engine base

.clang-format

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+BasedOnStyle: LLVM
+IndentWidth: 8
+UseTab: AlignWithSpaces
+BreakBeforeBraces: Linux
+AllowShortIfStatementsOnASingleLine: false
+IndentCaseLabels: false
+ColumnLimit: 80
+AlignConsecutiveMacros: true
+AlwaysBreakAfterReturnType: TopLevelDefinitions

.gitignore

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+build-cg/
+build-fx/
+*.g3a
+CMakeLists.txt~
+*.png~

CMakeLists.txt

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+# Configure with [fxsdk build-fx] or [fxsdk build-cg], which provide the
+# toolchain file and module path of the fxSDK
+
+cmake_minimum_required(VERSION 3.18)
+project(RC C)
+
+include(GenerateG3A)
+include(Fxconv)
+
+find_package(Gint 2.5.3 REQUIRED)
+find_package(LibImg 2.4.0 REQUIRED)
+
+include_directories(include)
+
+set(SOURCES
+	src/main.c
+	src/entity/collide.c
+	src/entity/draw_hitbox.c
+	src/entity/init.c
+	src/wall/init.c
+	src/player/init.c
+)
+
+set(ASSETS
+)
+
+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
+)
+
+fxconv_declare_assets(${ASSETS} WITH_METADATA)
+
+add_executable(${PROJECT_NAME} ${SOURCES} ${ASSETS})
+target_compile_options(${PROJECT_NAME} PRIVATE ${FLAGS})
+target_link_libraries(${PROJECT_NAME} Gint::Gint)
+target_link_libraries(${PROJECT_NAME} LibImg::LibImg)
+target_link_options(${PROJECT_NAME} PRIVATE -Wl,-Map=map)
+
+generate_g3a(TARGET ${PROJECT_NAME}
+	OUTPUT "${PROJECT_NAME}.g3a"
+	NAME "${PROJECT_NAME}"
+	ICONS assets/graphics/icon-uns.png assets/graphics/icon-sel.png)

include/entity.h

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+#pragma once
+#include <gint/display.h>
+
+struct Entity {
+	int x;
+	int y;
+	int hb_x;
+	int hb_y;
+	int hb_w;
+	int hb_h;
+	color_t hb_color;
+};
+
+#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, color_t hb_color);
+void entity_deinit(void *restrict entity);
+void entity_draw_hitbox(void *restrict entity);
+void entity_grid_draw_hitboxes(void);
+int entity_collide(void *restrict entity);

include/player.h

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+#pragma once
+#include "entity.h"
+
+struct Player {
+	struct Entity;
+	float spd_x;
+	float spd_y;
+	float rem_x;
+	float rem_y;
+};
+
+void player_init(struct Player *restrict, int x, int y);

include/tiles.h

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+#pragma once
+
+enum Tile {
+	TILE_VOID,
+	TILE_SOLID,
+};
+#define TILE_OOB TILE_VOID

include/wall.h

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+#pragma once
+#include "entity.h"
+
+struct Wall {
+	struct Entity;
+};
+
+void wall_init(struct Wall *restrict, int x, int y, int width, int height);

src/entity/collide.c

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+#include "entity.h"
+
+static int entity_collide_with(struct Entity *restrict,
+                               struct Entity *restrict);
+
+int
+entity_collide(void *restrict entity)
+{
+	struct Entity *const e = entity;
+	int i;
+
+	i = ENTITY_GRID_SIZE;
+	while (i-- > 0)
+		if (entity_collide_with(e, g_entity_grid[i]))
+			return 1;
+
+	return 0;
+}
+
+/* axis aligned bounding box collision checking */
+static int
+entity_collide_with(struct Entity *restrict self, struct Entity *restrict other)
+{
+	const int sx = self->x + self->hb_x;
+	const int sy = self->y + self->hb_y;
+	const int ox = other->x + other->hb_x;
+	const int oy = other->y + other->hb_y;
+
+	if (self == NULL || other == NULL || self == other)
+		return 0;
+
+	return sx < ox + other->hb_w && sx + self->hb_w > ox &&
+	       sy < oy + other->hb_h && sy + self->hb_h > oy;
+}

src/entity/draw_hitbox.c

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+#include "entity.h"
+#include <gint/display.h>
+
+void
+entity_draw_hitbox(void *restrict entity)
+{
+	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);
+	drect_border(x, y, x + e->hb_w - 1, y + e->hb_h - 1, C_NONE, 1,
+	             e->hb_color);
+}
+
+void
+entity_grid_draw_hitboxes(void)
+{
+	int i;
+	i = ENTITY_GRID_SIZE;
+	while (i-- > 0)
+		if (g_entity_grid[i] != NULL)
+			entity_draw_hitbox(g_entity_grid[i]);
+}

src/entity/init.c

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+#include "entity.h"
+#include <gint/display.h>
+
+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, color_t hb_color)
+{
+	static int init_grid = 1;
+	struct Entity *const e = entity;
+	int i;
+	e->x = x;
+	e->y = y;
+	e->hb_x = hb_x;
+	e->hb_y = hb_y;
+	e->hb_w = hb_w;
+	e->hb_h = hb_h;
+	e->hb_color = hb_color;
+
+	if (init_grid) {
+		init_grid = 0;
+		i = ENTITY_GRID_SIZE;
+		while (i-- > 0)
+			g_entity_grid[i] = NULL;
+	}
+
+	/* add to grid */
+	i = ENTITY_GRID_SIZE;
+	while (i-- > 0)
+		if (g_entity_grid[i] == NULL)
+			break;
+	g_entity_grid[i] = entity;
+}
+
+void
+entity_deinit(void *restrict entity)
+{
+	int i;
+	/* remove from grid */
+	i = ENTITY_GRID_SIZE;
+	while (i-- > 0)
+		if (g_entity_grid[i] == entity)
+			break;
+	g_entity_grid[i] = NULL;
+}

src/main.c

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+#include "entity.h"
+#include "player.h"
+#include "wall.h"
+#include <gint/display.h>
+#include <gint/keyboard.h>
+
+void
+main(void)
+{
+	struct Player player;
+	struct Wall walls[5];
+
+	player_init(&player, 16, 32);
+	wall_init(&walls[0], 16, 0, DWIDTH - 32, 16);
+	wall_init(&walls[1], 16, DHEIGHT - 16, DWIDTH - 32, 16);
+	wall_init(&walls[2], 0, 0, 16, DHEIGHT);
+	wall_init(&walls[3], DWIDTH - 16, 0, 16, DHEIGHT);
+	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();
+		dupdate();
+		clearevents();
+		player.x += keydown(KEY_RIGHT) - keydown(KEY_LEFT);
+		player.y += keydown(KEY_DOWN) - keydown(KEY_UP);
+		if (entity_collide(&player)) {
+			player.x = previous_x;
+			player.y = previous_y;
+		}
+	} while (!keydown(KEY_EXIT));
+
+	return;
+}

src/player/init.c

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+#include "player.h"
+#include <gint/display.h>
+
+void
+player_init(struct Player *restrict p, int x, int y)
+{
+	entity_init(p, x, y, 2, 2, 12, 12, C_BLUE);
+	p->spd_x = 0.0;
+	p->spd_y = 0.0;
+	p->rem_x = 0.0;
+	p->rem_y = 0.0;
+}

src/wall/init.c

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+#include "wall.h"
+#include <gint/display.h>
+
+void
+wall_init(struct Wall *restrict w, int x, int y, int width, int height)
+{
+	entity_init(w, x, y, 0, 0, width, height, C_DARK);
+}