Merge pull request 'add 2048 bare minimum example' (#27) from feat/add-2048-example into dev

Reviewed-on: #27

.gitignore

@@ -1,2 +1,6 @@
 .clangd
-*.sublime-*
+*.sublime-*
+build/
+src/engine/CMakeFiles
+examples/CMakeFiles
+*.xopp

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "third_party/munit"]
+	path = third_party/munit
+	url = https://github.com/nemequ/munit.git

CMakeLists.txt

@@ -0,0 +1,14 @@
+cmake_minimum_required(VERSION 3.20)
+
+project(dangerzone LANGUAGES C)
+
+set(CMAKE_C_STANDARD 11)
+set(CMAKE_C_STANDARD_REQUIRED ON)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
+find_package(PkgConfig REQUIRED)
+pkg_check_modules(SDL3 REQUIRED IMPORTED_TARGET sdl3)
+
+add_subdirectory(src/engine)
+add_subdirectory(src/examples)
+add_subdirectory(tests)

LICENSE

@@ -0,0 +1,675 @@
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+  If the Program specifies that a proxy can decide which future
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+public statement of acceptance of a version permanently authorizes you
+to choose that version for the Program.
+
+  Later license versions may give you additional or different
+permissions.  However, no additional obligations are imposed on any
+author or copyright holder as a result of your choosing to follow a
+later version.
+
+  15. Disclaimer of Warranty.
+
+  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
+OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+  16. Limitation of Liability.
+
+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+    <program>  Copyright (C) <year>  <name of author>
+    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<https://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<https://www.gnu.org/licenses/why-not-lgpl.html>.

Makefile

@@ -1,41 +0,0 @@
-CC := gcc
-LIBS := `pkg-config --libs sdl3`
-INC := `pkg-config --cflags sdl3` -I./include
-SRC := src/engine/engine.c \
-	src/engine/engine_init.c \
-	src/engine/render.c \
-	src/engine/text.c
-OUT := build/main
-SNAKE_SRC := src/examples/snake.c $(SRC)
-SNAKE := build/snake
-2048_SRC := src/examples/2048.c $(SRC)
-2048 := build/2048
-
-build:
-	$(CC) -o $(OUT) -O3 -DNDEBUG src/main.c $(SRC) $(INC) $(LIBS)
-
-run:
-	$(OUT)
-
-build-snake:
-	$(CC) -o $(SNAKE) -O3 -DNDEBUG $(SNAKE_SRC) $(INC) $(LIBS)
-
-run-snake:
-	$(SNAKE)
-
-clean-snake:
-	rm $(SNAKE)
-
-build-2048:
-	$(CC) -o $(2048) -O3 -DNDEBUG $(2048_SRC) $(INC) $(LIBS)
-
-run-2048:
-	$(2048)
-
-clean-2048:
-	rm $(2048)
-
-clean:
-	rm $(OUT)
-
-.PHONY: build run

include/dangerzone/engine.h

@@ -0,0 +1,31 @@
+#pragma once
+
+#include <SDL3/SDL.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+typedef struct {
+	SDL_Event event;
+	bool is_running;
+	bool framebuffer_dirty;
+	SDL_Rect dirty_rect;
+	uint16_t width, height;
+	uint32_t *framebuffer;
+} game_state_t;
+
+extern game_state_t *game_state;
+
+bool
+engine_init(
+	uint32_t window_width,
+	uint32_t window_height,
+	const char window_name[],
+	void (*engine_poll_events)(void),
+	void (*engine_update_framebuffer)(void)
+);
+
+void
+engine_start();
+
+void
+engine_stop();

include/dangerzone/render/misc.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#include <stdint.h>
+
+void 
+put_pixel(
+	unsigned int x, 
+	unsigned int y, 
+	uint32_t color
+);
+
+void 
+clear_framebuffer(
+	uint32_t color
+);

include/dangerzone/render/rect.h

@@ -0,0 +1,18 @@
+#pragma once
+
+#include <stdint.h>
+
+void
+put_rect(
+	uint32_t x, 
+	uint32_t y, 
+	uint32_t w, 
+	uint32_t h,
+	uint32_t color
+);
+
+void
+clear_rect(int x, int y, int w, int h, uint32_t color);
+
+void
+mark_dirty_rect(int x, int y, int w, int h);

include/dangerzone/render/text.h

@@ -0,0 +1,25 @@
+#pragma once
+
+#include <stdint.h>
+
+void
+put_char(
+	char c,
+	uint32_t x, 
+	uint32_t y,
+	uint32_t size,
+	uint32_t fg_color,
+	uint32_t bg_color
+);
+
+void
+put_string(
+    const char *text,
+    uint32_t x,
+    uint32_t y,
+    uint32_t size,
+    uint32_t spacing,
+    uint32_t line_spacing,
+    uint32_t fg_color,
+    uint32_t bg_color
+);

include/engine.h

@@ -1,119 +0,0 @@
-#pragma once
-
-#include <SDL3/SDL.h>
-#include <stdbool.h>
-#include <stdlib.h>
-#include <string.h>
-#include <stdint.h>
-
-#define WINDOW_WIDTH 1280
-#define WINDOW_HEIGHT 720
-#define DEFAULT_WINDOW_NAME "Dangerzone"
-#define WINDOW_NAME_LENGTH 128
-#define TARGET_FRAME 1.0 / 60.0
-#define FONT_ROWS 7
-#define FONT_COLS 5
-
-typedef struct {
-	char window_name[WINDOW_NAME_LENGTH];
-	uint16_t width, height;
-	SDL_Window *window;
-	SDL_Renderer *renderer;
-	SDL_Texture *texture;
-} engine_sdl_state_t;
-
-typedef struct {
-	/**
-	 * this function runs inside of the SDL_PollEvent loop
-	 * useful for user input, quitting the program and so on
-	 */
-	void (*engine_poll_events)(void);
-	/**
-	 * meant as the "area" for manupulating the framebuffer;
-	 * after this is executed, the contents of 
-	 * game_state->framebuffer get drawn
-	 */
-	void (*engine_update_framebuffer)(void);
-	engine_sdl_state_t *sdl_state;
-} engine_internal_state_t;
-
-typedef struct {
-	uint32_t framebuffer[WINDOW_WIDTH * WINDOW_HEIGHT];
-	SDL_Event event;
-	bool is_running;
-	bool framebuffer_dirty;
-	SDL_Rect dirty_rect;
-	uint16_t width, height;
-} game_state_t;
-
-extern engine_internal_state_t *internal_state;
-extern game_state_t *game_state;
-
-engine_sdl_state_t*
-engine_sdl_init();
-
-void 
-engine_sdl_destroy(
-	engine_sdl_state_t *state
-);
-
-bool
-engine_init(
-	void (*engine_poll_events)(void),
-	void (*engine_update_framebuffer)(void)
-);
-
-void
-engine_start();
-
-void
-engine_stop();
-
-void 
-put_pixel(
-	unsigned int x, 
-	unsigned int y, 
-	uint32_t color
-);
-
-void
-put_rect(
-	uint32_t x, 
-	uint32_t y, 
-	uint32_t w, 
-	uint32_t h,
-	uint32_t color
-);
-
-void 
-clear_framebuffer(
-	uint32_t color
-);
-
-void
-clear_rect(int x, int y, int w, int h, uint32_t color);
-
-void
-mark_dirty_rect(int x, int y, int w, int h);
-
-void
-put_char(
-	char c,
-	uint32_t x, 
-	uint32_t y,
-	uint32_t size,
-	uint32_t fg_color,
-	uint32_t bg_color
-);
-
-void
-put_string(
-    const char *text,
-    uint32_t x,
-    uint32_t y,
-    uint32_t size,
-    uint32_t spacing,
-    uint32_t line_spacing,
-    uint32_t fg_color,
-    uint32_t bg_color
-);

src/engine/CMakeLists.txt

@@ -0,0 +1,19 @@
+file(GLOB_RECURSE ENGINE_SOURCES CONFIGURE_DEPENDS
+    "${CMAKE_CURRENT_SOURCE_DIR}/*.c"
+)
+
+add_library(dangerzone_engine STATIC
+    ${ENGINE_SOURCES}
+)
+
+target_include_directories(dangerzone_engine
+    PUBLIC
+        ${PROJECT_SOURCE_DIR}/include
+    PRIVATE
+        ${PROJECT_SOURCE_DIR}/src
+)
+
+target_link_libraries(dangerzone_engine
+    PUBLIC
+        PkgConfig::SDL3
+)

src/engine/engine.c

@@ -1,4 +1,6 @@
-#include "engine.h"
+#include <dangerzone/engine.h>
+
+#include "internal/engine_internal.h"
 
 engine_internal_state_t *internal_state = NULL;
 game_state_t *game_state = NULL;
@@ -172,5 +174,6 @@ void
 engine_stop() {
 	engine_sdl_destroy(internal_state->sdl_state);
 	free(internal_state);
-	free(game_state);
+	free(game_state->framebuffer);
+    free(game_state);
 }

src/engine/engine_init.c

@@ -1,10 +1,15 @@
-#include "engine.h"
+#include <dangerzone/engine.h>
-#include "error.h"
+
-#include <SDL3/SDL_render.h>
+#include "internal/engine_internal.h"
-#include <SDL3/SDL_video.h>
+#include "internal/util/error.h"
 
 bool
-engine_sdl_init_state(engine_sdl_state_t **state) {
+engine_sdl_init_state(
+	engine_sdl_state_t **state,
+	uint32_t window_width,
+	uint32_t window_height,
+	const char window_name[]
+) {
  	*state = (engine_sdl_state_t *)
 	 	malloc(sizeof(engine_sdl_state_t));
 
@@ -13,12 +18,13 @@ engine_sdl_init_state(engine_sdl_state_t **state) {
 		return RCODE_FAILURE;
 	}
 
-	(*state)->width = WINDOW_WIDTH;
+	(*state)->width = window_width;
-	(*state)->height = WINDOW_HEIGHT;
+	(*state)->height = window_height;
 	strncpy(
-		(*state)->window_name, DEFAULT_WINDOW_NAME, 
+		(*state)->window_name, window_name,
-		WINDOW_NAME_LENGTH
+		WINDOW_NAME_MAX_LENGTH - 1
 	);
+	(*state)->window_name[WINDOW_NAME_MAX_LENGTH - 1] = '\0';
 
 	return RCODE_SUCCESS;
 }
@@ -94,11 +100,19 @@ engine_sdl_init_texture(
 }
 
 engine_sdl_state_t*
-engine_sdl_init() 
+engine_sdl_init(
-{
+	uint32_t window_width,
+	uint32_t window_height,
+	const char window_name[]
+) {
 	engine_sdl_state_t *state;
 
-	if (!engine_sdl_init_state(&state) || 
+	if (!engine_sdl_init_state(
+			&state,
+			window_width,
+			window_height,
+			window_name
+		) || 
 		!engine_sdl_init_root() || 
 		!engine_sdl_init_window(state) ||
 		!engine_sdl_init_renderer(state) ||
@@ -127,6 +141,9 @@ engine_sdl_destroy(
 
 bool
 engine_init(
+	uint32_t window_width,
+	uint32_t window_height,
+	const char window_name[],
 	void (*engine_poll_events)(void),
 	void (*engine_update_framebuffer)(void)
 ) {
@@ -143,15 +160,28 @@ engine_init(
 		return RCODE_FAILURE;
 	}
 
+	game_state->framebuffer = (uint32_t *)
+		malloc(sizeof(uint32_t) * window_width * window_height);
+	if (game_state->framebuffer == NULL) {
+		free(internal_state);
+		free(game_state);
+		return RCODE_FAILURE;
+	}
+
 	internal_state->engine_poll_events
 		= engine_poll_events;
 
 	internal_state->engine_update_framebuffer
 		= engine_update_framebuffer;
 
-	internal_state->sdl_state = engine_sdl_init();
+	internal_state->sdl_state = engine_sdl_init(
+		window_width,
+		window_height,
+		window_name
+	);
 	if (internal_state->sdl_state == NULL) {
 		free(internal_state);
+		free(game_state->framebuffer);
 		free(game_state);
 		return RCODE_FAILURE;
 	}

src/engine/render/misc.c

@@ -0,0 +1,48 @@
+#include <dangerzone/engine.h>
+#include <dangerzone/render/misc.h>
+#include <dangerzone/render/rect.h>
+
+#include "internal/util/error.h"
+#include <stdint.h>
+
+// alter a pixel at an imaginary x & y coordinates
+void 
+put_pixel(
+	unsigned int x, 
+	unsigned int y, 
+	uint32_t color
+) {
+	uint16_t w = game_state->width;
+	uint16_t h = game_state->height;
+
+	if (x < 0 || x >= w || y < 0 || y >= h) {
+		eprintf(
+			"CRITICAL: attempted buffer overflow in put_pixel\n"
+			"at x = %d, y = %d", x, y
+		);
+	} else {
+		game_state->framebuffer[game_state->width * y + x]
+			= color;
+
+	    mark_dirty_rect(x, y, 1, 1);
+	}
+}
+
+// fill the entire framebuffer with a given color
+void
+clear_framebuffer(
+	uint32_t color
+) {
+    for (size_t i = 0;
+         i < (size_t)game_state->width * game_state->height;
+         ++i) {
+        game_state->framebuffer[i] = color;
+    }
+
+    mark_dirty_rect(
+        0,
+        0,
+        game_state->width,
+        game_state->height
+    );
+}

src/engine/render/rect.c

@@ -1,30 +1,9 @@
-#include "engine.h"
+#include <dangerzone/engine.h>
-#include "error.h"
+#include <dangerzone/render/misc.h>
+#include <dangerzone/render/rect.h>
+
 #include <stdint.h>
 
-// alter a pixel at an imaginary x & y coordinates
-void 
-put_pixel(
-	unsigned int x, 
-	unsigned int y, 
-	uint32_t color
-) {
-	uint16_t w = game_state->width;
-	uint16_t h = game_state->height;
-
-	if (x < 0 || x >= w || y < 0 || y >= h) {
-		eprintf(
-			"CRITICAL: attempted buffer overflow in put_pixel\n"
-			"at x = %d, y = %d", x, y
-		);
-	} else {
-		game_state->framebuffer[game_state->width * y + x]
-			= color;
-
-	    mark_dirty_rect(x, y, 1, 1);
-	}
-}
-
 /**
  * draws a rectangle with its left-top corner at (x,y) with
  * a width of 'w' and height of 'h' filled with color 'color'
@@ -45,25 +24,6 @@ put_rect(
 	mark_dirty_rect(x, y, w, h);
 }
 
-// fill the entire framebuffer with a given color
-void
-clear_framebuffer(
-	uint32_t color
-) {
-    for (size_t i = 0;
-         i < (size_t)game_state->width * game_state->height;
-         ++i) {
-        game_state->framebuffer[i] = color;
-    }
-
-    mark_dirty_rect(
-        0,
-        0,
-        game_state->width,
-        game_state->height
-    );
-}
-
 void
 clear_rect(int x, int y, int w, int h, uint32_t color)
 {

src/engine/render/text.c

@@ -1,7 +1,10 @@
 // rendering characters in the framebuffer
 
-#include "engine.h"
+#include <dangerzone/engine.h>
-#include <stdint.h>
+#include <dangerzone/render/rect.h>
+#include <dangerzone/render/text.h>
+
+#include "internal/engine_internal.h"
 
 /*
  * each character has 8 rows

src/examples/2048.c

@@ -1,4 +1,251 @@
-#include "engine.h"
+#include "dangerzone/render/rect.h"
+#include <dangerzone/engine.h>
+#include <dangerzone/render/misc.h>
+#include <dangerzone/render/text.h>
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+#define SIZE 4
+
+typedef enum {
+    LEFT,
+    RIGHT,
+    UP,
+    DOWN
+} dir_e;
+
+typedef struct {
+    uint32_t x;
+    uint32_t y;
+} v2_t;
+
+typedef struct {
+    uint32_t area[SIZE][SIZE];
+    dir_e direction;
+    uint32_t score;
+} game_t;
+
+static game_t game;
+
+void
+print_area()
+{
+    printf("AREA:\n");
+    for (int i = 0; i < SIZE; i++) {
+        printf("[");
+        for (int j = 0; j < SIZE - 1; j++) {
+            printf("%d, ", game.area[i][j]);
+        }
+        printf("%d]\n", game.area[i][SIZE - 1]);
+    }
+    printf("\n");
+}
+
+bool
+move()
+{
+    bool retval = false;
+    switch (game.direction) {
+    case LEFT:
+        for (int i = 0; i < SIZE; i++) {
+            for (int j = 0; j < SIZE; j++) {
+                for (int k = 0; k < SIZE - 1; k++) {
+                    if (game.area[i][k] == 0 && game.area[i][k + 1] != 0) {
+                        game.area[i][k] = game.area[i][k + 1];
+                        game.area[i][k + 1] = 0;
+                        retval = true;
+                    }
+                }
+            }
+        }
+        break;
+    case RIGHT:
+        for (int i = 0; i < SIZE; i++) {
+            uint32_t *row = game.area[i];
+            for (int j = 0; j < SIZE; j++) {
+                for (int k = SIZE - 1; k > 0; k--) {
+                    if (game.area[i][k] == 0 && game.area[i][k - 1] != 0) {
+                        game.area[i][k] = game.area[i][k - 1];
+                        game.area[i][k - 1] = 0;
+                        retval = true;
+                    }
+                }
+            }
+        }
+        break;
+    case UP:
+        for (int i = 0; i < SIZE; i++) {
+            for (int j = 0; j < SIZE; j++) {
+                for (int k = 0; k < SIZE - 1; k++) {
+                    if (game.area[k][i] == 0 && game.area[k + 1][i] != 0) {
+                        game.area[k][i] = game.area[k + 1][i];
+                        game.area[k + 1][i] = 0;
+                        retval = true;
+                    }
+                }
+            }
+        }
+        break;
+    case DOWN:
+        for (int i = 0; i < SIZE; i++) {
+            for (int j = 0; j < SIZE; j++) {
+                for (int k = SIZE - 1; k > 0; k--) {
+                    if (game.area[k][i] == 0 && game.area[k - 1][i] != 0) {
+                        game.area[k][i] = game.area[k - 1][i];
+                        game.area[k - 1][i] = 0;
+                        retval = true;
+                    }
+                }
+            }
+        }
+        break;
+    default:
+        break;
+    }
+
+    return retval;
+}
+
+bool
+combine_horizontal(
+    bool has_moved
+) {
+    bool retval = has_moved;
+    int8_t direction;
+    uint32_t start, end;
+    switch (game.direction) {
+    case LEFT:
+        // combine left
+        direction = -1;
+        start = 0;
+        end = SIZE - 1;
+        break;
+    case RIGHT:
+        // combine right
+        direction = 1;
+        start = SIZE - 1;
+        end = 0;
+        break;
+    default:
+        break;
+    }
+
+    for (int row_index = 0; row_index < SIZE; row_index++) {
+        uint32_t *row = game.area[row_index];
+
+        for (int i = start; (game.direction == LEFT) ? i < end : i > end; i -= direction) {
+            if (row[i] == 0) {
+                continue;
+            }
+            if (row[i] == row[i - direction]) {
+                retval = true;
+                row[i] *= 2;
+                game.score += row[i];
+                row[i - direction] = 0;
+                for (int j = i - direction; (game.direction == LEFT) ? j < end : j > end; j -= direction) {
+                    row[j] = row[j - direction];
+                }
+                row[end] = 0;
+            }
+        }
+    }
+
+    return retval;
+} 
+
+bool
+combine_vertical(
+    bool has_moved
+) {
+    bool retval = has_moved;
+    int8_t direction;
+    uint32_t start, end;
+    switch (game.direction) {
+    case UP:
+        // combine up
+        direction = -1;
+        start = 0;
+        end = SIZE - 1;
+        break;
+    case DOWN:
+        // combine down
+        direction = 1;
+        start = SIZE - 1;
+        end = 0;
+        break;
+    default:
+        break;
+    }
+
+    for (int col_index = 0; col_index < SIZE; col_index++) {
+        for (int i = start; (game.direction == UP) ? i < end : i > end; i -= direction) {
+            if (game.area[i][col_index] == 0) {
+                continue;
+            }
+            if (game.area[i][col_index] == game.area[i - direction][col_index]) {
+                retval = true;
+                game.area[i][col_index] *= 2;
+                game.score += game.area[i][col_index];
+                game.area[i - direction][col_index] = 0;
+                for (int j = i - direction; (game.direction == UP) ? j < end : j > end; j -= direction) {
+                    game.area[j][col_index] = game.area[j - direction][col_index];
+                }
+                game.area[end][col_index] = 0;
+            }
+        }
+    }
+
+    return retval;
+}
+
+bool
+combine(
+    bool has_moved
+) {
+    if (game.direction == LEFT || game.direction == RIGHT) {
+        return combine_horizontal(has_moved);
+    } else {
+        return combine_vertical(has_moved);
+    }
+}
+
+// finds a random empty position and puts a two there
+void
+new_2()
+{
+    uint32_t row = rand() % SIZE;
+    uint32_t col = rand() % SIZE;
+    while (game.area[row][col] != 0) {
+        row = rand() % SIZE;
+        col = rand() % SIZE;
+    }
+
+    game.area[row][col] = 2;
+}
+
+void
+slide()
+{
+    // 1. move all squares in one direction
+    bool has_moved = move();
+
+    // 2. then combine them and shift the potential rest by one in the given direction
+    bool has_combined = combine(has_moved);
+    
+    // printf("moved? %s, combined? %s\n", (has_moved) ? "true" : "false", (has_combined) ? "true" : "false");
+
+    // 3. generate a new 2
+    if (has_moved || has_combined) {
+        new_2();
+    }
+
+    // printf("score: %d\n", game.score);
+    
+    // print_area();
+}
 
 // polling events every frame
 void
@@ -15,30 +262,231 @@ client_poll_event()
 		case SDLK_Q:
 			game_state->is_running = false;
 			break;
+        case SDLK_W:
+            game.direction = UP;
+            slide();
+            break;
+        case SDLK_S:
+            game.direction = DOWN;
+            slide();
+            break;
+        case SDLK_A:
+            game.direction = LEFT;
+            slide();
+            break;
+        case SDLK_D:
+            game.direction = RIGHT;
+            slide();
+            break;
 		default:
 			break;
 		}
 	}
 }
 
+#define CHR(ord) ((ord) + 48)
+#define ORD(chr) ((chr) - 48)
+
+uint32_t
+colors(
+    uint32_t number
+) {
+    switch (number) {
+    case 0:
+        return 0xFFFFFF;
+    case 2:
+        return 0x00FF00;
+    case 4:
+        return 0xFF0000;
+    case 8:
+        return 0x0000FF;
+    default:
+        return 0xFFFFFF;
+    }
+}
+
+uint32_t
+numlen(
+    uint32_t n
+) {
+    uint32_t len = 0;
+
+    while (n > 0) {
+        len++;
+        n /= 10;
+    }
+
+    return len;
+}
+
+uint32_t
+power(
+    uint32_t x,
+    uint32_t n
+) {
+    // x ^ n
+    uint32_t acc = 1;
+    for (int i = 0; i < n; i++) {
+        acc *= x;
+    }
+
+    return acc;
+}
+
+uint32_t
+numrev(
+    uint32_t n
+) {
+    uint32_t len = numlen(n);
+    uint32_t new = 0;
+    int i = 0;
+
+    while (n > 0) {
+        new += (n % 10) * power(10, len - (++i));
+        n /= 10;
+    }
+
+    return new;
+}
+
 // performed every frame
 void
 client_update_framebuffer()
 {
-	// single green demo pixel
+	// clear_framebuffer(0xFFFF00);
-	game_state->framebuffer[0] = 0x00FF00;
+	// put_string("Welcome to the most\n*DANGEROUS* 2048 game!",
+	// 	20, 20, 2, 2, 3, 0x000000, 0xFFFF00
+	// );
 
-	put_rect(0, 0, 1100, 200, 0xFFFF00);
+    clear_framebuffer(0x000000);
-	put_string("Hello, traveller. You have come\nto the right place!",
+
-		20, 20, 2, 2, 3, 0x000000, 0xFFFF00
+    uint32_t tile_size = game_state->width / SIZE;
-	);
+    uint8_t border_width = 10;
+    char *n_str;
+    bool alloced = false;
+    for (int i = 0; i < SIZE; i++) {
+        for (int j = 0; j < SIZE; j++) {
+            alloced = true;
+            // background
+            uint32_t x = (border_width / 2) + i * tile_size;
+            uint32_t y = (border_width / 2) + j * tile_size;
+            uint32_t w = tile_size - border_width;
+            uint32_t h = tile_size - border_width;
+            uint32_t background_color = colors(game.area[j][i]);
+            put_rect(x, y, w, h, background_color);
+
+            // number in foreground
+            uint32_t foreground_color = 0x000000;
+            uint8_t font_size = 3;
+            
+            uint32_t n = game.area[j][i];
+            uint32_t n_len = numlen(n);
+            n_str = calloc(n_len, sizeof(char));
+            if (n_str == NULL) {
+                game_state->is_running = false;
+            }
+            sprintf(n_str, "%d", n);
+            uint32_t n_rev = numrev(n);
+            uint32_t digit_offset = 1;
+            if (n != 0) {
+                put_string(n_str, x + border_width, y + border_width, font_size, digit_offset, 12, foreground_color, background_color);
+            }
+        }
+    }
+
+    // score display line (single line)
+    char *score_text = calloc(numlen(game.score), sizeof(char));
+    if (score_text == NULL) {
+        game_state->is_running = false;
+    }
+    alloced = true;
+
+    sprintf(score_text, "score: %6d", game.score);
+    put_string(score_text, border_width / 2, tile_size * SIZE + border_width / 2, 6, 1, 12, 0xFFFFFF, 0x000000);
+
+    if (alloced) {
+        free(n_str);
+        free(score_text);
+    }
+}
+
+bool
+v2_eq(v2_t a, v2_t b)
+{
+    return a.x == b.x && a.y == b.y;
+}
+
+bool
+v2_contains(v2_t v[], size_t size, v2_t elem)
+{
+    for (int i = 0; i < size; i++) {
+        if (v2_eq(v[i], elem)) {
+            return true;
+        }
+    }
+
+    return false;
+}
+
+void
+game_init()
+{
+    srand(time(NULL));
+
+    // generate MAX_NUMBER_OF_4 + MAX_NUMBER_OF_2 random indices in range 0..15 (row in 0..3, col in 0..3)
+    // this means that there will be at least MAX_NUMBER_OF_2 of 2s and MAX_NUMBER_OF_4 <= MAX_NUMBER_OF_2 4s
+    // => usually less 4s than 2s because the indices can get replaced
+#define MAX_NUMBER_OF_4 1
+#define MAX_NUMBER_OF_2 2
+
+    uint8_t row, col;
+    v2_t elem;
+    v2_t fours[MAX_NUMBER_OF_4], twos[MAX_NUMBER_OF_2];
+
+    int i = 0;
+    while (i < MAX_NUMBER_OF_4) {
+        row = rand() % SIZE;
+        col = rand() % SIZE;
+        elem = (v2_t){ .x = col, .y = row };
+        if (!v2_contains(twos, MAX_NUMBER_OF_4, elem)) {
+            fours[i++] = elem;
+        }
+    }
+    
+    i = 0;
+    while (i < MAX_NUMBER_OF_2) {
+        row = rand() % SIZE;
+        col = rand() % SIZE;
+        elem = (v2_t){ .x = col, .y = row };
+        if (!v2_contains(twos, MAX_NUMBER_OF_2, elem)) {
+            twos[i++] = elem;
+        }
+    }
+
+    for (i = 0; i < MAX_NUMBER_OF_4; i++) {
+        game.area[fours[i].y][fours[i].x] = 4;
+    }
+
+    for (i = 0; i < MAX_NUMBER_OF_2; i++) {
+        game.area[twos[i].y][twos[i].x] = 2;
+    }
+    
+    game.direction = RIGHT;
+    game.score = 0;
 }
 
 int 
 main()
 {
+    uint32_t window_width = 500;
+    uint32_t window_height = window_width * 1.12f;
+
+    game_init();
+
 	// initialize the engine
 	if (engine_init(
+		window_width, window_height,
+		"Dangerous 2048",
 		client_poll_event,
 		client_update_framebuffer
 	)) {
@@ -48,4 +496,4 @@ main()
 	} else {
 		return 1;
 	}
-}
+}

src/examples/CMakeLists.txt

@@ -0,0 +1,8 @@
+add_executable(game_snake snake.c)
+target_link_libraries(game_snake PRIVATE dangerzone_engine)
+
+add_executable(game_2048 2048.c)
+target_link_libraries(game_2048 PRIVATE dangerzone_engine)
+
+add_executable(game_window window.c)
+target_link_libraries(game_window PRIVATE dangerzone_engine)

src/examples/snake.c

@@ -1,4 +1,8 @@
-#include "engine.h"
+#include <dangerzone/engine.h>
+#include <dangerzone/render/rect.h>
+#include <dangerzone/render/text.h>
+#include <dangerzone/render/misc.h>
+
 #include <stdint.h>
 #include <stdlib.h>
 #include <stdbool.h>
@@ -331,6 +335,8 @@ main()
 
 	// initialize the engine
 	if (engine_init(
+		500, 500,
+		"Dangerous Snake",
 		client_poll_event,
 		client_update_framebuffer
 	)) {

src/examples/window.c

@@ -1,4 +1,6 @@
-#include "engine.h"
+#include <dangerzone/engine.h>
+#include <dangerzone/render/misc.h>
+#include <dangerzone/render/text.h>
 
 // polling events every frame
 void
@@ -25,10 +27,8 @@ client_poll_event()
 void
 client_update_framebuffer()
 {
-	// single green demo pixel
+	// example window contents
-	game_state->framebuffer[0] = 0x00FF00;
+	clear_framebuffer(0xFFFF00);
-
-	put_rect(0, 0, 1100, 200, 0xFFFF00);
 	put_string("Hello, traveller. You have come\nto the right place!",
 		20, 20, 2, 2, 3, 0x000000, 0xFFFF00
 	);
@@ -39,6 +39,8 @@ main()
 {
 	// initialize the engine
 	if (engine_init(
+		500, 100,
+		"Dangerzone",
 		client_poll_event,
 		client_update_framebuffer
 	)) {

src/internal/engine_internal.h

@@ -0,0 +1,49 @@
+#pragma once
+
+#include <SDL3/SDL.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+
+#define WINDOW_NAME_MAX_LENGTH 128
+#define FONT_ROWS 7
+#define FONT_COLS 5
+
+typedef struct {
+	char window_name[WINDOW_NAME_MAX_LENGTH];
+	uint16_t width, height;
+	SDL_Window *window;
+	SDL_Renderer *renderer;
+	SDL_Texture *texture;
+} engine_sdl_state_t;
+
+typedef struct {
+	/**
+	 * this function runs inside of the SDL_PollEvent loop
+	 * useful for user input, quitting the program and so on
+	 */
+	void (*engine_poll_events)(void);
+	/**
+	 * meant as the "area" for manupulating the framebuffer;
+	 * after this is executed, the contents of 
+	 * game_state->framebuffer get drawn
+	 */
+	void (*engine_update_framebuffer)(void);
+	engine_sdl_state_t *sdl_state;
+} engine_internal_state_t;
+
+extern engine_internal_state_t *internal_state;
+
+engine_sdl_state_t*
+engine_sdl_init(
+	uint32_t window_width,
+	uint32_t window_height,
+	const char window_name[]
+);
+
+void
+engine_sdl_destroy(
+	engine_sdl_state_t *state
+);
+

tests/CMakeLists.txt

@@ -0,0 +1,40 @@
+add_library(munit STATIC
+    "${PROJECT_SOURCE_DIR}/third_party/munit/munit.c"
+)
+
+target_include_directories(munit
+    PUBLIC
+        ${PROJECT_SOURCE_DIR}/third_party
+)
+
+file(GLOB TEST_SOURCES CONFIGURE_DEPENDS
+    "${CMAKE_CURRENT_SOURCE_DIR}/suites/*.c"
+)
+
+add_library(dangerzone_tests STATIC
+    ${TEST_SOURCES}
+)
+
+target_include_directories(dangerzone_tests
+    PUBLIC
+        ${PROJECT_SOURCE_DIR}/include
+        ${PROJECT_SOURCE_DIR}/src
+        ${PROJECT_SOURCE_DIR}/third_party
+)
+
+add_executable(test_runner 
+    main.c
+)
+
+target_link_libraries(test_runner 
+    PRIVATE
+        dangerzone_tests
+        munit
+        dangerzone_engine
+)
+
+add_custom_target(test
+    COMMAND tests/test_runner
+    DEPENDS test_runner
+    WORKING_DIRECTORY ${PROJECT_BINARY_DIR}
+)

tests/main.c

@@ -0,0 +1,26 @@
+#include "munit/munit.h"
+
+extern const MunitSuite sdl_suite;
+
+int main(int argc, char *argv[]) {
+    MunitSuite sub_suites[] = {
+        sdl_suite,
+        { // terminator
+            NULL,
+            NULL,
+            NULL,
+            0,
+            MUNIT_SUITE_OPTION_NONE
+        }
+    };
+
+    MunitSuite master_suite = {
+        "",
+        NULL,
+        sub_suites,
+        1,
+        MUNIT_SUITE_OPTION_NONE
+    };
+
+    return munit_suite_main(&master_suite, NULL, argc, argv);
+}

tests/suites/sdl.c

@@ -0,0 +1,90 @@
+#include <dangerzone/engine.h>
+#include "internal/engine_internal.h"
+
+#include "munit/munit.h"
+
+static void*
+test_setup(
+    const MunitParameter params[],
+    void* data
+) {
+    (void)params;
+    (void)data;
+
+    internal_state = (engine_internal_state_t *)
+		malloc(sizeof(engine_internal_state_t));
+    munit_assert_not_null(internal_state);
+
+ 	internal_state->sdl_state = (engine_sdl_state_t *)
+	 	malloc(sizeof(engine_sdl_state_t));
+ 	munit_assert_not_null(internal_state->sdl_state);
+
+	internal_state->sdl_state->width = 500;
+	internal_state->sdl_state->height = 500;
+	strncpy(
+		internal_state->sdl_state->window_name, "Dangerzone",
+		WINDOW_NAME_MAX_LENGTH - 1
+	);
+	internal_state->sdl_state->window_name[WINDOW_NAME_MAX_LENGTH - 1] = '\0';
+
+    return internal_state;
+}
+
+static void
+test_teardown(
+    void *fixture
+) {
+    engine_internal_state_t *state = fixture;
+
+    if (state->sdl_state != NULL) {
+        free(state->sdl_state);
+        free(state);
+    }
+
+    internal_state = NULL;
+}
+
+static MunitResult
+test_window_parameters(
+    const MunitParameter params[], 
+    void* data
+) {
+    (void)params;
+
+    engine_internal_state_t *state = data;
+
+    munit_assert_not_null(state);
+    munit_assert_not_null(state->sdl_state);
+    munit_assert_int(state->sdl_state->width, ==, 500);
+    munit_assert_int(state->sdl_state->height, ==, 500);
+    munit_assert_int(strcmp(state->sdl_state->window_name, "Dangerzone"), ==, 0);
+
+    return MUNIT_OK;
+}
+
+MunitTest tests[] = {
+    {
+        "/window-parameters",
+        test_window_parameters,
+        test_setup,
+        test_teardown,
+        MUNIT_TEST_OPTION_NONE,
+        NULL
+    },
+    { // terminator
+        NULL,
+        NULL,
+        NULL,
+        NULL,
+        MUNIT_TEST_OPTION_NONE,
+        NULL
+    }
+};
+
+const MunitSuite sdl_suite = {
+    "/sdl",
+    tests,
+    NULL,
+    1,
+    MUNIT_SUITE_OPTION_NONE
+};