From dd2552145b859fd48c9d61c60c4ce82effea011f Mon Sep 17 00:00:00 2001
From: Daniel Jones <admin@danieljon.es>
Date: Fri, 21 Dec 2018 01:06:16 +1030
Subject: first code commit

---
 matrix.c | 126 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 126 insertions(+)
 create mode 100644 matrix.c

diff --git a/matrix.c b/matrix.c
new file mode 100644
index 0000000..ae474e0
--- /dev/null
+++ b/matrix.c
@@ -0,0 +1,126 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <time.h>
+
+#define CIRCLE "◯"
+#define BLACKCIRCLE "⬤"
+#define BALLS 2
+
+struct led
+{
+	/*
+	 * 8x8 matrix, we only need 3 bits for each x/y position
+	 * 1 byte per led
+	 * 1 bit  -> led on/off
+	 * 3 bits -> x pos (0-7)
+	 * 3 bits -> y pos (0-7)
+	 * 1 bit  -> unused
+	*/
+	unsigned char enabled:1;
+	unsigned char x:3;
+	unsigned char y:3;
+	unsigned char unused:1;
+} matrix[8][8];
+
+struct ball
+{
+	unsigned char x:3;
+	unsigned char y:3;
+	unsigned char dirx:1; /* 0 = left, 1 = right */
+	unsigned char diry:1; /* 0 = down, 1 = up */
+} balls[BALLS];
+
+void
+printleds(void)
+{
+	printf("\0337");
+	printf("%s", "\033[8;0F");
+	printf("%s", "\033[0J");
+	for (int x = 0; x < 8; x++)
+	{
+		for (int y = 0; y < 8; y++)
+		{
+			printf("%s ", (matrix[x][y].enabled) ? BLACKCIRCLE : CIRCLE);
+		}
+		puts("");
+	}
+	printf("\0338");
+}
+
+void
+playball()
+{
+	for (int i = 0; i < BALLS; i++)
+	{
+		if (balls[i].x == 0)
+			balls[i].dirx = 1;
+		else if (balls[i].x == 7)
+			balls[i].dirx = 0;
+		
+		if (balls[i].y == 7)
+			balls[i].diry = 1;
+		else if (balls[i].y == 0)
+			balls[i].diry = 0;
+
+		if (balls[i].dirx == 1)
+			balls[i].x++;
+		else
+			balls[i].x--;
+
+		if (balls[i].diry == 1)
+			balls[i].y--;
+		else
+			balls[i].y++;
+	}
+
+}
+
+int
+main(void)
+{
+	for (int x = 0; x < 8; x++)
+	{
+		for (int y = 0; y < 8; y++)
+		{
+			matrix[x][y].enabled = 0;
+			matrix[x][y].x = x;
+			matrix[x][y].y = y;
+		}
+	}
+	printf("\n\n\n\n\n\n\n\n\n");
+	int x, y = 0;
+	srand(time(NULL));
+	for (int i = 0; i < BALLS; i++)
+	{
+		balls[i].x = rand() % 7;
+		balls[i].y = rand() % 7;
+		balls[i].dirx = rand() % 2;
+		balls[i].diry = rand() % 2;
+	}
+	while (1)
+	{
+		/*
+		matrix[0][y].enabled = !matrix[0][y].enabled;
+		matrix[2][y].enabled = !matrix[2][y].enabled;
+		matrix[4][y].enabled = !matrix[4][y].enabled;
+		matrix[6][y].enabled = !matrix[6][y].enabled;
+		matrix[8][y].enabled = !matrix[8][y].enabled;
+		*/
+		for (int i = 0; i < BALLS; i++)
+			matrix[balls[i].y][balls[i].x].enabled = 0;
+		playball();
+		for (int i = 0; i < BALLS; i++)
+			matrix[balls[i].y][balls[i].x].enabled = 1;
+		printleds();
+		x++;
+		y++;
+		if (x == 8 || y == 8)
+		{
+			x = 0;
+			y = 0;
+		}
+		usleep(100000);
+	}
+	return 0;
+}
-- 
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