From 13c9481b0430d0bf6fc50b0952bcd81229022abc Mon Sep 17 00:00:00 2001
From: John Tsiombikas <nuclear@mutantstargoat.com>
Date: Wed, 16 Nov 2016 10:00:14 +0200
Subject: [PATCH] rudimentary gamepad controls

---
 src/app.cc  |   48 ++++++++++++++++++++++++++++++++++++++++++++++++
 src/app.h   |    3 +++
 src/main.cc |   19 ++++++++++++++++++-
 3 files changed, 69 insertions(+), 1 deletion(-)

diff --git a/src/app.cc b/src/app.cc
index 4fd3690..59c8f07 100644
--- a/src/app.cc
+++ b/src/app.cc
@@ -42,6 +42,8 @@ static bool have_headtracking, should_swap;
 static int prev_mx, prev_my;
 static bool bnstate[8];
 static bool keystate[256];
+static Vec2 joy_move, joy_look;
+static float joy_deadzone = 0.1;
 
 static Mat4 view_matrix, mouse_view_matrix, proj_matrix;
 static TextureSet texman;
@@ -166,6 +168,29 @@ static void update(float dt)
 	float speed = walk_speed * dt;
 	Vec3 dir;
 
+	// joystick
+	float jdeadsq = joy_deadzone * joy_deadzone;
+	float jmove_lensq = length_sq(joy_move);
+	float jlook_lensq = length_sq(joy_look);
+
+	if(jmove_lensq > jdeadsq) {
+		float len = sqrt(jmove_lensq);
+		jmove_lensq -= jdeadsq;
+
+		dir.x += joy_move.x / len * speed;
+		dir.z += joy_move.y / len * speed;
+	}
+	if(jlook_lensq > jdeadsq) {
+		float len = sqrt(jlook_lensq);
+		jlook_lensq -= jdeadsq;
+
+		cam_theta += joy_look.x / len * mouse_speed * 2.0;
+		cam_phi += joy_look.y / len * mouse_speed * 1.0;
+		if(cam_phi < -90.0f) cam_phi = -90.0f;
+		if(cam_phi > 90.0f) cam_phi = 90.0f;
+	}
+
+	// keyboard move
 	if(keystate[(int)'w']) {
 		dir.z -= speed;
 	}
@@ -467,3 +492,26 @@ void app_mouse_delta(int dx, int dy)
 		mouse_look(dx * mouse_speed, dy * mouse_speed);
 	}
 }
+
+void app_gamepad_axis(int axis, float val)
+{
+	switch(axis) {
+	case 0:
+		joy_move.x = val;
+		break;
+	case 1:
+		joy_move.y = val;
+		break;
+
+	case 2:
+		joy_look.x = val;
+		break;
+	case 3:
+		joy_look.y = val;
+		break;
+	}
+}
+
+void app_gamepad_button(int bn, bool pressed)
+{
+}
diff --git a/src/app.h b/src/app.h
index 09b1c82..d81b848 100644
--- a/src/app.h
+++ b/src/app.h
@@ -26,6 +26,9 @@ void app_mouse_button(int bn, bool pressed, int x, int y);
 void app_mouse_motion(int x, int y);
 void app_mouse_delta(int dx, int dy);
 
+void app_gamepad_axis(int axis, float val);
+void app_gamepad_button(int bn, bool pressed);
+
 // the following functions are implemented by the backend (main.cc)
 void app_quit();
 void app_swap_buffers();
diff --git a/src/main.cc b/src/main.cc
index 4efca60..58e01de 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -17,11 +17,13 @@ static bool quit;
 static unsigned int start_time;
 static unsigned int modkeys;
 
+SDL_GameController *gamepad;
+
 static int scale_factor = 1;
 
 int main(int argc, char **argv)
 {
-	if(SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER) != 0) {
+	if(SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER | SDL_INIT_GAMECONTROLLER) != 0) {
 		fprintf(stderr, "failed to initialize SDL\n");
 		return 1;
 	}
@@ -55,6 +57,17 @@ int main(int argc, char **argv)
 	SDL_GL_GetDrawableSize(win, &win_width, &win_height);
 	win_aspect = (float)win_width / (float)win_height;
 
+	printf("detected %d joysticks\n", SDL_NumJoysticks());
+	for(int i=0; i<SDL_NumJoysticks(); i++) {
+		if(SDL_IsGameController(i)) {
+			if(!(gamepad = SDL_GameControllerOpen(i))) {
+				fprintf(stderr, "failed to open game controller %i: %s\n", i, SDL_GetError());
+				continue;
+			}
+			printf("Using gamepad: %s\n", SDL_GameControllerNameForIndex(i));
+		}
+	}
+
 	if(!init(argc, argv)) {
 		SDL_Quit();
 		return 1;
@@ -186,6 +199,10 @@ static void process_event(SDL_Event *ev)
 			app_reshape(win_width, win_height);
 		}
 		break;
+
+	case SDL_CONTROLLERAXISMOTION:
+		app_gamepad_axis(ev->caxis.axis, ev->caxis.value / 65535.0f);
+		break;
 	}
 }
 
-- 
1.7.10.4