simplify code & add `entity_move()`

CMakeLists.txt

@@ -17,8 +17,10 @@ set(SOURCES
 	src/entity/collide.c
 	src/entity/draw_hitbox.c
 	src/entity/init.c
+	src/entity/move.c
 	src/wall/init.c
 	src/player/init.c
+	src/util.c
 )
 
 set(ASSETS
@@ -28,7 +30,7 @@ set(FLAGS
 	-Wall -Wextra -Wshadow -Wswitch-default -Wswitch-enum
 	-Wunreachable-code -Wstrict-prototypes -Wmissing-prototypes
 	-Wold-style-definition -Werror-implicit-function-declaration
-	-fms-extensions -std=c99 -O3
+	-fplan9-extensions -std=c99 -O3
 )
 
 fxconv_declare_assets(${ASSETS} WITH_METADATA)

include/entity.h

@@ -15,9 +15,16 @@ struct Entity {
 #define ENTITY_GRID_SIZE 256
 extern struct Entity *g_entity_grid[ENTITY_GRID_SIZE];
 
-void entity_init(void *restrict entity, int x, int y, int hb_x, int hb_y,
-                 int hb_w, int hb_h, int layer, color_t hb_color);
-void entity_deinit(void *restrict entity);
-void entity_draw_hitbox(void *restrict entity);
+void entity_init(struct Entity *, int x, int y, int hb_x, int hb_y, int hb_w,
+                 int hb_h, int layer, color_t hb_color);
+void entity_deinit(struct Entity *);
+void entity_draw_hitbox(struct Entity *);
 void entity_grid_draw_hitboxes(void);
-struct Entity *entity_collide(void *restrict entity, int mask);
+/* return first entity colliding on mask */
+struct Entity *entity_collide(struct Entity *, int mask);
+/* return bool */
+int entity_collide_with(struct Entity *self, struct Entity *other, int mask);
+/* return bitmask
+ * bit 1: collide on x
+ * bit 2: collide on y */
+int entity_move(struct Entity *e, int mask, int move_x, int move_y);

include/layers.h

@@ -4,6 +4,6 @@ enum Layers {
 	L_NONE = 0,
 	L_SOLID = 1 << 1,
 	L_SEMISOLID = 1 << 2,
-	L_HARMFULL = 1 << 3,
+	L_HARMFUL = 1 << 3,
 	L_PUSHABLE = 1 << 4,
 };

include/util.h

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

src/entity/collide.c

@@ -1,12 +1,8 @@
 #include "entity.h"
 
-static int entity_collide_with(struct Entity *restrict, struct Entity *restrict,
-                               int mask);
-
 struct Entity *
-entity_collide(void *restrict entity, int mask)
+entity_collide(struct Entity *e, int mask)
 {
-	struct Entity *const e = entity;
 	int i;
 
 	i = ENTITY_GRID_SIZE;
@@ -18,9 +14,8 @@ entity_collide(void *restrict entity, int mask)
 }
 
 /* axis aligned bounding box collision checking */
-static int
-entity_collide_with(struct Entity *restrict self, struct Entity *restrict other,
-                    int mask)
+int
+entity_collide_with(struct Entity *self, struct Entity *other, int mask)
 {
 	const int sx = self->x + self->hb_x;
 	const int sy = self->y + self->hb_y;

src/entity/draw_hitbox.c

@@ -2,9 +2,8 @@
 #include <gint/display.h>
 
 void
-entity_draw_hitbox(void *restrict entity)
+entity_draw_hitbox(struct Entity *e)
 {
-	const struct Entity *const e = entity;
 	const int x = e->x + e->hb_x;
 	const int y = e->y + e->hb_y;
 	drect_border(e->x, e->y, e->x + 2, e->y + 2, C_NONE, 1, e->hb_color);

src/entity/init.c

@@ -5,11 +5,10 @@
 struct Entity *g_entity_grid[ENTITY_GRID_SIZE];
 
 void
-entity_init(void *restrict entity, int x, int y, int hb_x, int hb_y, int hb_w,
+entity_init(struct Entity *e, int x, int y, int hb_x, int hb_y, int hb_w,
             int hb_h, int layer, color_t hb_color)
 {
 	static int init_grid = 1;
-	struct Entity *const e = entity;
 	int i;
 	e->x = x;
 	e->y = y;
@@ -32,17 +31,17 @@ entity_init(void *restrict entity, int x, int y, int hb_x, int hb_y, int hb_w,
 	while (i-- > 0)
 		if (g_entity_grid[i] == NULL)
 			break;
-	g_entity_grid[i] = entity;
+	g_entity_grid[i] = e;
 }
 
 void
-entity_deinit(void *restrict entity)
+entity_deinit(struct Entity *e)
 {
 	int i;
 	/* remove from grid */
 	i = ENTITY_GRID_SIZE;
 	while (i-- > 0)
-		if (g_entity_grid[i] == entity)
+		if (g_entity_grid[i] == e)
 			break;
 	g_entity_grid[i] = NULL;
 }

src/entity/move.c

@@ -0,0 +1,43 @@
+#include "entity.h"
+#include "util.h"
+
+/* only provide non-nul value on `move_x` OR `move_y` */
+static int entity_move_single_axis(struct Entity *, int mask, int move_x,
+                                   int move_y);
+
+int
+entity_move(struct Entity *e, int mask, int move_x, int move_y)
+{
+	int collided = 0;
+
+	collided |= entity_move_single_axis(e, mask, move_x, 0);
+	collided |= entity_move_single_axis(e, mask, 0, move_y) << 1;
+
+	return collided;
+}
+
+static int
+entity_move_single_axis(struct Entity *e, int mask, int move_x, int move_y)
+{
+	struct Entity *other;
+	int collided = 0;
+	const int sign_move_x = sign(move_x);
+	const int sign_move_y = sign(move_y);
+
+	if (!move_x && !move_y)
+		return 0;
+
+	e->x += move_x;
+	e->y += move_y;
+	do {
+		other = entity_collide(e, mask);
+		if (other != NULL)
+			collided = 1;
+		while (entity_collide_with(e, other, mask)) {
+			e->x -= sign_move_x;
+			e->y -= sign_move_y;
+		}
+	} while (other != NULL);
+
+	return collided;
+}

src/main.c

@@ -11,6 +11,7 @@ main(void)
 	struct Player player;
 	struct Player newb;
 	struct Wall walls[5];
+	int collided = 0;
 
 	player_init(&player, 16, 32);
 	player_init(&newb, 64, 128);
@@ -21,18 +22,14 @@ main(void)
 	wall_init(&walls[4], DWIDTH / 2 - 24, DHEIGHT - 64, 48, 48);
 
 	do {
-		const int previous_x = player.x;
-		const int previous_y = player.y;
 		dclear(C_BLACK);
 		entity_grid_draw_hitboxes();
+		dprint(2, 2, C_WHITE, "%d", collided);
 		dupdate();
 		clearevents();
-		player.x += keydown(KEY_RIGHT) - keydown(KEY_LEFT);
-		player.y += keydown(KEY_DOWN) - keydown(KEY_UP);
-		if (entity_collide(&player, L_SOLID) != NULL) {
-			player.x = previous_x;
-			player.y = previous_y;
-		}
+		collided = entity_move(&player, L_SOLID,
+		                       keydown(KEY_RIGHT) - keydown(KEY_LEFT),
+		                       keydown(KEY_DOWN) - keydown(KEY_UP));
 	} while (!keydown(KEY_EXIT));
 
 	return;

src/util.c

@@ -0,0 +1,7 @@
+#include "util.h"
+
+int
+sign(int n)
+{
+	return (n > 0) - (n < 0);
+}