N3DS port (squashed)

A dedicated renderer using Citro3D would likely allow for better
much better graphical performances.

src/power/SDL_power.c

@@ -71,6 +71,9 @@ static SDL_GetPowerInfo_Impl implementations[] = {
 #ifdef SDL_POWER_VITA        /* handles PSVita. */
     SDL_GetPowerInfo_VITA,
 #endif
+#ifdef SDL_POWER_N3DS        /* handles N3DS. */
+    SDL_GetPowerInfo_N3DS,
+#endif
 #ifdef SDL_POWER_WINRT          /* handles WinRT */
     SDL_GetPowerInfo_WinRT,
 #endif

src/power/SDL_syspower.h

@@ -39,6 +39,7 @@ SDL_bool SDL_GetPowerInfo_Haiku(SDL_PowerState *, int *, int *);
 SDL_bool SDL_GetPowerInfo_Android(SDL_PowerState *, int *, int *);
 SDL_bool SDL_GetPowerInfo_PSP(SDL_PowerState *, int *, int *);
 SDL_bool SDL_GetPowerInfo_VITA(SDL_PowerState *, int *, int *);
+SDL_bool SDL_GetPowerInfo_N3DS(SDL_PowerState *, int *, int *);
 SDL_bool SDL_GetPowerInfo_WinRT(SDL_PowerState *, int *, int *);
 SDL_bool SDL_GetPowerInfo_Emscripten(SDL_PowerState *, int *, int *);
 

src/power/n3ds/SDL_syspower.c

@@ -0,0 +1,111 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2022 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+#include "../../SDL_internal.h"
+
+#if !defined(SDL_POWER_DISABLED) && defined(SDL_POWER_N3DS)
+
+#include <3ds.h>
+
+#include "SDL_error.h"
+#include "SDL_power.h"
+
+SDL_FORCE_INLINE SDL_PowerState GetPowerState(void);
+SDL_FORCE_INLINE int ReadStateFromPTMU(bool *is_plugged, u8 *is_charging);
+SDL_FORCE_INLINE int GetBatteryPercentage(void);
+
+#define BATTERY_PERCENT_REG      0xB
+#define BATTERY_PERCENT_REG_SIZE 2
+
+SDL_bool
+SDL_GetPowerInfo_N3DS(SDL_PowerState *state, int *seconds, int *percent)
+{
+    *state = GetPowerState();
+    *percent = GetBatteryPercentage();
+    *seconds = -1; /* libctru doesn't provide a way to estimate battery life */
+
+    return SDL_TRUE;
+}
+
+SDL_FORCE_INLINE SDL_PowerState
+GetPowerState(void)
+{
+    bool is_plugged;
+    u8 is_charging;
+
+    if (ReadStateFromPTMU(&is_plugged, &is_charging) < 0) {
+        return SDL_POWERSTATE_UNKNOWN;
+    }
+
+    if (is_charging) {
+        return SDL_POWERSTATE_CHARGING;
+    }
+
+    if (is_plugged) {
+        return SDL_POWERSTATE_CHARGED;
+    }
+
+    return SDL_POWERSTATE_ON_BATTERY;
+}
+
+SDL_FORCE_INLINE int
+ReadStateFromPTMU(bool *is_plugged, u8 *is_charging)
+{
+    if (R_FAILED(ptmuInit())) {
+        return SDL_SetError("Failed to initialise PTMU service");
+    }
+
+    if (R_FAILED(PTMU_GetAdapterState(is_plugged))) {
+        ptmuExit();
+        return SDL_SetError("Failed to read adapter state");
+    }
+
+    if (R_FAILED(PTMU_GetBatteryChargeState(is_charging))) {
+        ptmuExit();
+        return SDL_SetError("Failed to read battery charge state");
+    }
+
+    ptmuExit();
+    return 0;
+}
+
+SDL_FORCE_INLINE int
+GetBatteryPercentage(void)
+{
+    u8 data[BATTERY_PERCENT_REG_SIZE];
+
+    if (R_FAILED(mcuHwcInit())) {
+        return SDL_SetError("Failed to initialise mcuHwc service");
+    }
+
+    if (R_FAILED(MCUHWC_ReadRegister(BATTERY_PERCENT_REG, data, BATTERY_PERCENT_REG_SIZE))) {
+        mcuHwcExit();
+        return SDL_SetError("Failed to read battery register");
+    }
+
+    mcuHwcExit();
+
+    return (int) SDL_round(data[0] + data[1] / 256.0);
+}
+
+#endif /* !SDL_POWER_DISABLED && SDL_POWER_N3DS */
+
+/* vi: set sts=4 ts=4 sw=4 expandtab: */