From 8e7615994bd4f76038484b376fdc67e96a22a313 Mon Sep 17 00:00:00 2001
From: James <james.mckenzie@citrix.com>
Date: Sun, 13 Oct 2013 13:44:07 +0100
Subject: fish

---
 src/pong.c | 280 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 280 insertions(+)
 create mode 100644 src/pong.c

(limited to 'src/pong.c')

diff --git a/src/pong.c b/src/pong.c
new file mode 100644
index 0000000..aba6ae6
--- /dev/null
+++ b/src/pong.c
@@ -0,0 +1,280 @@
+#include <io.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+#include "system.h"
+
+#include "GPU.h"
+
+#define msleep(msec) usleep(1000*msec);
+
+
+static void
+pio_write (unsigned int data)
+{
+  IOWR (PIO_0_BASE, 0, data);
+}
+
+
+static void
+gpu_write (unsigned int reg, unsigned int data)
+{
+  IOWR (GPU_0_BASE, reg << 2, data);
+}
+
+
+static void
+update_gpu (int x, int y, int bat0, int bat1)
+{
+  // set locations
+  gpu_write (GPU_REG_SPRITE_X, x + GPU_OFFSET);
+  gpu_write (GPU_REG_SPRITE_Y, y + GPU_OFFSET);
+  gpu_write (GPU_REG_BAT0_Y, bat0 + GPU_OFFSET);
+  gpu_write (GPU_REG_BAT1_Y, bat1 + GPU_OFFSET);
+
+
+  // enable video
+  gpu_write (GPU_REG_BLANK, 0);
+}
+
+
+static void
+show_score (int score)
+{
+  // int to seven segment lookup: MSB dp g f e d c b a LSB
+  const uint8_t lookup[10] =
+    { 0x3F, 0x6, 0x5B, 0x4F, 0x66, 0x6D, 0x7D, 0x7, 0x7F, 0x6F };
+
+  uint8_t ss = 0;
+
+  // show negative with DP
+  if (score < 0)
+    {
+      ss |= 0x80;
+      score = -score;
+    }
+
+  if (score > 9)
+    score = 9;
+
+  ss |= lookup[score];
+
+  pio_write (ss);
+}
+
+static void
+load_sprite (void)
+{
+  const uint16_t sprite[16] =
+    { 0x00C0, 0x03E0, 0x0FF8, 0x1FFE, 0x3FC7, 0x3F83, 0x3933, 0x3987, 0x3D37,
+    0x3D37, 0x3D87, 0x3FFF, 0x1FFE, 0x07F8, 0x01E0, 0x00C0
+  };
+  const unsigned int n = sizeof (sprite) / sizeof (uint16_t);
+  unsigned int i;
+
+  gpu_write (GPU_REG_SPRITE_COLOUR, GPU_RGB(7,2,0));
+
+  // squirt the bromium logo into the sprite
+  for (i = 0; i < n; ++i)
+    gpu_write (GPU_REG_SPRITE_BASE + i, sprite[i]);
+}
+
+
+static int
+dir (int a, int b)
+{
+  if (a > b)
+    return 1;
+  if (a < b)
+    return -1;
+  return 0;
+}
+
+static void
+move_bat (int *b, int db)
+{
+  *b += dir (db, *b);
+}
+
+static int
+squish (int *v, int min, int max)
+{
+  if (*v < min)
+    {
+      *v = min;
+      return 1;
+    }
+  if (*v >= max)
+    {
+      *v = max - 1;
+      return 1;
+    }
+  return 0;
+}
+
+static int
+find_intersection (int x, int y, int xd, int yd, int t)
+{
+
+  // super lazy - we should use the power of MATHS
+
+  while (x != t)
+    {
+      x += xd;
+      y += yd;
+
+      if (squish (&y, 0, GPU_HEIGHT))
+        yd = -yd;
+
+      if (squish (&x, 0, GPU_WIDTH))
+        xd = -xd;
+    }
+
+  return y;
+}
+
+static int
+has_missed (int y1, int y2)
+{
+  y1 = y1 - y2;
+  if (y1 < 0)
+    y1 = -y1;
+  if (y1 > 20)
+    return 1;
+  return 0;
+}
+
+static int
+x_speed (void)
+{
+  return (rand () % 10) + 1;
+}
+
+static int
+y_speed (void)
+{
+  return (rand () % 9) - 4;
+}
+
+
+int
+main (void)
+{
+  int x, y, xd, yd;
+  int bat0, dbat0;
+  int bat1, dbat1;
+  int score = 0;
+  int serve = 0;
+  int i;
+
+  printf ("Working...\n");
+
+  srand (12392184);
+
+  bat0 = GPU_HEIGHT / 2;
+  bat1 = GPU_HEIGHT / 2;
+
+  load_sprite ();
+
+  for (;;)
+    {
+      xd = x_speed ();
+      yd = y_speed ();
+
+      show_score (score);
+
+      if (!serve)
+        {
+          x = 1;
+          y = bat0;
+          dbat0 = GPU_HEIGHT / 2;
+          dbat1 = find_intersection (x + xd, y + yd, xd, yd, GPU_WIDTH - 1);
+        }
+      else
+        {
+          x = GPU_WIDTH - 2;
+          y = bat1;
+          yd = -yd;
+          dbat0 = find_intersection (x + xd, y + yd, xd, yd, 0);
+          dbat1 = GPU_HEIGHT / 2;
+        }
+      serve = !serve;
+
+      for (;;)
+        {
+          x += xd;
+          y += yd;
+
+
+          if (squish (&y, 0, GPU_HEIGHT))
+            yd = -yd;
+
+          if (squish (&x, 0, GPU_WIDTH))
+            {
+              xd = x_speed ();
+              if (x)
+                xd = -xd;
+              yd = y_speed ();
+
+              if (x)
+                {
+
+                  if (has_missed (y, bat1))
+                    {
+                      score++;
+                      break;
+                    }
+                  dbat0 = find_intersection (x + xd, y + yd, xd, yd, 0);
+                  dbat1 = GPU_HEIGHT / 2;
+
+                }
+              else
+                {
+
+                  if (has_missed (y, bat0))
+                    {
+                      score--;
+                      break;
+                    }
+                  dbat0 = GPU_HEIGHT / 2;
+                  dbat1 =
+                    find_intersection (x + xd, y + yd, xd, yd, GPU_WIDTH - 1);
+
+                }
+            }
+
+          move_bat (&bat0, dbat0);
+          move_bat (&bat1, dbat1);
+
+          update_gpu (x, y, bat0, bat1);
+
+          msleep (2);
+        }
+
+      if (!serve)
+        {
+          dbat1 = GPU_HEIGHT / 2;
+          dbat0 = bat0;
+        }
+      else
+        {
+          dbat0 = GPU_HEIGHT / 2;
+          dbat1 = bat1;
+        }
+
+      for (i = 0; i < 200; ++i)
+        {
+          if (i == 100)
+            show_score (score);
+
+          move_bat (&bat0, dbat0);
+          move_bat (&bat1, dbat1);
+
+          update_gpu (x, y, bat0, bat1);
+          msleep (2);
+
+        }
+    }
+}
-- 
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