Give lovrCanvasCreateFromHandle the option of not deleting framebuffer on canvas delete, also fix default texture issue

src/graphics/canvas.h

@@ -24,7 +24,7 @@ typedef struct {
 typedef struct Canvas Canvas;
 
 Canvas* lovrCanvasCreate(int width, int height, CanvasFlags flags);
-Canvas* lovrCanvasCreateFromHandle(int width, int height, CanvasFlags flags, uint32_t handle, int attachmentCount);
+Canvas* lovrCanvasCreateFromHandle(int width, int height, CanvasFlags flags, uint32_t handle, int attachmentCount, bool immortal);
 void lovrCanvasDestroy(void* ref);
 const Attachment* lovrCanvasGetAttachments(Canvas* canvas, int* count);
 void lovrCanvasSetAttachments(Canvas* canvas, Attachment* attachments, int count);

src/graphics/opengl.c

@@ -135,6 +135,7 @@ struct Canvas {
   int attachmentCount;
   bool needsAttach;
   bool needsResolve;
+  bool immortal;
 };
 
 typedef struct {
@@ -1232,7 +1233,7 @@ Canvas* lovrCanvasCreate(int width, int height, CanvasFlags flags) {
   return canvas;
 }
 
-Canvas* lovrCanvasCreateFromHandle(int width, int height, CanvasFlags flags, uint32_t handle, int attachmentCount) {
+Canvas* lovrCanvasCreateFromHandle(int width, int height, CanvasFlags flags, uint32_t handle, int attachmentCount, bool immortal) {
   Canvas* canvas = lovrAlloc(Canvas, lovrCanvasDestroy);
   if (!canvas) return NULL;
 
@@ -1241,15 +1242,18 @@ Canvas* lovrCanvasCreateFromHandle(int width, int height, CanvasFlags flags, uin
   canvas->width = width;
   canvas->height = height;
   canvas->flags = flags;
+  canvas->immortal = immortal;
 
   return canvas;
 }
 
 void lovrCanvasDestroy(void* ref) {
   Canvas* canvas = ref;
-  glDeleteFramebuffers(1, &canvas->framebuffer);
-  glDeleteRenderbuffers(1, &canvas->depthBuffer);
-  glDeleteFramebuffers(1, &canvas->resolveBuffer);
+  if (!canvas->immortal) {
+    glDeleteFramebuffers(1, &canvas->framebuffer);
+    glDeleteRenderbuffers(1, &canvas->depthBuffer);
+    glDeleteFramebuffers(1, &canvas->resolveBuffer);
+  }
   for (int i = 0; i < canvas->attachmentCount; i++) {
     lovrRelease(canvas->attachments[i].texture);
   }

src/headset/oculus_mobile.c

@@ -10,8 +10,10 @@ static void (*renderCallback)(void*);
 static void* renderUserdata;
 
 void lovrOculusMobileDraw(int framebuffer, int width, int height, float *eyeViewMatrix, float *projectionMatrix) {
+  lovrGpuDirtyTexture();
+
   CanvasFlags flags = {0};
-  Canvas *canvas = lovrCanvasCreateFromHandle(width, height, flags, framebuffer, 1);
+  Canvas *canvas = lovrCanvasCreateFromHandle(width, height, flags, framebuffer, 1, true);
 
   Camera camera = { .canvas = canvas, .stereo = false };
   memcpy(camera.viewMatrix[0], eyeViewMatrix, sizeof(camera.viewMatrix[0]));