add panning and zooming

src/boid-playground.hpp

@@ -64,6 +64,8 @@ struct Visuals {
 	Color boid_color = BLACK;
 	Color bg_color = RAYWHITE;
 
+	Camera2D camera;
+
 	bool show_control_panel = true;
 
 	bool draw_boid_direction = false;

src/main.cpp

@@ -25,6 +25,8 @@ static World g_world;
 static Visuals g_visuals;
 static UI g_ui;
 
+// TODO: Add controls window
+
 // TODO: Make boids form specific shapes defined by user, options:
 //   Circles, triangles, by image, text.
 
@@ -41,7 +43,7 @@ int main() {
     int screen_height = 720;
 
     raylib::Window window(screen_width, screen_height, "Boid Playground");
-	window.SetState(FLAG_VSYNC_HINT);
+	window.SetState(FLAG_VSYNC_HINT | FLAG_WINDOW_RESIZABLE);
 
 	GuiLoadStyleDefault();
 
@@ -56,6 +58,7 @@ int main() {
 		g_world.boids.push_back(boid);
 	}
 	g_ui.target_boid_count = g_world.boids.size();
+	visuals_init(&g_world, &g_visuals);
 
 #ifdef __EMSCRIPTEN__
 	emscripten_set_main_loop(UpdateDrawFrame, 0, 1);
@@ -111,6 +114,9 @@ static void profiling_test() {
 void UpdateDrawFrame() {
 	float dt = GetFrameTime();
 
+	g_world.size.x = GetScreenWidth();
+	g_world.size.y = GetScreenHeight();
+
 	RPROF_START("Update");
 #ifdef PLATFORM_WEB
 	// If user goes to another tab and comes back, the time that the user was gone needs to be ignored.
@@ -121,6 +127,7 @@ void UpdateDrawFrame() {
 #else
 	world_update(&g_world, dt);
 #endif
+	visuals_update(&g_world, &g_visuals);
 	RPROF_STOP();
 
 	// Draw

src/world.cpp

@@ -117,6 +117,11 @@ static void world_init(World *world, float width, float height) {
 	world->size = { width, height };
 }
 
+static void visuals_init(World *world, Visuals *visuals) {
+	visuals->camera = { 0 };
+	visuals->camera.zoom = 1;
+}
+
 static void world_free(World *world) {
 	arena_free(&world->frame_arena);
 }
@@ -305,7 +310,7 @@ static void world_compute_local_boids(BoidList *local_boids, World *world, Chunk
 	int boid_count = world->boids.size();
 	MemoryArena *arena = &world->frame_arena;
 
-	boid_pair b2b_cmps[B2B_CAPACITY + SIMD_32B_LANES];
+	boid_pair *b2b_cmps = (boid_pair*)arena_malloc(arena, (B2B_CAPACITY + SIMD_32B_LANES)*sizeof(boid_pair));
 	int b2b_cmps_count = 0;
 
 	RPROF_START("Move chunk data to static arrays");
@@ -415,6 +420,27 @@ static BoidList* world_compute_local_boids(World *world) {
 	return all_local_boids;
 }
 
+static void aggregate_flock_modifiers(World *world, BoidList *flock, Boid *boid, Vector2 *center, Vector2 *heading, Vector2 *separation_force) {
+	*center  = { 0, 0 };
+	*heading = { 0, 0 };
+	*separation_force = { 0, 0 };
+
+	uboid_t boid_id;
+	BoidsListNodeIterator it = boid_list_get_iterator(flock);
+	while (boid_list_iterator_next(&it, &boid_id)) {
+		Boid *flock_boid = &world->boids[boid_id];
+		*heading = Vector2Add(*heading, flock_boid->dir);
+		*center  = Vector2Add(*center , flock_boid->pos);
+
+		Vector2 pos_diff = Vector2Subtract(boid->pos, flock_boid->pos);
+		float dist_sqr = Vector2LengthSqr(pos_diff);
+		if (dist_sqr <= world->separation_radius * world->separation_radius) {
+			*separation_force = Vector2Add(*separation_force, vector2_div_value(pos_diff, dist_sqr));
+		}
+	}
+	*center = vector2_div_value(*center, flock->count);
+}
+
 static void world_update(World *world, float dt) {
 	if (world->freeze) return;
 
@@ -422,7 +448,7 @@ static void world_update(World *world, float dt) {
 
 	Boid *boids = world->boids.data();
 	int boid_count = world->boids.size();
-	assert(boid_count <= MAX_BOIDS);
+	DEBUG_ASSERT(boid_count <= MAX_BOIDS);
 
 	BoidList *list_of_local_boids = world_compute_local_boids(world);
 
@@ -438,24 +464,8 @@ static void world_update(World *world, float dt) {
 		BoidList *local_boids = &list_of_local_boids[i];
 
 		if (local_boids->count > 0) {
-			Vector2 separation_force = { 0, 0 };
-			Vector2 flock_center  = { 0, 0 };
-			Vector2 flock_heading = { 0, 0 };
-
-			uboid_t local_boid_id;
-			BoidsListNodeIterator it = boid_list_get_iterator(local_boids);
-			while (boid_list_iterator_next(&it, &local_boid_id)) {
-				Boid *local_boid = &boids[local_boid_id];
-				flock_heading = Vector2Add(flock_heading, local_boid->dir);
-				flock_center  = Vector2Add(flock_center , local_boid->pos);
-
-				Vector2 pos_diff = Vector2Subtract(boid->pos, local_boid->pos);
-				float dist_sqr = Vector2LengthSqr(pos_diff);
-				if (dist_sqr <= world->separation_radius * world->separation_radius) {
-					separation_force = Vector2Add(separation_force, vector2_div_value(pos_diff, dist_sqr));
-				}
-			}
-			flock_center = vector2_div_value(flock_center, local_boids->count);
+			Vector2 separation_force, flock_center, flock_heading;
+			aggregate_flock_modifiers(world, local_boids, boid, &flock_center, &flock_heading, &separation_force);
 
 			Vector2 alignment_force = Vector2Normalize(flock_heading);
 			acc = Vector2Add(acc, vector2_mul_value(alignment_force, world->alignment_strength));
@@ -633,11 +643,55 @@ static void draw_boids(World *world, Visuals *visuals) {
 	rlEnd();
 }
 
+static void visuals_update(World *world, Visuals *visuals) {
+	Camera2D *camera = &visuals->camera;
+
+	if (IsKeyPressed(KEY_R)) {
+		*camera = { 0 };
+		camera->zoom = 1;
+	}
+
+	if (IsMouseButtonDown(MOUSE_BUTTON_MIDDLE)) {
+		Vector2 delta = GetMouseDelta();
+		delta = Vector2Scale(delta, -1.0f/camera->zoom);
+
+		camera->target = Vector2Add(camera->target, delta);
+	}
+
+	float wheel = GetMouseWheelMove();
+	if (wheel != 0) {
+		// Get the world point that is under the mouse
+		Vector2 mouseWorldPos = GetScreenToWorld2D(GetMousePosition(), *camera);
+
+		// Set the offset to where the mouse is
+		camera->offset = GetMousePosition();
+
+		// Set the target to match, so that the camera maps the world space point
+		// under the cursor to the screen space point under the cursor at any zoom
+		camera->target = mouseWorldPos;
+
+		// Zoom increment
+		const float zoom_speed = 0.125f;
+
+		camera->zoom = camera->zoom*(1+zoom_speed*wheel);
+		if (camera->zoom < zoom_speed) camera->zoom = zoom_speed;
+	}
+}
+
 static void world_draw(World *world, Visuals *visuals) {
+	BeginMode2D(visuals->camera);
 	for (int i = 0; i < world->obstacles.size(); i++) {
 		draw_obstacle(&world->obstacles[i], GRAY);
 	}
 
+	Color border_color = RED;
+	float world_width = world->size.x;
+	float world_height = world->size.y;
+	DrawLine(0, -1, world_width, -1, RED);
+	DrawLine(-1, 0, -1, world_height, RED);
+	DrawLine(0, world_height+1, world_width, world_height+1, RED);
+	DrawLine(world_width+1, 0, world_width+1, world_height, RED);
+
 	if (visuals->draw_view_cone) {
 		Color view_cone_color = Fade(GRAY, 0.4);
 		for (int i = 0; i < world->boids.size(); i++) {
@@ -673,4 +727,5 @@ static void world_draw(World *world, Visuals *visuals) {
 			DrawLine(boid->pos.x, boid->pos.y, look_pos.x, look_pos.y, RED);
 		}
 	}
+	EndMode2D();
 }