From 36cee9aff877a098b1c712dd24d7886a8aa6fda9 Mon Sep 17 00:00:00 2001
From: kichikuou <KichikuouChrome@gmail.com>
Date: Fri, 3 Mar 2023 10:50:54 +0900
Subject: [PATCH] Treat touches outside the viewport as right-clicks

The old method to simulate right click (two-finger touch) still works.
---
 src/sdlmain.cpp        |  1 +
 src/sys/nact_input.cpp | 40 ++++++++++++++++++++++++++++++----------
 2 files changed, 31 insertions(+), 10 deletions(-)

diff --git a/src/sdlmain.cpp b/src/sdlmain.cpp
index 1ae4498..052ba15 100644
--- a/src/sdlmain.cpp
+++ b/src/sdlmain.cpp
@@ -33,6 +33,7 @@ int main(int argc, char *argv[])
 	}
 
 	SDL_Init(SDL_INIT_VIDEO);
+	SDL_SetHint(SDL_HINT_TOUCH_MOUSE_EVENTS, "0");
 #ifdef __EMSCRIPTEN__
 	// Stop SDL from calling emscripten_sleep() in functions that are called
 	// indirectly, which does not work with ASYNCIFY_IGNORE_INDIRECT=1. For
diff --git a/src/sys/nact_input.cpp b/src/sys/nact_input.cpp
index 43e6c9e..92890a9 100644
--- a/src/sys/nact_input.cpp
+++ b/src/sys/nact_input.cpp
@@ -13,8 +13,15 @@
 #include "ags.h"
 #include "texthook.h"
 
+enum TouchState {
+	TOUCH_NONE,
+	TOUCH_LBUTTON,
+	TOUCH_RBUTTON,
+};
+
 extern SDL_Window* g_window;
-static int mousex, mousey, fingers;
+static int mousex, mousey;
+static TouchState touch_state = TOUCH_NONE;
 
 void NACT::pump_events()
 {
@@ -47,7 +54,25 @@ void NACT::pump_events()
 		case SDL_FINGERMOTION:
 			mousex = e.tfinger.x * 640;
 			mousey = e.tfinger.y * ags->screen_height;
-			fingers = SDL_GetNumTouchFingers(e.tfinger.touchId);
+			switch (SDL_GetNumTouchFingers(e.tfinger.touchId)) {
+			case 0:
+				touch_state = TOUCH_NONE;
+				break;
+			case 1:
+				// A touch outside of the viewport (SDL clamps it to 0.0-1.0) is
+				// a right-click.
+				if (e.tfinger.x == 0.0f || e.tfinger.x == 1.0f ||
+					e.tfinger.y == 0.0f || e.tfinger.y == 1.0f) {
+					touch_state = TOUCH_RBUTTON;
+				} else {
+					touch_state = TOUCH_LBUTTON;
+				}
+				break;
+			case 2:
+				// Two-finger touch is a right-click.
+				touch_state = TOUCH_RBUTTON;
+				break;
+			}
 			break;
 
 		case SDL_APP_DIDENTERFOREGROUND:
@@ -67,19 +92,14 @@ uint8 NACT::get_key()
 
 	// キーボード＆マウス
 	const Uint8* key = SDL_GetKeyboardState(NULL);
-	Uint32 mouse;
-	if (fingers) {
-		mouse = fingers == 1 ? SDL_BUTTON_LMASK : SDL_BUTTON_RMASK;
-	} else {
-		mouse = SDL_GetMouseState(NULL, NULL);
-	}
+	Uint32 mouse = SDL_GetMouseState(NULL, NULL);
 
 	if(key[SDL_SCANCODE_UP    ] || key[SDL_SCANCODE_KP_8 ] ) val |= 0x01;
 	if(key[SDL_SCANCODE_DOWN  ] || key[SDL_SCANCODE_KP_2 ] ) val |= 0x02;
 	if(key[SDL_SCANCODE_LEFT  ] || key[SDL_SCANCODE_KP_4 ] ) val |= 0x04;
 	if(key[SDL_SCANCODE_RIGHT ] || key[SDL_SCANCODE_KP_6 ] ) val |= 0x08;
-	if(key[SDL_SCANCODE_RETURN] || mouse & SDL_BUTTON_LMASK) val |= 0x10;
-	if(key[SDL_SCANCODE_SPACE ] || mouse & SDL_BUTTON_RMASK) val |= 0x20;
+	if(key[SDL_SCANCODE_RETURN] || mouse & SDL_BUTTON_LMASK || touch_state == TOUCH_LBUTTON) val |= 0x10;
+	if(key[SDL_SCANCODE_SPACE ] || mouse & SDL_BUTTON_RMASK || touch_state == TOUCH_RBUTTON) val |= 0x20;
 	if(key[SDL_SCANCODE_ESCAPE]                            ) val |= 0x40;
 	if(key[SDL_SCANCODE_TAB   ]                            ) val |= 0x80;