added do {..}while(0) to a macro

Reviewed-on: #20

CMakeLists.txt

@@ -17,17 +17,20 @@ find_package(SDL2)
 find_package(SDL2_image)
 find_package(SDL2_ttf)
 
-file(GLOB_RECURSE
+file(
+	GLOB_RECURSE
 	SOURCE_C
 	"${CMAKE_SOURCE_DIR}/src/**.c")
-file(GLOB_RECURSE
+file(
+	GLOB_RECURSE
 	SOURCE_CPP
 	"${CMAKE_SOURCE_DIR}/src/**.c*")
 
-add_executable(${PROJECT}
+add_executable(
+	${PROJECT}
 	${SOURCE_C}
 	${SOURCE_CPP})
 
-target_link_libraries(${PROJECT} SDL2 SDL2_image SDL2_ttf)
+target_link_libraries(${PROJECT} SDL2 SDL2_image SDL2_ttf m)
 
 target_include_directories(${PROJECT} PRIVATE "${CMAKE_SOURCE_DIR}/include/" "${CMAKE_SOURCE_DIR}/src/corelib" "${CMAKE_SOURCE_DIR}/src/ui")

src/corelib/assets.c

@@ -18,7 +18,7 @@ static resource_t* insert_asset(const resource_t* resource) {
     return inserted;
 }
 
-void add_arbitrary_asset(void* memory, deleter_t deleter) {
+void add_arbitrary_asset(void* memory, deleter_fn deleter) {
     char name_buf[99];
     // generate the name of the arbitrary block based on adresses
     sprintf(name_buf, "%p%p", memory, deleter);

src/corelib/assets.h

@@ -17,7 +17,7 @@ typedef enum resourcetype_t {
     RESOURCETYPE_MAX
 } resourcetype_t;
 
-typedef void(*deleter_t)(void* target);
+typedef void(*deleter_fn)(void* target);
 
 typedef struct resource_t {
     resourcetype_t type;
@@ -31,13 +31,13 @@ typedef struct resource_t {
         } font;
         struct {
             void* memory;
-			deleter_t deleter;
+            deleter_fn deleter;
         } arbitrary_type;
     };
 } resource_t;
 
-extern void add_arbitrary_asset(void* memory, deleter_t deleter);
-extern void add_arbitrary_asset_by_name(void* memory, deleter_t deleter, const char* name);
+extern void add_arbitrary_asset(void* memory, deleter_fn deleter);
+extern void add_arbitrary_asset_by_name(void* memory, deleter_fn deleter, const char* name);
 extern SDL_Texture* load_texture(const char* file);
 extern TTF_Font* load_font(const char* file, int size);
 extern SDL_Texture* get_texture(const char* file);

src/corelib/corelib.h

@@ -0,0 +1,6 @@
+#include "object.h"
+#include "render.h"
+#include "assets.h"
+#include "physics.h"
+#include "world.h"
+#include "entry.h"

src/corelib/entry.c

@@ -0,0 +1,102 @@
+#include "entry.h"
+#include "world.h"
+#include "assets.h"
+#include "render.h"
+#include "input.h"
+
+#include "time.h"
+
+static double _delta_time = 0;
+static double _min_frame_interval = 0;
+static struct timespec start_last_frame;
+
+#define CURRENT_TIME(__out) do { struct timespect ts; timespec_get(&ts, TIME_UTC); __out = ts.tv_sec + tv.nsec * 1E-09; } while(0)
+
+inline static
+double timespec_to_sec(struct timespec spec) {
+    return (double)spec.tv_sec + (double)spec.tv_nsec * 1E-09;
+}
+
+inline float delta_time() {
+    return (float)_delta_time;
+}
+
+void set_frame_interval(double frame_interval) {
+    _min_frame_interval = frame_interval;
+}
+
+void set_frame_rate_limit(int fps) {
+    _min_frame_interval = 1.0/(double)fps;
+}
+
+static inline
+int _engine_start() {
+    init_context();
+    return 0;
+}
+
+static inline
+int _engine_shutdown() {
+    game_exit();
+    clean_assets();
+    close_context();
+    exit(0);
+}
+
+static inline
+void _handle_events() {
+    while(SDL_PollEvent(&g_context.event)) {
+        input_notify_event(g_context.event);
+        switch(g_context.event.type) {
+    case SDL_QUIT:
+            g_context.running = 0;
+            break;
+        }
+    }
+}
+
+static inline
+int _engine_run() {
+    SDL_DisplayMode mode;
+    SDL_GetDesktopDisplayMode(0, &mode);
+    SDL_Window* window = SDL_CreateWindow("Tabletop", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, mode.w, mode.h, SDL_WINDOW_FULLSCREEN_DESKTOP);
+
+    g_context = (context_t){
+        .window = window,
+        .renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED),
+        .running = 1,
+    };
+
+    input_init();
+    world_clear();
+    start_game();
+
+    timespec_get(&start_last_frame, TIME_UTC);
+    struct timespec next_time;
+    while(g_context.running) {
+        timespec_get(&next_time, TIME_UTC);
+        _delta_time = timespec_to_sec(next_time) - timespec_to_sec(start_last_frame);
+        start_last_frame = next_time;
+        _handle_events();
+        update_input();
+        _render_mode = 1;
+        update_ui();
+        _render_mode = 0;
+        update_game();
+        world_update();    // update world objects
+        world_draw();        // draw world objects
+        swap_buffer();
+        do {
+            timespec_get(&next_time, TIME_UTC);
+            _delta_time = timespec_to_sec(next_time) - timespec_to_sec(start_last_frame);
+            SDL_PumpEvents();
+        } while(_delta_time < _min_frame_interval);
+    }
+    return 0;
+}
+
+int main(int argc, char* argv[]) {
+    _engine_start();
+    _engine_run();
+    _engine_shutdown();
+}

src/corelib/entry.h

@@ -1,11 +1,9 @@
 #ifndef _engine_h
 #define _engine_h
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 extern float delta_time();
+extern void set_frame_interval(double frame_interval);
+extern void set_frame_rate_limit(int fps);
 
 /* TO BE DEFINED IN GAME */
 
@@ -14,8 +12,4 @@ extern void update_game();
 extern void update_ui();
 extern void game_exit();
 
-#ifdef __cplusplus
-}
-#endif
-
 #endif /* _engine_h */

src/corelib/input.c

@@ -6,6 +6,34 @@
 #include "SDL2/SDL_render.h"
 #include <SDL2/SDL_events.h>
 
+enum INPUT_LISTENER_TYPE_T {
+    INPUT_LISTENER_MOUSE,
+    INPUT_LISTENER_AXIS,
+    INPUT_LISTENER_SCROLL,
+    INPUT_LISTENER_BUTTON,
+};
+
+typedef struct input_listener_t {
+    enum INPUT_LISTENER_TYPE_T type;
+    union {
+        struct {
+            input_axis_fn delegate;
+            SDL_Scancode positive, negative;
+            int last_positive, last_negative;
+        } axis;
+        struct {
+            input_mouse_fn delegate;
+        } mouse;
+        struct {
+            input_button_fn delegate;
+            uint32_t button;
+            int last;
+        } button;
+        struct {
+            input_scroll_fn delegate;
+        } scroll;
+    };
+} input_listener_t;
 
 const Uint8* g_key_states = NULL;
 input_listener_t g_key_listeners[24];
@@ -17,24 +45,25 @@ static uint32_t _mouse_left_seconds = 0;
 static float _scroll_delta = 0;
 
 void add_key_listener(SDL_Scancode negative, SDL_Scancode positive,
-						input_axis_delegate_t delegate) {
+                        input_axis_fn delegate) {
     memset(g_key_listeners_endptr, 0x0, sizeof(input_listener_t));
     g_key_listeners_endptr->type = INPUT_LISTENER_AXIS;
     g_key_listeners_endptr->axis.delegate = delegate;
     g_key_listeners_endptr->axis.positive = positive;
     g_key_listeners_endptr->axis.negative = negative;
-	g_key_listeners_endptr->axis.last = 0;
+    g_key_listeners_endptr->axis.last_positive =
+        g_key_listeners_endptr->axis.last_negative = 0;
     ++g_key_listeners_endptr;
 }
 
-void add_mouse_listener(input_mouse_delegate_t delegate) {
+void add_mouse_listener(input_mouse_fn delegate) {
     memset(g_key_listeners_endptr, 0x0, sizeof(input_listener_t));
     g_key_listeners_endptr->type = INPUT_LISTENER_MOUSE;
     g_key_listeners_endptr->mouse.delegate = delegate;
     ++g_key_listeners_endptr;
 }
 
-void add_mouse_button_listener(uint32_t button, input_button_delegate_t delegate) {
+void add_mouse_button_listener(uint32_t button, input_button_fn delegate) {
     memset(g_key_listeners_endptr, 0x0, sizeof(input_listener_t));
     g_key_listeners_endptr->type = INPUT_LISTENER_BUTTON;
     g_key_listeners_endptr->button.delegate = delegate;
@@ -43,7 +72,7 @@ void add_mouse_button_listener(uint32_t button, input_button_delegate_t delegate
     ++g_key_listeners_endptr;
 }
 
-void add_scroll_listener(input_scroll_delegate_t delegate) {
+void add_scroll_listener(input_scroll_fn delegate) {
     memset(g_key_listeners_endptr, 0x0, sizeof(input_listener_t));
     g_key_listeners_endptr->type = INPUT_LISTENER_SCROLL;
     g_key_listeners_endptr->scroll.delegate = delegate;
@@ -70,21 +99,6 @@ void input_init() {
     g_key_states = SDL_GetKeyboardState(NULL);
 }
 
-static inline
-void _process_axis_listener(input_listener_t* listener) {
-	int val = 0;
-	if(g_key_states[listener->axis.negative]) {
-		val = -1;
-	}
-	if(g_key_states[listener->axis.positive]) {
-		val += 1;
-	}
-	if(val != listener->axis.last) {
-		listener->axis.last = val;
-		listener->axis.delegate(val);
-	}
-}
-
 static inline
 void _process_mouse_listener(input_listener_t* listener, float dx, float dy) {
     if(dx != 0.0 && dy != 0.0) {
@@ -92,23 +106,6 @@ void _process_mouse_listener(input_listener_t* listener, float dx, float dy) {
     }
 }
 
-static inline
-void _process_button_listener(input_listener_t* listener) {
-	uint32_t state = SDL_GetMouseState(NULL, NULL);
-	int is_down = (state & (listener->button.button)) != 0;
-	if(is_down != listener->button.last) {
-		listener->button.delegate(is_down);
-	}
-	listener->button.last = is_down;
-}
-
-static inline
-void _process_scroll_listener(input_listener_t* listener) {
-	if(_scroll_delta != 0) {
-		listener->scroll.delegate(_scroll_delta);
-	}
-}
-
 void update_input() {
     float dx, dy;
     int px, py;
@@ -118,19 +115,8 @@ void update_input() {
     dx = (float)(px - _last_mouse_x)/width; dy = (float)(py - _last_mouse_y)/width;
 
     for(input_listener_t* listener = g_key_listeners; listener != g_key_listeners_endptr; ++listener) {
-		switch(listener->type) {
-			case INPUT_LISTENER_AXIS:
-				_process_axis_listener(listener);
-				break;
-			case INPUT_LISTENER_MOUSE:
+        if(listener->type == INPUT_LISTENER_MOUSE) {
                 _process_mouse_listener(listener, dx, dy);
-				break;
-			case INPUT_LISTENER_SCROLL:
-				_process_scroll_listener(listener);
-				break;
-			case INPUT_LISTENER_BUTTON:
-				_process_button_listener(listener);
-				break;
         }
     }    
 
@@ -140,13 +126,65 @@ void update_input() {
     _scroll_delta = 0;
 }
 
+static inline
+void _handle_key_event(const SDL_Event event) {
+    for(input_listener_t* listener = g_key_listeners; listener < g_key_listeners_endptr; ++listener) {
+        if(listener->type == INPUT_LISTENER_AXIS) {
+            const SDL_Scancode scode = event.key.keysym.scancode;
+            int changed = 0;
+            if(listener->axis.positive == scode) {
+                int new = event.key.state == SDL_PRESSED;
+                changed = new != listener->axis.last_positive;
+                listener->axis.last_positive = new;
+            }
+            else if(listener->axis.negative == scode) {
+                int new = event.key.state == SDL_PRESSED;
+                changed = new != listener->axis.last_negative;
+                listener->axis.last_negative = new;
+            }
+
+            if(changed)
+                listener->axis.delegate(listener->axis.last_positive - listener->axis.last_negative);
+        }
+    }
+}
+
+static inline
+void _handle_scroll_event(const SDL_Event event) {
+    _scroll_delta = event.wheel.y;
+    for(input_listener_t* listener = g_key_listeners; listener < g_key_listeners_endptr; ++listener) {
+        if(listener->type == INPUT_LISTENER_SCROLL) {
+            listener->scroll.delegate(_scroll_delta);
+        }
+    }
+}
+
+static inline
+void _handle_mousebutton_event(const SDL_Event event) {
+    for(input_listener_t* listener = g_key_listeners; listener < g_key_listeners_endptr; ++listener) {
+        if(listener->type == INPUT_LISTENER_BUTTON
+        || listener->button.button == event.button.button) {
+            listener->button.last = event.button.state == SDL_PRESSED;
+            listener->button.delegate(listener->button.last);
+        }
+    }
+}
+
 void input_notify_event(SDL_Event event) {
     switch(event.type) {
         default:
             return;
+        case SDL_KEYUP:
+        case SDL_KEYDOWN:
+            _handle_key_event(event);
+            return;
         case SDL_MOUSEWHEEL:
-			_scroll_delta = event.wheel.y;
-			break;
+            _handle_scroll_event(event);
+            return;
+        case SDL_MOUSEBUTTONUP:
+        case SDL_MOUSEBUTTONDOWN:
+            _handle_mousebutton_event(event);
+            return;
     }
 }
 
@@ -158,3 +196,7 @@ int input_get_mousedown(int mousebtn) {
     uint32_t mask = SDL_BUTTON(mousebtn);
     return (SDL_GetMouseState(NULL, NULL) & mask) != 0;
 }
+
+void input_disconnect_all() {
+    g_key_listeners_endptr = g_key_listeners;
+}

src/corelib/input.h

@@ -7,56 +7,30 @@ extern "C" {
 
 #include "SDL2/SDL.h"
 
-typedef void(*input_axis_delegate_t)(int value);
-typedef void(*input_mouse_delegate_t)(float dx, float dy);
-typedef void(*input_button_delegate_t)(int down);
-typedef void(*input_scroll_delegate_t)(float delta);
-
-enum INPUT_LISTENER_TYPE_T {
-	INPUT_LISTENER_MOUSE,
-	INPUT_LISTENER_AXIS,
-	INPUT_LISTENER_SCROLL,
-	INPUT_LISTENER_BUTTON,
-};
-
-typedef struct input_listener_t {
-	enum INPUT_LISTENER_TYPE_T type;
-	union {
-		struct {
-			input_axis_delegate_t delegate;
-			SDL_Scancode positive, negative;
-			int last;
-		} axis;
-		struct {
-			input_mouse_delegate_t delegate;
-		} mouse;
-		struct {
-			input_button_delegate_t delegate;
-			uint32_t button;
-			int last;
-		} button;
-		struct {
-			input_scroll_delegate_t delegate;
-		} scroll;
-	};
-} input_listener_t;
+typedef void(*input_axis_fn)(int value);
+typedef void(*input_mouse_fn)(float dx, float dy);
+typedef void(*input_button_fn)(int down);
+typedef void(*input_scroll_fn)(float delta);
 
 extern const Uint8* g_key_states;
 
 extern void add_key_listener(SDL_Scancode negative, SDL_Scancode positive,
-							   input_axis_delegate_t delegate);
-extern void add_mouse_listener(input_mouse_delegate_t delegate);
-extern void add_mouse_button_listener(uint32_t button, input_button_delegate_t delegate);
-extern void add_scroll_listener(input_scroll_delegate_t delegate);
-extern void remove_listener_at(size_t index);
+                               input_axis_fn delegate);
+extern void add_mouse_listener(input_mouse_fn delegate);
+extern void add_mouse_button_listener(uint32_t button, input_button_fn delegate);
+extern void add_scroll_listener(input_scroll_fn delegate);
+
 extern void mouse_screen_position(float* ox, float* oy);
 extern void mouse_world_position(float* ox, float* oy);
 
+extern int input_get_keydown(SDL_Scancode scancode);
+extern int input_get_mousedown(int mousebtn);
+
 extern void input_init();
 extern void update_input();
 extern void input_notify_event(SDL_Event event);
-extern int input_get_keydown(SDL_Scancode scancode);
-extern int input_get_mousedown(int mousebtn);
+
+extern void input_disconnect_all();
 
 #ifdef __cplusplus
 }

src/corelib/math/vec.h

@@ -0,0 +1,54 @@
+#ifndef _vec_math_h
+#define _vec_math_h
+
+#include "math.h"
+
+static inline
+void clamp_magnitude(float* xx, float* yy, float max_magnitude) {
+	float x = *xx, y = *yy;
+	const float m = sqrtf(x*x + y*y);
+	if(m > max_magnitude) {
+		x /= m; y /= m;
+		x *= max_magnitude; y *= max_magnitude;
+	} else {
+		*xx = x; *yy = y;
+	}
+}
+
+static inline
+void normalize(float x, float y, float* xx, float* yy) {
+	if(x != 0 || y != 0) {
+		const float m = sqrtf(x*x + y*y);
+		*xx = x / m; *yy = y / m;
+	} else {
+		*xx = x; *yy = y;
+	}
+}
+
+#define NORMALIZE(_xx, _yy) \
+if(_xx != 0 || _yy != 0) { \
+	const float m = sqrtf(_xx*_xx + _yy*_yy); \
+	_xx /= m; _yy /= m; \
+} else { \
+	_xx = 0; _yy = 0; \
+}
+
+static inline
+int move_towards(float* out_x, float* out_y, float x, float y, float tx, float ty, float max_delta) {
+	const float diff_x = tx - x,
+		diff_y = ty - y;
+	const float m = sqrtf(diff_x*diff_x + diff_y*diff_y);
+	const float dir_x = diff_x / m * max_delta,
+		dir_y = diff_y / m * max_delta;
+	if(fabsf(dir_x) < fabsf(diff_x) || fabsf(dir_y) < fabsf(diff_y)) {
+		*out_x = x + dir_x;
+		*out_y = y + dir_y;
+		return 0;
+	} else {
+		*out_x = tx;
+		*out_y = ty;
+		return 1;
+	}
+}
+
+#endif /* _vec_math_h */

src/corelib/object.c

@@ -0,0 +1,15 @@
+#include "object.h"
+
+object_t object_default() {
+  return (object_t){
+    .active = 1,
+    .physics = physics_default(),
+    .evt_draw = &object_draw_sprite,
+    .evt_update = NULL,
+    .sprite = sprite_default(),
+  };
+}
+
+void object_draw_sprite(object_t* object) {
+    draw_sprite(&object->sprite);
+}

src/corelib/object.h

@@ -0,0 +1,32 @@
+#ifndef _object_h
+#define _object_h
+
+#include "render.h"
+#include "physics.h"
+
+typedef struct object_t object_t;
+
+typedef void(*tick_fn)(struct object_t*);
+typedef void(*draw_fn)(struct object_t*);
+
+struct object_t {
+    sprite_t sprite;
+    int active; // 1 if this object's events should be triggered by the game world update.
+    int wants_to_be_deleted;
+    physics_t physics; // the collider to use for this object's physics interaction.
+
+    uintptr_t timer; // free to use for whatever
+
+    tick_fn evt_update;
+    draw_fn evt_draw;
+};
+
+object_t object_default();
+
+void object_draw_sprite(object_t* object);
+static inline
+int object_is_valid(const object_t* object) {
+    return object != NULL && object->wants_to_be_deleted == 0;
+}
+
+#endif /* _object_h */

src/corelib/physics.c

@@ -0,0 +1,272 @@
+#include "physics.h"
+#include "object.h"
+#include "world.h"
+#include "math/vec.h"
+
+static inline
+float fclampf(float x, float min_, float max_) {
+    return fminf(max_, fmaxf(min_, x));
+}
+
+
+physics_t physics_default() {
+    return (physics_t) {
+        .type=COLLIDERTYPE_NONE,
+        .velocity_x = 0.f,
+        .velocity_y = 0.f,
+        .solver = &solve_collision_slide
+    };
+}
+
+void object_broadcast_collision(object_t* this, object_t* other) {
+    if(this->physics.evt_collision != NULL) {
+        this->physics.evt_collision(this, other);
+    }
+}
+short can_collide(const object_t* this) {
+    return object_is_valid(this);
+}
+
+static inline
+int _rect_overlap(float aminx, float aminy, float amaxx, float amaxy, float bminx, float bminy, float bmaxx, float bmaxy) {
+    return
+    (
+        (aminx < bmaxx && aminx > bminx) 
+        ||
+        (bminx < amaxx  && bminx > aminx)
+    ) && (
+        (aminy < bmaxy && aminy > bminy)
+        ||
+        (bminy < amaxy && bminy > aminy)
+    );
+}
+
+static inline
+short _collision_aabb_aabb(const object_t* a, const object_t* b) {
+    const float aminx = a->physics.aabb.x + a->sprite.x,
+                  aminy = a->physics.aabb.y + a->sprite.y;
+    const float amaxx = aminx + a->physics.aabb.w,
+                  amaxy = aminy + a->physics.aabb.h;
+
+    const float bminx = b->physics.aabb.x + b->sprite.x,
+                bminy = b->physics.aabb.y + b->sprite.y;
+    const float bmaxx = bminx + b->physics.aabb.w,
+                bmaxy = bminy + b->physics.aabb.h;
+
+    return _rect_overlap(aminx, aminy, amaxx, amaxy, bminx, bminy, bmaxx, bmaxy);
+}
+
+static inline
+short _collision_circle_circle(const object_t* a, const object_t* b) {
+    const float ax = a->sprite.x + a->physics.circle.x,
+                  ay = a->sprite.y + a->physics.circle.y,
+                  bx = b->sprite.x + b->physics.circle.x,
+                by = b->sprite.y + b->physics.circle.y;
+    const float dx = fabsf(ax-bx), dy = fabsf(ay-by);
+    const float sqrdist = dx*dx+dy*dy;
+    const float mindist = a->physics.circle.radius + b->physics.circle.radius;
+    const float mindistsqr = mindist*mindist;
+    return sqrdist < mindistsqr;
+}
+
+static inline
+short _collision_circle_aabb(const object_t* circle, const object_t* aabb) {
+    // generate a point on the edge of the rectangle that is closest to the circle
+    const float bbminx = aabb->physics.aabb.x + aabb->sprite.x, bbmaxx = bbminx + aabb->physics.aabb.w,
+                bbminy = aabb->physics.aabb.y + aabb->sprite.y, bbmaxy = bbminy + aabb->physics.aabb.h;
+    const float cx = circle->sprite.x + circle->physics.circle.x,
+                cy = circle->sprite.y + circle->physics.circle.y;
+    const float x = fclampf(cx, bbminx, bbmaxx),
+                y = fclampf(cy, bbminy, bbmaxy);
+    const float dx = fabsf(cx - x), dy = fabsf(cy - y);
+
+    // calculate the square distance from the centre of the circle to the edge of the aabb
+    const float distsqr = dx*dx+dy*dy;
+    const float rsqr = circle->physics.circle.radius*circle->physics.circle.radius;
+
+    // return if the square distance is larger than the square of the radius
+    return distsqr < rsqr;
+}
+
+static inline
+short _collision_check(const object_t* a, const object_t* b) {
+    if(a->physics.type == COLLIDERTYPE_AABB && b->physics.type == COLLIDERTYPE_AABB) {
+        return _collision_aabb_aabb(a, b);
+    } else if(a->physics.type == COLLIDERTYPE_CIRCLE && b->physics.type == COLLIDERTYPE_CIRCLE) {
+        return _collision_circle_circle(a, b);
+    } else if(a->physics.type == COLLIDERTYPE_CIRCLE && b->physics.type == COLLIDERTYPE_AABB) {
+        return _collision_circle_aabb(a, b);
+    } else if(a->physics.type == COLLIDERTYPE_AABB && b->physics.type == COLLIDERTYPE_CIRCLE) {
+        return _collision_circle_aabb(b, a);
+    }
+    return 0;
+}
+
+static inline
+float _solve_circle_aabb(const object_t* circle, const object_t* aabb, float* out_px, float* out_py) {
+    // generate a point on the edge of the rectangle that is closest to the circle
+    const float bbminx = aabb->physics.aabb.x + aabb->sprite.x, bbmaxx = bbminx + aabb->physics.aabb.w,
+                bbminy = aabb->physics.aabb.y + aabb->sprite.y, bbmaxy = bbminy + aabb->physics.aabb.h;
+    // the centre of the circle in world space
+    const float cx = circle->sprite.x + circle->physics.circle.x,
+                cy = circle->sprite.y + circle->physics.circle.y;
+    // the point on the rectangle closest to the centre of the circle
+    const float x = fclampf(cx, bbminx, bbmaxx),
+                y = fclampf(cy, bbminy, bbmaxy);
+    // the relative position of the point on the rectangle 
+    const float dif_x = cx - x,
+                dif_y = cy - y;
+    // absolute difference for use in calculating euclidean distance 
+    const float dist_x = fabsf(dif_x),
+                dist_y = fabsf(dif_y);
+    // euclidean distance
+    const float dist = sqrt(dist_x*dist_x + dist_y*dist_y);
+    const float solve_distance = circle->physics.circle.radius - dist;
+    // distance to solve collision
+    float solve_x, solve_y;
+    normalize(dif_x, dif_y, &solve_x, &solve_y);
+    *out_px = solve_x * solve_distance;
+    *out_py = solve_y * solve_distance;
+    return solve_distance;
+}
+
+static inline
+float _solve_circle_circle(const object_t* a, const object_t* b, float* out_px, float* out_py) {
+    const float x1 = a->physics.circle.x + a->sprite.x, y1 = a->physics.circle.y + a->sprite.y;
+    const float x2 = b->physics.circle.x + b->sprite.x, y2 = b->physics.circle.y + b->sprite.y;
+    const float dif_x = x1 - x2, dif_y = y1 - y2;
+    const float difference = sqrtf(fabsf(dif_x*dif_x) + fabsf(dif_y*dif_y));
+    const float target_difference = a->physics.circle.radius + b->physics.circle.radius;
+    float dir_x, dir_y;
+    normalize(dif_x, dif_y, &dir_x, &dir_y);
+    *out_px = dir_x * target_difference;
+    *out_py = dir_y * target_difference;
+    return target_difference;
+}
+
+static inline
+float _solve_aabb_aabb(const object_t* a, const object_t* b, float* out_px, float* out_py) {
+    float aminx = a->physics.aabb.x + a->sprite.x;
+    float amaxx = aminx + a->physics.aabb.w;
+    float bminx = b->physics.aabb.x + b->sprite.x;
+    float bmaxx = bminx + b->physics.aabb.w;
+
+    float aminy = a->physics.aabb.y + a->sprite.y;
+    float amaxy = aminy + a->physics.aabb.h;
+    float bminy = b->physics.aabb.y + b->sprite.y;
+    float bmaxy = bminy + b->physics.aabb.h;
+
+    float right = bmaxx - aminx;
+    float left = bminx - amaxx;
+    float top = bminy - amaxy;
+    float bottom = bmaxy - aminy;
+
+    float ret = right;
+    *out_px = right;
+    *out_py = 0.f;
+    if(fabsf(left) < fabsf(ret)) {
+        *out_px = left;
+        *out_py = 0.f;
+        ret = left;
+    }
+    if(fabsf(top) < fabsf(ret)) {
+        *out_px = 0.f;
+        *out_py = top;
+        ret = top;
+    }
+
+    if(fabsf(bottom) < fabsf(ret)) {
+        *out_px = 0.f;
+        *out_py = bottom;
+        return bottom;
+    }
+
+    return ret;
+}
+
+float get_solve_force(const object_t* a, const object_t* b, float* out_px, float* out_py) {
+    if(a->physics.type == COLLIDERTYPE_AABB && b->physics.type == COLLIDERTYPE_AABB) {
+        return _solve_aabb_aabb(a, b, out_px, out_py);
+    } else if(a->physics.type == COLLIDERTYPE_AABB && b->physics.type == COLLIDERTYPE_CIRCLE) {
+        float penetration_distance = _solve_circle_aabb(b, a, out_px, out_py);
+        *out_px = -(*out_px);
+        *out_py = -(*out_py);
+    } else if(a->physics.type == COLLIDERTYPE_CIRCLE && b->physics.type == COLLIDERTYPE_AABB) {
+        return _solve_circle_aabb(a, b, out_px, out_py);
+    } else if(a->physics.type == COLLIDERTYPE_CIRCLE && b->physics.type == COLLIDERTYPE_CIRCLE) {
+        return _solve_circle_circle(a, b, out_px, out_py);
+    }
+}
+
+void solve_collision_slide(object_t* left, object_t* right) {
+    float dx, dy;
+    get_solve_force(left, right, &dx, &dy);
+    left->sprite.x += dx;
+    left->sprite.y += dy;
+}
+
+static inline
+void _solve_move(object_t* this) {
+    // loop over all objects and check collision if applicable
+    for(int i = 0; i < world_num_objects(); ++i) {
+        // get pointer to other object
+        object_t* other = world_get_object(i);
+        // check collision, return if found
+        if(can_collide(other) && this != other && _collision_check(other, this)) {
+            object_broadcast_collision(other, this);
+            object_broadcast_collision(this, other);
+            this->physics.solver(this, other);
+        }
+    }
+}
+
+void physics_move(object_t* this, float delta_time) {
+    const float max_step_size = this->physics.max_interpolate_step_size;
+    // calculate step delta
+    float dx = this->physics.velocity_x * delta_time, dy = this->physics.velocity_y * delta_time;
+    const float target_x = this->sprite.x + dx,
+                target_y = this->sprite.y + dy;
+    if(dx == 0 && dy == 0)
+        return;
+
+    // calculate direction x,y
+    float m = sqrtf(dx*dx + dy*dy);
+    dx = dx / m * max_step_size;
+    dy = dy / m * max_step_size;
+
+    const int step_count = max_step_size / m;
+
+    // ensure this object would ever collide
+    // if it wouldn't collide anyway, just set position
+    if(!can_collide(this)) {
+        this->sprite.x = target_x;
+        this->sprite.y = target_y;
+        return;
+    }
+
+    if(step_count == 0) {
+        this->sprite.x = target_x;
+        this->sprite.y = target_y;
+        _solve_move(this);
+        return;
+    }
+
+    /*
+     * 1. move towards target
+     * 2. check collision with every other object
+     */
+    for(int steps = 0; steps <= step_count && (this->sprite.x != target_x || this->sprite.y != target_y); ++steps) {
+        // move towards target, snap to target if distance is too low
+        const float distx = fabsf(this->sprite.x - target_x), disty = fabsf(this->sprite.y - target_y);
+        const float sqdist = distx*distx + disty*disty;
+        if(sqdist > max_step_size*max_step_size) {
+            this->sprite.x += dx;
+            this->sprite.y += dy;
+        } else {
+            this->sprite.x = target_x;
+            this->sprite.y = target_y;
+        }
+
+        _solve_move(this);
+    }
+}

src/corelib/physics.h

@@ -0,0 +1,43 @@
+#ifndef _physics_h
+#define _physics_h
+
+#include "SDL2/SDL_rect.h"
+
+typedef struct object_t object_t;
+
+typedef void(*collided_fn)(object_t*, object_t*);
+typedef void(*solver_fn)(object_t* left, object_t* right);
+
+typedef enum collider_type_t {
+    COLLIDERTYPE_MIN,
+    COLLIDERTYPE_NONE,
+    COLLIDERTYPE_CIRCLE,
+    COLLIDERTYPE_AABB,
+    COLLIDERTYPE_MAX,
+} collider_type_t;
+
+typedef struct circle_t {
+    float x, y;
+    float radius;
+} circle_t;
+
+typedef struct physics_t {
+    collider_type_t type;
+    collided_fn evt_collision;
+    solver_fn solver;
+    float velocity_x, velocity_y;
+    float max_interpolate_step_size;
+    union {
+        circle_t circle;
+        SDL_FRect aabb;
+    };
+} physics_t;
+
+extern physics_t physics_default();
+extern void object_broadcast_evt_collision(object_t* this, object_t* other);
+extern void physics_move(object_t* this, float delta_time);
+extern short can_collide(const object_t* this);
+extern void solve_collision_slide(object_t* left, object_t* right);
+extern float get_solve_force(const object_t* this, const object_t* other, float* solve_x, float* solve_y);
+
+#endif /* _physics_h */

src/corelib/render.c

@@ -253,6 +253,19 @@ void _exec_text_cmd(const drawcmd_t* cmd) {
     free(cmd->text.text);
 }
 
+sprite_t sprite_default() {
+    return (sprite_t){
+        .texture = NULL,
+        .x = 0.f, .y = 0.f,
+        .origin = (SDL_FPoint){0.f, 0.f},
+        .sx = 1.f, .sy = 1.f,
+        .rot = 0.f,
+        .depth = RLAYER_SPRITES,
+        .uv = (SDL_Rect){0.f, 0.f, 0.f, 0.f},
+        .flip = SDL_FLIP_NONE,
+    };
+}
+
 sprite_t render_text(const char* str, SDL_FRect area, text_style_t style) {
     SDL_FRect r = area;
     int fh = TTF_FontHeight(style.font);
@@ -443,7 +456,7 @@ sprite_t make_sprite(const char* file, float x, float y) {
     sprite_t sprite=(sprite_t){
         .texture=get_texture(file),
         .x=x,.y=y,
-		.origin=(SDL_FPoint){.x=0,.y=0},
+        .origin=(SDL_FPoint){.x=0.0,.y=0.0},
         .sx=1.0,.sy=1.0,
         .rot=0,
         .depth=RLAYER_SPRITES,
@@ -451,7 +464,6 @@ sprite_t make_sprite(const char* file, float x, float y) {
         .flip=SDL_FLIP_NONE,
     };
     SDL_QueryTexture(sprite.texture, NULL, NULL, &sprite.uv.w, &sprite.uv.h);
-	sprite.origin.x = -(float)sprite.uv.h/2.f; sprite.origin.y = -(float)sprite.uv.h/2.f;
     return sprite;
 }
 

src/corelib/render.h

@@ -91,6 +91,8 @@ extern void screen_to_view(float* x, float* y);
 extern void clear_buffer();
 extern void swap_buffer();
 
+extern sprite_t sprite_default();
+
 extern sprite_t render_text(const char* str, SDL_FRect area, text_style_t style);
 extern void draw_sprite(const sprite_t* sprite);
 extern void draw_rect(const rectshape_t* rect);
@@ -102,7 +104,6 @@ extern sprite_t make_sprite(const char* file, float x, float y);
 extern sprite_t sprite_from_spritesheet(spritesheet_t* sheet, int index);
 extern text_style_t make_text_style(const char* font, SDL_Color color, int dpi, float size);
 extern SDL_Rect get_srcrect_from(spritesheet_t* sheet, int index);
-extern void set_active_view(const view_t* view);
 
 #define no_sprite (sprite_t){NULL, 0.0, 0.0, {0.0, 0.0}, 0.0, 0.0, 0.0, 0, {0, 0, 0, 0}}
 

src/corelib/scene.c

@@ -0,0 +1,220 @@
+#include "scene.h"
+
+#include "ctype.h"
+#include "input.h"
+#include "stdint.h"
+#include "stddef.h"
+#include "stdlib.h"
+#include "string.h"
+#include "stdio.h"
+#include "hash.h"
+#include "malloc.h"
+#include "math.h"
+#include "world.h"
+
+static
+struct type_handler_t {
+    uintptr_t hash;
+    char* type;
+    type_handler_fn handler;
+} _type_handlers[99];
+
+static
+int _type_handler_num = 0;
+
+static
+struct type_handler_t* _find_handler_for(const char* type) {
+    uintptr_t hash = hashstr(type);
+    for(int i = 0; i < 99; ++i) {
+        if(_type_handlers[i].hash == hash && strcmp(type, _type_handlers[i].type) == 0) {
+            return _type_handlers + i;
+        }
+    }
+    return NULL;
+}
+
+static
+struct type_handler_t* _new_handler_for(const char* type) {
+    _type_handlers[_type_handler_num].type = malloc(strlen(type) * sizeof(char));
+    strcpy(_type_handlers[_type_handler_num].type, type);
+    _type_handlers[_type_handler_num].hash = hashstr(type);
+    struct type_handler_t* ptr = _type_handlers + _type_handler_num;
+    ++_type_handler_num;
+    return ptr;
+}
+
+void set_type_handler(const char* type, type_handler_fn handler) {
+    struct type_handler_t* ptr = _find_handler_for(type);
+    if(ptr == NULL) {
+        ptr = _new_handler_for(type);
+    }
+    ptr->handler = handler;
+}
+
+static
+int fpeekc(FILE* file) {
+    int c = fgetc(file);
+    ungetc(c, file);
+    return c;
+}
+
+static
+void freadto(FILE* file, char c) {
+    char read;
+    do {
+        read = fgetc(file);
+    } while(read != c);
+}
+
+static
+int nextnw(FILE* file) {
+    int next;
+    char c;
+    do {
+        next = fgetc(file);
+        c = (char)next;
+    } while(isspace(c));
+    return next;
+}
+
+static
+int _parse_key(FILE* file, char* out) {
+    char c;
+    do {
+        c = fgetc(file);
+        if(c == ':' || c == ';') {
+            *out = '\0';
+        } else if(c == '#') {
+            freadto(file, '\n');
+        } else if(!isspace(c)) {
+            *out = c;
+            ++out;
+        }
+    } while(c != ':' && c != ';');
+
+    return c == ':';
+}
+
+static
+void _parse_value(FILE* file, char* out, int* _argc, char** argv) {
+    char c;
+    int argc = 0;
+    argv[argc] = out;
+    ++argc;
+    do {
+        c = fgetc(file);
+        switch(c) {
+        case '#':
+            freadto(file, '\n');
+            // fall through
+        case '\n':
+            ungetc(nextnw(file), file);
+            break;
+        case ';':
+            *out = '\0';
+            break;
+        case ',':
+            *out = '\0';
+            ++out;
+            argv[argc] = out;
+            ++argc;
+            ungetc(nextnw(file), file);
+            break;
+        default:
+            *out = c;
+            ++out;
+            break;
+        }
+    } while(c != ';');
+    *_argc = argc;
+}
+
+static
+void _parse_config(FILE* file) {
+    char key[24];
+    char value[128];
+    int argc = 0;
+    char* argv[24];
+
+    char begin = nextnw(file);
+    ungetc(begin, file);
+
+    int has_args = _parse_key(file, key);
+    ungetc(nextnw(file), file);
+    if(has_args) {
+        _parse_value(file, value, &argc, argv);
+    }
+
+    struct type_handler_t* handler = _find_handler_for(key);
+
+    if(handler != NULL) {
+        if(begin == '!') {
+            handler->handler(NULL, argc, argv);
+        } else {
+            handler->handler(make_object(), argc, argv);
+        }
+    }
+    if(fpeekc(file) == EOF) return;
+}
+
+static
+void _parse_scene(FILE* file) {
+    int next;
+    do {
+        _parse_config(file);
+        next = nextnw(file);
+        ungetc(next, file);
+    } while(next != EOF);
+}
+
+static
+int _validate_config(FILE* file) {
+    char c;
+    int colon_count = 0;
+    do {
+        c = nextnw(file);
+        switch(c) {
+        default: break;
+        case ':':
+            colon_count++;
+            break;
+        }
+    } while(c != ';');
+
+    return colon_count <= 1;
+}
+
+static
+int _validate_scene(FILE* file) {
+    if(file == NULL) return 0;
+
+    int next;
+    int validated;
+    do {
+        validated = _validate_config(file);
+        next = nextnw(file);
+        ungetc(next, file);
+    } while(validated == 1 && next != EOF);
+
+    rewind(file);
+
+    return validated;
+}
+
+void load_scene(const char* filename) {
+    FILE* file = fopen(filename, "r");
+    if(_validate_scene(file)) {
+        input_disconnect_all();
+        world_clear();
+        _parse_scene(file);
+        fclose(file);
+    }
+}
+
+void load_scene_additive(const char* filename) {
+    FILE* file = fopen(filename, "r");
+    if(_validate_scene(file)) {
+        _parse_scene(file);
+        fclose(file);
+    }
+}

src/corelib/scene.h

@@ -0,0 +1,22 @@
+#ifndef _corelib_scene_h
+#define _corelib_scene_h
+
+#include "memory.h"
+
+typedef struct object_t object_t;
+
+typedef void(*type_handler_fn)(object_t* this, int argc, char** argv);
+
+// Add or replace the type handler for [Object] entries of a given key.
+// Will delete the handler entry if handler == NULL.
+void set_type_handler(const char* type, type_handler_fn handler);
+
+// Load a scene exclusively. Clears the current scene before parsing file.
+void load_scene(const char* file);
+
+// Load a scene additively.
+// Will not clear the currently active objects before parsing file.
+void load_scene_additive(const char* file);
+
+#endif /* _corelib_scene_h */
+

src/corelib/world.c

@@ -1,206 +1,122 @@
 #include "world.h"
+#include "memory.h"
+#include "assert.h"
+#include "math/vec.h"
+#include "object.h"
 
-object_t g_objects[WORLD_NUM_OBJECTS];
+struct {
+    size_t num;
+    object_t** objects;
+} _world_objects = {
+    .num = 0,
+    .objects = NULL
+};
+
+static inline
+int _expand_world() {
+    size_t new_num = _world_objects.num * 2;
+    if(new_num == 0) {
+        new_num = 16;
+    }
+    object_t** new_list = realloc(_world_objects.objects, new_num * sizeof(object_t*));
+
+    if(new_list == NULL) {
+        assert(!"ERROR: Out of memory");
+        exit(-10);
+    }
+
+    for(size_t i = _world_objects.num; i < new_num; ++i) {
+        new_list[i] = NULL;
+    }
+
+    _world_objects.objects = new_list;
+    _world_objects.num = new_num;
+    return 1;
+}
+
+static inline
+size_t _find_free_object() {
+    for(int i = 0; i < _world_objects.num; ++i) {
+        if(!object_is_valid(_world_objects.objects[i])) {
+            return i;
+        }
+    }
+    size_t num = _world_objects.num;
+    _expand_world();
+    return num;
+}
 
 void world_clear() {
-	for(int i = 0; i < WORLD_NUM_OBJECTS; ++i) {
-		g_objects[i].active = 0;
-		g_objects[i].enabled = 0;
+    // free all allocated objects
+    for(int i = 0; i < _world_objects.num; ++i) {
+        object_t* object = _world_objects.objects[i];
+        if(object != NULL) {
+            free(object);
         }
     }
-
-void object_draw_sprite(object_t* object) {
-	draw_sprite(&object->sprite);
-}
-
-object_t* _find_free_object() {
-	for(int i = 0; i < WORLD_NUM_OBJECTS; ++i) {
-		if(g_objects[i].active == 0) {
-			return g_objects + i;
-		}
-	}
-	return NULL;
+    // free world array
+    free(_world_objects.objects);
+    // reset world objects struct
+    _world_objects.objects = NULL;
+    _world_objects.num = 0;
 }
 
 object_t* make_object() {
-	object_t* o = _find_free_object();
-	o->active = 1;
-	o->enabled = 1;
-	o->collider = collider_default();
-	o->evt_draw = &object_draw_sprite;
-	o->evt_update = NULL;
-	memset(&o->sprite, 0, sizeof(sprite_t));
+    // acquire pointer to empty slot
+    size_t index = _find_free_object();
+    // allocate new object
+    if(_world_objects.objects[index] == NULL) {
+        _world_objects.objects[index] = malloc(sizeof(object_t));
+    }
+    // initialize object to default
+    object_t* o = _world_objects.objects[index];
+    *o = object_default();
+
     return o;
 }
 
 object_t* instantiate_object(const object_t *original) {
+    // create new object with default settings
     object_t* obj = make_object();
     *obj = *original;
     obj->active = 1;
     return obj;
 }
 
-collider_t collider_default() {
-	return (collider_t) {
-		.type=COLLIDERTYPE_NONE
-	};
-}
-
-void update_objects() {
-	for(int i = 0; i < WORLD_NUM_OBJECTS; ++i) {
-		if(g_objects[i].active == 1
-		&& g_objects[i].enabled == 1
-		&& g_objects[i].evt_update != NULL) {
-			g_objects[i].evt_update(g_objects + i);
+void world_update() {
+    for(int i = 0; i < _world_objects.num; ++i) {
+        object_t* object = world_get_object(i);
+        if(object_is_valid(object)
+        && object->evt_update != NULL) {
+            object->evt_update(object);
         }
     }
 }
 
-void draw_objects() {
-	for(int i = 0; i < WORLD_NUM_OBJECTS; ++i) {
-		if(g_objects[i].active == 1
-		&& g_objects[i].enabled == 1
-		&& g_objects[i].evt_draw != NULL) {
-			g_objects[i].evt_draw(g_objects + i);
+void world_draw() {
+    for(int i = 0; i < _world_objects.num; ++i) {
+        object_t* object = world_get_object(i);
+        if(object_is_valid(object)
+        && object->evt_draw != NULL) {
+            object->evt_draw(object);
         }
     }
 }
 
-static inline
-int _rect_overlap(float aminx, float aminy, float amaxx, float amaxy, float bminx, float bminy, float bmaxx, float bmaxy) {
-	return
-	(
-		(aminx < bmaxx && aminx > bmaxx) 
-		||
-		(amaxx > bminx && amaxx < bmaxx)
-	) && (
-		(aminy < bmaxy && aminy > bmaxy)
-		||
-		(amaxy > bminy && amaxy < bmaxy)
-	);
-}
-
-static inline
-short _collision_aabb_aabb(const object_t* a, const object_t* b) {
-	const float aminx = a->collider.aabb.x + a->sprite.x, aminy = a->collider.aabb.y + a->sprite.x;
-	const float amaxx = aminx + a->collider.aabb.w, amaxy = aminy + a->collider.aabb.h;
-	const float bminx = b->collider.aabb.x, bminy = b->collider.aabb.y;
-	const float bmaxx = b->collider.aabb.x + b->collider.aabb.w, bmaxy = b->collider.aabb.y + b->collider.aabb.h;
-
-	return _rect_overlap(aminx, aminy, amaxx, amaxy, bminx, bminy, bmaxx, bmaxy);
-}
-
-static inline
-short _collision_circle_circle(const object_t* a, const object_t* b) {
-	const float ax = a->sprite.x + a->collider.circle.x, ay = a->sprite.y + a->collider.circle.y,
-		  		bx = b->sprite.x + b->collider.circle.x, by = b->sprite.y + b->collider.circle.y;
-	const float dx = fabsf(ax-bx), dy = fabsf(ay-by);
-	const float sqrdist = dx*dx+dy*dy;
-	const float mindist = a->collider.circle.radius + b->collider.circle.radius;
-	const float mindistsqr = mindist*mindist;
-	return sqrdist < mindistsqr;
-}
-
-static inline
-float fclampf(float x, float min_, float max_) {
-	return fminf(max_, fmaxf(min_, x));
-}
-
-static inline
-short _collision_circle_aabb(const object_t* circle, const object_t* aabb) {
-	// generate a point on the edge of the rectangle that is closest to the circle
-	const float bbminx = aabb->collider.aabb.x + aabb->sprite.x, bbmaxx = bbminx + aabb->collider.aabb.w,
-				bbminy = aabb->collider.aabb.y + aabb->sprite.x, bbmaxy = bbminy + aabb->collider.aabb.h;
-	const float cx = circle->sprite.x + circle->collider.circle.x,
-				cy = circle->sprite.y + circle->collider.circle.y;
-	const float x = fclampf(cx, bbminx, bbmaxx),
-				y = fclampf(cy, bbminy, bbmaxy);
-	const float dx = fabsf(cx - x), dy = fabsf(cy - y);
-
-	// calculate the square distance from the centre of the circle to the edge of the aabb
-	const float distsqr = dx*dx+dy*dy;
-	const float rsqr = circle->collider.circle.radius*circle->collider.circle.radius;
-
-	// return if the square distance is larger than the square of the radius
-	return distsqr < rsqr;
-}
-
-static inline
-short _collision_check(const object_t* a, const object_t* b) {
-	if(a->collider.type == COLLIDERTYPE_AABB && b->collider.type == COLLIDERTYPE_AABB) {
-		return _collision_aabb_aabb(a, b);
-	} else if(a->collider.type == COLLIDERTYPE_CIRCLE && b->collider.type == COLLIDERTYPE_CIRCLE) {
-		return _collision_circle_circle(a, b);
-	} else if(a->collider.type == COLLIDERTYPE_CIRCLE && b->collider.type == COLLIDERTYPE_AABB) {
-		return _collision_circle_aabb(a, b);
-	} else if(a->collider.type == COLLIDERTYPE_AABB && b->collider.type == COLLIDERTYPE_CIRCLE) {
-		return _collision_circle_aabb(b, a);
-	}
-	return 0;
-}
-
-static inline
-short _can_collide(const object_t* object) {
-	return object->active && object->enabled && object->collider.evt_collision != NULL;
-}
-
-void update_collision() {
-	for(int outer = 0; outer < WORLD_NUM_OBJECTS; ++outer) {
-		object_t* oobject = g_objects + outer;
-		if(!_can_collide(oobject)) continue;
-		for(int inner = 0; inner < WORLD_NUM_OBJECTS; ++inner) {
-			object_t* iobject = g_objects + inner;
-			if(!_can_collide(oobject)) continue;
-
-			if(outer != inner && _collision_check(iobject, oobject)) {
-				oobject->collider.evt_collision(oobject, iobject);
-				iobject->collider.evt_collision(iobject, oobject);
-			}
-		}
-	}
-}
-
-object_t* interpolate_move(object_t* object, float target_x, float target_y, float max_step_size) {
-	// calculate step delta
-	float dx = target_x - object->sprite.x, dy = target_y - object->sprite.y;
-	// calculate direction x,y
-	float m = sqrtf(dx*dx + dy*dy);
-	dx /= m; dy /= m;
-	dx *= max_step_size; dy *= max_step_size;
-
-	// ensure this object would ever collide
-	// if it wouldn't collide anyway, just set position
-	if(_can_collide(object)) {
-		object->sprite.x = target_x;
-		object->sprite.y = target_y;
-		return NULL;
-	}
-
-	/*
-	 * 1. check collision with every other object
-	 * 2. move towards target
-	 */
-	while(object->sprite.x != target_x || object->sprite.y != target_y) {
-		for(int i = 0; i < WORLD_NUM_OBJECTS; ++i) {
-			object_t* other = g_objects + i;
-			if(!_can_collide(other)) continue;
-			if(object != other && _collision_check(other, object)) {
-				other->collider.evt_collision(other, object);
-				object->collider.evt_collision(object, other);
-				return other;
-			}
-		}
-
-		// move towards target, snap to target if distance is too low
-		float distx = fabsf(object->sprite.x - target_x), disty = fabsf(object->sprite.y - target_y);
-		if(distx < fabsf(dx) && disty < fabsf(dy)) {
-			object->sprite.x += dx; object->sprite.y += dy;
+object_t* world_get_object(size_t at) {
+    if(at < _world_objects.num) {
+        return _world_objects.objects[at];
     } else {
-			object->sprite.x = target_x;
-			object->sprite.y = target_y;
+        return NULL;
     }
 }
 
-	// no collision, return nothing
-	return NULL;
+size_t world_num_objects() {
+    return _world_objects.num;
+}
+
+void world_reserve_objects(size_t min) {
+    while(_world_objects.num < min) {
+        _expand_world();
+    }
 }

src/corelib/world.h

@@ -1,66 +1,23 @@
 #ifndef _world_h
 #define _world_h
 
-#include "render.h"
-#include <stdint.h>
+#include "object.h"
 
-#define WORLD_NUM_OBJECTS 255
+#define BASE_WORLD_SIZE 24
 
 typedef struct object_t object_t;
 
-typedef void(*tick_fn)(struct object_t*);
-typedef void(*draw_fn)(struct object_t*);
-typedef void(*collided_fn)(struct object_t*, struct object_t*);
+extern object_t* make_object();
+extern object_t* instantiate_object(const object_t* original);
 
-typedef enum collider_type_t {
-	COLLIDERTYPE_MIN,
-	COLLIDERTYPE_NONE,
-	COLLIDERTYPE_CIRCLE,
-	COLLIDERTYPE_AABB,
-	COLLIDERTYPE_MAX,
-} collider_type_t;
+extern void world_clear();
 
-typedef struct collider_t {
-	collider_type_t type;
-	collided_fn evt_collision;
-	union {
-		struct {
-			float x, y;
-			float radius;
-		} circle;
-		SDL_FRect aabb;
-	};
-} collider_t;
+extern void world_update();
+extern void world_draw();
 
-struct object_t {
-	sprite_t sprite;
-	int active; // 1 if this object is in use and should not be overriden.
-	int enabled; // 1 if this object's events should be triggered.
-	collider_t collider; // the collider to use for this object's physics interaction.
+extern object_t* world_get_object(size_t at);
 
-	uintptr_t timer; // free to use for whatever
-
-	tick_fn evt_update;
-	draw_fn evt_draw;
-};
-
-extern object_t g_objects[WORLD_NUM_OBJECTS];
-
-void world_clear();
-
-
-object_t* make_object();
-object_t* instantiate_object(const object_t* original);
-
-collider_t collider_default();
-
-void object_draw_sprite(object_t* object);
-
-void update_objects();
-void draw_objects();
-
-void update_collision();
-
-object_t* interpolate_move(object_t* object, float target_x, float target_y, float max_step_size);
+extern size_t world_num_objects();
+extern void world_reserve_objects(size_t min);
 
 #endif /* _world_h */

src/engine.c

@@ -1,81 +0,0 @@
-#include "engine.h"
-#include "world.h"
-#include "corelib/assets.h"
-#include "corelib/render.h"
-#include "corelib/input.h"
-#include "time.h"
-
-static float _delta_time = 0;
-static struct timespec start_last_frame;
-
-inline float delta_time() {
-	return _delta_time;
-}
-
-static inline
-int _engine_start() {
-	init_context();
-	return 0;
-}
-
-static inline
-int _engine_shutdown() {
-	game_exit();
-	clean_assets();
-	close_context();
-	exit(0);
-}
-
-static inline
-void _handle_events() {
-	while(SDL_PollEvent(&g_context.event)) {
-		input_notify_event(g_context.event);
-		switch(g_context.event.type) {
-	case SDL_QUIT:
-			g_context.running = 0;
-			break;
-		}
-	}
-}
-
-static inline
-int _engine_run() {
-	SDL_DisplayMode mode;
-	SDL_GetDesktopDisplayMode(0, &mode);
-	SDL_Window* window = SDL_CreateWindow("Tabletop", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, mode.w, mode.h, SDL_WINDOW_FULLSCREEN_DESKTOP);
-
-	g_context = (context_t){
-		.window = window,
-		.renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED),
-		.running = 1,
-	};
-
-	input_init();
-	world_clear();
-	start_game();
-	
-	timespec_get(&start_last_frame, TIME_UTC);
-	struct timespec next_time;
-	while(g_context.running) {
-		timespec_get(&next_time, TIME_UTC);
-		_delta_time = (next_time.tv_nsec - start_last_frame.tv_nsec) * 1E-9;
-		if(next_time.tv_nsec < start_last_frame.tv_nsec) _delta_time = 0;
-		start_last_frame = next_time;
-		_handle_events();
-		update_input();
-		_render_mode = 1;
-		update_ui();
-		_render_mode = 0;
-		update_game();
-		update_objects();	// update world objects
-		draw_objects();		// draw world objects
-		swap_buffer();
-	}
-	return 0;
-}
-
-int main(int argc, char* argv[]) {
-	_engine_start();
-	_engine_run();
-	_engine_shutdown();
-}

src/game.c

@@ -1,41 +1,12 @@
-#include "engine.h"
-#include "world.h"
+#include "corelib/entry.h"
+#include "corelib/world.h"
 #include "corelib/input.h"
 #include "corelib/render.h"
 #include "corelib/assets.h"
 #include "corelib/layers.h"
-#include "SDL2/SDL_mouse.h"
-#include "SDL2/SDL_scancode.h"
-
-void on_quit_key(int down) {
-	// Q is pressed or released
-	if(down) {
-		// stop running when Q is pressed
-		g_context.running = 0;
-	}
-}
-
-void on_horizontal(int axis) {
-	// when A or D is pressed or released
-}
-
-void on_vertical(int axis) {
-	// W or S is pressed or released
-}
-
-void on_click(int down) {
-	// when the left mouse button is pressed down
-	// float mouse_x, mouse_y;
-	// mouse_world_position(&mouse_x, &mouse_y);
-}
 
 void start_game() {
     // called when the game is done initializing the backend and ready to start
-	g_active_view.width = 21;
-	add_key_listener(SDL_SCANCODE_UNKNOWN, SDL_SCANCODE_Q, &on_quit_key);
-	add_key_listener(SDL_SCANCODE_S, SDL_SCANCODE_W, &on_horizontal);
-	add_key_listener(SDL_SCANCODE_A, SDL_SCANCODE_D, &on_vertical);
-	add_mouse_button_listener(SDL_BUTTON_LMASK, &on_click);
 }
 
 void update_game() {
@@ -48,4 +19,6 @@ void update_ui() {
     // render calls made in this function will be in *screen* space
 }
 
-void game_exit() {}
+void game_exit() {
+    // called when the game shuts down
+}