Add ability to change display windows is on and check display count

Author: Kasparsu

docs/modules/dome.md

@@ -80,6 +80,9 @@ Returns the generic name of the operating system or platform, where possible.
 #### `time: Number`
 Returns the integer number of seconds since the unix epoch (1st January 1970).
 
+#### `displayCount: Number`
+Returns the integer number of displays on the system.
+
 ## Process
 
 ### Static Fields
@@ -144,6 +147,10 @@ Default is `false`.
 
 This is the height of the window/viewport, in pixels.
 
+#### `static display: Number`
+
+This is the display window is rendered on. Default is `0` which is users primary/main display. When going out of bounds (less than `0` or more than number of displays) will automatically loop back around 
+
 #### `static integerScale: Boolean`
 
 If set to true, the Canvas within the Window will be scaled by integer scaling factors only. This is useful for avoiding the "fat-pixel" look

src/modules/dome.c

@@ -114,6 +114,33 @@ WINDOW_getHeight(WrenVM* vm) {
   wrenSetSlotDouble(vm, 0, height);
 }
 
+internal void
+WINDOW_setDisplay(WrenVM* vm) {
+  ENGINE* engine = (ENGINE*)wrenGetUserData(vm);
+  ASSERT_SLOT_TYPE(vm, 1, NUM, "display");
+  int32_t display = wrenGetSlotDouble(vm, 1);
+  if(display < 0) {
+    display = SDL_GetNumVideoDisplays() - 1;
+  }
+  DISPLAY = display;
+  uint32_t flags = SDL_GetWindowFlags(engine->window);
+  bool fullscreen = (flags & SDL_WINDOW_FULLSCREEN_DESKTOP) != 0;
+  if(fullscreen) {
+    SDL_SetWindowFullscreen(engine->window, SDL_WINDOW_SHOWN);
+  }
+  SDL_SetWindowPosition(engine->window, SDL_WINDOWPOS_CENTERED_DISPLAY(DISPLAY), SDL_WINDOWPOS_CENTERED_DISPLAY(DISPLAY));
+  if(fullscreen) {
+    SDL_SetWindowFullscreen(engine->window, SDL_WINDOW_FULLSCREEN_DESKTOP);
+  }
+}
+
+internal void
+WINDOW_getDisplay(WrenVM* vm) {
+  ENGINE* engine = (ENGINE*)wrenGetUserData(vm);
+  int display = SDL_GetWindowDisplayIndex(engine->window);
+  wrenSetSlotDouble(vm, 0, display);
+}
+
 internal void
 WINDOW_setTitle(WrenVM* vm) {
   ENGINE* engine = (ENGINE*)wrenGetUserData(vm);

src/modules/dome.wren

@@ -115,6 +115,8 @@ class Process {
 
 
 class Window {
+  foreign static display=(value)
+  foreign static display
   foreign static title=(value)
   foreign static title
   foreign static vsync=(value)

src/modules/platform.c

@@ -9,3 +9,9 @@ PLATFORM_getName(WrenVM* vm) {
   wrenEnsureSlots(vm, 1);
   wrenSetSlotString(vm, 0, SDL_GetPlatform());
 }
+
+internal void
+PLATFORM_getDisplayCount(WrenVM* vm) {
+  int displays = SDL_GetNumVideoDisplays();
+  wrenSetSlotDouble(vm, 0, displays);
+}

src/modules/platform.wren

@@ -1,4 +1,5 @@
 class Platform {
   foreign static time
   foreign static name
+  foreign static displayCount
 }

src/vm.c

@@ -184,6 +184,8 @@ internal WrenVM* VM_create(ENGINE* engine) {
   MAP_addFunction(&engine->moduleMap, "dome", "static Log.print(_,_,_)", LOG_print);
   MAP_addFunction(&engine->moduleMap, "dome", "static Log.f_level=(_)", LOG_setLevel);
   MAP_addFunction(&engine->moduleMap, "dome", "static Log.level", LOG_getLevel);
+  MAP_addFunction(&engine->moduleMap, "dome", "static Window.display=(_)", WINDOW_setDisplay);
+  MAP_addFunction(&engine->moduleMap, "dome", "static Window.display", WINDOW_getDisplay);
   MAP_addFunction(&engine->moduleMap, "dome", "static Window.title=(_)", WINDOW_setTitle);
   MAP_addFunction(&engine->moduleMap, "dome", "static Window.title", WINDOW_getTitle);
   MAP_addFunction(&engine->moduleMap, "dome", "static Window.integerScale=(_)", WINDOW_setIntegerScale);
@@ -338,6 +340,7 @@ internal WrenVM* VM_create(ENGINE* engine) {
   // Platform
   MAP_addFunction(&engine->moduleMap, "platform", "static Platform.time", PLATFORM_getTime);
   MAP_addFunction(&engine->moduleMap, "platform", "static Platform.name", PLATFORM_getName);
+  MAP_addFunction(&engine->moduleMap, "platform", "static Platform.displayCount", PLATFORM_getDisplayCount);
   MAP_lockModule(&engine->moduleMap, "platform");
 
   // Plugin