Clear up & fix high dpi handling.

Author: Jupeyy

src/engine/client/backend_sdl.cpp

@@ -1,3 +1,5 @@
+#include <SDL_stdinc.h>
+#include <SDL_vulkan.h>
 #include <base/detect.h>
 
 #ifndef CONF_BACKEND_OPENGL_ES
@@ -987,9 +989,13 @@ void CGraphicsBackend_SDL_GL::GetCurrentVideoMode(CVideoMode &CurMode, float HiD
 		{
 			int Width = 0;
 			int Height = 0;
-			SDL_GL_GetDrawableSize(m_pWindow, &Width, &Height);
-			DpMode.w = Width;
-			DpMode.h = Height;
+			if(m_BackendType != EBackendType::BACKEND_TYPE_VULKAN)
+				SDL_GL_GetDrawableSize(m_pWindow, &Width, &Height);
+			else
+				SDL_Vulkan_GetDrawableSize(m_pWindow, &Width, &Height);
+			// SDL video modes are in screen space which are logical pixels
+			DpMode.w = Width / HiDPIScale;
+			DpMode.h = Height / HiDPIScale;
 		}
 	}
 	DisplayToVideoMode(&CurMode, &DpMode, HiDPIScale, DpMode.refresh_rate);
@@ -1243,8 +1249,13 @@ int CGraphicsBackend_SDL_GL::Init(const char *pName, int *pScreen, int *pWidth,
 	InitError = IsVersionSupportedGlew(m_BackendType, g_Config.m_GfxGLMajor, g_Config.m_GfxGLMinor, g_Config.m_GfxGLPatch, GlewMajor, GlewMinor, GlewPatch);
 
 	// SDL_GL_GetDrawableSize reports HiDPI resolution even with SDL_WINDOW_ALLOW_HIGHDPI not set, which is wrong
-	if(SdlFlags & SDL_WINDOW_ALLOW_HIGHDPI && IsOpenGLFamilyBackend)
-		SDL_GL_GetDrawableSize(m_pWindow, pCurrentWidth, pCurrentHeight);
+	if(SdlFlags & SDL_WINDOW_ALLOW_HIGHDPI)
+	{
+		if(IsOpenGLFamilyBackend)
+			SDL_GL_GetDrawableSize(m_pWindow, pCurrentWidth, pCurrentHeight);
+		else
+			SDL_Vulkan_GetDrawableSize(m_pWindow, pCurrentWidth, pCurrentHeight);
+	}
 	else
 		SDL_GetWindowSize(m_pWindow, pCurrentWidth, pCurrentHeight);
 	SDL_GetWindowSize(m_pWindow, pWidth, pHeight);
@@ -1616,7 +1627,10 @@ bool CGraphicsBackend_SDL_GL::ResizeWindow(int w, int h, int RefreshRate)
 
 void CGraphicsBackend_SDL_GL::GetViewportSize(int &w, int &h)
 {
-	SDL_GL_GetDrawableSize(m_pWindow, &w, &h);
+	if(m_BackendType != EBackendType::BACKEND_TYPE_VULKAN)
+		SDL_GL_GetDrawableSize(m_pWindow, &w, &h);
+	else
+		SDL_Vulkan_GetDrawableSize(m_pWindow, &w, &h);
 }
 
 void CGraphicsBackend_SDL_GL::NotifyWindow()

src/engine/client/graphics_threaded.cpp

@@ -2596,8 +2596,18 @@ void CGraphics_Threaded::GotResized(int w, int h, int RefreshRate)
 	g_Config.m_GfxScreenWidth = w;
 	g_Config.m_GfxScreenHeight = h;
 	g_Config.m_GfxScreenRefreshRate = m_ScreenRefreshRate;
+
+	auto OldDpi = m_ScreenHiDPIScale;
 	m_ScreenHiDPIScale = m_ScreenWidth / (float)g_Config.m_GfxScreenWidth;
 
+	// A DPI change must notify the listeners, since e.g. video modes
+	// currently depend on it.
+	if(OldDpi != m_ScreenHiDPIScale)
+	{
+		for(auto &PropChangedListener : m_vPropChangeListeners)
+			PropChangedListener();
+	}
+
 	UpdateViewport(0, 0, m_ScreenWidth, m_ScreenHeight, true);
 
 	// kick the command buffer and wait