From eb20ed46486594681a1aeb3642ecd093479e90be Mon Sep 17 00:00:00 2001
From: Charlie Birks <charlie@daft.games>
Date: Mon, 12 Aug 2024 19:47:49 +0100
Subject: [PATCH] Support double-buffered hires, enable by default on RP2350

---
 32blit-pico/config.h    |  8 ++++++++
 32blit-pico/display.cpp | 12 +++++++++---
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/32blit-pico/config.h b/32blit-pico/config.h
index 67a6d26da..a7ba2d7fb 100644
--- a/32blit-pico/config.h
+++ b/32blit-pico/config.h
@@ -10,6 +10,14 @@
 #define ALLOW_HIRES 1
 #endif
 
+#ifndef DOUBLE_BUFFERED_HIRES
+#ifdef PICO_RP2350
+#define DOUBLE_BUFFERED_HIRES 1
+#else
+#define DOUBLE_BUFFERED_HIRES 0
+#endif
+#endif
+
 #ifndef BUTTON_LEFT_PIN
 #define BUTTON_LEFT_PIN -1
 #define BUTTON_LEFT_BI_DECL
diff --git a/32blit-pico/display.cpp b/32blit-pico/display.cpp
index 8f72ac20b..fafd4570e 100644
--- a/32blit-pico/display.cpp
+++ b/32blit-pico/display.cpp
@@ -8,16 +8,22 @@ using namespace blit;
 // this is in bytes
 static const int lores_page_size = (DISPLAY_WIDTH / 2) * ((DISPLAY_HEIGHT + 1) / 2) * 2;
 
+#if ALLOW_HIRES && DOUBLE_BUFFERED_HIRES
+static const int fb_size = DISPLAY_WIDTH * DISPLAY_HEIGHT * 2;
+#elif ALLOW_HIRES
+static const int fb_size = DISPLAY_WIDTH * DISPLAY_HEIGHT;
+#else
+static const int fb_size = lores_page_size; // double-buffered
+#endif
+
 SurfaceInfo cur_surf_info;
 
 bool fb_double_buffer = true;
 
 #if defined(BLIT_BOARD_PIMORONI_PICOVISION)
 static const uint16_t *screen_fb = nullptr;
-#elif ALLOW_HIRES
-uint16_t screen_fb[DISPLAY_WIDTH * DISPLAY_HEIGHT];
 #else
-uint16_t screen_fb[lores_page_size]; // double-buffered
+uint16_t screen_fb[fb_size];
 #endif
 
 static const Size lores_screen_size(DISPLAY_WIDTH / 2, DISPLAY_HEIGHT / 2);