Detect render target support when renderer is created, log if it is absent.

src/common/FrameBufferSDL2.cxx

@@ -32,7 +32,8 @@ FrameBufferSDL2::FrameBufferSDL2(OSystem& osystem)
   : FrameBuffer(osystem),
     myWindow(nullptr),
     myRenderer(nullptr),
-    myCenter(false)
+    myCenter(false),
+    myRenderTargetSupport(false)
 {
   ASSERT_MAIN_THREAD;
 
@@ -318,7 +319,10 @@ bool FrameBufferSDL2::setVideoMode(const string& title, const VideoMode& mode)
   const string& video = myOSystem.settings().getString("video");  // Render hint
   if(video != "")
     SDL_SetHint(SDL_HINT_RENDER_DRIVER, video.c_str());
+
   myRenderer = SDL_CreateRenderer(myWindow, -1, renderFlags);
+  detectFeatures();
+
   if(myRenderer == nullptr)
   {
     string msg = "ERROR: Unable to create SDL renderer: " + string(SDL_GetError());
@@ -468,3 +472,44 @@ const SDL_PixelFormat& FrameBufferSDL2::pixelFormat() const
 {
   return *myPixelFormat;
 }
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+void FrameBufferSDL2::detectFeatures()
+{
+  myRenderTargetSupport = detectRenderTargetSupport();
+
+  if (myRenderer) {
+    if (!myRenderTargetSupport) {
+      Logger::info("Render targets are not supported --- QIS not available");
+    }
+  }
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+bool FrameBufferSDL2::detectRenderTargetSupport()
+{
+  if (myRenderer == nullptr) return false;
+
+  SDL_RendererInfo info;
+
+  SDL_GetRendererInfo(myRenderer, &info);
+
+  if (!(info.flags & SDL_RENDERER_TARGETTEXTURE)) return false;
+
+  SDL_Texture* tex = SDL_CreateTexture(myRenderer, myPixelFormat->format, SDL_TEXTUREACCESS_TARGET, 16, 16);
+
+  if (!tex) return false;
+
+  int sdlError = SDL_SetRenderTarget(myRenderer, tex);
+  SDL_SetRenderTarget(myRenderer, nullptr);
+
+  SDL_DestroyTexture(tex);
+
+  return sdlError == 0;
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+bool FrameBufferSDL2::hasRenderTargetSupport() const
+{
+  return myRenderTargetSupport;
+}

src/common/FrameBufferSDL2.hxx

@@ -129,6 +129,11 @@ class FrameBufferSDL2 : public FrameBuffer
      */
     bool isInitialized() const;
 
+    /**
+      Does the renderer support render targets?
+     */
+    bool hasRenderTargetSupport() const;
+
   protected:
     //////////////////////////////////////////////////////////////////////
     // The following are derived from protected methods in FrameBuffer.hxx
@@ -193,6 +198,16 @@ class FrameBufferSDL2 : public FrameBuffer
     */
     void renderToScreen() override;
 
+    /**
+      After the renderer has been created, detect the features it supports.
+     */
+    void detectFeatures();
+
+    /**
+      Detect render target support;
+     */
+    bool detectRenderTargetSupport();
+
   private:
     // The SDL video buffer
     SDL_Window* myWindow;
@@ -207,6 +222,8 @@ class FrameBufferSDL2 : public FrameBuffer
     // last position of windowed window
     Common::Point myWindowedPos;
 
+    bool myRenderTargetSupport;
+
   private:
     // Following constructors and assignment operators not supported
     FrameBufferSDL2() = delete;

src/common/sdl_blitter/HqBlitter.cxx

@@ -39,26 +39,9 @@ HqBlitter::~HqBlitter()
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 bool HqBlitter::isSupported(FrameBufferSDL2 &fb)
 {
-  ASSERT_MAIN_THREAD;
-
   if (!fb.isInitialized()) throw runtime_error("framebuffer not initialized");
 
-  SDL_RendererInfo info;
-
-  SDL_GetRendererInfo(fb.renderer(), &info);
-
-  if (!(info.flags & SDL_RENDERER_TARGETTEXTURE)) return false;
-
-  SDL_Texture* tex = SDL_CreateTexture(fb.renderer(), fb.pixelFormat().format, SDL_TEXTUREACCESS_TARGET, 16, 16);
-
-  if (!tex) return false;
-
-  int sdlError = SDL_SetRenderTarget(fb.renderer(), tex);
-  SDL_SetRenderTarget(fb.renderer(), nullptr);
-
-  SDL_DestroyTexture(tex);
-
-  return sdlError == 0;
+  return fb.hasRenderTargetSupport();
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -