clean-up display modes

platformio.ini

@@ -30,6 +30,8 @@ build_flags =
     -DENABLE_SDCARD=1
     -DENABLE_LCD_DMA=1
     -DENABLE_LCD_FRAMEBUFFER=1
+    -DENABLE_FRAMEBUFFER_FLIP_X_Y=1
+    -DENABLE_DOUBLE_BUFFERING=1
     -DENABLE_USB_STORAGE_DEVICE=0
     -DPEANUT_FULL_GBC_SUPPORT=1
     -DUSE_TINYUSB

src/lcd_core.cpp

@@ -19,9 +19,24 @@
 
 TFT_eSPI tft = TFT_eSPI();
 #if ENABLE_LCD_FRAMEBUFFER
-static TFT_eSprite framebuffer = TFT_eSprite(&tft);
+#if ENABLE_FRAMEBUFFER_FLIP_X_Y
+#define FRAMEBUFFER_WIDTH DISPLAY_HEIGHT
+#define FRAMEBUFFER_HEIGHT DISPLAY_WIDTH
 #else
-static TFT_eSPI& framebuffer = tft;
+#define FRAMEBUFFER_WIDTH DISPLAY_WIDTH
+#define FRAMEBUFFER_HEIGHT DISPLAY_HEIGHT
+#endif
+#define FRAMEBUFFER_PIXELS (FRAMEBUFFER_WIDTH * FRAMEBUFFER_HEIGHT)
+#if ENABLE_LCD_DMA && ENABLE_DOUBLE_BUFFERING
+#define BUFFER_COUNT 2
+#else // !ENABLE_LCD_DMA
+#define BUFFER_COUNT 1 // no use in double buffering without DMA
+#endif
+static uint16_t framebuffers[BUFFER_COUNT][FRAMEBUFFER_PIXELS];
+static int8_t activeFramebufferId = 0;
+#else // !ENABLE_LCD_FRAMEBUFFER
+// Note DMA mode does not have a measurable effect without a framebuffer
+static uint16_t linebuffer[DISPLAY_WIDTH];
 #endif
 
 static uint8_t scaledLineOffsetTable[LCD_HEIGHT]; // scaled to 240 lines
@@ -45,13 +60,24 @@ static void calcExtraLineTable() {
 
 void lcd_init(bool isCore1) {
   tft.init();
+
 #if ENABLE_LCD_DMA
   // do not enable DMA on core0 as it fails on core1 if it is already enabled
   if (isCore1 && !tft.initDMA(/*ctrl_cs not supported in RP2040 implementation*/)) {
     error("Failed to initialize TFT DMA");
   }
 #endif
-  tft.setRotation(1);
+
+  bool rotate = true;
+#if ENABLE_FRAMEBUFFER_FLIP_X_Y
+  // the rotation only flips x and y in GRAM but does not change the LCD screen refresh direction.
+  // If the display is a native portrait (and not landscape) lcd, rotating the lcd to landscape results in ugly
+  // diagonal update lines. Keeping it in portrait mode and Flipping x and y in the framebuffer results in nicer
+  // horizontal update lines. Even better would be VSync or TE line handling (which is not present in most cheap displays)
+  rotate = !isCore1; // rotate in start menu but not in-game 
+#endif
+  tft.setRotation(rotate ? 1 : 0);
+
   tft.fillScreen(TFT_BLACK);
 }
 
@@ -73,37 +99,39 @@ void lcd_draw_line(struct gb_s* gb, const uint8_t pixels[LCD_WIDTH], const uint_
 }
 
 #if ENABLE_LCD_FRAMEBUFFER
-void lcd_pushColors(size_t offset, const uint16_t* pixels, uint_fast16_t count) {
+void lcd_pushLine(uint16_t screenColOffset, uint16_t screenLineOffset, uint16_t line, const uint16_t* pixels, uint_fast16_t width) {
-  uint16_t* image = (uint16_t*) framebuffer.getPointer();
+  uint16_t* framebuffer = framebuffers[activeFramebufferId];
-  memcpy(&image[offset], pixels, count * sizeof(uint16_t));
+#if ENABLE_FRAMEBUFFER_FLIP_X_Y
+  uint_fast16_t pos = (screenColOffset * DISPLAY_HEIGHT) + DISPLAY_HEIGHT - (screenLineOffset + line) - 1;
+  for (uint_fast16_t i = 0; i < width; ++i) {
+    framebuffer[pos] = pixels[i];
+    pos += DISPLAY_HEIGHT;
   }
 #else
-void lcd_pushColors(uint16_t colOffset, uint16_t lineOffset, const uint16_t* pixels, uint_fast16_t count) {
+  uint32_t offset = screenColOffset + (uint32_t)(screenLineOffset + line) * DISPLAY_WIDTH;
-  framebuffer.setAddrWindow(colOffset, lineOffset, count, 1);
+  memcpy(&framebuffer[offset], pixels, width * sizeof(uint16_t));
+#endif
+}
+#else // !ENABLE_LCD_FRAMEBUFFER
+void lcd_pushLine(uint16_t screenColOffset, uint16_t screenLineOffset, uint16_t line, const uint16_t* pixels, uint_fast16_t width) {
+  tft.setAddrWindow(screenColOffset, screenLineOffset + line, width, 1);
 #if ENABLE_LCD_DMA
-  // DMA mode does not have a measurable effect without a framebuffer
-  static uint16_t dmaBuffer[DISPLAY_WIDTH];
   tft.dmaWait();
-  memcpy(dmaBuffer, pixels, count * sizeof(uint16_t));
+  memcpy(linebuffer, pixels, width * sizeof(uint16_t));
   tft.setSwapBytes(true);
   tft.startWrite(); // manual start required as DMA transfer is asynchronous
-  tft.pushPixelsDMA((uint16_t*) dmaBuffer, count);
+  tft.pushPixelsDMA((uint16_t*) linebuffer, width);
   //tft.endWrite(); // do not call endWrite(), as it will wait for the DMA transfer to finish, which results in no performance gain
 #else
-  tft.pushColors((uint16_t*) pixels, count, true);
+  tft.pushColors((uint16_t*) pixels, width, true);
 #endif
 }
 #endif
 
 void lcd_write_pixels_normal(const uint16_t* pixels, uint8_t line, uint_fast16_t count) {
-  const uint16_t colOffset = (DISPLAY_WIDTH - count) / 2;
+  const uint16_t colOffset = (DISPLAY_WIDTH - LCD_WIDTH) / 2;
   const uint16_t screenLineOffset = (DISPLAY_HEIGHT - LCD_HEIGHT) / 2;
-  const uint16_t lineOffset = screenLineOffset + line;
+  lcd_pushLine(colOffset, screenLineOffset, line, pixels, count);
-#if ENABLE_LCD_FRAMEBUFFER
-  lcd_pushColors(lineOffset * DISPLAY_WIDTH + colOffset, pixels, count);
-#else
-  lcd_pushColors(colOffset, lineOffset, pixels, count);
-#endif
 }
 
 void lcd_write_pixels_stretched(const uint16_t* pixels, uint8_t line, uint_fast16_t count) {
@@ -117,18 +145,10 @@ void lcd_write_pixels_stretched(const uint16_t* pixels, uint8_t line, uint_fast1
 
   const uint8_t lineRepeated = IS_REPEATED(line);
   const uint16_t lineOffset = scaledLineOffsetTable[line];
-#if ENABLE_LCD_FRAMEBUFFER
+  lcd_pushLine(0, 0, lineOffset, doubledPixels, stretchedWidth);
-  size_t offset = lineOffset * DISPLAY_WIDTH;
-  lcd_pushColors(offset, doubledPixels, stretchedWidth);
   if (lineRepeated) {
-    lcd_pushColors(offset + DISPLAY_WIDTH, doubledPixels, stretchedWidth);
+    lcd_pushLine(0, 0, lineOffset + 1, doubledPixels, stretchedWidth);
   }
-#else
-  lcd_pushColors(0, lineOffset, doubledPixels, stretchedWidth);
-  if (lineRepeated) {
-    lcd_pushColors(0, lineOffset + 1, doubledPixels, stretchedWidth);
-  }
-#endif
 }
 
 void lcd_write_pixels_stretched_keep_aspect(const uint16_t* pixels, uint8_t line, uint_fast16_t count) {
@@ -144,58 +164,65 @@ void lcd_write_pixels_stretched_keep_aspect(const uint16_t* pixels, uint8_t line
 
   const uint16_t colOffset = (DISPLAY_WIDTH - stretchedWidth) / 2;
  
-  uint8_t lineRepeated = IS_REPEATED(line);
+  const uint8_t lineRepeated = IS_REPEATED(line);
   const uint16_t lineOffset = scaledLineOffsetTable[line];
-#if ENABLE_LCD_FRAMEBUFFER
+  lcd_pushLine(colOffset, 0, lineOffset, doubledPixels, stretchedWidth);
-  size_t offset = lineOffset * DISPLAY_WIDTH + colOffset;
-  lcd_pushColors(offset, doubledPixels, stretchedWidth);
   if (lineRepeated) {
-    lcd_pushColors(offset + DISPLAY_WIDTH, doubledPixels, stretchedWidth);
+    lcd_pushLine(colOffset, 0, lineOffset + 1, doubledPixels, stretchedWidth);
   }
-#else
-  lcd_pushColors(colOffset, lineOffset, doubledPixels, stretchedWidth);
-  if (lineRepeated) {
-    lcd_pushColors(colOffset, lineOffset + 1, doubledPixels, stretchedWidth);
-  }
-#endif
 }
 
 // Writes pixels to screen or framebuffer
-void lcd_write_pixels(const uint16_t* pixels, uint8_t line, uint_fast16_t nmemb) {
+void lcd_write_pixels(const uint16_t* pixels, uint8_t line, uint_fast16_t count) {
   switch (scalingMode)
   {
   case ScalingMode::STRETCH:
-    lcd_write_pixels_stretched(pixels, line, nmemb);
+    lcd_write_pixels_stretched(pixels, line, count);
     break;
   case ScalingMode::STRETCH_KEEP_ASPECT:
-    lcd_write_pixels_stretched_keep_aspect(pixels, line, nmemb);
+    lcd_write_pixels_stretched_keep_aspect(pixels, line, count);
     break;
   case ScalingMode::NORMAL:
   default:
-    lcd_write_pixels_normal(pixels, line, nmemb);
+    lcd_write_pixels_normal(pixels, line, count);
     break;
   }
 }
 
+
 #if ENABLE_LCD_FRAMEBUFFER
-// Writes framebuffer to screen
+
-void lcd_write_framebuffer_to_screen() {
+void lcd_swap_buffers() {
-    tft.setSwapBytes(true);
+#if BUFFER_COUNT == 2
-#ifdef ENABLE_LCD_DMA
+  activeFramebufferId = (activeFramebufferId == 0) ? 1 : 0;
-    tft.startWrite(); // manual start required as DMA transfer is asynchronous
-    tft.pushImageDMA(0, 0, framebuffer.width(), framebuffer.height(), (uint16_t *) framebuffer.getPointer());
-    //tft.endWrite(); // do not call endWrite(), as it will wait for the DMA transfer to finish, which results in no performance gain
-#else
-    tft.pushImage(0, 0, framebuffer.width(), framebuffer.height(), (uint16_t *) framebuffer.getPointer());
 #endif
 }
+
+// Writes framebuffer to screen
+void lcd_write_framebuffer_to_screen() {
+  uint16_t* framebuffer = framebuffers[activeFramebufferId];
+  tft.setSwapBytes(true);
+#if ENABLE_LCD_DMA
+  tft.startWrite(); // manual start required as DMA transfer is asynchronous
+  tft.pushImageDMA(0, 0, FRAMEBUFFER_WIDTH, FRAMEBUFFER_HEIGHT, framebuffer);
+  //tft.endWrite(); // do not call endWrite(), as it will wait for the DMA transfer to finish, which results in no performance gain
+  lcd_swap_buffers();
+#else
+  tft.pushImage(0, 0, FRAMEBUFFER_WIDTH, FRAMEBUFFER_HEIGHT, framebuffer);
+#endif
+}
+
 #endif
 
-void lcd_fill(uint16_t color) {
+
+void lcd_clear() {
 #if ENABLE_LCD_FRAMEBUFFER
-  framebuffer.fillSprite(color);
+  memset(framebuffers[0], 0, FRAMEBUFFER_PIXELS * sizeof(uint16_t));
+#if BUFFER_COUNT == 2
+  memset(framebuffers[1], 0, FRAMEBUFFER_PIXELS * sizeof(uint16_t));
+#endif
 #else
-  tft.fillScreen(color);
+  tft.fillScreen(TFT_BLACK);
 #endif
 }
 
@@ -226,7 +253,7 @@ void core1_lcd_draw_line(const uint_fast8_t line) {
 void core1DispatchLoop() {
   union core_cmd cmd;
 
-  /* Handle commands coming from core0. */
+  // Handle commands coming from core0
   cmd.full = multicore_fifo_pop_blocking();
   switch (cmd.cmd) {
   case CORE_CMD_LCD_LINE:
@@ -234,7 +261,7 @@ void core1DispatchLoop() {
     break;
 
   case CORE_CMD_IDLE_SET:
-    lcd_fill(TFT_BLACK);
+    lcd_clear();
     break;
 
   case CORE_CMD_NOP:
@@ -244,16 +271,10 @@ void core1DispatchLoop() {
 }
 
 void core1_init() {
-  /* Initialise and control LCD on core 1. */
+  // Initialise and control LCD on core 1
   lcd_init(true);
 
-#if ENABLE_LCD_FRAMEBUFFER
+  lcd_clear();
-  framebuffer.setColorDepth(16);
-  framebuffer.createSprite(tft.width(), tft.height());
-#endif
-
-  /* Clear LCD screen. */
-  lcd_fill(TFT_BLACK);
 
   calcExtraLineTable();