random walk toy

1 files changed, 165 insertions, 0 deletions

diff --git a/rwalk/src/main.c b/rwalk/src/main.c
new file mode 100644
index 0000000..28592e4
--- /dev/null
+++ b/rwalk/src/main.c
@@ -0,0 +1,165 @@
+#include <stdlib.h>
+#include <stdbool.h>
+#include <stdio.h>
+
+#include <allegro5/allegro5.h>
+#include <allegro5/allegro_primitives.h>
+
+#include <sodium.h>
+
+#define DO_INIT(check, desc) \
+	if (!(check)) { \
+		fprintf(stderr, "err: can't initialise %s\n", desc); \
+		rval = 1; \
+		goto done; \
+	}
+
+int main(int argc, char **argv)
+{
+	int rval = 0;
+	unsigned goframes;
+	uint32_t randbytes;
+
+	struct {
+		uint32_t middle;
+		uint32_t upper;
+		uint32_t lower;
+	} biases[4] = {
+		/* unbiased */
+		{
+			.middle = 0x80000000,
+			.upper = 0xc0000000,
+			.lower = 0x40000000,
+		},
+		/* 1/64 */
+		{
+			.middle = 0x7c000000,
+			.upper = 0xbe000000,
+			.lower = 0x3e000000,
+		},
+		/* 1/32 */
+		{
+			.middle = 0x78000000,
+			.upper = 0xbc000000,
+			.lower = 0x3c000000,
+		},
+		/* 1/16 */
+		{
+			.middle = 0x70000000,
+			.upper = 0xb8000000,
+			.lower = 0x38000000,
+		}
+	};
+	unsigned setting = 0;
+
+	ALLEGRO_DISPLAY* d = NULL;
+	ALLEGRO_TIMER* t = NULL;
+	ALLEGRO_EVENT_QUEUE* eq = NULL;
+	ALLEGRO_EVENT e;
+
+	float x = 320.0, y = 240.0;
+
+
+	DO_INIT(sodium_init() >= 0, "sodium");
+
+	DO_INIT(al_init(), "allegro");
+	DO_INIT(al_init_primitives_addon(), "primitives");
+	DO_INIT(al_install_keyboard(), "keyboard");
+
+	DO_INIT(t = al_create_timer(1.0 / 30.0), "timer");
+	DO_INIT(eq = al_create_event_queue(), "event queue");
+
+	al_set_new_display_option(ALLEGRO_SINGLE_BUFFER, 1, ALLEGRO_REQUIRE);
+	DO_INIT(d = al_create_display(641, 481), "display");
+
+	al_register_event_source(eq, al_get_keyboard_event_source());
+	al_register_event_source(eq, al_get_display_event_source(d));
+	al_register_event_source(eq, al_get_timer_event_source(t));
+
+	al_clear_to_color(al_map_rgb(0, 0, 0));
+
+
+	goframes = 0;
+	al_start_timer(t);
+	while(true) {
+		al_wait_for_event(eq, &e);
+
+		switch (e.type) {
+
+		case ALLEGRO_EVENT_DISPLAY_CLOSE:
+			goto done;
+
+		case ALLEGRO_EVENT_KEY_DOWN:
+			switch(e.keyboard.keycode) {
+
+			case ALLEGRO_KEY_1:
+				setting = 0;
+				puts("1");
+				break;
+
+			case ALLEGRO_KEY_2:
+				setting = 1;
+				puts("2");
+				break;
+
+			case ALLEGRO_KEY_3:
+				setting = 2;
+				puts("3");
+				break;
+
+			case ALLEGRO_KEY_4:
+				setting = 3;
+				puts("4");
+				break;
+
+			default:
+				break;
+
+			}
+
+			if (! (e.keyboard.keycode == ALLEGRO_KEY_ENTER) )
+				continue;
+
+			goframes = 1000;
+		case ALLEGRO_EVENT_TIMER:
+			if (goframes == 0) {
+				al_flip_display();
+				break;
+			}
+
+			al_draw_filled_rectangle(x, y, x + 1.0, y + 1.0, al_map_rgb(255, 255, 255));
+
+			randbytes = randombytes_random();
+
+			if (randbytes >= biases[setting].middle) {
+				if (randbytes >= biases[setting].upper)
+					x += 1;
+				else
+					y += 1;
+			} else {
+				if (randbytes >= biases[setting].lower)
+					x -= 1;
+				else
+					y -= 1;
+			}
+
+			al_flip_display();
+
+			goframes--;
+			if (goframes == 0)
+				puts("next");
+		}
+	}
+
+
+done:
+
+	if (d)
+		al_destroy_display(d);
+	if (t)
+		al_destroy_timer(t);
+	if (eq)
+		al_destroy_event_queue(eq);
+	
+	return rval;
+}