fps counter

Firmware/main/src/apps/gameboy_app.cpp

@@ -40,6 +40,7 @@ public:
     void onStart() override {
         prevInput = {};
         statusMessage.clear();
+        resetFpsStats();
         ensureFilesystemReady();
         refreshRomList();
         mode         = Mode::Browse;
@@ -63,6 +64,7 @@ public:
                     browserDirty = true;
                     break;
                 }
+                DispTools::draw_to_display_async_wait();
                 gb_run_frame(&gb);
                 renderGameFrame();
                 break;
@@ -94,14 +96,16 @@ private:
     InputState            prevInput{};
 
     // Emulator state
-    struct gb_s                                 gb{};
+    struct gb_s          gb{};
-    bool                                        gbReady = false;
+    bool                 gbReady = false;
-    std::vector<uint8_t>                        romData;
+    std::vector<uint8_t> romData;
-    std::vector<uint8_t>                        cartRam;
+    std::vector<uint8_t> cartRam;
-    std::array<uint8_t, LCD_WIDTH * LCD_HEIGHT> frameBuffer{};
+    bool                 frameDirty      = false;
-    bool                                        frameDirty = false;
+    uint32_t             fpsLastSampleMs = 0;
-    std::string                                 activeRomName;
+    uint32_t             fpsFrameCounter = 0;
-    std::string                                 activeRomSavePath;
+    uint32_t             fpsCurrent      = 0;
+    std::string          activeRomName;
+    std::string          activeRomSavePath;
 
     bool ensureFilesystemReady() {
         esp_err_t err = FsHelper::get().mount();
@@ -233,7 +237,6 @@ private:
         browserDirty = false;
 
         DispTools::draw_to_display_async_wait();
-        framebuffer.clear(false);
 
         const std::string_view title      = "GAME BOY";
         const int              titleWidth = font16x8::measureText(title, 2, 1);
@@ -334,6 +337,9 @@ private:
         activeRomSavePath = buildSavePath(rom.fullPath);
         loadSaveFile();
 
+        resetFpsStats();
+        fpsLastSampleMs = context.clock.millis();
+
         gbReady       = true;
         mode          = Mode::Running;
         frameDirty    = true;
@@ -345,6 +351,7 @@ private:
 
     void unloadRom() {
         if (!gbReady) {
+            resetFpsStats();
             romData.clear();
             cartRam.clear();
             activeRomName.clear();
@@ -353,6 +360,7 @@ private:
         }
 
         maybeSaveRam();
+        resetFpsStats();
 
         gbReady = false;
         romData.clear();
@@ -401,27 +409,27 @@ private:
             return;
         frameDirty = false;
 
-        DispTools::draw_to_display_async_wait();
+        ++fpsFrameCounter;
-        framebuffer.clear(false);
+        const uint32_t nowMs = context.clock.millis();
-
+        if (fpsLastSampleMs == 0)
-        const int offsetX = (framebuffer.width() - LCD_WIDTH) / 2;
+            fpsLastSampleMs = nowMs;
-        const int offsetY = (framebuffer.height() - LCD_HEIGHT) / 2;
+        const uint32_t elapsed = nowMs - fpsLastSampleMs;
-
+        if (elapsed >= 1000U) {
-        for (int y = 0; y < LCD_HEIGHT; ++y) {
+            const uint64_t scaledFrames = static_cast<uint64_t>(fpsFrameCounter) * 1000ULL;
-            const int dstY = offsetY + y;
+            fpsCurrent                  = static_cast<uint32_t>(scaledFrames / elapsed);
-            if (dstY < 0 || dstY >= framebuffer.height())
+            fpsFrameCounter             = 0;
-                continue;
+            fpsLastSampleMs             = nowMs;
-            for (int x = 0; x < LCD_WIDTH; ++x) {
-                const int dstX = offsetX + x;
-                if (dstX < 0 || dstX >= framebuffer.width())
-                    continue;
-                const bool on = frameBuffer[static_cast<std::size_t>(y) * LCD_WIDTH + x] != 0;
-                framebuffer.drawPixel(dstX, dstY, on);
-            }
         }
 
+        char fpsBuf[16];
+        std::snprintf(fpsBuf, sizeof(fpsBuf), "%u FPS", static_cast<unsigned>(fpsCurrent));
+        const std::string fpsText(fpsBuf);
+        const int         fpsWidth = font16x8::measureText(fpsText, 1, 1);
+        const int         fpsX     = std::max(16, framebuffer.width() - fpsWidth - 16);
+
         if (!activeRomName.empty())
             font16x8::drawText(framebuffer, 16, 16, activeRomName, 1, true, 1);
+        font16x8::drawText(framebuffer, fpsX, 16, fpsText, 1, true, 1);
         font16x8::drawText(framebuffer, 16, framebuffer.height() - 24, "START+SELECT BACK", 1, true, 1);
 
         DispTools::draw_to_display_async_start();
@@ -464,6 +472,12 @@ private:
         browserDirty  = true;
     }
 
+    void resetFpsStats() {
+        fpsLastSampleMs = 0;
+        fpsFrameCounter = 0;
+        fpsCurrent      = 0;
+    }
+
     static std::string buildSavePath(const std::string& romPath) {
         std::string result = romPath;
         const auto  dot    = result.find_last_of('.');
@@ -516,11 +530,20 @@ private:
         if (!self || line >= LCD_HEIGHT)
             return;
 
-        const std::size_t offset = static_cast<std::size_t>(line) * LCD_WIDTH;
+        const int offsetX = (self->framebuffer.width() - LCD_WIDTH) / 2;
+        const int offsetY = (self->framebuffer.height() - LCD_HEIGHT) / 2;
+        const int dstY    = offsetY + static_cast<int>(line);
+        if (dstY < 0 || dstY >= self->framebuffer.height())
+            return;
+
         for (int x = 0; x < LCD_WIDTH; ++x) {
             // Collapse 2-bit colour into monochrome.
-            const uint8_t shade                                     = pixels[x] & 0x03u;
+            const uint8_t shade = pixels[x] & 0x03u;
-            self->frameBuffer[offset + static_cast<std::size_t>(x)] = (shade >= 2) ? 1 : 0;
+            const bool    on    = (shade >= 2);
+            const int     dstX  = offsetX + x;
+            if (dstX < 0 || dstX >= self->framebuffer.width())
+                continue;
+            self->framebuffer.drawPixel(dstX, dstY, on);
         }
         self->frameDirty = true;
     }

Firmware/main/src/display.cpp

@@ -102,13 +102,13 @@ void SMD::async_draw_start() {
     _tx.tx_buffer = dma_buf;
     _tx.length    = SMD::kLineDataBytes * 8;
     dma_buf[0]    = 0b10000000 | (_vcom << 6);
-    _inFlight = true;
+    _inFlight     = true;
     ESP_ERROR_CHECK(spi_device_queue_trans(_spi, &_tx, 0));
 }
 
 void SMD::async_draw_wait() {
-    if (uxSemaphoreGetCount(s_clearSem) || !_inFlight) {
+    if (!_inFlight || uxSemaphoreGetCount(s_clearSem)) {
-        assert((uxSemaphoreGetCount(s_clearSem) == 0) == _inFlight);
+        // assert((uxSemaphoreGetCount(s_clearSem) == 0) == _inFlight);
         return;
     }
     if (!xSemaphoreTake(s_clearSem, portMAX_DELAY))