[ion] Fix the emscripten build

Change-Id: Ia54c5de4191c47d9840854d9aad12f87a9110da3

ion/src/emscripten/display.cpp

@@ -0,0 +1,56 @@
+#include "display.h"
+extern "C" {
+#include <SDL/SDL.h>
+#include <assert.h>
+}
+
+SDL_Surface * screen = nullptr;
+
+namespace Ion {
+namespace Display {
+
+void pushRect(KDRect r, const KDColor * pixels) {
+  if (SDL_MUSTLOCK(screen)) {
+    SDL_LockSurface(screen);
+  }
+  int pixelNumber = 0;
+  for (int j=r.top(); j<r.bottom(); j++) {
+    for (int i=r.left(); i<r.right(); i++) {
+      KDColor c = pixels[pixelNumber++];
+      *((Uint32*)screen->pixels + j * Ion::Display::Width + i) = SDL_MapRGB(screen->format, c.red(), c.green(), c.blue());
+    }
+  }
+  if (SDL_MUSTLOCK(screen)) {
+    SDL_UnlockSurface(screen);
+  }
+  SDL_UpdateRect(screen, r.x(), r.y(), r.width(), r.height());
+}
+
+void pushRectUniform(KDRect r, KDColor c) {
+  Uint32 sdlColor = SDL_MapRGB(screen->format, c.red(), c.green(), c.blue());
+  SDL_Rect sdlRect = { r.x(), r.y(), r.width(), r.height() };
+  SDL_FillRect(screen, &sdlRect, sdlColor);
+  SDL_UpdateRect(screen, r.x(), r.y(), r.width(), r.height());
+}
+
+void pullRect(KDRect r, KDColor * pixels) {
+}
+
+void waitForVBlank() {
+}
+
+}
+}
+
+namespace Ion {
+namespace Display {
+namespace Emscripten {
+
+void init() {
+  SDL_Init(SDL_INIT_VIDEO);
+  screen = SDL_SetVideoMode(Ion::Display::Width, Ion::Display::Height, 32, SDL_HWSURFACE);
+}
+
+}
+}
+}