more screen modes

- add support for different aspect ratios
- add support for displaying only one screen at once

6 files changed, 311 insertions, 144 deletions

diff --git a/src/frontend/FrontendUtil.h b/src/frontend/FrontendUtil.h
index 83749d3..dfeb356 100644
--- a/src/frontend/FrontendUtil.h
+++ b/src/frontend/FrontendUtil.h
@@ -121,21 +121,36 @@ void EnableCheats(bool enable);
 //     0 = even (both screens get same size)
 //     1 = emphasize top screen (make top screen as big as possible, fit bottom screen in remaining space)
 //     2 = emphasize bottom screen
+//     4 = top only
+//     5 = bottom only
 // * screenGap: size of the gap between the two screens
 // * integerScale: force screens to be scaled up at integer scaling factors
 // * screenSwap: whether to swap the position of both screens
-void SetupScreenLayout(int screenWidth, int screenHeight, int screenLayout, int rotation, int sizing, int screenGap, bool integerScale, int swapScreens);
-
-// get a 2x3 transform matrix for each screen
+// * topAspect/botAspect: ratio by which to scale the top and bottom screen respectively
+void SetupScreenLayout(int screenWidth, int screenHeight,
+    int screenLayout,
+    int rotation,
+    int sizing,
+    int screenGap,
+    bool integerScale,
+    bool swapScreens,
+    float topAspect, float botAspect);
+
+const int MaxScreenTransforms = 3;
+
+// get a 2x3 transform matrix for each screen and whether it's a top or bottom screen
 // note: the transform assumes an origin point at the top left of the display,
 // X going left and Y going down
 // for each screen the source coordinates should be (0,0) and (256,192)
-// 'top' and 'bot' should point each to an array of 6 floats
-void GetScreenTransforms(float* top, float* bot);
+// 'out' should point to an array of 6*MaxScreenTransforms floats
+// 'kind' should point to an array of MaxScreenTransforms ints
+// (0 = indicates top screen, 1 = bottom screen)
+// returns the amount of screens
+int GetScreenTransforms(float* out, int* kind);
 
 // de-transform the provided host display coordinates to get coordinates
 // on the bottom screen
-void GetTouchCoords(int& x, int& y);
+bool GetTouchCoords(int& x, int& y);
 
 
 // initialize the audio utility
diff --git a/src/frontend/Util_Video.cpp b/src/frontend/Util_Video.cpp
index f096311..4265631 100644
--- a/src/frontend/Util_Video.cpp
+++ b/src/frontend/Util_Video.cpp
@@ -31,7 +31,8 @@ namespace Frontend
 float TopScreenMtx[6];
 float BotScreenMtx[6];
 float TouchMtx[6];
-
+bool TopEnable;
+bool BotEnable;
 
 void M23_Identity(float* m)
 {
@@ -47,6 +48,13 @@ void M23_Scale(float* m, float s)
     m[4] *= s; m[5] *= s;
 }
 
+void M23_Scale(float* m, float x, float y)
+{
+    m[0] *= x; m[1] *= y;
+    m[2] *= x; m[3] *= y;
+    m[4] *= x; m[5] *= y;
+}
+
 void M23_RotateFast(float* m, int angle)
 {
     if (angle == 0) return;
@@ -109,7 +117,14 @@ void M23_Transform(float* m, float& x, float& y)
 }
 
 
-void SetupScreenLayout(int screenWidth, int screenHeight, int screenLayout, int rotation, int sizing, int screenGap, bool integerScale, int swapScreens)
+void SetupScreenLayout(int screenWidth, int screenHeight,
+    int screenLayout,
+    int rotation,
+    int sizing,
+    int screenGap,
+    bool integerScale,
+    bool swapScreens,
+    float topAspect, float botAspect)
 {
     float refpoints[4][2] =
     {
@@ -130,6 +145,9 @@ void SetupScreenLayout(int screenWidth, int screenHeight, int screenLayout, int
     M23_Translate(TopScreenMtx, -256/2, -192/2);
     M23_Translate(BotScreenMtx, -256/2, -192/2);
 
+    M23_Scale(TopScreenMtx, topAspect, 1);
+    M23_Scale(BotScreenMtx, botAspect, 1);
+
     // rotation
     {
         float rotmtx[6];
@@ -145,136 +163,174 @@ void SetupScreenLayout(int screenWidth, int screenHeight, int screenLayout, int
         M23_Transform(BotScreenMtx, refpoints[3][0], refpoints[3][1]);
     }
 
-    // move screens apart
-    {
-        int idx = layout == 0 ? 1 : 0;
-        float offset =
-            (((layout == 0 && (rotation % 2 == 0)) || (layout == 1 && (rotation % 2 == 1))
-                ? 192.f : 256.f)
-            + screenGap) / 2.f;
-        if ((rotation == 1 || rotation == 2) ^ swapScreens)
-            offset *= -1.f;
-
-        M23_Translate(TopScreenMtx, (idx==0)?-offset:0, (idx==1)?-offset:0);
-        M23_Translate(BotScreenMtx, (idx==0)?offset:0, (idx==1)?offset:0);
-
-        refpoints[0][idx] -= offset;
-        refpoints[1][idx] -= offset;
-        refpoints[2][idx] += offset;
-        refpoints[3][idx] += offset;
-
-        botTrans[idx] = offset;
-    }
+    int posRefPointOffset = 0;
+    int posRefPointCount = 4;
 
-    // scale
+    if (sizing == 4 || sizing == 5)
     {
-        if (sizing == 0)
-        {
-            float minX = refpoints[0][0], maxX = minX;
-            float minY = refpoints[0][1], maxY = minY;
+        float* mtx = sizing == 4 ? TopScreenMtx : BotScreenMtx;
+        int primOffset = sizing == 4 ? 0 : 2;
+        int secOffset = sizing == 5 ? 2 : 0;
 
-            for (int i = 1; i < 4; i++)
-            {
-                minX = std::min(minX, refpoints[i][0]);
-                minY = std::min(minY, refpoints[i][1]);
-                maxX = std::max(maxX, refpoints[i][0]);
-                maxY = std::max(maxY, refpoints[i][1]);
-            }
+        float hSize = fabsf(refpoints[primOffset][0] - refpoints[primOffset+1][0]);
+        float vSize = fabsf(refpoints[primOffset][1] - refpoints[primOffset+1][1]);
+
+        float scale = std::min(screenWidth / hSize, screenHeight / vSize);
+        if (integerScale)
+            scale = floorf(scale);
 
-            float hSize = maxX - minX;
-            float vSize = maxY - minY;
+        TopEnable = sizing == 4;
+        BotEnable = sizing == 5;
+        botScale = scale;
 
-            // scale evenly
-            float scale = std::min(screenWidth / hSize, screenHeight / vSize);
+        M23_Scale(mtx, scale);
+        refpoints[primOffset][0] *= scale;
+        refpoints[primOffset][1] *= scale;
+        refpoints[primOffset+1][0] *= scale;
+        refpoints[primOffset+1][1] *= scale;
 
-            if (integerScale)
-                scale = floor(scale);
+        posRefPointOffset = primOffset;
+        posRefPointCount = 2;
+    }
+    else
+    {
+        TopEnable = BotEnable = true;
+        // move screens apart
+        {
+            int idx = layout == 0 ? 1 : 0;
 
-            M23_Scale(TopScreenMtx, scale);
-            M23_Scale(BotScreenMtx, scale);
+            bool moveV = rotation % 2 == layout;
 
-            for (int i = 0; i < 4; i++)
+            float offsetTop = (moveV ? 192 : 256 * topAspect) / 2 + screenGap / 2;
+            float offsetBot = (moveV ? 192 : 256 * botAspect) / 2 + screenGap / 2;
+
+            if ((rotation == 1 || rotation == 2) ^ swapScreens)
             {
-                refpoints[i][0] *= scale;
-                refpoints[i][1] *= scale;
+                offsetTop *= -1;
+                offsetBot *= -1;
             }
 
-            botScale = scale;
+            M23_Translate(TopScreenMtx, (idx==0)?-offsetTop:0, (idx==1)?-offsetTop:0);
+            M23_Translate(BotScreenMtx, (idx==0)?offsetBot:0, (idx==1)?offsetBot:0);
+
+            refpoints[0][idx] -= offsetTop;
+            refpoints[1][idx] -= offsetTop;
+            refpoints[2][idx] += offsetBot;
+            refpoints[3][idx] += offsetBot;
+
+            botTrans[idx] = offsetBot;
         }
-        else
+
+        // scale
         {
-            int primOffset = (sizing == 1) ? 0 : 2;
-            int secOffset = (sizing == 1) ? 2 : 0;
-            float* primMtx = (sizing == 1) ? TopScreenMtx : BotScreenMtx;
-            float* secMtx = (sizing == 1) ? BotScreenMtx : TopScreenMtx;
+            if (sizing == 0)
+            {
+                float minX = refpoints[0][0], maxX = minX;
+                float minY = refpoints[0][1], maxY = minY;
 
-            float primMinX = refpoints[primOffset][0], primMaxX = primMinX;
-            float primMinY = refpoints[primOffset][1], primMaxY = primMinY;
-            float secMinX = refpoints[secOffset][0], secMaxX = secMinX;
-            float secMinY = refpoints[secOffset][1], secMaxY = secMinY;
+                for (int i = 1; i < 4; i++)
+                {
+                    minX = std::min(minX, refpoints[i][0]);
+                    minY = std::min(minY, refpoints[i][1]);
+                    maxX = std::max(maxX, refpoints[i][0]);
+                    maxY = std::max(maxY, refpoints[i][1]);
+                }
 
-            primMinX = std::min(primMinX, refpoints[primOffset+1][0]);
-            primMinY = std::min(primMinY, refpoints[primOffset+1][1]);
-            primMaxX = std::max(primMaxX, refpoints[primOffset+1][0]);
-            primMaxY = std::max(primMaxY, refpoints[primOffset+1][1]);
+                float hSize = maxX - minX;
+                float vSize = maxY - minY;
 
-            secMinX = std::min(secMinX, refpoints[secOffset+1][0]);
-            secMinY = std::min(secMinY, refpoints[secOffset+1][1]);
-            secMaxX = std::max(secMaxX, refpoints[secOffset+1][0]);
-            secMaxY = std::max(secMaxY, refpoints[secOffset+1][1]);
+                // scale evenly
+                float scale = std::min(screenWidth / hSize, screenHeight / vSize);
 
-            float primHSize = layout == 1 ? std::max(primMaxX, -primMinX) : primMaxX - primMinX;
-            float primVSize = layout == 0 ? std::max(primMaxY, -primMinY) : primMaxY - primMinY;
+                if (integerScale)
+                    scale = floor(scale);
 
-            float secHSize = layout == 1 ? std::max(secMaxX, -secMinX) : secMaxX - secMinX;
-            float secVSize = layout == 0 ? std::max(secMaxY, -secMinY) : secMaxY - secMinY;
+                M23_Scale(TopScreenMtx, scale);
+                M23_Scale(BotScreenMtx, scale);
 
-            float primScale = std::min(screenWidth / primHSize, screenHeight / primVSize);
-            float secScale = 1.f;
+                for (int i = 0; i < 4; i++)
+                {
+                    refpoints[i][0] *= scale;
+                    refpoints[i][1] *= scale;
+                }
 
-            if (layout == 0)
-            {
-                if (screenHeight - primVSize * primScale < secVSize)
-                    primScale = std::min(screenWidth / primHSize, (screenHeight - secVSize) / primVSize);
-                else
-                    secScale = std::min((screenHeight - primVSize * primScale) / secVSize, screenWidth / secHSize);
+                botScale = scale;
             }
             else
             {
-                if (screenWidth - primHSize * primScale < secHSize)
-                    primScale = std::min((screenWidth - secHSize) / primHSize, screenHeight / primVSize);
+                int primOffset = (sizing == 1) ? 0 : 2;
+                int secOffset = (sizing == 1) ? 2 : 0;
+                float* primMtx = (sizing == 1) ? TopScreenMtx : BotScreenMtx;
+                float* secMtx = (sizing == 1) ? BotScreenMtx : TopScreenMtx;
+
+                float primMinX = refpoints[primOffset][0], primMaxX = primMinX;
+                float primMinY = refpoints[primOffset][1], primMaxY = primMinY;
+                float secMinX = refpoints[secOffset][0], secMaxX = secMinX;
+                float secMinY = refpoints[secOffset][1], secMaxY = secMinY;
+
+                primMinX = std::min(primMinX, refpoints[primOffset+1][0]);
+                primMinY = std::min(primMinY, refpoints[primOffset+1][1]);
+                primMaxX = std::max(primMaxX, refpoints[primOffset+1][0]);
+                primMaxY = std::max(primMaxY, refpoints[primOffset+1][1]);
+
+                secMinX = std::min(secMinX, refpoints[secOffset+1][0]);
+                secMinY = std::min(secMinY, refpoints[secOffset+1][1]);
+                secMaxX = std::max(secMaxX, refpoints[secOffset+1][0]);
+                secMaxY = std::max(secMaxY, refpoints[secOffset+1][1]);
+
+                float primHSize = layout == 1 ? std::max(primMaxX, -primMinX) : primMaxX - primMinX;
+                float primVSize = layout == 0 ? std::max(primMaxY, -primMinY) : primMaxY - primMinY;
+
+                float secHSize = layout == 1 ? std::max(secMaxX, -secMinX) : secMaxX - secMinX;
+                float secVSize = layout == 0 ? std::max(secMaxY, -secMinY) : secMaxY - secMinY;
+
+                float primScale = std::min(screenWidth / primHSize, screenHeight / primVSize);
+                float secScale = 1.f;
+
+                if (layout == 0)
+                {
+                    if (screenHeight - primVSize * primScale < secVSize)
+                        primScale = std::min(screenWidth / primHSize, (screenHeight - secVSize) / primVSize);
+                    else
+                        secScale = std::min((screenHeight - primVSize * primScale) / secVSize, screenWidth / secHSize);
+                }
                 else
-                    secScale = std::min((screenWidth - primHSize * primScale) / secHSize, screenHeight / secVSize);
+                {
+                    if (screenWidth - primHSize * primScale < secHSize)
+                        primScale = std::min((screenWidth - secHSize) / primHSize, screenHeight / primVSize);
+                    else
+                        secScale = std::min((screenWidth - primHSize * primScale) / secHSize, screenHeight / secVSize);
+                }
+
+                if (integerScale)
+                {
+                    primScale = floor(primScale);
+                    secScale = floor(secScale);
+                }
+
+                M23_Scale(primMtx, primScale);
+                M23_Scale(secMtx, secScale);
+
+                refpoints[primOffset+0][0] *= primScale;
+                refpoints[primOffset+0][1] *= primScale;
+                refpoints[primOffset+1][0] *= primScale;
+                refpoints[primOffset+1][1] *= primScale;
+                refpoints[secOffset+0][0] *= secScale;
+                refpoints[secOffset+0][1] *= secScale;
+                refpoints[secOffset+1][0] *= secScale;
+                refpoints[secOffset+1][1] *= secScale;
+
+                botScale = (sizing == 1) ? secScale : primScale;
             }
-
-            if (integerScale)
-            {
-                primScale = floor(primScale);
-                secScale = floor(secScale);
-            }
-
-            M23_Scale(primMtx, primScale);
-            M23_Scale(secMtx, secScale);
-
-            refpoints[primOffset+0][0] *= primScale;
-            refpoints[primOffset+0][1] *= primScale;
-            refpoints[primOffset+1][0] *= primScale;
-            refpoints[primOffset+1][1] *= primScale;
-            refpoints[secOffset+0][0] *= secScale;
-            refpoints[secOffset+0][1] *= secScale;
-            refpoints[secOffset+1][0] *= secScale;
-            refpoints[secOffset+1][1] *= secScale;
-
-            botScale = (sizing == 1) ? secScale : primScale;
         }
     }
 
     // position
     {
-        float minX = refpoints[0][0], maxX = minX;
-        float minY = refpoints[0][1], maxY = minY;
+        float minX = refpoints[posRefPointOffset][0], maxX = minX;
+        float minY = refpoints[posRefPointOffset][1], maxY = minY;
 
-        for (int i = 1; i < 4; i++)
+        for (int i = posRefPointOffset + 1; i < posRefPointOffset + posRefPointCount; i++)
         {
             minX = std::min(minX, refpoints[i][0]);
             minY = std::min(minY, refpoints[i][1]);
@@ -297,6 +353,7 @@ void SetupScreenLayout(int screenWidth, int screenHeight, int screenLayout, int
     // prepare a 'reverse' matrix for the touchscreen
     // this matrix undoes the transforms applied to the bottom screen
     // and can be used to calculate touchscreen coords from host screen coords
+    if (BotEnable)
     {
         M23_Identity(TouchMtx);
 
@@ -309,25 +366,45 @@ void SetupScreenLayout(int screenWidth, int screenHeight, int screenLayout, int
         M23_RotateFast(rotmtx, (4-rotation) & 3);
         M23_Multiply(TouchMtx, rotmtx, TouchMtx);
 
+        M23_Scale(TouchMtx, 1.f/botAspect, 1);
         M23_Translate(TouchMtx, 256/2, 192/2);
     }
 }
 
-void GetScreenTransforms(float* top, float* bot)
+int GetScreenTransforms(float* out, int* kind)
 {
-    memcpy(top, TopScreenMtx, 6*sizeof(float));
-    memcpy(bot, BotScreenMtx, 6*sizeof(float));
+    int num = 0;
+    if (TopEnable)
+    {
+        memcpy(out + 6*num, TopScreenMtx, sizeof(TopScreenMtx));
+        kind[num] = 0;
+        num++;
+    }
+    if (BotEnable)
+    {
+        memcpy(out + 6*num, BotScreenMtx, sizeof(BotScreenMtx));
+        kind[num] = 1;
+        num++;
+    }
+    return num;
 }
 
-void GetTouchCoords(int& x, int& y)
+bool GetTouchCoords(int& x, int& y)
 {
-    float vx = x;
-    float vy = y;
+    if (BotEnable)
+    {
+        float vx = x;
+        float vy = y;
 
-    M23_Transform(TouchMtx, vx, vy);
+        M23_Transform(TouchMtx, vx, vy);
 
-    x = (int)vx;
-    y = (int)vy;
+        x = (int)vx;
+        y = (int)vy;
+
+        if (x >= 0 && x < 256 && y >= 0 && y < 192)
+            return true;
+    }
+    return false;
 }
 
 }
diff --git a/src/frontend/qt_sdl/PlatformConfig.cpp b/src/frontend/qt_sdl/PlatformConfig.cpp
index 0f67b9a..ffab9fb 100644
--- a/src/frontend/qt_sdl/PlatformConfig.cpp
+++ b/src/frontend/qt_sdl/PlatformConfig.cpp
@@ -42,6 +42,8 @@ int ScreenLayout;
 int ScreenSwap;
 int ScreenSizing;
 int IntegerScaling;
+int ScreenAspectTop;
+int ScreenAspectBot;
 int ScreenFilter;
 
 int ScreenUseGL;
@@ -146,6 +148,8 @@ ConfigEntry PlatformConfigFile[] =
     {"ScreenSwap",     0, &ScreenSwap,     0, NULL, 0},
     {"ScreenSizing",   0, &ScreenSizing,   0, NULL, 0},
     {"IntegerScaling", 0, &IntegerScaling, 0, NULL, 0},
+    {"ScreenAspectTop",0, &ScreenAspectTop,0, NULL, 0},
+    {"ScreenAspectBot",0, &ScreenAspectBot,0, NULL, 0},
     {"ScreenFilter",   0, &ScreenFilter,   1, NULL, 0},
 
     {"ScreenUseGL",         0, &ScreenUseGL,         0, NULL, 0},
diff --git a/src/frontend/qt_sdl/PlatformConfig.h b/src/frontend/qt_sdl/PlatformConfig.h
index bf5fc60..02230ab 100644
--- a/src/frontend/qt_sdl/PlatformConfig.h
+++ b/src/frontend/qt_sdl/PlatformConfig.h
@@ -56,6 +56,8 @@ extern int ScreenGap;
 extern int ScreenLayout;
 extern int ScreenSwap;
 extern int ScreenSizing;
+extern int ScreenAspectTop;
+extern int ScreenAspectBot;
 extern int IntegerScaling;
 extern int ScreenFilter;
 
diff --git a/src/frontend/qt_sdl/main.cpp b/src/frontend/qt_sdl/main.cpp
index baa4716..cc5ef6e 100644
--- a/src/frontend/qt_sdl/main.cpp
+++ b/src/frontend/qt_sdl/main.cpp
@@ -646,15 +646,25 @@ void ScreenHandler::screenSetupLayout(int w, int h)
     int sizing = Config::ScreenSizing;
     if (sizing == 3) sizing = autoScreenSizing;
 
+    float aspectRatios[] =
+    {
+        1.f,
+        (16.f/9)/(4.f/3),
+        (21.f/9)/(4.f/3),
+        ((float)w/h)/(4.f/3)
+    };
+
     Frontend::SetupScreenLayout(w, h,
                                 Config::ScreenLayout,
                                 Config::ScreenRotation,
                                 sizing,
                                 Config::ScreenGap,
                                 Config::IntegerScaling != 0,
-                                Config::ScreenSwap != 0);
+                                Config::ScreenSwap != 0,
+                                aspectRatios[Config::ScreenAspectTop],
+                                aspectRatios[Config::ScreenAspectBot]);
 
-    Frontend::GetScreenTransforms(screenMatrix[0], screenMatrix[1]);
+    numScreens = Frontend::GetScreenTransforms(screenMatrix[0], screenKind);
 }
 
 QSize ScreenHandler::screenGetMinSize()
@@ -779,19 +789,16 @@ void ScreenPanelNative::setupScreenLayout()
 {
     int w = width();
     int h = height();
-    float* mtx;
 
     screenSetupLayout(w, h);
 
-    mtx = screenMatrix[0];
-    screenTrans[0].setMatrix(mtx[0], mtx[1], 0.f,
-                             mtx[2], mtx[3], 0.f,
-                             mtx[4], mtx[5], 1.f);
-
-    mtx = screenMatrix[1];
-    screenTrans[1].setMatrix(mtx[0], mtx[1], 0.f,
-                             mtx[2], mtx[3], 0.f,
-                             mtx[4], mtx[5], 1.f);
+    for (int i = 0; i < numScreens; i++)
+    {
+        float* mtx = screenMatrix[i];
+        screenTrans[i].setMatrix(mtx[0], mtx[1], 0.f,
+                                mtx[2], mtx[3], 0.f,
+                                mtx[4], mtx[5], 1.f);
+    }
 }
 
 void ScreenPanelNative::paintEvent(QPaintEvent* event)
@@ -811,11 +818,11 @@ void ScreenPanelNative::paintEvent(QPaintEvent* event)
 
     QRect screenrc(0, 0, 256, 192);
 
-    painter.setTransform(screenTrans[0]);
-    painter.drawImage(screenrc, screen[0]);
-
-    painter.setTransform(screenTrans[1]);
-    painter.drawImage(screenrc, screen[1]);
+    for (int i = 0; i < numScreens; i++)
+    {
+        painter.setTransform(screenTrans[i]);
+        painter.drawImage(screenrc, screen[screenKind[i]]);
+    }
 
     OSD::Update(nullptr);
     OSD::DrawNative(painter);
@@ -1002,11 +1009,11 @@ void ScreenPanelGL::paintGL()
 
     GLint transloc = screenShader->uniformLocation("uTransform");
 
-    glUniformMatrix2x3fv(transloc, 1, GL_TRUE, screenMatrix[0]);
-    glDrawArrays(GL_TRIANGLES, 0, 2*3);
-
-    glUniformMatrix2x3fv(transloc, 1, GL_TRUE, screenMatrix[1]);
-    glDrawArrays(GL_TRIANGLES, 2*3, 2*3);
+    for (int i = 0; i < numScreens; i++)
+    {
+        glUniformMatrix2x3fv(transloc, 1, GL_TRUE, screenMatrix[i]);
+        glDrawArrays(GL_TRIANGLES, screenKind[i] == 0 ? 0 : 2*3, 2*3);
+    }
 
     screenShader->release();
 
@@ -1272,9 +1279,9 @@ MainWindow::MainWindow(QWidget* parent) : QMainWindow(parent)
             QMenu* submenu = menu->addMenu("Screen sizing");
             grpScreenSizing = new QActionGroup(submenu);
 
-            const char* screensizing[] = {"Even", "Emphasize top", "Emphasize bottom", "Auto"};
+            const char* screensizing[] = {"Even", "Emphasize top", "Emphasize bottom", "Auto", "Top only", "Bottom only"};
 
-            for (int i = 0; i < 4; i++)
+            for (int i = 0; i < 6; i++)
             {
                 actScreenSizing[i] = submenu->addAction(QString(screensizing[i]));
                 actScreenSizing[i]->setActionGroup(grpScreenSizing);
@@ -1290,6 +1297,38 @@ MainWindow::MainWindow(QWidget* parent) : QMainWindow(parent)
             actIntegerScaling->setCheckable(true);
             connect(actIntegerScaling, &QAction::triggered, this, &MainWindow::onChangeIntegerScaling);
         }
+        {
+            QMenu* submenu = menu->addMenu("Aspect ratio");
+            grpScreenAspectTop = new QActionGroup(submenu);
+
+            const char* aspectRatiosTop[] = {"Top 4:3 (native)", "Top 16:9", "Top 21:9", "Top window"};
+
+            for (int i = 0; i < 4; i++)
+            {
+                actScreenAspectTop[i] = submenu->addAction(QString(aspectRatiosTop[i]));
+                actScreenAspectTop[i]->setActionGroup(grpScreenAspectTop);
+                actScreenAspectTop[i]->setData(QVariant(i));
+                actScreenAspectTop[i]->setCheckable(true);
+            }
+
+            connect(grpScreenAspectTop, &QActionGroup::triggered, this, &MainWindow::onChangeScreenAspectTop);
+
+            submenu->addSeparator();
+
+            grpScreenAspectBot = new QActionGroup(submenu);
+
+            const char* aspectRatiosBot[] = {"Bottom 4:3 (native)", "Bottom 16:9", "Bottom 21:9", "Bottom window"};
+
+            for (int i = 0; i < 4; i++)
+            {
+                actScreenAspectBot[i] = submenu->addAction(QString(aspectRatiosBot[i]));
+                actScreenAspectBot[i]->setActionGroup(grpScreenAspectBot);
+                actScreenAspectBot[i]->setData(QVariant(i));
+                actScreenAspectBot[i]->setCheckable(true);
+            }
+
+            connect(grpScreenAspectBot, &QActionGroup::triggered, this, &MainWindow::onChangeScreenAspectBot);
+        }
 
         actScreenFiltering = menu->addAction("Screen filtering");
         actScreenFiltering->setCheckable(true);
@@ -1352,6 +1391,9 @@ MainWindow::MainWindow(QWidget* parent) : QMainWindow(parent)
 
     actScreenSwap->setChecked(Config::ScreenSwap != 0);
 
+    actScreenAspectTop[Config::ScreenAspectTop]->setChecked(true);
+    actScreenAspectBot[Config::ScreenAspectBot]->setChecked(true);
+
     actScreenFiltering->setChecked(Config::ScreenFilter != 0);
     actShowOSD->setChecked(Config::ShowOSD != 0);
 
@@ -2264,6 +2306,22 @@ void MainWindow::onChangeScreenSizing(QAction* act)
     emit screenLayoutChange();
 }
 
+void MainWindow::onChangeScreenAspectTop(QAction* act)
+{
+    int aspect = act->data().toInt();
+    Config::ScreenAspectTop = aspect;
+
+    emit screenLayoutChange();
+}
+
+void MainWindow::onChangeScreenAspectBot(QAction* act)
+{
+    int aspect = act->data().toInt();
+    Config::ScreenAspectBot = aspect;
+
+    emit screenLayoutChange();
+}
+
 void MainWindow::onChangeIntegerScaling(bool checked)
 {
     Config::IntegerScaling = checked?1:0;
@@ -2444,7 +2502,9 @@ int main(int argc, char** argv)
     SANITIZE(Config::ScreenRotation, 0, 3);
     SANITIZE(Config::ScreenGap, 0, 500);
     SANITIZE(Config::ScreenLayout, 0, 2);
-    SANITIZE(Config::ScreenSizing, 0, 3);
+    SANITIZE(Config::ScreenSizing, 0, 5);
+    SANITIZE(Config::ScreenAspectTop, 0, 4);
+    SANITIZE(Config::ScreenAspectBot, 0, 4);
 #undef SANITIZE
 
     QSurfaceFormat format;
diff --git a/src/frontend/qt_sdl/main.h b/src/frontend/qt_sdl/main.h
index ec7bd74..a79c245 100644
--- a/src/frontend/qt_sdl/main.h
+++ b/src/frontend/qt_sdl/main.h
@@ -34,6 +34,7 @@
 #include <QOpenGLFunctions_3_2_Core>
 #include <QOpenGLShaderProgram>
 
+#include "FrontendUtil.h"
 
 class EmuThread : public QThread
 {
@@ -105,7 +106,9 @@ protected:
     void screenOnMouseRelease(QMouseEvent* event);
     void screenOnMouseMove(QMouseEvent* event);
 
-    float screenMatrix[2][6];
+    float screenMatrix[Frontend::MaxScreenTransforms][6];
+    int screenKind[Frontend::MaxScreenTransforms];
+    int numScreens;
 
     bool touching;
     
@@ -137,7 +140,7 @@ private:
     void setupScreenLayout();
 
     QImage screen[2];
-    QTransform screenTrans[2];
+    QTransform screenTrans[Frontend::MaxScreenTransforms];
 };
 
 
@@ -237,6 +240,8 @@ private slots:
     void onChangeScreenLayout(QAction* act);
     void onChangeScreenSwap(bool checked);
     void onChangeScreenSizing(QAction* act);
+    void onChangeScreenAspectTop(QAction* act);
+    void onChangeScreenAspectBot(QAction* act);
     void onChangeIntegerScaling(bool checked);
     void onChangeScreenFiltering(bool checked);
     void onChangeShowOSD(bool checked);
@@ -303,8 +308,12 @@ public:
     QAction* actScreenLayout[3];
     QAction* actScreenSwap;
     QActionGroup* grpScreenSizing;
-    QAction* actScreenSizing[4];
+    QAction* actScreenSizing[6];
     QAction* actIntegerScaling;
+    QActionGroup* grpScreenAspectTop;
+    QAction* actScreenAspectTop[4];
+    QActionGroup* grpScreenAspectBot;
+    QAction* actScreenAspectBot[4];
     QAction* actScreenFiltering;
     QAction* actShowOSD;
     QAction* actLimitFramerate;