From 7d876aaf2d9cc07595b56e41005516caac26411e Mon Sep 17 00:00:00 2001
From: Camden Dixie O'Brien <cobrien@witekio.com>
Date: Mon, 13 Oct 2025 21:04:50 +0100
Subject: [PATCH] Refactor to seperate shapes and physics

---
 main.c | 147 +++++++++++++++++++++++++++++++++++++++------------------
 1 file changed, 102 insertions(+), 45 deletions(-)

diff --git a/main.c b/main.c
index c89aa13..974678c 100644
--- a/main.c
+++ b/main.c
@@ -5,12 +5,62 @@
 #include <stdio.h>
 #include <sys/select.h>
 
+#define SHIP 0
+#define FIRE 1
+
 #define LIN_PWR 0.0001
-#define ROT_PWR 0.001
+#define ROT_PWR 0.002
+
+#define MAX_SHAPES 8U
+#define MAX_ENTITIES 8U
 
 #define MAX(a, b) ((a) < (b) ? (b) : (a))
 #define NELEMS(arr) (sizeof(arr) / sizeof(arr[0]))
 
+typedef struct {
+	bool visible;
+	int entity;
+	unsigned vert_count;
+	vec2_t verts[MAX_VERTS];
+} shape_t;
+
+typedef struct {
+	vec2_t pos;
+	vec2_t vel;
+	mat2_t dir;
+	float omg;
+} entity_t;
+
+static shape_t shapes[MAX_SHAPES] = {
+	{
+		.visible = true,
+		.entity = SHIP,
+		.vert_count = 4,
+		.verts = {
+			{ 0.0, 0.08 },
+			{ 0.05, -0.1 },
+			{ 0.0, -0.07 },
+			{ -0.05, -0.1 },
+		},
+	},
+	{
+		.visible = false,
+		.entity = SHIP,
+		.vert_count = 3,
+		.verts = {
+			{ 0.015, -0.1 },
+			{ -0.015, -0.1 },
+			{ 0.0, -0.15 },
+		},
+	},
+};
+
+static entity_t entities[MAX_ENTITIES] = {
+	{ .dir = { { 1, 0 }, { 0, 1 } } },
+};
+
+static unsigned shape_count = 2;
+static unsigned entity_count = 1;
 static float aspect;
 static bool quit = false;
 
@@ -19,27 +69,6 @@ static struct {
 	int fwd;
 } input;
 
-static struct {
-	vec2_t pos;
-	vec2_t vel;
-	mat2_t dir;
-	float omg;
-} state;
-
-static const vec2_t ship[] = {
-	{ 0.0, 0.08 },
-	{ 0.05, -0.1 },
-	{ 0.0, -0.07 },
-	{ -0.05, -0.1 },
-};
-static const vec2_t fire[] = {
-	{ 0.015, -0.1 },
-	{ -0.015, -0.1 },
-	{ 0.0, -0.15 },
-};
-
-static const vec2_t thrust = { 0, LIN_PWR };
-
 static void key_press_callback(int key)
 {
 	switch (key) {
@@ -86,27 +115,58 @@ static void key_release_callback(int key)
 	}
 }
 
-static mat3_t update()
+static mat3_t entity_transform(unsigned id)
 {
-	state.omg += ROT_PWR * (float)input.rot;
-	state.dir = mat2_mul_mat2(mat2_rotation(state.omg), state.dir);
+	const entity_t *e = entities + id;
+	return mat3_mul_mat3(mat3_translation(e->pos), mat2_extend(e->dir));
+}
 
-	const vec2_t acc
-	    = mat2_mul_vec2(state.dir, vec2_scale(thrust, (float)input.fwd));
-	state.vel = vec2_add(state.vel, acc);
-	state.pos = vec2_add(state.pos, state.vel);
+static void ship_update()
+{
+	entity_t *ship = entities + SHIP;
 
-	if (state.pos.y > 1)
-		state.pos.y -= 2;
-	else if (state.pos.y < -1)
-		state.pos.y += 2;
-	if (state.pos.x > aspect)
-		state.pos.x -= 2 * aspect;
-	else if (state.pos.x < -aspect)
-		state.pos.x += 2 * aspect;
+	ship->omg += ROT_PWR * (float)input.rot;
 
-	return mat3_mul_mat3(
-	    mat3_translation(state.pos), mat2_extend(state.dir));
+	const vec2_t thrust = { 0, (float)input.fwd * LIN_PWR };
+	const vec2_t acc = mat2_mul_vec2(ship->dir, thrust);
+	ship->vel = vec2_add(ship->vel, acc);
+
+	shapes[FIRE].visible = input.fwd != 0;
+}
+
+static void update()
+{
+	ship_update();
+
+	for (unsigned i = 0; i < entity_count; ++i) {
+		entity_t *e = entities + i;
+
+		e->dir = mat2_mul_mat2(mat2_rotation(e->omg), e->dir);
+		e->pos = vec2_add(e->pos, e->vel);
+
+		if (e->pos.y > 1)
+			e->pos.y -= 2;
+		else if (e->pos.y < -1)
+			e->pos.y += 2;
+		if (e->pos.x > aspect)
+			e->pos.x -= 2 * aspect;
+		else if (e->pos.x < -aspect)
+			e->pos.x += 2 * aspect;
+	}
+}
+
+static void draw()
+{
+	static mat3_t transforms[MAX_ENTITIES];
+	for (unsigned i = 0; i < entity_count; ++i)
+		transforms[i] = entity_transform(i);
+
+	for (unsigned i = 0; i < shape_count; ++i) {
+		if (!shapes[i].visible)
+			continue;
+		const mat3_t transform = transforms[shapes[i].entity];
+		renderer_draw(shapes[i].verts, shapes[i].vert_count, transform);
+	}
 }
 
 int main()
@@ -121,8 +181,6 @@ int main()
 	renderer_clear();
 	renderer_swap();
 
-	state.dir = (mat2_t) { { 1, 0 }, { 0, 1 } };
-
 	const int max_fd = MAX(input_fd, drm_fd);
 	fd_set set;
 
@@ -139,12 +197,11 @@ int main()
 		if (FD_ISSET(drm_fd, &set)) {
 			renderer_handle();
 
-			const mat3_t m = update();
+			update();
 
 			renderer_clear();
-			renderer_draw(ship, NELEMS(ship), m);
-			if (input.fwd != 0)
-				renderer_draw(fire, NELEMS(fire), m);
+			draw();
+
 			renderer_swap();
 		}
 	}