optimize spike drawing

src/game.c

@@ -3,6 +3,7 @@
 #include "map.h"
 #include "player.h"
 #include "cfg.h"
+#include "rotrect.h"
 #include "spike.h"
 #include <string.h>
 
@@ -24,7 +25,8 @@ void
 game_update(Game *this)
 {
 	extern double tick;
-	this->spike_angle = tick / 16;
+	this->spike_rect = rotrect_create(10, 10, tick / 16);
+	this->spike_irect = rotrect_create(10, 10, -tick / 16);
 	if (this->queue_restart_scene > 0) {
 		if (--this->queue_restart_scene == 0)
 			game_restart_scene(this);

src/game.h

@@ -1,5 +1,6 @@
 #pragma once
 #include "entity.h"
+#include "rotrect.h"
 
 enum { MAX_ENTITIES = 128 };
 
@@ -9,7 +10,8 @@ typedef struct Game {
 	int queue_restart_scene;
 	int player_dir;
 	int show_ui;
-	double spike_angle;
+	Rect spike_rect;
+	Rect spike_irect;
 	Entity entities[MAX_ENTITIES];
 } Game;
 

src/rotrect.c

@@ -15,8 +15,8 @@ rotate(double *x, double *y, double angle)
 	*y = ox * s + oy * c;
 }
 
-void
-rotrect(double x, double y, double width, double height, double angle)
+Rect
+rotrect_create(double width, double height, double angle)
 {
 	double xs[4] = {
 		width / 2.0,
@@ -30,14 +30,30 @@ rotrect(double x, double y, double width, double height, double angle)
 		height / 2.0,
 		-height / 2.0,
 	};
-	for (int i = 0; i < 4; i++) {
+	for (int i = 0; i < 4; i++)
 		rotate(&xs[i], &ys[i], angle);
-		xs[i] = round(xs[i] + x);
-		ys[i] = round(ys[i] + y);
-	}
+	return (Rect){ xs[0], ys[0], xs[1], ys[1], xs[2], ys[2], xs[3], ys[3] };
+}
+
+void
+rotrect_draw(Rect rect, double x, double y)
+{
+	const int xs[4] = {
+		round(rect.x0 + x), round(rect.x1) + x,
+		round(rect.x2 + x), round(rect.x3) + x
+	};
+	const int ys[4] = {
+		round(rect.y0 + y), round(rect.y1) + y,
+		round(rect.y2 + y), round(rect.y3) + y,
+	};
 	LZY_DrawLine(xs[0], ys[0], xs[1], ys[1]);
 	LZY_DrawLine(xs[1], ys[1], xs[2], ys[2]);
 	LZY_DrawLine(xs[2], ys[2], xs[3], ys[3]);
 	LZY_DrawLine(xs[3], ys[3], xs[0], ys[0]);
 }
 
+void
+rotrect(double x, double y, double width, double height, double angle)
+{
+	rotrect_draw(rotrect_create(width, height, angle), x, y);
+}

src/rotrect.h

@@ -1,3 +1,7 @@
 #pragma once
 
+typedef struct { double x0, y0, x1, y1, x2, y2, x3, y3; } Rect;
+
+Rect rotrect_create(double width, double height, double angle);
+void rotrect_draw(Rect rect, double x, double y);
 void rotrect(double x, double y, double width, double height, double angle);

src/spike.c

@@ -7,8 +7,8 @@ IMPL_UPDATE() {
 } IMPL_END
 
 IMPL_DRAW() {
-	rotrect(this->pos[0], this->pos[1], 10, 10, g->spike_angle);
-	rotrect(this->pos[0], this->pos[1], 10, 10, -g->spike_angle);
+	rotrect_draw(g->spike_rect, this->pos[0], this->pos[1]);
+	rotrect_draw(g->spike_irect, this->pos[0], this->pos[1]);
 } IMPL_END
 
 IMPL_INIT(spike) {