Update README

README

@@ -3,8 +3,10 @@
 This is a clone (ish) of the classic game Asteroids, written in C23
 for Linux.  To build the program, you'll need the Linux headers, a
 C23-compatible compiler and libdrm, along with its headers.  There is
-a build script that uses GCC; simply running this (`./build.sh`) is
+a build script that uses GCC; simply running this (./build.sh) is
-likely to work on many systems.
+likely to work on many systems.  However, you will likely need to
+adjust the input and video devices used (in input.c and renderer.c
+respectively) to match your system.
 
 The game directly uses Linux DRM, so it doesn't play nice with X,
 display managers etc.  You'll likely want to change to a virtual TTY

asteroids.c

@@ -13,9 +13,9 @@
 #define MIN_VERTS 5
 #define VERT_RANGE (MAX_VERTS - MIN_VERTS)
 #define A_JITTER 0.8
-#define V_JITTER 0.001
+#define V_JITTER 0.0005
 #define ROT_JITTER 0.005
-#define R_JITTER 0.02
+#define R_JITTER 0.01
 #define MIN_DIST 0.8
 
 #define REPLACE_MIN 3
@@ -41,10 +41,10 @@ static unsigned count;
 static entry_t entries[MAX_ENTITIES];
 
 static float radii[] = {
-	[ASTEROID_SMALL] = 0.05f,
+	[ASTEROID_SMALL] = 0.025f,
-	[ASTEROID_MEDIUM] = 0.1f,
+	[ASTEROID_MEDIUM] = 0.05f,
-	[ASTEROID_LARGE] = 0.2f,
+	[ASTEROID_LARGE] = 0.1f,
-	[ASTEROID_HUGE] = 0.4f,
+	[ASTEROID_HUGE] = 0.2f,
 };
 
 static void update(unsigned new_entity_id, void *ref)

build.sh

@@ -9,4 +9,5 @@ defs="-D_POSIX_C_SOURCE=200809L"
 $cc $warn $flags $libs $defs \
 	-o asteroids \
 	asteroids.c collisions.c entity.c fb.c game.c input.c \
-	main.c maths.c physics.c scene.c renderer.c rng.c text.c
+	main.c maths.c physics.c scene.c renderer.c rng.c \
+	self_destruct.c text.c

game.c

@@ -8,6 +8,7 @@
 #include "renderer.h"
 #include "rng.h"
 #include "scene.h"
+#include "self_destruct.h"
 #include "text.h"
 
 #include <assert.h>
@@ -15,32 +16,34 @@
 #include <math.h>
 #include <string.h>
 
+#define FPS 60
+
 #define INIT_LEVEL 1
 
-#define SHIP_COLLIDE_R 0.05
+#define SHIP_COLLIDE_R 0.025
-#define SHIP_MASS 0.02
+#define SHIP_MASS 0.01
 
-#define FIRE_MEAN -0.15
+#define FIRE_JITTER 0.005
-#define FIRE_JITTER 0.01
 
-#define LIN_PWR 0.0001
+#define LIN_PWR 0.00005
 #define ROT_PWR 0.002
 
 #define SHOT_VEL 0.03
-#define SHOT_COLLIDE_R 0.03
+#define SHOT_COLLIDE_R 0.015
-#define SHOT_MASS 0.001
+#define SHOT_MASS 0.00025
+#define SHOT_LIFETIME_S 4
 
-#define ARROW_SCALE 0.025
+#define ARROW_SCALE 0.0125
 #define ARROW_WIDTH 4
 #define ARROW_HEIGHT 4
 #define COUNTER_MASK (1 << 6)
 
 #define ITEM_SPAWN_R 0.9
-#define ITEM_COLLIDE_R 0.025
+#define ITEM_COLLIDE_R 0.0125
 #define ITEM_SPAWN_EXP_S 40
 #define ITEM_MIN_SCORE 32
 
-#define ARMOUR_COEFF 5e-6
+#define ARMOUR_COEFF 2.5e-6
 
 #define NELEMS(arr) (sizeof(arr) / sizeof(arr[0]))
 
@@ -51,17 +54,17 @@ enum {
 };
 
 static const vec2_t ship_verts[] = {
-	{ 0.0, 0.11 },
+	{ 0.0, 0.055 },
-	{ 0.05, -0.07 },
+	{ 0.025, -0.035 },
-	{ 0.0, -0.04 },
+	{ 0.0, -0.02 },
-	{ -0.05, -0.07 },
+	{ -0.025, -0.035 },
 };
 static const vec2_t fire_verts[] = {
-	{ 0.0, -0.15 },
+	{ 0.0, -0.075 },
-	{ 0.015, -0.07 },
+	{ 0.0075, -0.035 },
-	{ -0.015, -0.07 },
+	{ -0.0075, -0.035 },
 };
-static const vec2_t shot_verts[] = { { 0.0, -0.02 }, { 0.0, 0.02 } };
+static const vec2_t shot_verts[] = { { 0.0, -0.01 }, { 0.0, 0.01 } };
 
 static const vec2_t arrow_verts[][MAX_VERTS] = {
 	{ { 1, 2 }, { 2, 0 }, { 1, -2 } },
@@ -70,8 +73,8 @@ static const vec2_t arrow_verts[][MAX_VERTS] = {
 static const unsigned arrow_counts[NELEMS(arrow_verts)] = { 3, 2 };
 
 static const vec2_t item_verts[][MAX_VERTS] = {
-	{ { -0.025, -0.025 }, { 0.025, 0.025 } },
+	{ { -0.0125, -0.0125 }, { 0.0125, 0.0125 } },
-	{ { -0.025, 0.025 }, { 0.025, -0.025 } },
+	{ { -0.0125, 0.0125 }, { 0.0125, -0.0125 } },
 };
 static const unsigned item_counts[NELEMS(item_verts)] = { 2, 2 };
 
@@ -175,6 +178,7 @@ static void shoot()
 	scene_add(id, shot_verts, NELEMS(shot_verts), false);
 	physics_add(id, pos, ship->dir, vel, 0, SHOT_MASS);
 	collisions_add(id, SHOT_COLLIDE_R, SHOT_COLLIDE_PRIOR, shot_collide);
+	self_destruct_add(id, FPS * SHOT_LIFETIME_S);
 
 	const vec2_t p_ship = vec2_scale(ship->vel, ship->mass);
 	const vec2_t p_shot = vec2_scale(vel, SHOT_MASS);
@@ -190,19 +194,13 @@ static void draw_arrow()
 		{ tx, 0, 1 },
 	};
 
-	const vec3_t c_mod = { 0, 0, 1 };
-	const vec3_t s_mod = { ARROW_WIDTH + 2, ARROW_HEIGHT + 2, 0 };
-	const vec3_t c = mat3_mul_vec3(m, c_mod);
-	const vec3_t s = mat3_mul_vec3(m, s_mod);
-	renderer_clear_rect(vec3_reduce(c), (vec2_t) { s.x, s.y });
-
 	for (unsigned i = 0; i < NELEMS(arrow_verts); ++i)
 		renderer_draw(arrow_verts[i], arrow_counts[i], m, false);
 }
 
 static void anim_fire(vec2_t *verts)
 {
-	verts[0].y = FIRE_MEAN + FIRE_JITTER * rng_plusminus();
+	verts[0].y = fire_verts[0].y + FIRE_JITTER * rng_plusminus();
 }
 
 static void create_field()
@@ -220,6 +218,7 @@ static void create_field()
 	scene_clear();
 	physics_init();
 	collisions_init();
+	self_destruct_clear();
 
 	ship_entity_id = entity_add();
 	scene_add(ship_entity_id, ship_verts, NELEMS(ship_verts), true);
@@ -316,14 +315,16 @@ void game_update()
 
 	ship_update();
 	physics_update();
+	self_destruct_update();
 	collisions_update();
 	scene_update();
 
 	entities_purge();
 
-	const bool items_enabled = score >= ITEM_MIN_SCORE;
+	const bool items_enabled
+	    = !clear && score >= ITEM_MIN_SCORE && armour_level < 9;
 	if (items_enabled && !item
-	    && rng_canon() < 1.0f / (60 * ITEM_SPAWN_EXP_S))
+	    && rng_canon() < 1.0f / (FPS * ITEM_SPAWN_EXP_S))
 		add_item();
 }
 

self_destruct.c

@@ -0,0 +1,60 @@
+#include "self_destruct.h"
+
+#include "entity.h"
+
+#include <assert.h>
+#include <string.h>
+
+#define MAX 256U
+
+typedef struct {
+	unsigned entity_id;
+	unsigned component_id;
+	unsigned rem;
+} cmp_t;
+
+static unsigned count;
+static cmp_t cmps[MAX];
+
+static void update(unsigned new_entity_id, void *ref)
+{
+	cmp_t *c = (cmp_t *)ref;
+	c->entity_id = new_entity_id;
+}
+
+static void remove(void *ref)
+{
+	cmp_t *c = (cmp_t *)ref;
+	const cmp_t *last = cmps + (count - 1);
+	if (c < last) {
+		memcpy(c, last, sizeof(cmp_t));
+		entity_update_component(c->entity_id, c->component_id, c);
+	}
+	--count;
+}
+
+void self_destruct_clear()
+{
+	count = 0;
+}
+
+void self_destruct_update()
+{
+	for (unsigned i = 0; i < count; ++i) {
+		if (cmps[i].rem == 0)
+			entity_mark(cmps[i].entity_id);
+		else
+			--cmps[i].rem;
+	}
+}
+
+void self_destruct_add(unsigned id, unsigned frames)
+{
+	assert(count < MAX);
+	cmp_t *c = cmps + count++;
+	*c = (cmp_t) {
+		.entity_id = id,
+		.rem = frames,
+		.component_id = entity_add_component(id, update, remove, c),
+	};
+}

self_destruct.h

@@ -0,0 +1,8 @@
+#ifndef SELF_DESTRUCT_H
+#define SELF_DESTRUCT_H
+
+void self_destruct_clear();
+void self_destruct_update();
+void self_destruct_add(unsigned id, unsigned frames);
+
+#endif

text.c

@@ -9,7 +9,7 @@
 #define MAX_LINES 2
 
 #define TEXT_HEIGHT 8
-#define TEXT_SCALE 0.025
+#define TEXT_SCALE 0.0125
 #define LETTER_WIDTH 3
 #define SPACE_WIDTH 1