acceleration and friction

CMakeLists.txt

@@ -15,6 +15,7 @@ set(SOURCES
   src/draw.c
   src/player.c
   src/input.c
+  src/tools.c
 )
 
 set(ASSETS_cg

include/conf.h

@@ -1,3 +1,9 @@
 #pragma once
 
 #define PLAYER_S 12
+
+#define PLAYER_ACC    1
+#define PLAYER_FRIC   0.2
+#define PLAYER_JUMP   7
+#define PLAYER_COYOTE 3
+#define GRAVITY       0.4

include/tools.h

@@ -0,0 +1,3 @@
+#pragma once
+
+int sign(int x);

src/player.c

@@ -2,11 +2,13 @@
 #include "conf.h"
 #include "draw.h"
 #include "input.h"
+#include "tools.h"
 
 static int k_up, k_down, k_left, k_right, k_jump;
 static struct Player player;
 static void player_get_input(void);
-static void player_move(void);
+static void player_move(struct Vec2 mov);
+static int player_collide(void);
 
 void
 player_init(void)
@@ -21,10 +23,7 @@ player_update(void)
 	player_get_input();
 
 	const struct Vec2 mov = (struct Vec2){k_right - k_left, k_down - k_up};
-	player.spd.x = mov.x;
-	player.spd.y = mov.y;
-
-	player_move();
+	player_move(mov);
 }
 
 void
@@ -44,8 +43,46 @@ player_get_input(void)
 }
 
 static void
-player_move(void)
+player_move(struct Vec2 mov)
 {
-	player.pos.x += player.spd.x;
-	player.pos.y += player.spd.y;
+	if (player_collide()) {
+		return;
+	}
+
+	player.spd.x *= (1 - PLAYER_FRIC);
+	player.spd.x += mov.x * PLAYER_ACC;
+
+	player.spd.y *= (1 - PLAYER_FRIC);
+	player.spd.y += mov.y * PLAYER_ACC;
+
+	if (!player.spd.x && !player.spd.y) {
+		return;
+	}
+
+	const int sign_x = sign(player.spd.x);
+	const int Ispd_x = player.spd.x;
+	player.pos.x += Ispd_x;
+	if (player_collide()) {
+		player.spd.x = 0.0f;
+		while (player_collide()) {
+			player.pos.x -= sign_x;
+		}
+	}
+
+	const int sign_y = sign(player.spd.y);
+	const int Ispd_y = player.spd.y;
+	player.pos.y += Ispd_y;
+	if (player_collide()) {
+		player.spd.y = 0.0f;
+		while (player_collide()) {
+			player.pos.y -= sign_y;
+		}
+	}
+}
+
+static int
+player_collide(void)
+{
+	/* Je ne fais qu'acte de présence, rien de plus */
+	return 0;
 }

src/tools.c

@@ -0,0 +1,7 @@
+#include "tools.h"
+
+int
+sign(int x)
+{
+	return (x > 0) - (x < 0); /* from jtmm2 */
+}