From d521c997697c9beacf63abee3324415c4fed6a33 Mon Sep 17 00:00:00 2001
From: fincs <fincs@devkitpro.org>
Date: Sat, 13 Jun 2020 22:48:36 +0200
Subject: [PATCH] gfx: Add support for the top screen's 800px high resolution
 mode (!!!)

---
 libctru/include/3ds/gfx.h | 20 +++++++++++++
 libctru/source/gfx.c      | 63 +++++++++++++++++++++++++++++----------
 2 files changed, 68 insertions(+), 15 deletions(-)

diff --git a/libctru/include/3ds/gfx.h b/libctru/include/3ds/gfx.h
index bc52f09..ca69b85 100644
--- a/libctru/include/3ds/gfx.h
+++ b/libctru/include/3ds/gfx.h
@@ -5,6 +5,10 @@
  * This API provides basic functionality needed to bring up framebuffers for both screens,
  * as well as managing display mode (stereoscopic 3D) and double buffering.
  * It is mainly an abstraction over the gsp service.
+ *
+ * Please note that the 3DS uses *portrait* screens rotated 90 degrees counterclockwise.
+ * Width/height refer to the physical dimensions of the screen; that is, the top screen
+ * is 240 pixels wide and 400 pixels tall; while the bottom screen is 240x320.
  */
 #pragma once
 
@@ -80,6 +84,22 @@ void gfxSet3D(bool enable);
  */
 bool gfxIs3D(void);
 
+/**
+ * @brief Retrieves the status of the 800px (double-height) high resolution display mode of the top screen.
+ * @return true if wide mode enabled, false otherwise.
+ */
+bool gfxIsWide(void);
+
+/**
+ * @brief Enables or disables the 800px (double-height) high resolution display mode of the top screen.
+ * @param enable Pass true to enable, false to disable.
+ * @note Wide mode is disabled by default.
+ * @note Wide and stereoscopic 3D modes are mutually exclusive.
+ * @note In wide mode pixels are not square, since scanlines are half as tall as they normally are.
+ * @warning Wide mode does not work on Old 2DS consoles (however it does work on New 2DS XL consoles).
+ */
+void gfxSetWide(bool enable);
+
 /**
  * @brief Changes the pixel format of a screen.
  * @param screen Screen ID (see \ref gfxScreen_t)
diff --git a/libctru/source/gfx.c b/libctru/source/gfx.c
index 5482959..2baafc3 100644
--- a/libctru/source/gfx.c
+++ b/libctru/source/gfx.c
@@ -10,7 +10,12 @@ static u32 gfxTopFramebufferMaxSize;
 static u32 gfxBottomFramebufferMaxSize;
 static GSPGPU_FramebufferFormat gfxFramebufferFormats[2];
 
-static bool gfxEnable3D, gfxIsVram;
+static enum {
+	MODE_2D   = 0,
+	MODE_3D   = 1,
+	MODE_WIDE = 2,
+} gfxTopMode;
+static bool gfxIsVram;
 static u8 gfxCurBuf[2];
 static u8 gfxIsDoubleBuf[2];
 
@@ -19,12 +24,22 @@ static void *(*screenAlloc)(size_t);
 
 void gfxSet3D(bool enable)
 {
-	gfxEnable3D = enable;
+	gfxTopMode = enable ? MODE_3D : MODE_2D;
 }
 
 bool gfxIs3D(void)
 {
-	return gfxEnable3D;
+	return gfxTopMode == MODE_3D;
+}
+
+void gfxSetWide(bool enable)
+{
+	gfxTopMode = enable ? MODE_WIDE : MODE_2D;
+}
+
+bool gfxIsWide(void)
+{
+	return gfxTopMode == MODE_WIDE;
 }
 
 void gfxSetScreenFormat(gfxScreen_t screen, GSPGPU_FramebufferFormat format)
@@ -77,15 +92,20 @@ static void gfxPresentFramebuffer(gfxScreen_t screen, u8 id)
 	if (screen == GFX_TOP)
 	{
 		fb_a = gfxTopFramebuffers[id];
-		if (gfxEnable3D)
+		switch (gfxTopMode)
 		{
-			mode |= BIT(5);
-			fb_b = fb_a + gfxTopFramebufferMaxSize/2;
-		}
-		else
-		{
-			mode |= BIT(6);
-			fb_b = fb_a;
+			default:
+			case MODE_2D:
+				mode |= BIT(6);
+				fb_b = fb_a;
+				break;
+			case MODE_3D:
+				mode |= BIT(5);
+				fb_b = fb_a + gfxTopFramebufferMaxSize/2;
+				break;
+			case MODE_WIDE:
+				fb_b = fb_a;
+				break;
 		}
 	}
 	else
@@ -173,8 +193,19 @@ u8* gfxGetFramebuffer(gfxScreen_t screen, gfx3dSide_t side, u16* width, u16* hei
 	{
 		fb = gfxTopFramebuffers[id];
 		scr_height = GSP_SCREEN_HEIGHT_TOP;
-		if (gfxEnable3D && side != GFX_LEFT)
-			fb += gfxTopFramebufferMaxSize/2;
+		switch (gfxTopMode)
+		{
+			default:
+			case MODE_2D:
+				break;
+			case MODE_3D:
+				if (side != GFX_LEFT)
+					fb += gfxTopFramebufferMaxSize/2;
+				break;
+			case MODE_WIDE:
+				scr_height = GSP_SCREEN_HEIGHT_TOP_2X;
+				break;
+		}
 	}
 	else // GFX_BOTTOM
 	{
@@ -194,10 +225,12 @@ void gfxFlushBuffers(void)
 {
 	const u32 baseSize   = GSP_SCREEN_WIDTH * gspGetBytesPerPixel(gfxGetScreenFormat(GFX_TOP));
 	const u32 topSize    = GSP_SCREEN_HEIGHT_TOP * baseSize;
+	const u32 topSize2x  = GSP_SCREEN_HEIGHT_TOP_2X * baseSize;
 	const u32 bottomSize = GSP_SCREEN_HEIGHT_BOTTOM * baseSize;
 
-	GSPGPU_FlushDataCache(gfxGetFramebuffer(GFX_TOP, GFX_LEFT, NULL, NULL), topSize);
-	if(gfxEnable3D)GSPGPU_FlushDataCache(gfxGetFramebuffer(GFX_TOP, GFX_RIGHT, NULL, NULL), topSize);
+	GSPGPU_FlushDataCache(gfxGetFramebuffer(GFX_TOP, GFX_LEFT, NULL, NULL), gfxTopMode == MODE_WIDE ? topSize2x : topSize);
+	if (gfxTopMode == MODE_3D)
+		GSPGPU_FlushDataCache(gfxGetFramebuffer(GFX_TOP, GFX_RIGHT, NULL, NULL), topSize);
 	GSPGPU_FlushDataCache(gfxGetFramebuffer(GFX_BOTTOM, GFX_LEFT, NULL, NULL), bottomSize);
 }