Make window mono by default;

The window is now mono by default to make the error screen better and better enable non-stereo uses.  The Camera can now request that the window be treated as stereo.

src/graphics/graphics.c

@@ -137,6 +137,7 @@ void lovrGraphicsSetCamera(Camera* camera, bool clear) {
 
   if (!camera) {
     state.camera.canvas = NULL;
+    state.camera.stereo = false;
     for (int i = 0; i < 2; i++) {
       mat4_identity(state.camera.viewMatrix[i]);
       mat4_perspective(state.camera.projection[i], .01f, 100.f, 67 * M_PI / 180., (float) state.width / state.height);
@@ -414,7 +415,7 @@ void lovrGraphicsDraw(DrawOptions* draw) {
   }
 
   Canvas* canvas = state.pipelines[state.pipeline].canvas ? state.pipelines[state.pipeline].canvas : state.camera.canvas;
-  bool stereo = !draw->forceMono && (!canvas || lovrCanvasIsStereo(canvas));
+  bool stereo = !draw->forceMono && (canvas ? lovrCanvasIsStereo(canvas) : state.camera.stereo);
   float w = (canvas ? lovrCanvasGetWidth(canvas) : state.width) >> stereo;
   float h = canvas ? lovrCanvasGetHeight(canvas) : state.height;
   int viewportCount = 1 + stereo;

src/graphics/graphics.h

@@ -95,6 +95,7 @@ typedef struct {
 } GraphicsStats;
 
 typedef struct {
+  bool stereo;
   Canvas* canvas;
   float viewMatrix[2][16];
   float projection[2][16];

src/headset/fake.c

@@ -282,7 +282,7 @@ static void fakeRenderTo(void (*callback)(void*), void* userdata) {
 
   int width, height;
   fakeGetDisplayDimensions(&width, &height);
-  Camera camera = { .canvas = NULL };
+  Camera camera = { .canvas = NULL, .stereo = true };
   mat4_perspective(camera.projection[0], state.clipNear, state.clipFar, 67 * M_PI / 180., (float) width / 2 / height);
   mat4_identity(camera.viewMatrix[0]);
   mat4_translate(camera.viewMatrix[0], 0, state.offset, 0);

src/headset/webvr.c

@@ -90,7 +90,7 @@ static void onFrame(float* leftView, float* rightView, float* leftProjection, fl
   int width, height;
   webvrGetDisplayDimensions(&width, &height);
 
-  Camera camera = { .canvas = NULL };
+  Camera camera = { .canvas = NULL, .stereo = true };
   memcpy(camera.projection[0], leftProjection, 16 * sizeof(float));
   memcpy(camera.projection[1], rightProjection, 16 * sizeof(float));
   memcpy(camera.viewMatrix[0], leftView, 16 * sizeof(float));