camera: Fix rotations on iOS.

Author: icculus

src/camera/coremedia/SDL_camera_coremedia.m

@@ -29,12 +29,8 @@
 #import <AVFoundation/AVFoundation.h>
 #import <CoreMedia/CoreMedia.h>
 
-// this is a codepath that tracks iOS device orientation to try to correct
-// video frame rotation, but currently it looks like iOS is doing this work
-// for us, and better. This is disabled for now, so the code lives in revision
-// control before I remove it outright.
 #if defined(SDL_PLATFORM_IOS) && !defined(SDL_PLATFORM_TVOS)
-//#define USE_UIKIT_DEVICE_ROTATION
+#define USE_UIKIT_DEVICE_ROTATION
 #endif
 
 #ifdef USE_UIKIT_DEVICE_ROTATION
@@ -242,12 +238,26 @@ static SDL_CameraFrameResult COREMEDIA_AcquireFrame(SDL_Camera *device, SDL_Surf
         hidden.last_device_orientation = device_orientation;  // update the last known-good orientation for later.
     }
 
-    switch (device_orientation) {
-        case UIDeviceOrientationPortrait: *rotation = 0; break;
-        case UIDeviceOrientationPortraitUpsideDown: *rotation = 180; break;
-        case UIDeviceOrientationLandscapeRight: *rotation = 90; break;  // !!! FIXME: might be backwards.
-        case UIDeviceOrientationLandscapeLeft: *rotation = 270; break;  // !!! FIXME: might be backwards.
-        default: SDL_assert(!"Unexpected device orientation!"); *rotation = 0; break;
+    const UIInterfaceOrientation ui_orientation = [UIApplication sharedApplication].statusBarOrientation;
+
+    // there is probably math for this, but this is easy to slap into a table.
+    // rotation = rotations[uiorientation-1][devorientation-1];
+    if (device->position == SDL_CAMERA_POSITION_BACK_FACING) {
+        static const int back_rotations[4][4] = {
+            {   90,  90,  90,  90 },  // ui portrait
+            {  270, 270, 270, 270 },  // ui portait upside down
+            {    0,   0,   0,   0 },  // ui landscape left
+            {  180, 180, 180, 180 }   // ui landscape right
+        };
+        *rotation = back_rotations[ui_orientation - 1][device_orientation - 1];
+    } else {
+        static const int front_rotations[4][4] = {
+            {   90,  90, 270, 270 },  // ui portrait
+            {  270, 270,  90,  90 },  // ui portait upside down
+            {    0,   0, 180, 180 },  // ui landscape left
+            {  180, 180,   0,   0 }   // ui landscape right
+        };
+        *rotation = front_rotations[ui_orientation - 1][device_orientation - 1];
     }
     #endif