Add shooting

main.c

@@ -1,9 +1,11 @@
 #include "input.h"
 #include "renderer.h"
 
+#include <assert.h>
 #include <linux/input-event-codes.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <sys/select.h>
 #include <sys/time.h>
 
@@ -16,8 +18,11 @@
 #define LIN_PWR 0.0001
 #define ROT_PWR 0.002
 
+#define SHOT_VEL 0.04
+
 #define MAX_SHAPES 8U
 #define MAX_ENTITIES 8U
+#define MAX_SHAPES_PER_ENTITY 2
 
 #define MAX(a, b) ((a) < (b) ? (b) : (a))
 #define NELEMS(arr) (sizeof(arr) / sizeof(arr[0]))
@@ -34,8 +39,13 @@ typedef struct {
 	vec2_t vel;
 	mat2_t dir;
 	float omg;
+	unsigned shapes[MAX_SHAPES_PER_ENTITY];
+	unsigned shape_count;
+	bool wrap;
 } entity_t;
 
+static vec2_t shot_verts[] = { { 0.0, -0.015 }, { 0.0, 0.015 } };
+
 static shape_t shapes[MAX_SHAPES] = {
 	{
 		.visible = true,
@@ -61,7 +71,12 @@ static shape_t shapes[MAX_SHAPES] = {
 };
 
 static entity_t entities[MAX_ENTITIES] = {
-	{ .dir = { { 1, 0 }, { 0, 1 } } },
+	{
+	    .dir = { { 1, 0 }, { 0, 1 } },
+	    .shape_count = 2,
+	    .shapes = { 0, 1 },
+	    .wrap = true,
+	},
 };
 
 static mat3_t transforms[MAX_ENTITIES];
@@ -76,6 +91,67 @@ static struct {
 	int fwd;
 } input;
 
+static void shoot()
+{
+	if (entity_count >= MAX_ENTITIES || shape_count >= MAX_SHAPES)
+		return;
+
+	const entity_t *ship = entities + SHIP;
+	const shape_t *ship_shape = shapes + SHIP;
+
+	const int id = entity_count++;
+	entity_t *e = entities + id;
+	e->dir = ship->dir;
+	e->pos = vec2_add(
+	    ship->pos, mat2_mul_vec2(ship->dir, ship_shape->verts[0]));
+	e->vel = vec2_add(
+	    ship->vel, mat2_mul_vec2(ship->dir, (vec2_t) { 0, SHOT_VEL }));
+	e->omg = 0;
+
+	const int shape_id = shape_count++;
+	shape_t *s = shapes + shape_id;
+	s->visible = true;
+	s->entity = id;
+	s->vert_count = NELEMS(shot_verts);
+	memcpy(s->verts, shot_verts, sizeof(shot_verts));
+
+	e->shapes[0] = shape_id;
+	e->shape_count = 1;
+}
+
+static void remove_shape(unsigned id)
+{
+	if (id < shape_count - 1) {
+		const shape_t *last = shapes + shape_count - 1;
+		memcpy(shapes + id, shapes + shape_count - 1, sizeof(shape_t));
+		for (unsigned i = 0; i < entities[last->entity].shape_count; ++i) {
+			if (entities[last->entity].shapes[i] == shape_count - 1) {
+				entities[last->entity].shapes[i] = id;
+				break;
+			}
+		}
+	}
+	--shape_count;
+}
+
+static void remove_entity(unsigned id)
+{
+	assert(id != SHIP);
+
+	entity_t *e = entities + id;
+	for (unsigned i = 0; i < e->shape_count; ++i)
+		remove_shape(e->shapes[i]);
+
+	if (id < entity_count - 1) {
+		const entity_t *last = entities + entity_count - 1;
+		memcpy(e, last, sizeof(entity_t));
+		for (unsigned i = 0; i < e->shape_count; ++i)
+			shapes[e->shapes[i]].entity = id;
+	}
+
+	--entity_count;
+}
+
 static void key_press_callback(int key)
 {
 	switch (key) {
@@ -94,6 +170,10 @@ static void key_press_callback(int key)
 		--input.rot;
 		break;
 
+	case KEY_SPACE:
+		shoot();
+		break;
+
 	default:
 		break;
 	}
@@ -102,10 +182,6 @@ static void key_press_callback(int key)
 static void key_release_callback(int key)
 {
 	switch (key) {
-	case KEY_Q:
-		quit = true;
-		break;
-
 	case KEY_UP:
 		--input.fwd;
 		break;
@@ -122,6 +198,15 @@ static void key_release_callback(int key)
 	}
 }
 
+static void key_repeat_callback(int key)
+{
+	switch (key) {
+	case KEY_SPACE:
+		shoot();
+		break;
+	}
+}
+
 static mat3_t entity_transform(unsigned id)
 {
 	const entity_t *e = entities + id;
@@ -157,14 +242,22 @@ static void update()
 		e->dir = mat2_mul_mat2(mat2_rotation(e->omg), e->dir);
 		e->pos = vec2_add(e->pos, e->vel);
 
+		if (e->wrap) {
 			if (e->pos.y > 1)
 				e->pos.y -= 2;
-		else if (e->pos.y < -1)
+			else if (e->pos.y <= -1)
 				e->pos.y += 2;
-		if (e->pos.x > aspect)
+			if (e->pos.x >= aspect)
 				e->pos.x -= 2 * aspect;
 			else if (e->pos.x < -aspect)
 				e->pos.x += 2 * aspect;
+		} else {
+			if (e->pos.y > 1 || e->pos.y <= -1 || e->pos.x >= aspect
+			    || e->pos.x < -aspect) {
+				remove_entity(i--);
+				continue;
+			}
+		}
 
 		transforms[i] = entity_transform(i);
 	}
@@ -190,6 +283,7 @@ int main()
 	const int input_fd = input_init();
 	input_on_press(key_press_callback);
 	input_on_release(key_release_callback);
+	input_on_repeat(key_repeat_callback);
 
 	const renderer_params_t renderer_params = renderer_init();
 	aspect = renderer_params.aspect;