1 files changed, 35 insertions, 14 deletions

diff --git a/src/graphics.cpp b/src/graphics.cpp
index b4c65b0a..d5c1e1a0 100644
--- a/src/graphics.cpp
+++ b/src/graphics.cpp
@@ -64,14 +64,13 @@ bool Graphics::setVideoMode(int w, int h, bool fs)
     if (!window)
         return false;
 
-    SDL_SetWindowMinimumSize(window, 640, 480);
+    SDL_SetWindowMinimumSize(window, 640, 360);
     SDL_SetRenderDrawBlendMode(renderer, SDL_BLENDMODE_BLEND);
 
     setTarget(window);
 
     mRenderer = renderer;
-    mWidth = w;
-    mHeight = h;
+    videoResized(w, h);
     mFullscreen = fs;
 
     if (const char *driver = SDL_GetCurrentVideoDriver())
@@ -127,18 +126,26 @@ bool Graphics::changeVideoMode(int w, int h, bool fs)
 
 void Graphics::videoResized(int w, int h)
 {
-    mWidth = w;
-    mHeight = h;
-}
+    const int prevWidth = mWidth;
+    const int prevHeight = mHeight;
 
-int Graphics::getWidth() const
-{
-    return mWidth;
-}
+    mScale = getScale(w, h);
+    mWidth = w / mScale;
+    mHeight = h / mScale;
 
-int Graphics::getHeight() const
-{
-    return mHeight;
+    if (mWidth != prevWidth || mHeight != prevHeight) {
+        if (mScreenTexture) {
+            SDL_DestroyTexture(mScreenTexture);
+            mScreenTexture = nullptr;
+        }
+
+        if (mScale > 1) {
+            auto pixelFormat = SDL_GetWindowPixelFormat(mTarget);
+            mScreenTexture = SDL_CreateTexture(mRenderer, pixelFormat, SDL_TEXTUREACCESS_TARGET, mWidth, mHeight);
+        }
+
+        SDL_SetRenderTarget(mRenderer, mScreenTexture);
+    }
 }
 
 bool Graphics::drawImage(Image *image, int x, int y)
@@ -292,7 +299,16 @@ void Graphics::drawImageRect(int x, int y, int w, int h,
 
 void Graphics::updateScreen()
 {
-    SDL_RenderPresent(mRenderer);
+    if (!mScreenTexture) {
+        // Simple case when we're rendering directly to the window
+        SDL_RenderPresent(mRenderer);
+    } else {
+        // Otherwise, we now render the screen surface to the window
+        SDL_SetRenderTarget(mRenderer, NULL);
+        SDL_RenderCopy(mRenderer, mScreenTexture, NULL, NULL);
+        SDL_RenderPresent(mRenderer);
+        SDL_SetRenderTarget(mRenderer, mScreenTexture);
+    }
 }
 
 SDL_Surface *Graphics::getScreenshot()
@@ -346,6 +362,11 @@ void Graphics::updateSDLClipRect()
     SDL_RenderSetClipRect(mRenderer, &rect);
 }
 
+int Graphics::getScale(int w, int h)
+{
+    return std::max(w / 640, h / 360);
+}
+
 void Graphics::drawPoint(int x, int y)
 {
     if (mClipStack.empty())