Merge pull request #772 from wheremyfoodat/screen-layout

Better screen layout support

CMakeLists.txt

@@ -328,7 +328,7 @@ set(SOURCE_FILES src/emulator.cpp src/io_file.cpp src/config.cpp
                  src/core/memory.cpp src/renderer.cpp src/core/renderer_null/renderer_null.cpp
                  src/http_server.cpp src/stb_image_write.c src/core/cheats.cpp src/core/action_replay.cpp
                  src/discord_rpc.cpp src/lua.cpp src/memory_mapped_file.cpp src/renderdoc.cpp
-                 src/frontend_settings.cpp src/miniaudio/miniaudio.cpp
+                 src/frontend_settings.cpp src/miniaudio/miniaudio.cpp src/core/screen_layout.cpp
 )
 set(CRYPTO_SOURCE_FILES src/core/crypto/aes_engine.cpp)
 set(KERNEL_SOURCE_FILES src/core/kernel/kernel.cpp src/core/kernel/resource_limits.cpp
@@ -416,6 +416,7 @@ set(HEADER_FILES include/emulator.hpp include/helpers.hpp include/termcolor.hpp
                  include/fs/archive_twl_sound.hpp include/fs/archive_card_spi.hpp include/services/ns.hpp include/audio/audio_device.hpp
                  include/audio/audio_device_interface.hpp include/audio/libretro_audio_device.hpp include/services/ir/ir_types.hpp
                  include/services/ir/ir_device.hpp include/services/ir/circlepad_pro.hpp include/services/service_intercept.hpp
+                 include/screen_layout.hpp
 )
 
 if(IOS)

include/PICA/gpu.hpp

@@ -89,6 +89,7 @@ class GPU {
 	PICA::Vertex getImmediateModeVertex();
 
 	void getAcceleratedDrawInfo(PICA::DrawAcceleration& accel, bool indexed);
+
   public:
 	// 256 entries per LUT with each LUT as its own row forming a 2D image 256 * LUT_COUNT
 	// Encoded in PICA native format
@@ -134,6 +135,8 @@ class GPU {
 
 	// Used for setting the size of the window we'll be outputting graphics to
 	void setOutputSize(u32 width, u32 height) { renderer->setOutputSize(width, height); }
+	// Used for notifying the renderer the screen layout has changed
+	void reloadScreenLayout() { renderer->reloadScreenLayout(); }
 
 	// TODO: Emulate the transfer engine & its registers
 	// Then this can be emulated by just writing the appropriate values there
@@ -181,6 +184,7 @@ class GPU {
 	}
 
 	Renderer* getRenderer() { return renderer.get(); }
+
   private:
 	// GPU external registers
 	// We have them in the end of the struct for cache locality reasons. Tl;dr we want the more commonly used things to be packed in the start
@@ -189,8 +193,8 @@ class GPU {
 
 	ALWAYS_INLINE void setVsOutputMask(u32 val) {
 		val &= 0xffff;
-	
+
-		// Avoid recomputing this if not necessary 
+		// Avoid recomputing this if not necessary
 		if (oldVsOutputMask != val) [[unlikely]] {
 			oldVsOutputMask = val;
 

include/config.hpp

@@ -2,6 +2,7 @@
 #include <filesystem>
 #include <string>
 
+#include "screen_layout.hpp"
 #include "audio/dsp_core.hpp"
 #include "frontend_settings.hpp"
 #include "renderer.hpp"
@@ -69,6 +70,9 @@ struct EmulatorConfig {
 	bool accelerateShaders = accelerateShadersDefault;
 	bool hashTextures = hashTexturesDefault;
 
+	ScreenLayout::Layout screenLayout = ScreenLayout::Layout::Default;
+	float topScreenSize = 0.5;
+
 	bool accurateShaderMul = false;
 	bool discordRpcEnabled = false;
 

include/emulator.hpp

@@ -115,6 +115,8 @@ class Emulator {
 
 	RomFS::DumpingResult dumpRomFS(const std::filesystem::path& path);
 	void setOutputSize(u32 width, u32 height) { gpu.setOutputSize(width, height); }
+	void reloadScreenLayout() { gpu.reloadScreenLayout(); }
+
 	void deinitGraphicsContext() { gpu.deinitGraphicsContext(); }
 
 	// Reloads some settings that require special handling, such as audio enable

include/panda_qt/screen.hpp

@@ -3,6 +3,7 @@
 #include <functional>
 #include <memory>
 
+#include "screen_layout.hpp"
 #include "gl/context.h"
 #include "window_info.h"
 
@@ -29,6 +30,15 @@ class ScreenWidget : public QWidget {
 	u32 previousWidth = 0;
 	u32 previousHeight = 0;
 
+	// Coordinates (x/y/width/height) for the two screens in window space, used for properly handling touchscreen regardless
+	// of layout or resizing
+	ScreenLayout::WindowCoordinates screenCoordinates;
+	// Screen layouts and sizes
+	ScreenLayout::Layout screenLayout = ScreenLayout::Layout::Default;
+	float topScreenSize = 0.5f;
+
+	void reloadScreenLayout(ScreenLayout::Layout newLayout, float newTopScreenSize);
+
   private:
 	std::unique_ptr<GL::Context> glContext = nullptr;
 	ResizeCallback resizeCallback;
@@ -39,4 +49,6 @@ class ScreenWidget : public QWidget {
 	int scaledWindowWidth() const;
 	int scaledWindowHeight() const;
 	std::optional<WindowInfo> getWindowInfo();
+
+	void reloadScreenCoordinates();
 };

include/panda_sdl/frontend_sdl.hpp

@@ -4,6 +4,7 @@
 
 #include <filesystem>
 
+#include "screen_layout.hpp"
 #include "emulator.hpp"
 #include "input_mappings.hpp"
 
@@ -27,7 +28,11 @@ class FrontendSDL {
 	u32 windowHeight = 480;
 	int gameControllerID;
 	bool programRunning = true;
-	
+
+	// Coordinates (x/y/width/height) for the two screens in window space, used for properly handling touchscreen regardless
+	// of layout or resizing
+	ScreenLayout::WindowCoordinates screenCoordinates;
+
 	// For tracking whether to update gyroscope
 	// We bind gyro to right click + mouse movement
 	bool holdingRightClick = false;
@@ -38,5 +43,7 @@ class FrontendSDL {
 	bool keyboardAnalogX = false;
 	bool keyboardAnalogY = false;
 
+  private:
 	void setupControllerSensors(SDL_GameController* controller);
+	void handleLeftClick(int mouseX, int mouseY);
 };

include/renderer.hpp

@@ -130,4 +130,5 @@ class Renderer {
 
 	void setConfig(EmulatorConfig* config) { emulatorConfig = config; }
 	void setHashTextures(bool setting) { hashTextures = setting; }
+	void reloadScreenLayout() { outputSizeChanged = true; }
 };

include/renderer_gl/renderer_gl.hpp

@@ -147,12 +147,24 @@ class RendererGL final : public Renderer {
 	OpenGL::Driver driverInfo;
 
 	// Information about the final 3DS screen -> Window blit, accounting for things like scaling and shifting the output based on
-	// the window's dimensions.
+	// the window's dimensions. Updated whenever the screen size or layout changes.
 	struct {
+		int topScreenX = 0;
+		int topScreenY = 0;
+		int topScreenWidth = 400;
+		int topScreenHeight = 240;
+
+		int bottomScreenX = 40;
+		int bottomScreenY = 240;
+		int bottomScreenWidth = 320;
+		int bottomScreenHeight = 240;
+
+		// For optimizing the final screen blit into a single blit instead of 2 when possible:
 		int destX = 0;
 		int destY = 0;
 		int destWidth = 400;
 		int destHeight = 480;
+		bool canDoSingleBlit = true;
 	} blitInfo;
 
 	MAKE_LOG_FUNCTION(log, rendererLogger)

include/renderer_mtl/renderer_mtl.hpp

@@ -89,13 +89,17 @@ class RendererMTL final : public Renderer {
 	MTL::Texture* lastDepthTexture = nullptr;
 
 	// Information about the final 3DS screen -> Window blit, accounting for things like scaling and shifting the output based on
-	// the window's dimensions.
+	// the window's dimensions. Updated whenever the screen size or layout changes.
 	struct {
 		float topScreenX = 0;
 		float topScreenY = 0;
+		float topScreenWidth = 400;
+		float topScreenHeight = 240;
+
 		float bottomScreenX = 40;
 		float bottomScreenY = 240;
-		float scale = 1.0;
+		float bottomScreenWidth = 320;
+		float bottomScreenHeight = 240;
 	} blitInfo;
 
 	// Debug

include/screen_layout.hpp

@@ -0,0 +1,58 @@
+#pragma once
+#include <string>
+
+#include "helpers.hpp"
+
+namespace ScreenLayout {
+	static constexpr u32 TOP_SCREEN_WIDTH = 400;
+	static constexpr u32 BOTTOM_SCREEN_WIDTH = 320;
+	static constexpr u32 TOP_SCREEN_HEIGHT = 240;
+	static constexpr u32 BOTTOM_SCREEN_HEIGHT = 240;
+
+	// The bottom screen is less wide by 80 pixels, so we center it by offsetting it 40 pixels right
+	static constexpr u32 BOTTOM_SCREEN_X_OFFSET = 40;
+	static constexpr u32 CONSOLE_HEIGHT = TOP_SCREEN_HEIGHT + BOTTOM_SCREEN_HEIGHT;
+
+	enum class Layout {
+		Default = 0,        // Top screen up, bottom screen down
+		DefaultFlipped,     // Top screen down, bottom screen up
+		SideBySide,         // Top screen left, bottom screen right,
+		SideBySideFlipped,  // Top screen right, bottom screen left,
+	};
+
+	// For properly handling touchscreen, we have to remember what window coordinates our screens map to
+	// We also remember some more information that is useful to our renderers, particularly for the final screen blit.
+	struct WindowCoordinates {
+		u32 topScreenX = 0;
+		u32 topScreenY = 0;
+		u32 topScreenWidth = TOP_SCREEN_WIDTH;
+		u32 topScreenHeight = TOP_SCREEN_HEIGHT;
+
+		u32 bottomScreenX = BOTTOM_SCREEN_X_OFFSET;
+		u32 bottomScreenY = TOP_SCREEN_HEIGHT;
+		u32 bottomScreenWidth = BOTTOM_SCREEN_WIDTH;
+		u32 bottomScreenHeight = BOTTOM_SCREEN_HEIGHT;
+
+		u32 windowWidth = topScreenWidth;
+		u32 windowHeight = topScreenHeight + bottomScreenHeight;
+
+		// Information used when optimizing the final screen blit into a single blit
+		struct {
+			// Can we actually render both of the screens in a single blit?
+			bool canDoSingleBlit = false;
+			// Blit information used if we can
+			int destX = 0, destY = 0;
+			int destWidth = TOP_SCREEN_WIDTH;
+			int destHeight = CONSOLE_HEIGHT;
+		} singleBlitInfo;
+	};
+
+	// Calculate screen coordinates on the screen for a given layout & a given size for the output window
+	// Used in both the renderers and in the frontends (To eg calculate touch screen boundaries)
+	void calculateCoordinates(
+		WindowCoordinates& coordinates, u32 outputWindowWidth, u32 outputWindowHeight, float topScreenPercentage, Layout layout
+	);
+
+	Layout layoutFromString(std::string inString);
+	const char* layoutToString(Layout layout);
+}  // namespace ScreenLayout

src/config.cpp

@@ -93,6 +93,10 @@ void EmulatorConfig::load() {
 			lightShadergenThreshold = toml::find_or<toml::integer>(gpu, "ShadergenLightThreshold", 1);
 			hashTextures = toml::find_or<toml::boolean>(gpu, "HashTextures", hashTexturesDefault);
 			enableRenderdoc = toml::find_or<toml::boolean>(gpu, "EnableRenderdoc", false);
+
+			auto screenLayoutName = toml::find_or<std::string>(gpu, "ScreenLayout", "Default");
+			screenLayout = ScreenLayout::layoutFromString(screenLayoutName);
+			topScreenSize = float(std::clamp(toml::find_or<toml::floating>(gpu, "TopScreenSize", 0.5), 0.0, 1.0));
 		}
 	}
 
@@ -194,6 +198,8 @@ void EmulatorConfig::save() {
 	data["GPU"]["AccelerateShaders"] = accelerateShaders;
 	data["GPU"]["EnableRenderdoc"] = enableRenderdoc;
 	data["GPU"]["HashTextures"] = hashTextures;
+	data["GPU"]["ScreenLayout"] = std::string(ScreenLayout::layoutToString(screenLayout));
+	data["GPU"]["TopScreenSize"] = double(topScreenSize);
 
 	data["Audio"]["DSPEmulation"] = std::string(Audio::DSPCore::typeToString(dspType));
 	data["Audio"]["EnableAudio"] = audioEnabled;

src/core/renderer_gl/renderer_gl.cpp

@@ -11,6 +11,7 @@
 #include "PICA/pica_hash.hpp"
 #include "PICA/pica_simd.hpp"
 #include "PICA/regs.hpp"
+#include "screen_layout.hpp"
 #include "PICA/shader_decompiler.hpp"
 #include "config.hpp"
 #include "math_util.hpp"
@@ -134,8 +135,8 @@ void RendererGL::initGraphicsContextInternal() {
 
 	auto prevTexture = OpenGL::getTex2D();
 
-	// Create a plain black texture for when a game reads an invalid texture. It is common for games to configure the PICA to read texture info from NULL.
+	// Create a plain black texture for when a game reads an invalid texture. It is common for games to configure the PICA to read texture info from
-	// Some games that do this are Pokemon X, Cars 2, Tomodachi Life, and more. We bind the texture to an FBO, clear it, and free the FBO
+	// NULL. Some games that do this are Pokemon X, Cars 2, Tomodachi Life, and more. We bind the texture to an FBO, clear it, and free the FBO
 	blankTexture.create(8, 8, GL_RGBA8);
 	blankTexture.bind();
 	blankTexture.setMinFilter(OpenGL::Linear);
@@ -228,7 +229,7 @@ void RendererGL::setupBlending() {
 	// Shows if blending is enabled. If it is not enabled, then logic ops are enabled instead
 	const bool blendingEnabled = (regs[PICA::InternalRegs::ColourOperation] & (1 << 8)) != 0;
 
-	if (!blendingEnabled) { // Logic ops are enabled
+	if (!blendingEnabled) {  // Logic ops are enabled
 		const u32 logicOp = getBits<0, 4>(regs[PICA::InternalRegs::LogicOp]);
 		gl.setLogicOp(logicOps[logicOp]);
 
@@ -269,20 +270,13 @@ void RendererGL::setupStencilTest(bool stencilEnable) {
 	}
 
 	static constexpr std::array<GLenum, 8> stencilFuncs = {
-		GL_NEVER,
+		GL_NEVER, GL_ALWAYS, GL_EQUAL, GL_NOTEQUAL, GL_LESS, GL_LEQUAL, GL_GREATER, GL_GEQUAL,
-		GL_ALWAYS,
-		GL_EQUAL,
-		GL_NOTEQUAL,
-		GL_LESS,
-		GL_LEQUAL,
-		GL_GREATER,
-		GL_GEQUAL
 	};
 	gl.enableStencil();
 
 	const u32 stencilConfig = regs[PICA::InternalRegs::StencilTest];
 	const u32 stencilFunc = getBits<4, 3>(stencilConfig);
-	const s32 reference = s8(getBits<16, 8>(stencilConfig)); // Signed reference value
+	const s32 reference = s8(getBits<16, 8>(stencilConfig));  // Signed reference value
 	const u32 stencilRefMask = getBits<24, 8>(stencilConfig);
 
 	const bool stencilWrite = regs[PICA::InternalRegs::DepthBufferWrite];
@@ -293,15 +287,9 @@ void RendererGL::setupStencilTest(bool stencilEnable) {
 	gl.setStencilMask(stencilBufferMask);
 
 	static constexpr std::array<GLenum, 8> stencilOps = {
-		GL_KEEP,
+		GL_KEEP, GL_ZERO, GL_REPLACE, GL_INCR, GL_DECR, GL_INVERT, GL_INCR_WRAP, GL_DECR_WRAP,
-		GL_ZERO,
-		GL_REPLACE,
-		GL_INCR,
-		GL_DECR,
-		GL_INVERT,
-		GL_INCR_WRAP,
-		GL_DECR_WRAP
 	};
+
 	const u32 stencilOpConfig = regs[PICA::InternalRegs::StencilOp];
 	const u32 stencilFailOp = getBits<0, 3>(stencilOpConfig);
 	const u32 depthFailOp = getBits<4, 3>(stencilOpConfig);
@@ -468,7 +456,10 @@ void RendererGL::drawVertices(PICA::PrimType primType, std::span<const Vertex> v
 	const int depthFunc = getBits<4, 3>(depthControl);
 	const int colourMask = getBits<8, 4>(depthControl);
 	gl.setColourMask(colourMask & 1, colourMask & 2, colourMask & 4, colourMask & 8);
-	static constexpr std::array<GLenum, 8> depthModes = {GL_NEVER, GL_ALWAYS, GL_EQUAL, GL_NOTEQUAL, GL_LESS, GL_LEQUAL, GL_GREATER, GL_GEQUAL};
+
+	static constexpr std::array<GLenum, 8> depthModes = {
+		GL_NEVER, GL_ALWAYS, GL_EQUAL, GL_NOTEQUAL, GL_LESS, GL_LEQUAL, GL_GREATER, GL_GEQUAL,
+	};
 
 	bindTexturesToSlots();
 	if (gpu.fogLUTDirty) {
@@ -565,14 +556,14 @@ void RendererGL::display() {
 
 	if (topScreen) {
 		topScreen->get().texture.bind();
-		OpenGL::setViewport(0, 240, 400, 240); // Top screen viewport
+		OpenGL::setViewport(0, 240, 400, 240);   // Top screen viewport
-		OpenGL::draw(OpenGL::TriangleStrip, 4); // Actually draw our 3DS screen
+		OpenGL::draw(OpenGL::TriangleStrip, 4);  // Actually draw our 3DS screen
 	}
 
 	const u32 bottomActiveFb = externalRegs[Framebuffer1Select] & 1;
 	const u32 bottomScreenAddr = externalRegs[bottomActiveFb == 0 ? Framebuffer1AFirstAddr : Framebuffer1ASecondAddr];
 	auto bottomScreen = colourBufferCache.findFromAddress(bottomScreenAddr);
-	
+
 	if (bottomScreen) {
 		bottomScreen->get().texture.bind();
 		OpenGL::setViewport(40, 0, 320, 240);
@@ -581,34 +572,59 @@ void RendererGL::display() {
 
 	if constexpr (!Helpers::isHydraCore()) {
 		glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
+		OpenGL::clearColor();
+
 		screenFramebuffer.bind(OpenGL::ReadFramebuffer);
 
 		if (outputSizeChanged) {
 			outputSizeChanged = false;
 
-			const float srcAspect = 400.0f / 480.0f; // 3DS aspect ratio
+			auto layout = emulatorConfig->screenLayout;
-			const float dstAspect = float(outputWindowWidth) / float(outputWindowHeight);
 
-			blitInfo.destWidth = outputWindowWidth;
+			// Get information about our new screen layout to use for blitting the output
-			blitInfo.destHeight = outputWindowHeight;
+			ScreenLayout::WindowCoordinates windowCoords;
-			blitInfo.destX = 0;
+			ScreenLayout::calculateCoordinates(windowCoords, outputWindowWidth, outputWindowHeight, emulatorConfig->topScreenSize, layout);
-			blitInfo.destY = 0;
 
-			if (dstAspect > srcAspect) {
+			blitInfo.topScreenX = windowCoords.topScreenX;
-				// Window is wider than source
+			blitInfo.topScreenY = windowCoords.topScreenY;
-				blitInfo.destWidth = int(outputWindowHeight * srcAspect + 0.5f);
+			blitInfo.topScreenWidth = windowCoords.topScreenWidth;
-				blitInfo.destX = (outputWindowWidth - blitInfo.destWidth) / 2;
+			blitInfo.topScreenHeight = windowCoords.topScreenHeight;
-			} else {
+
-				// Window is taller than source
+			blitInfo.bottomScreenX = windowCoords.bottomScreenX;
-				blitInfo.destHeight = int(outputWindowWidth / srcAspect + 0.5f);
+			blitInfo.bottomScreenY = windowCoords.bottomScreenY;
-				blitInfo.destY = (outputWindowHeight - blitInfo.destHeight) / 2;
+			blitInfo.bottomScreenWidth = windowCoords.bottomScreenWidth;
-			}
+			blitInfo.bottomScreenHeight = windowCoords.bottomScreenHeight;
+
+			// Flip topScreenY and bottomScreenY because glBlitFramebuffer uses bottom-left origin
+			blitInfo.topScreenY = outputWindowHeight - (blitInfo.topScreenY + blitInfo.topScreenHeight);
+			blitInfo.bottomScreenY = outputWindowHeight - (blitInfo.bottomScreenY + blitInfo.bottomScreenHeight);
+
+			// Used for optimizing the screen blit into a single blit
+			blitInfo.canDoSingleBlit = windowCoords.singleBlitInfo.canDoSingleBlit;
+			blitInfo.destX = windowCoords.singleBlitInfo.destX;
+			blitInfo.destY = windowCoords.singleBlitInfo.destY;
+			blitInfo.destWidth = windowCoords.singleBlitInfo.destWidth;
+			blitInfo.destHeight = windowCoords.singleBlitInfo.destHeight;
 		}
 
-		glBlitFramebuffer(
+		if (blitInfo.canDoSingleBlit) {
-			0, 0, 400, 480, blitInfo.destX, blitInfo.destY, blitInfo.destX + blitInfo.destWidth, blitInfo.destY + blitInfo.destHeight,
+			glBlitFramebuffer(
-			GL_COLOR_BUFFER_BIT, GL_LINEAR
+				0, 0, 400, 480, blitInfo.destX, blitInfo.destY, blitInfo.destX + blitInfo.destWidth, blitInfo.destY + blitInfo.destHeight,
-		);
+				GL_COLOR_BUFFER_BIT, GL_LINEAR
+			);
+		} else {
+			// Blit top screen
+			glBlitFramebuffer(
+				0, 240, 400, 480, blitInfo.topScreenX, blitInfo.topScreenY, blitInfo.topScreenX + blitInfo.topScreenWidth,
+				blitInfo.topScreenY + blitInfo.topScreenHeight, GL_COLOR_BUFFER_BIT, GL_LINEAR
+			);
+
+			// Blit bottom screen
+			glBlitFramebuffer(
+				40, 0, 360, 240, blitInfo.bottomScreenX, blitInfo.bottomScreenY, blitInfo.bottomScreenX + blitInfo.bottomScreenWidth,
+				blitInfo.bottomScreenY + blitInfo.bottomScreenHeight, GL_COLOR_BUFFER_BIT, GL_LINEAR
+			);
+		}
 	}
 }
 
@@ -735,8 +751,10 @@ void RendererGL::displayTransfer(u32 inputAddr, u32 outputAddr, u32 inputSize, u
 	u32 outputWidth = outputSize & 0xffff;
 	u32 outputHeight = outputSize >> 16;
 
-	OpenGL::DebugScope scope("DisplayTransfer inputAddr 0x%08X outputAddr 0x%08X inputWidth %d outputWidth %d inputHeight %d outputHeight %d",
+	OpenGL::DebugScope scope(
-							 inputAddr, outputAddr, inputWidth, outputWidth, inputHeight, outputHeight);
+		"DisplayTransfer inputAddr 0x%08X outputAddr 0x%08X inputWidth %d outputWidth %d inputHeight %d outputHeight %d", inputAddr, outputAddr,
+		inputWidth, outputWidth, inputHeight, outputHeight
+	);
 
 	auto srcFramebuffer = getColourBuffer(inputAddr, inputFormat, inputWidth, outputHeight);
 	Math::Rect<u32> srcRect = srcFramebuffer->getSubRect(inputAddr, outputWidth, outputHeight);
@@ -786,8 +804,10 @@ void RendererGL::textureCopy(u32 inputAddr, u32 outputAddr, u32 totalBytes, u32
 	const u32 outputWidth = (outputSize & 0xffff) << 4;
 	const u32 outputGap = (outputSize >> 16) << 4;
 
-	OpenGL::DebugScope scope("TextureCopy inputAddr 0x%08X outputAddr 0x%08X totalBytes %d inputWidth %d inputGap %d outputWidth %d outputGap %d",
+	OpenGL::DebugScope scope(
-							 inputAddr, outputAddr, totalBytes, inputWidth, inputGap, outputWidth, outputGap);
+		"TextureCopy inputAddr 0x%08X outputAddr 0x%08X totalBytes %d inputWidth %d inputGap %d outputWidth %d outputGap %d", inputAddr, outputAddr,
+		totalBytes, inputWidth, inputGap, outputWidth, outputGap
+	);
 
 	if (inputGap != 0 || outputGap != 0) {
 		// Helpers::warn("Strided texture copy\n");
@@ -825,7 +845,7 @@ void RendererGL::textureCopy(u32 inputAddr, u32 outputAddr, u32 totalBytes, u32
 	// Find the source surface.
 	auto srcFramebuffer = getColourBuffer(inputAddr, PICA::ColorFmt::RGBA8, copyStride, copyHeight, false);
 	if (!srcFramebuffer) {
-		static int shutUpCounter = 0; // Don't want to spam the console too much, so shut up after 5 times
+		static int shutUpCounter = 0;  // Don't want to spam the console too much, so shut up after 5 times
 
 		if (shutUpCounter < 5) {
 			shutUpCounter++;
@@ -1041,8 +1061,8 @@ bool RendererGL::prepareForDraw(ShaderUnit& shaderUnit, PICA::DrawAcceleration*
 				driverInfo.usingGLES ? PICA::ShaderGen::API::GLES : PICA::ShaderGen::API::GL, PICA::ShaderGen::Language::GLSL
 			);
 
-			// Empty source means compilation error, if the source is not empty then we convert the recompiled PICA code into a valid shader and upload
+			// Empty source means compilation error, if the source is not empty then we convert the recompiled PICA code into a valid shader and
-			// it to the GPU
+			// upload it to the GPU
 			if (!picaShaderSource.empty()) {
 				std::string vertexShaderSource = fragShaderGen.getVertexShaderAccelerated(picaShaderSource, vertexConfig, usingUbershader);
 				shader->create({vertexShaderSource}, OpenGL::Vertex);
@@ -1073,7 +1093,7 @@ bool RendererGL::prepareForDraw(ShaderUnit& shaderUnit, PICA::DrawAcceleration*
 	if (!usingUbershader) {
 		OpenGL::Program& program = getSpecializedShader();
 		gl.useProgram(program);
-	} else { // Bind ubershader & load ubershader uniforms
+	} else {  // Bind ubershader & load ubershader uniforms
 		gl.useProgram(triangleProgram);
 
 		const float depthScale = f24::fromRaw(regs[PICA::InternalRegs::DepthScale] & 0xffffff).toFloat32();
@@ -1243,7 +1263,7 @@ void RendererGL::accelerateVertexUpload(ShaderUnit& shaderUnit, PICA::DrawAccele
 	const u32 currentAttributeMask = accel->enabledAttributeMask;
 	// Use bitwise xor to calculate which attributes changed
 	u32 attributeMaskDiff = currentAttributeMask ^ previousAttributeMask;
-	
+
 	while (attributeMaskDiff != 0) {
 		// Get index of next different attribute and turn it off
 		const u32 index = 31 - std::countl_zero<u32>(attributeMaskDiff);

src/core/renderer_mtl/renderer_mtl.cpp

@@ -10,6 +10,7 @@
 
 #include "PICA/gpu.hpp"
 #include "PICA/pica_hash.hpp"
+#include "screen_layout.hpp"
 #include "SDL_metal.h"
 
 using namespace PICA;
@@ -105,32 +106,26 @@ void RendererMTL::display() {
 
 	if (outputSizeChanged) {
 		outputSizeChanged = false;
+		ScreenLayout::WindowCoordinates windowCoords;
+		ScreenLayout::calculateCoordinates(
+			windowCoords, outputWindowWidth, outputWindowHeight, emulatorConfig->topScreenSize, emulatorConfig->screenLayout
+		);
 
-		const float srcAspect = 400.0 / 480.0;
+		blitInfo.topScreenX = float(windowCoords.topScreenX);
-		const float destAspect = float(outputWindowWidth) / float(outputWindowHeight);
+		blitInfo.topScreenY = float(windowCoords.topScreenY);
-		int destX = 0, destY = 0, destWidth = outputWindowWidth, destHeight = outputWindowHeight;
+		blitInfo.bottomScreenX = float(windowCoords.bottomScreenX);
+		blitInfo.bottomScreenY = float(windowCoords.bottomScreenY);
 
-		if (destAspect > srcAspect) {
+		blitInfo.topScreenWidth = float(windowCoords.topScreenWidth);
-			// Window is wider than source
+		blitInfo.topScreenHeight = float(windowCoords.topScreenHeight);
-			destWidth = int(outputWindowHeight * srcAspect + 0.5f);
+		blitInfo.bottomScreenWidth = float(windowCoords.bottomScreenWidth);
-			destX = (outputWindowWidth - destWidth) / 2;
+		blitInfo.bottomScreenHeight = float(windowCoords.bottomScreenHeight);
-		} else {
-			// Window is taller than source
-			destHeight = int(outputWindowWidth / srcAspect + 0.5f);
-			destY = (outputWindowHeight - destHeight) / 2;
-		}
-
-		blitInfo.scale = float(destWidth) / 400.0f;
-		blitInfo.topScreenX = float(destX);
-		blitInfo.topScreenY = float(destY + (destHeight - int(480 * blitInfo.scale)) / 2);
-		blitInfo.bottomScreenX = float(destX) + 40 * blitInfo.scale;
-		blitInfo.bottomScreenY = blitInfo.topScreenY + 240 * blitInfo.scale;
 	}
 
 	// Top screen
 	if (topScreen) {
 		renderCommandEncoder->setViewport(
-			MTL::Viewport{blitInfo.topScreenX, blitInfo.topScreenY, 400 * blitInfo.scale, 240 * blitInfo.scale, 0.0f, 1.0f}
+			MTL::Viewport{blitInfo.topScreenX, blitInfo.topScreenY, blitInfo.topScreenWidth, blitInfo.topScreenHeight, 0.0f, 1.0f}
 		);
 		renderCommandEncoder->setFragmentTexture(topScreen->get().texture, 0);
 		renderCommandEncoder->drawPrimitives(MTL::PrimitiveTypeTriangleStrip, NS::UInteger(0), NS::UInteger(4));
@@ -139,7 +134,7 @@ void RendererMTL::display() {
 	// Bottom screen
 	if (bottomScreen) {
 		renderCommandEncoder->setViewport(
-			MTL::Viewport{blitInfo.bottomScreenX, blitInfo.bottomScreenY, 320 * blitInfo.scale, 240 * blitInfo.scale, 0.0f, 1.0f}
+			MTL::Viewport{blitInfo.bottomScreenX, blitInfo.bottomScreenY, blitInfo.bottomScreenWidth, blitInfo.bottomScreenHeight, 0.0f, 1.0f}
 		);
 		renderCommandEncoder->setFragmentTexture(bottomScreen->get().texture, 0);
 		renderCommandEncoder->drawPrimitives(MTL::PrimitiveTypeTriangleStrip, NS::UInteger(0), NS::UInteger(4));
@@ -800,7 +795,7 @@ void RendererMTL::updateLightingLUT(MTL::RenderCommandEncoder* encoder) {
 void RendererMTL::updateFogLUT(MTL::RenderCommandEncoder* encoder) {
 	gpu.fogLUTDirty = false;
 
-	std::array<float, FOG_LUT_TEXTURE_WIDTH* 2> fogLut = {0.0f};
+	std::array<float, FOG_LUT_TEXTURE_WIDTH * 2> fogLut = {0.0f};
 
 	for (int i = 0; i < fogLut.size(); i += 2) {
 		const uint32_t value = gpu.fogLUT[i >> 1];
@@ -835,8 +830,11 @@ void RendererMTL::textureCopyImpl(
 	commandEncoder.setRenderPipelineState(blitPipeline);
 
 	// Viewport
-	renderCommandEncoder->setViewport(MTL::Viewport{
+	renderCommandEncoder->setViewport(
-		double(destRect.left), double(destRect.bottom), double(destRect.right - destRect.left), double(destRect.top - destRect.bottom), 0.0, 1.0});
+		MTL::Viewport{
+			double(destRect.left), double(destRect.bottom), double(destRect.right - destRect.left), double(destRect.top - destRect.bottom), 0.0, 1.0
+		}
+	);
 
 	float srcRectNDC[4] = {
 		srcRect.left / (float)srcFramebuffer.size.u(),

src/core/screen_layout.cpp

@@ -0,0 +1,152 @@
+#include "screen_layout.hpp"
+
+#include <algorithm>
+#include <cstdio>
+#include <unordered_map>
+
+using namespace ScreenLayout;
+
+// Calculate screen coordinates on the screen for a given layout & a given size for the output window
+// Used in both the renderers and in the frontends (To eg calculate touch screen boundaries)
+void ScreenLayout::calculateCoordinates(
+	WindowCoordinates& coordinates, u32 outputWindowWidth, u32 outputWindowHeight, float topScreenPercentage, Layout layout
+) {
+	const float destAspect = float(outputWindowWidth) / float(outputWindowHeight);
+
+	if (layout == Layout::Default || layout == Layout::DefaultFlipped) {
+		// Calculate available height for each screen based on split
+		int availableTopHeight = int(outputWindowHeight * topScreenPercentage + 0.5f);
+		int availableBottomHeight = outputWindowHeight - availableTopHeight;
+
+		// Calculate scales for top and bottom screens, and then the actual sizes
+		float scaleTop = std::min(float(outputWindowWidth) / float(TOP_SCREEN_WIDTH), float(availableTopHeight) / float(TOP_SCREEN_HEIGHT));
+		float scaleBottom =
+			std::min(float(outputWindowWidth) / float(BOTTOM_SCREEN_WIDTH), float(availableBottomHeight) / float(BOTTOM_SCREEN_HEIGHT));
+
+		int topScreenWidth = int(TOP_SCREEN_WIDTH * scaleTop + 0.5f);
+		int topScreenHeight = int(TOP_SCREEN_HEIGHT * scaleTop + 0.5f);
+		int bottomScreenWidth = int(BOTTOM_SCREEN_WIDTH * scaleBottom + 0.5f);
+		int bottomScreenHeight = int(BOTTOM_SCREEN_HEIGHT * scaleBottom + 0.5f);
+
+		// Center screens horizontally
+		int topScreenX = (outputWindowWidth - topScreenWidth) / 2;
+		int bottomScreenX = (outputWindowWidth - bottomScreenWidth) / 2;
+
+		coordinates.topScreenWidth = topScreenWidth;
+		coordinates.topScreenHeight = topScreenHeight;
+		coordinates.bottomScreenWidth = bottomScreenWidth;
+		coordinates.bottomScreenHeight = bottomScreenHeight;
+
+		coordinates.topScreenX = topScreenX;
+		coordinates.bottomScreenX = bottomScreenX;
+
+		if (layout == Layout::Default) {
+			coordinates.topScreenY = 0;
+			coordinates.bottomScreenY = topScreenHeight;
+		} else {
+			coordinates.bottomScreenY = 0;
+			coordinates.topScreenY = bottomScreenHeight;
+		}
+
+		coordinates.windowWidth = outputWindowWidth;
+		coordinates.windowHeight = outputWindowHeight;
+
+		// Default layout can be rendered using a single blit, flipped layout can't
+		if (layout == Layout::Default) {
+			coordinates.singleBlitInfo.destX = coordinates.topScreenX;
+			coordinates.singleBlitInfo.destY = coordinates.topScreenY;
+			coordinates.singleBlitInfo.destWidth = coordinates.topScreenWidth;
+			coordinates.singleBlitInfo.destHeight = coordinates.topScreenHeight + coordinates.bottomScreenHeight;
+		} else {
+			// Dummy data for the single blit info, as we can't render the screen in 1 blit when the screens are side-by-sid
+			coordinates.singleBlitInfo.destX = 0;
+			coordinates.singleBlitInfo.destY = 0;
+			coordinates.singleBlitInfo.destWidth = 0;
+			coordinates.singleBlitInfo.destHeight = 0;
+		}
+
+		// Check if we can blit the screens in 1 blit. If not, we'll break it into two.
+		// TODO: Maybe add some more size-related checks too.
+		coordinates.singleBlitInfo.canDoSingleBlit = layout == Layout::Default && topScreenPercentage == 0.5 &&
+													 coordinates.topScreenY + coordinates.topScreenHeight == coordinates.bottomScreenY;
+	} else if (layout == Layout::SideBySide || layout == Layout::SideBySideFlipped) {
+		// Calculate available width for each screen based on split
+		int availableTopWidth = int(outputWindowWidth * topScreenPercentage + 0.5f);
+		int availableBottomWidth = outputWindowWidth - availableTopWidth;
+
+		// Calculate scales for top and bottom screens, and then the actual sizes
+		float scaleTop = std::min(float(availableTopWidth) / float(TOP_SCREEN_WIDTH), float(outputWindowHeight) / float(TOP_SCREEN_HEIGHT));
+		float scaleBottom =
+			std::min(float(availableBottomWidth) / float(BOTTOM_SCREEN_WIDTH), float(outputWindowHeight) / float(BOTTOM_SCREEN_HEIGHT));
+
+		int topScreenWidth = int(TOP_SCREEN_WIDTH * scaleTop + 0.5f);
+		int topScreenHeight = int(TOP_SCREEN_HEIGHT * scaleTop + 0.5f);
+		int bottomScreenWidth = int(BOTTOM_SCREEN_WIDTH * scaleBottom + 0.5f);
+		int bottomScreenHeight = int(BOTTOM_SCREEN_HEIGHT * scaleBottom + 0.5f);
+
+		// Vertically center the tallest screen
+		int maxHeight = std::max(topScreenHeight, bottomScreenHeight);
+		int centerY = (outputWindowHeight - maxHeight) / 2;
+
+		int topScreenY = centerY + (maxHeight - topScreenHeight) / 2;
+		int bottomScreenY = centerY + (maxHeight - bottomScreenHeight) / 2;
+
+		if (layout == Layout::SideBySide) {
+			coordinates.topScreenX = (outputWindowWidth - (topScreenWidth + bottomScreenWidth)) / 2;
+			coordinates.bottomScreenX = coordinates.topScreenX + topScreenWidth;
+		} else {
+			coordinates.bottomScreenX = (outputWindowWidth - (topScreenWidth + bottomScreenWidth)) / 2;
+			coordinates.topScreenX = coordinates.bottomScreenX + bottomScreenWidth;
+		}
+
+		coordinates.topScreenY = topScreenY;
+		coordinates.topScreenWidth = topScreenWidth;
+		coordinates.topScreenHeight = topScreenHeight;
+
+		coordinates.bottomScreenY = bottomScreenY;
+		coordinates.bottomScreenWidth = bottomScreenWidth;
+		coordinates.bottomScreenHeight = bottomScreenHeight;
+
+		coordinates.windowWidth = outputWindowWidth;
+		coordinates.windowHeight = outputWindowHeight;
+
+		// Dummy data for the single blit info, as we can't render the screen in 1 blit when the screens are side-by-side
+		coordinates.singleBlitInfo.canDoSingleBlit = false;
+		coordinates.singleBlitInfo.destX = 0;
+		coordinates.singleBlitInfo.destY = 0;
+		coordinates.singleBlitInfo.destWidth = 0;
+		coordinates.singleBlitInfo.destHeight = 0;
+	} else {
+		Helpers::panic("Unimplemented screen layout");
+	}
+}
+
+Layout ScreenLayout::layoutFromString(std::string inString) {
+	// Transform to lower-case to make the setting case-insensitive
+	std::transform(inString.begin(), inString.end(), inString.begin(), [](unsigned char c) { return std::tolower(c); });
+
+	static const std::unordered_map<std::string, Layout> map = {
+		{"default", Layout::Default},
+		{"defaultflipped", Layout::DefaultFlipped},
+		{"sidebyside", Layout::SideBySide},
+		{"sidebysideflipped", Layout::SideBySideFlipped},
+	};
+
+	if (auto search = map.find(inString); search != map.end()) {
+		return search->second;
+	}
+
+	printf("Invalid screen layout. Defaulting to Default\n");
+	return Layout::Default;
+}
+
+const char* ScreenLayout::layoutToString(Layout layout) {
+	switch (layout) {
+		case Layout::Default: return "default";
+		case Layout::DefaultFlipped: return "defaultFlipped";
+		case Layout::SideBySide: return "sideBySide";
+		case Layout::SideBySideFlipped: return "sideBySideFlipped";
+		default: return "invalid";
+	}
+}
+    

src/panda_qt/config_window.cpp

@@ -240,6 +240,36 @@ ConfigWindow::ConfigWindow(ConfigCallback configCallback, MainWindowCallback win
 	connectCheckbox(hashTextures, config.hashTextures);
 	gpuLayout->addRow(hashTextures);
 
+	QComboBox* screenLayout = new QComboBox();
+	screenLayout->addItem(tr("Default"));
+	screenLayout->addItem(tr("Default (Flipped)"));
+	screenLayout->addItem(tr("Side-by-Side"));
+	screenLayout->addItem(tr("Side-by-Side (Flipped)"));
+	screenLayout->setCurrentIndex(static_cast<int>(config.screenLayout));
+	connect(screenLayout, &QComboBox::currentIndexChanged, this, [&](int index) {
+		config.screenLayout = static_cast<ScreenLayout::Layout>(index);
+		updateConfig();
+	});
+	gpuLayout->addRow(tr("Screen Layout"), screenLayout);
+
+	// Screen size slider widgets
+	QLabel* topScreenSizeLabel = new QLabel(QString::number(int(config.topScreenSize * 100)));
+	QSlider* topScreenSizeSlider = new QSlider(Qt::Horizontal);
+
+	topScreenSizeSlider->setRange(0, 100);
+	topScreenSizeSlider->setValue(int(config.topScreenSize * 100));
+	connect(topScreenSizeSlider, &QSlider::valueChanged, this, [this, topScreenSizeLabel](int value) {
+		config.topScreenSize = float(value) / 100.0f;
+		topScreenSizeLabel->setText(QString::number(value));
+		updateConfig();
+	});
+
+	QHBoxLayout* screenSizeLayout = new QHBoxLayout();
+	screenSizeLayout->setSpacing(4);
+	screenSizeLayout->addWidget(topScreenSizeSlider);
+	screenSizeLayout->addWidget(topScreenSizeLabel);
+	gpuLayout->addRow(tr("Top screen size (%)"), screenSizeLayout);
+
 	QCheckBox* forceShadergenForLights = new QCheckBox(tr("Force shadergen when rendering lights"));
 	connectCheckbox(forceShadergenForLights, config.forceShadergenForLights);
 	gpuLayout->addRow(forceShadergenForLights);
@@ -302,7 +332,7 @@ ConfigWindow::ConfigWindow(ConfigCallback configCallback, MainWindowCallback win
 	volumeSlider->setRange(0, 200);
 	volumeSlider->setValue(int(config.audioDeviceConfig.volumeRaw * 100));
 	connect(volumeSlider, &QSlider::valueChanged, this, [this, volumeLabel](int value) {
-		config.audioDeviceConfig.volumeRaw = static_cast<float>(value) / 100.0f;
+		config.audioDeviceConfig.volumeRaw = float(value) / 100.0f;
 		volumeLabel->setText(QString::number(value));
 
 		updateConfig();
@@ -467,12 +497,14 @@ void ConfigWindow::setTheme(Theme theme) {
 			p.setColor(QPalette::Highlight, QColor(42, 130, 218));
 			p.setColor(QPalette::HighlightedText, Qt::black);
 			qApp->setPalette(p);
-			qApp->setStyleSheet("QLineEdit {"
+			qApp->setStyleSheet(
+				"QLineEdit {"
 				"background-color: #000000; color: #ffffff; border: 1px solid #a0a0a0; "
 				"border-radius: 4px; padding: 5px; }"
 
 				"QCheckBox::indicator:unchecked {"
-				"border: 1px solid #808080; border-radius: 4px; }");
+				"border: 1px solid #808080; border-radius: 4px; }"
+			);
 			break;
 		}
 

src/panda_qt/main_window.cpp

@@ -129,6 +129,8 @@ MainWindow::MainWindow(QApplication* app, QWidget* parent) : QMainWindow(parent)
 		if (config.printAppVersion) {
 			printf("Welcome to Panda3DS v%s!\n", PANDA3DS_VERSION);
 		}
+
+		screen->reloadScreenLayout(config.screenLayout, config.topScreenSize);
 	}
 
 	// The emulator graphics context for the thread should be initialized in the emulator thread due to how GL contexts work
@@ -435,13 +437,24 @@ void MainWindow::dispatchMessage(const EmulatorMessage& message) {
 			break;
 		}
 
-		case MessageType::UpdateConfig:
+		case MessageType::UpdateConfig: {
-			emu->getConfig() = configWindow->getConfig();
+			auto& emuConfig = emu->getConfig();
+			auto& newConfig = configWindow->getConfig();
+			// If the screen layout changed, we have to notify the emulator & the screen widget
+			bool reloadScreenLayout = (emuConfig.screenLayout != newConfig.screenLayout || emuConfig.topScreenSize != newConfig.topScreenSize);
+
+			emuConfig = newConfig;
 			emu->reloadSettings();
 
+			if (reloadScreenLayout) {
+				emu->reloadScreenLayout();
+				screen->reloadScreenLayout(newConfig.screenLayout, newConfig.topScreenSize);
+			}
+
 			// Save new settings to disk
-			emu->getConfig().save();
+			emuConfig.save();
 			break;
+		}
 	}
 }
 
@@ -525,25 +538,28 @@ void MainWindow::handleTouchscreenPress(QMouseEvent* event) {
 	const QPointF clickPos = event->globalPosition();
 	const QPointF widgetPos = screen->mapFromGlobal(clickPos);
 
+	const auto& coords = screen->screenCoordinates;
+	const float bottomScreenX = float(coords.bottomScreenX);
+	const float bottomScreenY = float(coords.bottomScreenY);
+	const float bottomScreenWidth = float(coords.bottomScreenWidth);
+	const float bottomScreenHeight = float(coords.bottomScreenHeight);
+
 	// Press is inside the screen area
-	if (widgetPos.x() >= 0 && widgetPos.x() < screen->width() && widgetPos.y() >= 0 && widgetPos.y() < screen->height()) {
+	if (widgetPos.x() >= bottomScreenX && widgetPos.x() < bottomScreenX + bottomScreenWidth && widgetPos.y() >= bottomScreenY &&
-		// Go from widget positions to [0, 400) for x and [0, 480) for y
+		widgetPos.y() < bottomScreenY + bottomScreenHeight) {
-		uint x = (uint)std::round(widgetPos.x() / screen->width() * 400.f);
+		// Map widget position to 3DS touchscreen coordinates, with (0, 0) = top left of touchscreen
-		uint y = (uint)std::round(widgetPos.y() / screen->height() * 480.f);
+		float relX = (widgetPos.x() - bottomScreenX) / bottomScreenWidth;
+		float relY = (widgetPos.y() - bottomScreenY) / bottomScreenHeight;
 
-		// Check if touch falls in the touch screen area
+		u16 x_converted = u16(std::clamp(relX * ScreenLayout::BOTTOM_SCREEN_WIDTH, 0.f, float(ScreenLayout::BOTTOM_SCREEN_WIDTH - 1)));
-		if (y >= 240 && y <= 480 && x >= 40 && x < 40 + 320) {
+		u16 y_converted = u16(std::clamp(relY * ScreenLayout::BOTTOM_SCREEN_HEIGHT, 0.f, float(ScreenLayout::BOTTOM_SCREEN_HEIGHT - 1)));
-			// Convert to 3DS coordinates
-			u16 x_converted = static_cast<u16>(x) - 40;
-			u16 y_converted = static_cast<u16>(y) - 240;
 
-			EmulatorMessage message{.type = MessageType::PressTouchscreen};
+		EmulatorMessage message{.type = MessageType::PressTouchscreen};
-			message.touchscreen.x = x_converted;
+		message.touchscreen.x = x_converted;
-			message.touchscreen.y = y_converted;
+		message.touchscreen.y = y_converted;
-			sendMessage(message);
+		sendMessage(message);
-		} else {
+	} else {
-			sendMessage(EmulatorMessage{.type = MessageType::ReleaseTouchscreen});
+		sendMessage(EmulatorMessage{.type = MessageType::ReleaseTouchscreen});
-		}
 	}
 }
 

src/panda_qt/screen.cpp

@@ -21,7 +21,7 @@
 ScreenWidget::ScreenWidget(ResizeCallback resizeCallback, QWidget* parent) : QWidget(parent), resizeCallback(resizeCallback) {
 	// Create a native window for use with our graphics API of choice
 	resize(800, 240 * 4);
-	
+
 	setAutoFillBackground(false);
 	setAttribute(Qt::WA_NativeWindow, true);
 	setAttribute(Qt::WA_NoSystemBackground, true);
@@ -47,6 +47,8 @@ void ScreenWidget::resizeEvent(QResizeEvent* event) {
 		this->windowInfo = *windowInfo;
 	}
 
+	reloadScreenCoordinates();
+
 	// This will call take care of calling resizeSurface from the emulator thread
 	resizeCallback(surfaceWidth, surfaceHeight);
 }
@@ -60,6 +62,17 @@ void ScreenWidget::resizeSurface(u32 width, u32 height) {
 	}
 }
 
+void ScreenWidget::reloadScreenCoordinates() {
+	ScreenLayout::calculateCoordinates(screenCoordinates, u32(width()), u32(height()), topScreenSize, screenLayout);
+}
+
+void ScreenWidget::reloadScreenLayout(ScreenLayout::Layout newLayout, float newTopScreenSize) {
+	screenLayout = newLayout;
+	topScreenSize = newTopScreenSize;
+
+	reloadScreenCoordinates();
+}
+
 bool ScreenWidget::createGLContext() {
 	// List of GL context versions we will try. Anything 4.1+ is good for desktop OpenGL, and 3.1+ for OpenGL ES
 	static constexpr std::array<GL::Context::Version, 8> versionsToTry = {

src/panda_sdl/frontend_sdl.cpp

@@ -55,7 +55,12 @@ FrontendSDL::FrontendSDL() : keyboardMappings(InputMappings::defaultKeyboardMapp
 		windowWidth = 400;
 		windowHeight = 480;
 	}
+
+	// Initialize output size and screen layout
 	emu.setOutputSize(windowWidth, windowHeight);
+	ScreenLayout::calculateCoordinates(
+		screenCoordinates, u32(windowWidth), u32(windowHeight), emu.getConfig().topScreenSize, emu.getConfig().screenLayout
+	);
 
 	if (needOpenGL) {
 		// Demand 4.1 core for OpenGL renderer (max available on MacOS), 3.3 for the software & null renderers
@@ -230,24 +235,7 @@ void FrontendSDL::run() {
 					if (emu.romType == ROMType::None) break;
 
 					if (event.button.button == SDL_BUTTON_LEFT) {
-						if (windowWidth == 0 || windowHeight == 0) [[unlikely]] {
+						handleLeftClick(event.button.x, event.button.y);
-							break;
-						}
-
-						// Go from window positions to [0, 400) for x and [0, 480) for y
-						const s32 x = (s32)std::round(event.button.x * 400.f / windowWidth);
-						const s32 y = (s32)std::round(event.button.y * 480.f / windowHeight);
-
-						// Check if touch falls in the touch screen area
-						if (y >= 240 && y <= 480 && x >= 40 && x < 40 + 320) {
-							// Convert to 3DS coordinates
-							u16 x_converted = static_cast<u16>(x) - 40;
-							u16 y_converted = static_cast<u16>(y) - 240;
-
-							hid.setTouchScreenPress(x_converted, y_converted);
-						} else {
-							hid.releaseTouchScreen();
-						}
 					} else if (event.button.button == SDL_BUTTON_RIGHT) {
 						holdingRightClick = true;
 					}
@@ -321,18 +309,7 @@ void FrontendSDL::run() {
 							break;
 						}
 
-						// Go from window positions to [0, 400) for x and [0, 480) for y
+						handleLeftClick(event.motion.x, event.motion.y);
-						const s32 x = (s32)std::round(event.motion.x * 400.f / windowWidth);
-						const s32 y = (s32)std::round(event.motion.y * 480.f / windowHeight);
-
-						// Check if touch falls in the touch screen area and register the new touch screen position
-						if (y >= 240 && y <= 480 && x >= 40 && x < 40 + 320) {
-							// Convert to 3DS coordinates
-							u16 x_converted = static_cast<u16>(x) - 40;
-							u16 y_converted = static_cast<u16>(y) - 240;
-
-							hid.setTouchScreenPress(x_converted, y_converted);
-						}
 					}
 
 					// We use right click to indicate we want to rotate the console. If right click is not held, then this is not a gyroscope rotation
@@ -393,6 +370,12 @@ void FrontendSDL::run() {
 					if (type == SDL_WINDOWEVENT_RESIZED) {
 						windowWidth = event.window.data1;
 						windowHeight = event.window.data2;
+
+						const auto& config = emu.getConfig();
+						ScreenLayout::calculateCoordinates(
+							screenCoordinates, u32(windowWidth), u32(windowHeight), emu.getConfig().topScreenSize, emu.getConfig().screenLayout
+						);
+
 						emu.setOutputSize(windowWidth, windowHeight);
 					}
 				}
@@ -471,3 +454,31 @@ void FrontendSDL::setupControllerSensors(SDL_GameController* controller) {
 		SDL_GameControllerSetSensorEnabled(controller, SDL_SENSOR_ACCEL, SDL_TRUE);
 	}
 }
+
+void FrontendSDL::handleLeftClick(int mouseX, int mouseY) {
+	if (windowWidth == 0 || windowHeight == 0) [[unlikely]] {
+		return;
+	}
+
+	const auto& coords = screenCoordinates;
+	const int bottomScreenX = int(coords.bottomScreenX);
+	const int bottomScreenY = int(coords.bottomScreenY);
+	const int bottomScreenWidth = int(coords.bottomScreenWidth);
+	const int bottomScreenHeight = int(coords.bottomScreenHeight);
+	auto& hid = emu.getServiceManager().getHID();
+
+	// Check if the mouse is inside the bottom screen area
+	if (mouseX >= int(bottomScreenX) && mouseX < int(bottomScreenX + bottomScreenWidth) && mouseY >= int(bottomScreenY) &&
+		mouseY < int(bottomScreenY + bottomScreenHeight)) {
+		// Map to 3DS touchscreen coordinates
+		float relX = float(mouseX - bottomScreenX) / float(bottomScreenWidth);
+		float relY = float(mouseY - bottomScreenY) / float(bottomScreenHeight);
+
+		u16 x_converted = static_cast<u16>(std::clamp(relX * ScreenLayout::BOTTOM_SCREEN_WIDTH, 0.f, float(ScreenLayout::BOTTOM_SCREEN_WIDTH - 1)));
+		u16 y_converted = static_cast<u16>(std::clamp(relY * ScreenLayout::BOTTOM_SCREEN_HEIGHT, 0.f, float(ScreenLayout::BOTTOM_SCREEN_HEIGHT - 1)));
+
+		hid.setTouchScreenPress(x_converted, y_converted);
+	} else {
+		hid.releaseTouchScreen();
+	}
+}