HighDPI support, hopefully

neo/framework/Dhewm3SettingsMenu.cpp

@@ -1,5 +1,7 @@
 #ifndef IMGUI_DISABLE
 
+#include <SDL.h> // to show display size
+
 #define IMGUI_DEFINE_MATH_OPERATORS
 
 #include "Common.h"
@@ -1833,6 +1835,22 @@ static void DrawVideoOptionsMenu()
 			AddTooltip( "r_customWidth / r_customHeight" );
 		}
 	}
+	int sdlDisplayIdx = SDL_GetWindowDisplayIndex( SDL_GL_GetCurrentWindow() );
+	SDL_Rect displayRect = {};
+	SDL_GetDisplayBounds( sdlDisplayIdx, &displayRect );
+	if ( (int)glConfig.winWidth != glConfig.vidWidth ) {
+		ImGui::TextDisabled( "Current Resolution: %g x %g (Physical: %d x %d)",
+		                     glConfig.winWidth, glConfig.winHeight, glConfig.vidWidth, glConfig.vidHeight );
+		AddDescrTooltip( "Apparently your system is using a HighDPI mode, where the logical resolution (used to specify"
+		                 " window sizes) is lower than the physical resolution (number of pixels actually rendered)." );
+		float scale = float(glConfig.vidWidth)/glConfig.winWidth;
+		int pw = scale * displayRect.w;
+		int ph = scale * displayRect.h;
+		ImGui::TextDisabled( "Display Size: %d x %d (Physical: %d x %d)", displayRect.w, displayRect.h, pw, ph );
+	} else {
+		ImGui::TextDisabled( "Current Resolution: %d x %d", glConfig.vidWidth, glConfig.vidHeight );
+		ImGui::TextDisabled( "Display Size: %d x %d", displayRect.w, displayRect.h );
+	}
 
 	static const char* msaaLevels[] = { "No Antialiasing", "2x", "4x", "8x", "16x" };
 	const char* curLvl = msaaLevels[msaaModeIndex];

neo/renderer/RenderSystem.h

@@ -79,6 +79,7 @@ typedef struct glconfig_s {
 	bool				textureNonPowerOfTwoAvailable;
 	bool				depthBoundsTestAvailable;
 
+	// GL framebuffer size, see also winWidth and winHeight
 	int					vidWidth, vidHeight;	// passed to R_BeginFrame
 
 	int					displayFrequency;
@@ -92,6 +93,23 @@ typedef struct glconfig_s {
 	// DG: current video backend is known to need opaque default framebuffer
 	//     used if r_fillWindowAlphaChan == -1
 	bool				shouldFillWindowAlpha;
+
+	// For some reason people decided that we need displays with ultra small pixels,
+	// so everything rendered on them must be scaled up to be legible.
+	// unfortunately, this bullshit feature was "improved" upon by deciding that the best
+	// way to implement "High DPI" was to pretend that windows have fewer pixels than they
+	// actually do, so the window size you get and mouse coordinates in them etc
+	// are in e.g. 1024x768, while the physical window size is e.g. 1536x1152 pixels
+	// (when the scaling factor is 1.5), and ideally the GL framebuffer has the physical
+	// window size so things still look crisp.
+	// Of course the reasonable solution would be to go back and time and nuke Cupertino,
+	// where this nonsense scheme was invented, but as I lack the necessary funds,
+	// I reluctantly add winWidth and winHeight and adjust the code that deals with window
+	// coordinates, as far as that's possible..
+	// (Isn't it fun that you have a 2256x1504 display, tell SDL to create a 1920x1080 window
+	//  and you get one that's much bigger and doesn't fit on the screen?)
+
+	float				winWidth, winHeight;	// logical window size (different to vidWidth/height in HighDPI cases)
 } glconfig_t;
 
 
@@ -171,7 +189,11 @@ public:
 	virtual bool			IsOpenGLRunning( void ) const = 0;
 
 	virtual bool			IsFullScreen( void ) const = 0;
+	// NOTE: this is the physical width of the GL drawable (framebuffer) in pixels,
+	//      *not* the logical window size (in case of HighDPI that's not the same!)
 	virtual int				GetScreenWidth( void ) const = 0;
+	// NOTE: this is the physical height of the GL drawable (framebuffer) in pixels,
+	//      *not* the logical window size (in case of HighDPI that's not the same!)
 	virtual int				GetScreenHeight( void ) const = 0;
 
 	// allocate a renderWorld to be used for drawing

neo/renderer/RenderSystem_init.cpp

@@ -1914,6 +1914,10 @@ static void GfxInfo_f( const idCmdArgs &args ) {
 		"fullscreen"
 	};
 
+	const char* fsmode = fsstrings[r_fullscreen.GetBool()];
+	if ( r_fullscreen.GetBool() && r_fullscreenDesktop.GetBool() )
+		fsmode = "desktop-fullscreen";
+
 	common->Printf( "\nGL_VENDOR: %s\n", glConfig.vendor_string );
 	common->Printf( "GL_RENDERER: %s\n", glConfig.renderer_string );
 	common->Printf( "GL_VERSION: %s\n", glConfig.version_string );
@@ -1923,13 +1927,14 @@ static void GfxInfo_f( const idCmdArgs &args ) {
 	common->Printf( "GL_MAX_TEXTURE_COORDS_ARB: %d\n", glConfig.maxTextureCoords );
 	common->Printf( "GL_MAX_TEXTURE_IMAGE_UNITS_ARB: %d\n", glConfig.maxTextureImageUnits );
 	common->Printf( "\nPIXELFORMAT: color(%d-bits) Z(%d-bit) stencil(%d-bits)\n", glConfig.colorBits, glConfig.depthBits, glConfig.stencilBits );
-	common->Printf( "MODE: %d, %d x %d %s hz:", r_mode.GetInteger(), glConfig.vidWidth, glConfig.vidHeight, fsstrings[r_fullscreen.GetBool()] );
+	common->Printf( "MODE: %d, %d x %d %s hz:", r_mode.GetInteger(), glConfig.vidWidth, glConfig.vidHeight, fsmode );
 
 	if ( glConfig.displayFrequency ) {
 		common->Printf( "%d\n", glConfig.displayFrequency );
 	} else {
 		common->Printf( "N/A\n" );
 	}
+	common->Printf( "Logical Window size: %g x %g\n", glConfig.winWidth, glConfig.winHeight );
 
 	const char *active[2] = { "", " (ACTIVE)" };
 
@@ -2033,8 +2038,8 @@ void R_VidRestart_f( const idCmdArgs &args ) {
 		globalImages->ReloadAllImages();
 	} else {
 		glimpParms_t	parms;
-		parms.width = glConfig.vidWidth;
-		parms.height = glConfig.vidHeight;
+		parms.width = glConfig.winWidth;   // DG: HighDPI adjustment: explicitly use window size
+		parms.height = glConfig.winHeight;
 		parms.fullScreen = ( forceWindow ) ? false : r_fullscreen.GetBool();
 		parms.displayHz = r_displayRefresh.GetInteger();
 		parms.multiSamples = r_multiSamples.GetInteger();

neo/sys/glimp.cpp

@@ -165,6 +165,8 @@ bool GLimp_Init(glimpParms_t parms) {
 	}
 
 #if SDL_VERSION_ATLEAST(2, 0, 0)
+	flags |= SDL_WINDOW_ALLOW_HIGHDPI;
+
 	/* Doom3 has the nasty habit of modifying the default framebuffer's alpha channel and then
 	 * relying on those modifications in blending operations (using GL_DST_(ONE_MINUS_)ALPHA).
 	 * So far that hasn't been much of a problem, because Windows, macOS, X11 etc
@@ -272,14 +274,14 @@ try_again:
 
 #if SDL_VERSION_ATLEAST(2, 0, 0)
 
-		const char* windowMode = "";
-		if(r_fullscreen.GetBool()) {
-			windowMode = r_fullscreenDesktop.GetBool() ? "desktop-fullscreen-" : "fullscreen-";
+		if ( r_fullscreen.GetBool() && r_fullscreenDesktop.GetBool() ) {
+			common->Printf( "Will create a pseudo-fullscreen window at the current desktop resolution\n" );
+		} else {
+			const char* windowMode = r_fullscreen.GetBool() ? "fullscreen-" : "";
+			common->Printf("Will create a %swindow with resolution %dx%d (r_mode = %d)\n",
+						   windowMode, parms.width, parms.height, r_mode.GetInteger());
 		}
 
-		common->Printf("Will create a %swindow with resolution %dx%d (r_mode = %d)\n",
-		               windowMode, parms.width, parms.height, r_mode.GetInteger());
-
 		int displayIndex = 0;
 #if SDL_VERSION_ATLEAST(2, 0, 4)
 		// try to put the window on the display the mousecursor currently is on
@@ -407,11 +409,23 @@ try_again:
 		GLimp_SetSwapInterval( r_swapInterval.GetInteger() );
 		r_swapInterval.ClearModified();
 
-		SDL_GetWindowSize(window, &glConfig.vidWidth, &glConfig.vidHeight);
+		// for HighDPI, window size and drawable size can differ
+		int ww=0, wh=0;
+		SDL_GetWindowSize(window, &ww, &wh);
+		glConfig.winWidth = ww;
+		glConfig.winHeight = wh;
+		SDL_GL_GetDrawableSize(window, &glConfig.vidWidth, &glConfig.vidHeight);
 
 		SetSDLIcon(); // for SDL2  this must be done after creating the window
 
 		glConfig.isFullscreen = (SDL_GetWindowFlags(window) & SDL_WINDOW_FULLSCREEN) == SDL_WINDOW_FULLSCREEN;
+		const char* fsStr = glConfig.isFullscreen ? "fullscreen " : "";
+		if ( ww != glConfig.vidWidth ) {
+			common->Printf( "Got a HighDPI %swindow with physical resolution %d x %d and virtual resolution %d x %d\n",
+							fsStr, glConfig.vidWidth, glConfig.vidHeight, ww, wh );
+		} else {
+			common->Printf( "Got a %swindow with resolution %d x %d\n", fsStr, ww, wh );
+		}
 #else
 		SDL_WM_SetCaption(ENGINE_VERSION, ENGINE_VERSION);
 

neo/sys/sys_imgui.cpp

@@ -187,6 +187,11 @@ static float GetDefaultDPI()
 
 static float GetDefaultScale()
 {
+	if ( glConfig.winWidth != glConfig.vidWidth ) {
+		// in HighDPI mode, the font sizes are already scaled (to window coordinates), apparently
+		return 1.0f;
+	}
+	// TODO: different reference DPI on mac? also, doesn't work that well on my laptop..
 	float ret = GetDefaultDPI() / 96.0f;
 	ret = round(ret*2.0)*0.5; // round to .0 or .5
 	return ret;
@@ -464,8 +469,8 @@ bool ShouldShowCursor()
 		// in a black bar (Doom3 cursor is not drawn there), show the ImGui cursor
 		if ( r_scaleMenusTo43.GetBool() ) {
 			ImVec2 mousePos = ImGui::GetMousePos();
-			float w = renderSystem->GetScreenWidth();
-			float h = renderSystem->GetScreenHeight();
+			float w = glConfig.winWidth;
+			float h = glConfig.winHeight;
 			float aspectRatio = w/h;
 			static const float virtualAspectRatio = float(VIRTUAL_WIDTH)/float(VIRTUAL_HEIGHT); // 4:3 = 1.333
 			if(aspectRatio > 1.4f) {

neo/ui/UserInterface.cpp

@@ -36,6 +36,8 @@ If you have questions concerning this license or the applicable additional terms
 
 #include "ui/UserInterfaceLocal.h"
 
+#include "renderer/tr_local.h" // glConfig for winWidth/winHeight
+
 extern idCVar r_skipGuiShaders;		// 1 = don't render any gui elements on surfaces
 extern idCVar r_scaleMenusTo43; // DG: for the "scale menus to 4:3" hack
 
@@ -355,12 +357,14 @@ const char *idUserInterfaceLocal::HandleEvent( const sysEvent_t *event, int _tim
 			// DG: this is a fullscreen GUI, scale the mousedelta added to cursorX/Y
 			//     by 640/w, because the GUI pretends that everything is 640x480
 			//     even if the actual resolution is higher => mouse moved too fast
-			float w = renderSystem->GetScreenWidth();
-			float h = renderSystem->GetScreenHeight();
+			float w = glConfig.winWidth;
+			float h = glConfig.winHeight;
 			if( w <= 0.0f || h <= 0.0f ) {
 				w = VIRTUAL_WIDTH;
 				h = VIRTUAL_HEIGHT;
 			}
+			const float realW = w;
+			const float realH = h;
 
 			if(r_scaleMenusTo43.GetBool()) {
 				// in case we're scaling menus to 4:3, we need to take that into account
@@ -387,8 +391,8 @@ const char *idUserInterfaceLocal::HandleEvent( const sysEvent_t *event, int _tim
 				// Note: In case of scaling to 4:3, w and h are already scaled down
 				//       to the 4:3 size that fits into the real resolution.
 				//       Otherwise xOffset/yOffset will just be 0
-				float xOffset = (renderSystem->GetScreenWidth()  - w) * 0.5f;
-				float yOffset = (renderSystem->GetScreenHeight() - h) * 0.5f;
+				float xOffset = (realW  - w) * 0.5f;
+				float yOffset = (realH - h) * 0.5f;
 				// offset the mouse coordinates into 4:3 area and scale down to 640x480
 				// yes, result could be negative, doesn't matter, code below checks that anyway
 				cursorX = (event->evValue  - xOffset) * (float(VIRTUAL_WIDTH)/w);