Merge pull request 'add better colors for 2048' (#32) from fix/add-2048-tile-colors into dev

Reviewed-on: #32

.gitignore

@@ -1,2 +1,6 @@
 .clangd
 *.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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+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 +1,40 @@
+#pragma once
+
+#include <SDL3/SDL.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+typedef enum {
+    BASE,
+    OVERDRAW
+} framebuffer_e;
+
+typedef struct {
+	SDL_Event event;
+	bool is_running;
+	bool framebuffer_base_dirty;
+	bool framebuffer_overdraw_dirty;
+	SDL_Rect dirty_rect;
+	uint16_t width, height;
+    // base layer ~ layer 0
+	uint32_t *framebuffer_base; 
+    // layer on top of that ~ layer 1
+    uint32_t *framebuffer_overdraw; 
+} 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/anim.h

@@ -0,0 +1,55 @@
+#ifndef DANGERZONE_RENDER_ANIM_H
+#define DANGERZONE_RENDER_ANIM_H
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#define ANIM_MAX_TRACKS 64
+
+typedef struct {
+    float x;
+    float y;
+    float w;
+    float h;
+} anim_rect_t;
+
+/* payload is application data; the animation module does not interpret it. */
+typedef struct {
+    uint32_t payload;
+    anim_rect_t from;
+    anim_rect_t to;
+} anim_track_t;
+
+typedef struct {
+    uint32_t payload;
+    anim_rect_t rect;
+} anim_item_t;
+
+typedef struct {
+    anim_track_t tracks[ANIM_MAX_TRACKS];
+    anim_item_t items[ANIM_MAX_TRACKS];
+    size_t count;
+    float elapsed;
+    float duration;
+    bool active;
+} anim_t;
+
+void anim_init(anim_t *anim);
+
+/*
+ * Start tracks from their initial rectangles to their destination rectangles.
+ * Returns false for invalid input or if count exceeds ANIM_MAX_TRACKS.
+ * A zero-duration animation completes immediately.
+ */
+bool anim_start(anim_t *anim, const anim_track_t *tracks,
+                size_t count, float duration);
+
+/* Advance by nonnegative seconds. Returns true once the animation is finished. */
+bool anim_update(anim_t *anim, float dt);
+
+bool anim_is_active(const anim_t *anim);
+size_t anim_count(const anim_t *anim);
+const anim_item_t *anim_items(const anim_t *anim);
+
+#endif

include/dangerzone/render/misc.h

@@ -0,0 +1,19 @@
+#pragma once
+
+#include <dangerzone/engine.h>
+
+#include <stdint.h>
+
+void 
+put_pixel(
+    framebuffer_e framebuffer,
+	unsigned int x, 
+	unsigned int y, 
+	uint32_t color
+);
+
+void 
+clear_framebuffer(
+    framebuffer_e framebuffer,
+	uint32_t color
+);

include/dangerzone/render/rect.h

@@ -0,0 +1,22 @@
+#pragma once
+
+#include <dangerzone/engine.h>
+
+#include <stdint.h>
+
+void
+put_rect(
+    framebuffer_e framebuffer,
+	uint32_t x, 
+	uint32_t y, 
+	uint32_t w, 
+	uint32_t h,
+	uint32_t color
+);
+
+// TODO: remove, deprecated, you can use put_rect for the same thing
+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 +1,29 @@
+#pragma once
+
+#include <dangerzone/engine.h>
+
+#include <stdint.h>
+
+void
+put_char(
+    framebuffer_e framebuffer,
+	char c,
+	uint32_t x, 
+	uint32_t y,
+	uint32_t size,
+	uint32_t fg_color,
+	uint32_t bg_color
+);
+
+void
+put_string(
+    framebuffer_e framebuffer,
+    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

@@ -1,123 +0,0 @@
-#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 TARGET_FRAME 1.0 / 60.0
-#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;
-
-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 engine_internal_state_t *internal_state;
-extern game_state_t *game_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
-);
-
-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();
-
-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 +1,8 @@
-#include "engine.h"
+#include <dangerzone/engine.h>
+
+#include "internal/engine_internal.h"
+
+#include <stdlib.h>
 
 engine_internal_state_t *internal_state = NULL;
 game_state_t *game_state = NULL;
@@ -40,9 +44,15 @@ mark_dirty_rect(int x, int y, int w, int h)
         .h = h
     };
 
-    if (!game_state->framebuffer_dirty) {
+    if (!game_state->framebuffer_base_dirty) {
         game_state->dirty_rect = rect;
-        game_state->framebuffer_dirty = true;
+        game_state->framebuffer_base_dirty = true;
+        return;
+    }
+    
+    if (!game_state->framebuffer_overdraw_dirty) {
+        game_state->dirty_rect = rect;
+        game_state->framebuffer_overdraw_dirty = true;
         return;
     }
 
@@ -81,9 +91,24 @@ mark_dirty_rect(int x, int y, int w, int h)
 }
 
 bool
-upload_dirty_texture(void)
+upload_dirty_texture(
-{
+    framebuffer_e framebuffer
-    if (!game_state->framebuffer_dirty) {
+) {
+    uint32_t *current_framebuffer;
+    switch (framebuffer) {
+    case BASE:
+        current_framebuffer = game_state->framebuffer_base;
+        break;
+    case OVERDRAW:
+        current_framebuffer = game_state->framebuffer_overdraw;
+        break;
+    default:
+        break;
+    }
+
+    if (!game_state->framebuffer_base_dirty &&
+        !game_state->framebuffer_overdraw_dirty
+    ) {
         return true;
     }
 
@@ -115,7 +140,7 @@ upload_dirty_texture(void)
         (size_t)rect.w * sizeof(uint32_t);
 
     const uint8_t *source =
-        (const uint8_t *)game_state->framebuffer +
+        (const uint8_t *)current_framebuffer +
         (size_t)rect.y * source_pitch +
         (size_t)rect.x * sizeof(uint32_t);
 
@@ -132,7 +157,16 @@ upload_dirty_texture(void)
 
     SDL_UnlockTexture(texture);
 
-    game_state->framebuffer_dirty = false;
+    switch (framebuffer) {
+    case BASE:
+        game_state->framebuffer_base_dirty = false;
+        break;
+    case OVERDRAW:
+        game_state->framebuffer_overdraw_dirty = false;
+        break;
+    default:
+        break;
+    }
 
     return true;
 }
@@ -150,7 +184,8 @@ engine_start() {
 		internal_state->engine_update_framebuffer();
 
 		// update the texture with the modified framebuffer
-		upload_dirty_texture();
+		upload_dirty_texture(BASE);
+		upload_dirty_texture(OVERDRAW);
 
 		SDL_RenderClear(
 			internal_state->sdl_state->renderer
@@ -172,6 +207,7 @@ void
 engine_stop() {
 	engine_sdl_destroy(internal_state->sdl_state);
 	free(internal_state);
-	free(game_state->framebuffer);
+	free(game_state->framebuffer_base);
+	free(game_state->framebuffer_overdraw);
     free(game_state);
 }

src/engine/engine_init.c

@@ -1,8 +1,9 @@
-#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"
-#include <stdint.h>
+
+#include <stdlib.h>
 
 bool
 engine_sdl_init_state(
@@ -161,14 +162,23 @@ engine_init(
 		return RCODE_FAILURE;
 	}
 
-	game_state->framebuffer = (uint32_t *)
+	game_state->framebuffer_base = (uint32_t *)
 		malloc(sizeof(uint32_t) * window_width * window_height);
-	if (game_state->framebuffer == NULL) {
+	if (game_state->framebuffer_base == NULL) {
 		free(internal_state);
 		free(game_state);
 		return RCODE_FAILURE;
 	}
 
+	game_state->framebuffer_overdraw = (uint32_t *)
+		malloc(sizeof(uint32_t) * window_width * window_height);
+	if (game_state->framebuffer_overdraw == NULL) {
+		free(internal_state);
+        free(game_state->framebuffer_base);
+		free(game_state);
+		return RCODE_FAILURE;
+	}
+
 	internal_state->engine_poll_events
 		= engine_poll_events;
 
@@ -182,13 +192,15 @@ engine_init(
 	);
 	if (internal_state->sdl_state == NULL) {
 		free(internal_state);
-		free(game_state->framebuffer);
+		free(game_state->framebuffer_base);
+		free(game_state->framebuffer_overdraw);
 		free(game_state);
 		return RCODE_FAILURE;
 	}
 
 	game_state->is_running = true;
-	game_state->framebuffer_dirty = true;
+	game_state->framebuffer_base_dirty = true;
+	game_state->framebuffer_overdraw_dirty = true;
 	game_state->dirty_rect = (SDL_Rect) {
 	    .x = 0,
 	    .y = 0,

src/engine/render.c

@@ -1,84 +0,0 @@
-#include "engine.h"
-#include "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);
-	}
-}
-
-/**
- * draws a rectangle with its left-top corner at (x,y) with
- * a width of 'w' and height of 'h' filled with color 'color'
- */ 
-void
-put_rect(
-	uint32_t x, 
-	uint32_t y, 
-	uint32_t w, 
-	uint32_t h,
-	uint32_t color
-) {
-	for (int i = x; i < x + w; i++) {
-		for (int j = y; j < y + h; j++) {
-			put_pixel(i, j, color);
-		}
-	}
-	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)
-{
-    for (int py = y; py < y + h; ++py) {
-        for (int px = x; px < x + w; ++px) {
-            if (px >= 0 &&
-                px < game_state->width &&
-                py >= 0 &&
-                py < game_state->height) {
-                game_state->framebuffer[
-                    py * game_state->width + px
-                ] = color;
-            }
-        }
-    }
-
-    mark_dirty_rect(x, y, w, h);
-}

src/engine/render/anim.c

@@ -0,0 +1,89 @@
+#include <dangerzone/render/anim.h>
+
+#include <string.h>
+
+void
+anim_init(anim_t *anim)
+{
+    if (anim != NULL)
+        memset(anim, 0, sizeof *anim);
+}
+
+bool
+anim_start(anim_t *anim, const anim_track_t *tracks,
+           size_t count, float duration)
+{
+    if (anim == NULL || (count != 0 && tracks == NULL) ||
+        count > ANIM_MAX_TRACKS || duration < 0.0f) {
+        return false;
+    }
+
+    anim->count = count;
+    anim->elapsed = 0.0f;
+    anim->duration = duration;
+    anim->active = duration > 0.0f && count > 0;
+
+    for (size_t i = 0; i < count; ++i) {
+        anim->tracks[i] = tracks[i];
+        anim->items[i].payload = tracks[i].payload;
+        anim->items[i].rect = tracks[i].from;
+    }
+
+    if (!anim->active) {
+        for (size_t i = 0; i < count; ++i)
+            anim->items[i].rect = tracks[i].to;
+    }
+
+    return true;
+}
+
+bool
+anim_update(anim_t *anim, float dt)
+{
+    if (anim == NULL || !anim->active)
+        return true;
+
+    if (dt < 0.0f)
+        dt = 0.0f;
+
+    anim->elapsed += dt;
+
+    float t = anim->elapsed / anim->duration;
+    if (t >= 1.0f) {
+        t = 1.0f;
+        anim->active = false;
+    }
+
+    /* Ease-out. Replace with t for linear motion. */
+    float eased = 1.0f - (1.0f - t) * (1.0f - t);
+
+    for (size_t i = 0; i < anim->count; ++i) {
+        const anim_track_t *track = &anim->tracks[i];
+        anim_rect_t *rect = &anim->items[i].rect;
+
+        rect->x = track->from.x + (track->to.x - track->from.x) * eased;
+        rect->y = track->from.y + (track->to.y - track->from.y) * eased;
+        rect->w = track->from.w + (track->to.w - track->from.w) * eased;
+        rect->h = track->from.h + (track->to.h - track->from.h) * eased;
+    }
+
+    return !anim->active;
+}
+
+bool
+anim_is_active(const anim_t *anim)
+{
+    return anim != NULL && anim->active;
+}
+
+size_t
+anim_count(const anim_t *anim)
+{
+    return anim != NULL ? anim->count : 0;
+}
+
+const anim_item_t *
+anim_items(const anim_t *anim)
+{
+    return anim != NULL ? anim->items : NULL;
+}

src/engine/render/misc.c

@@ -0,0 +1,71 @@
+#include <dangerzone/engine.h>
+#include <dangerzone/render/misc.h>
+#include <dangerzone/render/rect.h>
+
+#include "internal/engine_internal.h"
+#include "internal/util/error.h"
+
+#include <stdint.h>
+
+// helper function to return the correct pointer to a framebuffer for drawing selection
+uint32_t*
+get_framebuffer(
+    framebuffer_e framebuffer
+) {
+    switch (framebuffer) {
+    case BASE:
+        return game_state->framebuffer_base;
+    case OVERDRAW:
+        return game_state->framebuffer_overdraw;
+    default:
+        return game_state->framebuffer_base;
+    }
+}
+
+// alter a pixel at an imaginary x & y coordinates
+void 
+put_pixel(
+    framebuffer_e framebuffer,
+	unsigned int x, 
+	unsigned int y, 
+	uint32_t color
+) {
+    uint32_t *current_framebuffer = get_framebuffer(framebuffer);
+
+	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 {
+		current_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(
+    framebuffer_e framebuffer,
+	uint32_t color
+) {
+    uint32_t *current_framebuffer = get_framebuffer(framebuffer);
+    
+    for (size_t i = 0;
+         i < (size_t)game_state->width * game_state->height;
+         ++i) {
+        current_framebuffer[i] = color;
+    }
+
+    mark_dirty_rect(
+        0,
+        0,
+        game_state->width,
+        game_state->height
+    );
+}

src/engine/render/rect.c

@@ -0,0 +1,46 @@
+#include <dangerzone/engine.h>
+#include <dangerzone/render/misc.h>
+#include <dangerzone/render/rect.h>
+
+#include <stdint.h>
+
+/**
+ * draws a rectangle with its left-top corner at (x,y) with
+ * a width of 'w' and height of 'h' filled with color 'color'
+ */ 
+void
+put_rect(
+    framebuffer_e framebuffer,
+	uint32_t x, 
+	uint32_t y, 
+	uint32_t w, 
+	uint32_t h,
+	uint32_t color
+) { 
+	for (int i = x; i < x + w; i++) {
+		for (int j = y; j < y + h; j++) {
+			put_pixel(framebuffer, i, j, color);
+		}
+	}
+	mark_dirty_rect(x, y, w, h);
+}
+
+// TODO: remove, see rect.h
+void
+clear_rect(int x, int y, int w, int h, uint32_t color)
+{
+    for (int py = y; py < y + h; ++py) {
+        for (int px = x; px < x + w; ++px) {
+            if (px >= 0 &&
+                px < game_state->width &&
+                py >= 0 &&
+                py < game_state->height) {
+                game_state->framebuffer_base[
+                    py * game_state->width + px
+                ] = color;
+            }
+        }
+    }
+
+    mark_dirty_rect(x, y, w, h);
+}

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
@@ -78,6 +81,7 @@ static const uint8_t font[128][FONT_ROWS] = {
  */
 void
 put_char(
+    framebuffer_e framebuffer,
     char c,
     uint32_t x,
     uint32_t y,
@@ -104,6 +108,7 @@ put_char(
                     ? fg_color : bg_color;
 
             put_rect(
+                framebuffer,
                 x + col * size,
                 y + row * size,
                 size,
@@ -118,6 +123,7 @@ put_char(
 
 void
 put_string(
+    framebuffer_e framebuffer,
     const char *text,
     uint32_t x,
     uint32_t y,
@@ -134,7 +140,7 @@ put_string(
             x = start_x;
             y += (FONT_ROWS + line_spacing) * size;
         } else {
-            put_char(*text, x, y, size, fg_color, bg_color);
+            put_char(framebuffer, *text, x, y, size, fg_color, bg_color);
             x += (FONT_COLS + spacing) * size;
         }
 

src/examples/2048.c

@@ -1,51 +1,490 @@
-#include "engine.h"
+#include <dangerzone/engine.h>
+#include <dangerzone/render/anim.h>
+#include <dangerzone/render/misc.h>
+#include <dangerzone/render/rect.h>
+#include <dangerzone/render/text.h>
 
-// polling events every frame
+#include <stdbool.h>
-void
+#include <stdint.h>
-client_poll_event()
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <math.h>
+
+#define SIZE 4
+#define MOVE_DURATION 0.12f
+#define BORDER_WIDTH 10
+
+typedef enum {
+    LEFT,
+    RIGHT,
+    UP,
+    DOWN
+} dir_e;
+
+typedef struct {
+    uint32_t value;
+    int row;
+    int col;
+} line_tile_t;
+
+typedef enum {
+    GAME_PLAYING,
+    GAME_WON,
+    GAME_LOST
+} game_status_t;
+
+static game_status_t game_status;
+
+typedef struct {
+    uint32_t area[SIZE][SIZE];
+    dir_e direction;
+    uint32_t score;
+} game_t;
+
+static game_t game;
+
+static anim_t movement;
+static anim_track_t move_tracks[SIZE * SIZE];
+static size_t move_track_count;
+
+static double last_frame_time;
+
+static bool
+board_is_full(void)
 {
-	SDL_Event ev = game_state->event;
+    for (int r = 0; r < SIZE; ++r)
+        for (int c = 0; c < SIZE; ++c)
+            if (game.area[r][c] == 0)
+                return false;
 
-	if (ev.type == SDL_EVENT_QUIT) {
+    return true;
-		game_state->is_running = false;
-	}
-
-	if (ev.type == SDL_EVENT_KEY_DOWN) {
-		switch (ev.key.key) {
-		case SDLK_Q:
-			game_state->is_running = false;
-			break;
-		default:
-			break;
-		}
-	}
 }
 
-// performed every frame
+/* Pixel size is calculated from the current window size while drawing. */
-void
+static uint32_t
-client_update_framebuffer()
+colors(uint32_t number)
 {
-	// single green demo pixel
+    switch (number) {
-	game_state->framebuffer[0] = 0x00FF00;
+    case 0:  return 0xFFFFFF;
+    case 2:  return 0x00FF00;
+    case 4:  return 0xFF0000;
+    case 8:  return 0x0000FF;
+    default: return 0xFFFFFF;
+    }
+}
 
-	put_rect(0, 0, 1100, 200, 0xFFFF00);
+/* Maps positive values logarithmically: powers of two get evenly spaced hues.
-	put_string("Hello, traveller. You have come\nto the right place!",
+   Returns 0xRRGGBB. Values outside [min_value, max_value] are clamped. */
-		20, 20, 2, 2, 3, 0x000000, 0xFFFF00
+uint32_t
-	);
+color_for_value(double value, double min_value, double max_value)
+{
+    if (min_value <= 0.0 || max_value <= min_value || value <= 0.0)
+        return 0xFFFFFF;
+
+    if (value < min_value) value = min_value;
+    if (value > max_value) value = max_value;
+
+    double t = (log2(value) - log2(min_value)) /
+               (log2(max_value) - log2(min_value));
+    
+    t = sqrt(t);  /* accelerates color changes near the low end */
+
+    /* Sweep hue from blue to red in HSV; full saturation and brightness. */
+    // double h = (1.0 - t) * 240.0;
+
+    double exponent = log2(value / min_value);  /* 0 at min_value, 1 per doubling */
+    double h = fmod(20.0 + exponent * 45.0, 360.0);
+
+    double c = 1.0;
+    double x = 1.0 - fabs(fmod(h / 60.0, 2.0) - 1.0);
+    double r, g, b;
+
+    if      (h < 60.0)  { r = c; g = x; b = 0.0; }
+    else if (h < 120.0) { r = x; g = c; b = 0.0; }
+    else if (h < 180.0) { r = 0.0; g = c; b = x; }
+    else                { r = 0.0; g = x; b = c; }
+
+    return ((uint32_t)(r * 255.0) << 16) |
+           ((uint32_t)(g * 255.0) << 8)  |
+            (uint32_t)(b * 255.0);
+}
+
+/*
+ * Return the board coordinate for position p in a line, where p=0 is
+ * the side toward which tiles move.
+ */
+static void
+line_coordinate(dir_e direction, int line, int p, int *row, int *col)
+{
+    switch (direction) {
+    case LEFT:
+        *row = line;
+        *col = p;
+        break;
+    case RIGHT:
+        *row = line;
+        *col = SIZE - 1 - p;
+        break;
+    case UP:
+        *row = p;
+        *col = line;
+        break;
+    case DOWN:
+        *row = SIZE - 1 - p;
+        *col = line;
+        break;
+    }
+}
+
+/*
+ * Convert a board cell into the pixel rectangle used to draw its tile.
+ * Keep this consistent with draw_tile_rect() and the cell backgrounds.
+ */
+static anim_rect_t
+tile_rect(int row, int col, uint32_t tile_size)
+{
+    float side = (float)(tile_size - BORDER_WIDTH);
+
+    return (anim_rect_t) {
+        .x = BORDER_WIDTH / 2.0f + col * (float)tile_size,
+        .y = BORDER_WIDTH / 2.0f + row * (float)tile_size,
+        .w = side,
+        .h = side
+    };
+}
+
+static void
+add_move_track(uint32_t value,
+               int from_row, int from_col,
+               int to_row, int to_col)
+{
+    if (move_track_count >= SIZE * SIZE)
+        return;
+
+    uint32_t tile_size = game_state->width / SIZE;
+
+    move_tracks[move_track_count++] = (anim_track_t) {
+        .payload = value,
+        .from = tile_rect(from_row, from_col, tile_size),
+        .to = tile_rect(to_row, to_col, tile_size)
+    };
+}
+
+/*
+ * Process one row or column in movement order. Update the board and record
+ * pixel-space animation tracks for every original tile.
+ */
+static bool
+process_line(dir_e direction, int line, uint32_t output[SIZE])
+{
+    line_tile_t input[SIZE];
+    int input_count = 0;
+    int output_count = 0;
+
+    for (int p = 0; p < SIZE; ++p) {
+        int row, col;
+        line_coordinate(direction, line, p, &row, &col);
+
+        uint32_t value = game.area[row][col];
+        if (value != 0) {
+            input[input_count++] = (line_tile_t) {
+                .value = value,
+                .row = row,
+                .col = col
+            };
+        }
+    }
+
+    memset(output, 0, sizeof(uint32_t) * SIZE);
+
+    for (int i = 0; i < input_count; ) {
+        int dest_row, dest_col;
+        line_coordinate(direction, line, output_count,
+                        &dest_row, &dest_col);
+
+        if (i + 1 < input_count &&
+            input[i].value == input[i + 1].value) {
+            uint32_t merged_value = input[i].value * 2;
+            if (merged_value >= 2048)
+                game_status = GAME_WON;
+
+            output[output_count] = merged_value;
+            game.score += merged_value;
+
+            /* Both source tiles travel to the same merge destination. */
+            add_move_track(input[i].value,
+                           input[i].row, input[i].col,
+                           dest_row, dest_col);
+            add_move_track(input[i + 1].value,
+                           input[i + 1].row, input[i + 1].col,
+                           dest_row, dest_col);
+
+            i += 2;
+        } else {
+            output[output_count] = input[i].value;
+
+            add_move_track(input[i].value,
+                           input[i].row, input[i].col,
+                           dest_row, dest_col);
+
+            ++i;
+        }
+
+        ++output_count;
+    }
+
+    bool changed = false;
+    for (int p = 0; p < SIZE; ++p) {
+        int row, col;
+        line_coordinate(direction, line, p, &row, &col);
+
+        if (game.area[row][col] != output[p])
+            changed = true;
+
+        game.area[row][col] = output[p];
+    }
+
+    return changed;
+}
+
+static bool
+slide(dir_e direction)
+{
+    if (game_status != GAME_PLAYING || anim_is_active(&movement))
+        return false;
+
+    if (anim_is_active(&movement))
+        return false;
+
+    game.direction = direction;
+    move_track_count = 0;
+
+    bool changed = false;
+
+    for (int line = 0; line < SIZE; ++line) {
+        uint32_t output[SIZE];
+        if (process_line(direction, line, output))
+            changed = true;
+    }
+
+    if (!changed) {
+        move_track_count = 0;
+        return false;
+    }
+
+    return anim_start(&movement, move_tracks, move_track_count,
+                      MOVE_DURATION);
+}
+
+static void
+new_2(void)
+{
+    int empty_rows[SIZE * SIZE];
+    int empty_cols[SIZE * SIZE];
+    int count = 0;
+
+    for (int r = 0; r < SIZE; ++r) {
+        for (int c = 0; c < SIZE; ++c) {
+            if (game.area[r][c] == 0) {
+                empty_rows[count] = r;
+                empty_cols[count] = c;
+                ++count;
+            }
+        }
+    }
+
+    if (count == 0)
+        return;
+
+    int pick = rand() % count;
+    game.area[empty_rows[pick]][empty_cols[pick]] = 2;
+}
+
+/* Polling events every frame. */
+void
+client_poll_event(void)
+{
+    SDL_Event ev = game_state->event;
+
+    if (ev.type == SDL_EVENT_QUIT) {
+        game_state->is_running = false;
+        return;
+    }
+
+    if (ev.type != SDL_EVENT_KEY_DOWN)
+        return;
+
+    switch (ev.key.key) {
+    case SDLK_Q:
+        game_state->is_running = false;
+        break;
+    case SDLK_W:
+    case SDLK_UP:
+        if (game_status == GAME_PLAYING)
+           slide(UP);
+        break;
+    case SDLK_S:
+    case SDLK_DOWN:
+        if (game_status == GAME_PLAYING)
+            slide(DOWN);
+        break;
+    case SDLK_A:
+    case SDLK_LEFT:
+        if (game_status == GAME_PLAYING)
+            slide(LEFT);
+        break;
+    case SDLK_D:
+    case SDLK_RIGHT:
+        if (game_status == GAME_PLAYING)
+            slide(RIGHT);
+        break;
+    default:
+        break;
+    }
+}
+
+static double
+monotonic_seconds(void)
+{
+    struct timespec ts;
+    timespec_get(&ts, TIME_UTC);
+    return (double)ts.tv_sec + (double)ts.tv_nsec / 1e9;
+}
+
+static void
+draw_tile_rect(uint32_t value, float x, float y, float w, float h)
+{
+    uint32_t ix = (uint32_t)x;
+    uint32_t iy = (uint32_t)y;
+    uint32_t iw = (uint32_t)w;
+    uint32_t ih = (uint32_t)h;
+    uint32_t color = color_for_value((double)value, 2, 131072);
+
+    put_rect(OVERDRAW, ix, iy, iw, ih, color);
+
+    if (value != 0) {
+        char text[16];
+        snprintf(text, sizeof text, "%u", value);
+        put_string(OVERDRAW, text,
+                   ix + BORDER_WIDTH, iy + BORDER_WIDTH,
+                   3, 1, 12, 0x000000, color);
+    }
+}
+
+static void
+draw_tile(uint32_t value, int row, int col, uint32_t tile_size)
+{
+    anim_rect_t rect = tile_rect(row, col, tile_size);
+    draw_tile_rect(value, rect.x, rect.y, rect.w, rect.h);
+}
+
+void
+client_update_framebuffer(void)
+{
+    double now = monotonic_seconds();
+    float dt = last_frame_time == 0.0
+        ? 0.0f
+        : (float)(now - last_frame_time);
+    last_frame_time = now;
+
+    if (dt > 0.05f)
+        dt = 0.05f;
+
+    if (anim_is_active(&movement) && anim_update(&movement, dt)) {
+        if (game_status == GAME_PLAYING) {
+            new_2();
+
+            if (board_is_full())
+                game_status = GAME_LOST;
+        }
+    }
+
+    uint32_t tile_size = game_state->width / SIZE;
+    uint32_t border_width = BORDER_WIDTH;
+
+    clear_framebuffer(OVERDRAW, 0x000000);
+
+    char score_text[32];
+    snprintf(score_text, sizeof score_text, "score: %u", game.score);
+    put_string(OVERDRAW, score_text,
+               border_width / 2, tile_size * SIZE + border_width / 2,
+               6, 1, 12, 0xFFFFFF, 0x000000);
+    
+    if (game_status != GAME_PLAYING) {
+        clear_framebuffer(BASE, 0x000000);
+        const char *message =
+            game_status == GAME_WON ? "YOU WIN!" : "YOU LOSE!";
+
+        put_string(OVERDRAW, message,
+                   0 + border_width * 2,
+                   game_state->height / 2,
+                   6, 1, 12, 0xFFFFFF, 0x000000);
+
+        return;
+    }
+
+    /* Draw all cell backgrounds. */
+    for (int r = 0; r < SIZE; ++r) {
+        for (int c = 0; c < SIZE; ++c) {
+            uint32_t x = border_width / 2 + (uint32_t)c * tile_size;
+            uint32_t y = border_width / 2 + (uint32_t)r * tile_size;
+            uint32_t side = tile_size - border_width;
+
+            put_rect(BASE, x, y, side, side, 0xFFFFFF);
+            put_rect(OVERDRAW, x, y, side, side, 0xFFFFFF);
+        }
+    }
+
+    if (anim_is_active(&movement)) {
+        const anim_item_t *items = anim_items(&movement);
+        size_t count = anim_count(&movement);
+
+        for (size_t i = 0; i < count; ++i) {
+            draw_tile_rect(items[i].payload,
+                           items[i].rect.x, items[i].rect.y,
+                           items[i].rect.w, items[i].rect.h);
+        }
+    } else {
+        for (int r = 0; r < SIZE; ++r) {
+            for (int c = 0; c < SIZE; ++c) {
+                draw_tile(game.area[r][c], r, c, tile_size);
+            }
+        }
+    }
+}
+
+static void
+game_init(void)
+{
+    game_status = GAME_PLAYING;
+    memset(&game, 0, sizeof game);
+    anim_init(&movement);
+    srand((unsigned)time(NULL));
+
+    /* Start with two 2-tiles. */
+    new_2();
+    new_2();
 }
 
 int
-main()
+main(void)
 {
-	// initialize the engine
+    uint32_t window_width = 500;
-	if (engine_init(
+    uint32_t window_height = (uint32_t)(window_width * 1.12f);
-		client_poll_event,
+
-		client_update_framebuffer
+    game_init();
-	)) {
+
-		engine_start();
+    if (engine_init(window_width, window_height,
-		engine_stop();
+                    "Dangerous 2048",
-		return 0;
+                    client_poll_event,
-	} else {
+                    client_update_framebuffer)) {
-		return 1;
+        engine_start();
-	}
+        engine_stop();
+        return 0;
+    }
+
+    return 1;
 }
+

src/examples/CMakeLists.txt

@@ -0,0 +1,9 @@
+#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)
+target_link_libraries(game_2048 PRIVATE m)
+
+#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

src/internal/engine_internal.h

@@ -0,0 +1,53 @@
+#pragma once
+
+#include <dangerzone/engine.h>
+
+#include <SDL3/SDL.h>
+#include <stdbool.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
+);
+
+uint32_t*
+get_framebuffer(
+    framebuffer_e framebuffer
+);

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
+};