages
7  arising from the use of this software.
8
9  Permission is granted to anyone to use this software for any purpose,
10  including commercial applications, and to alter it and redistribute it
11  freely, subject to the following restrictions:
12
13  1. The origin of this software must not be misrepresented; you must not
14     claim that you wrote the original software. If you use this software
15     in a product, an acknowledgment in the product documentation would be
16     appreciated but is not required.
17  2. Altered source versions must be plainly marked as such, and must not be
18     misrepresented as being the original software.
19  3. This notice may not be removed or altered from any source distribution.
20*/
21#include "../../SDL_internal.h"
22
23#if SDL_VIDEO_DRIVER_UIKIT && (SDL_VIDEO_OPENGL_ES || SDL_VIDEO_OPENGL_ES2)
24
25#include "SDL_uikitopengles.h"
26#import "SDL_uikitopenglview.h"
27#include "SDL_uikitmodes.h"
28#include "SDL_uikitwindow.h"
29#include "SDL_uikitevents.h"
30#include "../SDL_sysvideo.h"
31#include "../../events/SDL_keyboard_c.h"
32#include "../../events/SDL_mouse_c.h"
33#include "../../power/uikit/SDL_syspower.h"
34#include "SDL_loadso.h"
35#include <dlfcn.h>
36
37@interface SDLEAGLContext : EAGLContext
38
39/* The OpenGL ES context owns a view / drawable. */
40@property (nonatomic, strong) SDL_uikitopenglview *sdlView;
41
42@end
43
44@implementation SDLEAGLContext
45
46- (void)dealloc
47{
48    /* When the context is deallocated, its view should be removed from any
49     * SDL window that it's attached to. */
50    [self.sdlView setSDLWindow:NULL];
51}
52
53@end
54
55void *
56UIKit_GL_GetProcAddress(_THIS, const char *proc)
57{
58    /* Look through all SO's for the proc symbol.  Here's why:
59     * -Looking for the path to the OpenGL Library seems not to work in the iOS Simulator.
60     * -We don't know that the path won't change in the future. */
61    return dlsym(RTLD_DEFAULT, proc);
62}
63
64/*
65  note that SDL_GL_DeleteContext makes it current without passing the window
66*/
67int
68UIKit_GL_MakeCurrent(_THIS, SDL_Window * window, SDL_GLContext context)
69{
70    @autoreleasepool {
71        SDLEAGLContext *eaglcontext = (__bridge SDLEAGLContext *) context;
72
73        if (![EAGLContext setCurrentContext:eaglcontext]) {
74            return SDL_SetError("Could not make EAGL context current");
75        }
76
77        if (eaglcontext) {
78            [eaglcontext.sdlView setSDLWindow:window];
79        }
80    }
81
82    return 0;
83}
84
85void
86UIKit_GL_GetDrawableSize(_THIS, SDL_Window * window, int * w, int * h)
87{
88    @autoreleasepool {
89        SDL_WindowData *data = (__bridge SDL_WindowData *)window->driverdata;
90        UIView *view = data.viewcontroller.view;
91        if ([view isKindOfClass:[SDL_uikitopenglview class]]) {
92            SDL_uikitopenglview *glview = (SDL_uikitopenglview *) view;
93            if (w) {
94                *w = glview.backingWidth;
95            }
96            if (h) {
97                *h = glview.backingHeight;
98            }
99        } else {
100            SDL_GetWindowSize(window, w, h);
101        }
102    }
103}
104
105int
106UIKit_GL_LoadLibrary(_THIS, const char *path)
107{
108    /* We shouldn't pass a path to this function, since we've already loaded the
109     * library. */
110    if (path != NULL) {
111        return SDL_SetError("iOS GL Load Library just here for compatibility");
112    }
113    return 0;
114}
115
116int UIKit_GL_SwapWindow(_THIS, SDL_Window * window)
117{
118    @autoreleasepool {
119        SDLEAGLContext *context = (__bridge SDLEAGLContext *) SDL_GL_GetCurrentContext();
120
121#if SDL_POWER_UIKIT
122        /* Check once a frame to see if we should turn off the battery monitor. */
123        SDL_UIKit_UpdateBatteryMonitoring();
124#endif
125
126        [context.sdlView swapBuffers];
127
128        /* You need to pump events in order for the OS to make changes visible.
129         * We don't pump events here because we don't want iOS application events
130         * (low memory, terminate, etc.) to happen inside low level rendering. */
131    }
132    return 0;
133}
134
135SDL_GLContext
136UIKit_GL_CreateContext(_THIS, SDL_Window * window)
137{
138    @autoreleasepool {
139        SDLEAGLContext *context = nil;
140        SDL_uikitopenglview *view;
141        SDL_WindowData *data = (__bridge SDL_WindowData *) window->driverdata;
142        CGRect frame = UIKit_ComputeViewFrame(window, data.uiwindow.screen);
143        EAGLSharegroup *sharegroup = nil;
144        CGFloat scale = 1.0;
145        int samples = 0;
146        int major = _this->gl_config.major_version;
147        int minor = _this->gl_config.minor_version;
148
149        /* The EAGLRenderingAPI enum values currently map 1:1 to major GLES
150         * versions. */
151        EAGLRenderingAPI api = major;
152
153        /* iOS currently doesn't support GLES >3.0. iOS 6 also only supports up
154         * to GLES 2.0. */
155        if (major > 3 || (major == 3 && (minor > 0 || !UIKit_IsSystemVersionAtLeast(7.0)))) {
156            SDL_SetError("OpenGL ES %d.%d context could not be created", major, minor);
157            return NULL;
158        }
159
160        if (_this->gl_config.multisamplebuffers > 0) {
161            samples = _this->gl_config.multisamplesamples;
162        }
163
164        if (_this->gl_config.share_with_current_context) {
165            EAGLContext *context = (__bridge EAGLContext *) SDL_GL_GetCurrentContext();
166            sharegroup = context.sharegroup;
167        }
168
169        if (window->flags & SDL_WINDOW_ALLOW_HIGHDPI) {
170            /* Set the scale to the natural scale factor of the screen - the
171             * backing dimensions of the OpenGL view will match the pixel
172             * dimensions of the screen rather than the dimensions in points. */
173            if ([data.uiwindow.screen respondsToSelector:@selector(nativeScale)]) {
174                scale = data.uiwindow.screen.nativeScale;
175            } else {
176                scale = data.uiwindow.screen.scale;
177            }
178        }
179
180        context = [[SDLEAGLContext alloc] initWithAPI:api sharegroup:sharegroup];
181        if (!context) {
182            SDL_SetError("OpenGL ES %d context could not be created", _this->gl_config.major_version);
183            return NULL;
184        }
185
186        /* construct our view, passing in SDL's OpenGL configuration data */
187        view = [[SDL_uikitopenglview alloc] initWithFrame:frame
188                                                    scale:scale
189                                            retainBacking:_this->gl_config.retained_backing
190                                                    rBits:_this->gl_config.red_size
191                                                    gBits:_this->gl_config.green_size
192                                                    bBits:_this->gl_config.blue_size
193                                                    aBits:_this->gl_config.alpha_size
194                                                depthBits:_this->gl_config.depth_size
195                                              stencilBits:_this->gl_config.stencil_size
196                                                     sRGB:_this->gl_config.framebuffer_srgb_capable
197                                             multisamples:samples
198                                                  context:context];
199
200        if (!view) {
201            return NULL;
202        }
203
204        /* The context owns the view / drawable. */
205        context.sdlView = view;
206
207        if (UIKit_GL_MakeCurrent(_this, window, (__bridge SDL_GLContext) context) < 0) {
208            UIKit_GL_DeleteContext(_this, (SDL_GLContext) CFBridgingRetain(context));
209            return NULL;
210        }
211
212        /* We return a +1'd context. The window's driverdata owns the view (via
213         * MakeCurrent.) */
214        return (SDL_GLContext) CFBridgingRetain(context);
215    }
216}
217
218void
219UIKit_GL_DeleteContext(_THIS, SDL_GLContext context)
220{
221    @autoreleasepool {
222        /* The context was retained in SDL_GL_CreateContext, so we release it
223         * here. The context's view will be detached from its window when the
224         * context is deallocated. */
225        CFRelease(context);
226    }
227}
228
229void
230UIKit_GL_RestoreCurrentContext(void)
231{
232    @autoreleasepool {
233        /* Some iOS system functionality (such as Dictation on the on-screen
234         keyboard) uses its own OpenGL ES context but doesn't restore the
235         previous one when it's done. This is a workaround to make sure the
236         expected SDL-created OpenGL ES context is active after the OS is
237         finished running its own code for the frame. If this isn't done, the
238         app may crash or have other nasty symptoms when Dictation is used.
239         */
240        EAGLContext *context = (__bridge EAGLContext *) SDL_GL_GetCurrentContext();
241        if (context != NULL && [EAGLContext currentContext] != context) {
242            [EAGLContext setCurrentContext:context];
243        }
244    }
245}
246
247#endif /* SDL_VIDEO_DRIVER_UIKIT */
248
249/* vi: set ts=4 sw=4 expandtab: */
250