[WIP] XRacer - a racing gamexracer

Plan:
-----

A simple racing game like Pole Position or Enduro.

Status:
-------
 - Currently generates a random road and scrolls through it
 - Random road generation (curves and hills)
 - Supports loading of maps from a file ("/output.xrm")
 - Sample map at http://a.pomf.se/ynhlwq.xrm

Todo:
-----
 - Convert to fixed-point math in all places (only one place left!)
 - Improve/fix track looping
 - Improve random road generation to start and end at the same height
 - Finish sprite code
 - Make sprites
 - Game-ify!

What's new:
-----------
 - NEW: uses greylib on low-depth targets!
 - Loadable maps implemented, UNTESTED!
 - Sprites in progress (see render() in graphics.c)

Change-Id: Ia2ff60b3c43d9f2e3a4f63e0ad90d2cb571c605e

1 files changed, 66 insertions, 0 deletions

diff --git a/apps/plugins/xracer/util.h b/apps/plugins/xracer/util.h
new file mode 100644
index 0000000..2112c88
--- /dev/null
+++ b/apps/plugins/xracer/util.h
@@ -0,0 +1,66 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2015 Franklin Wei
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ***************************************************************************/
+
+#include <stdint.h>
+
+#include "xracer.h"
+#include "fixedpoint.h"
+
+/* finds the address of a segment corresponding to a z coordinate */
+#define FIND_SEGMENT(z, r, l) (&r[(int)((float)z/SEGMENT_LENGTH)%l])
+
+/* linearly interpolates a and b with percent having FRACBITS fractional bits */
+#define INTERPOLATE(a, b, percent) (((a << FRACBITS) + fp_mul((b<<FRACBITS)-(a<<FRACBITS), percent, FRACBITS)) >> FRACBITS)
+
+/* rounds a fixed-point number with FRACBITS fractional bits */
+/* returns an integer */
+/* adds 1/2 and truncates the fractional bits */
+#define ROUND(x) ((x+(1<<(FRACBITS-1)))>>FRACBITS)
+
+#ifdef ROCKBOX_LITTLE_ENDIAN
+#define READ_BE_UINT16(p) ((((const uint8_t*)p)[0] << 8) | ((const uint8_t*)p)[1])
+#define READ_BE_UINT32(p) ((((const uint8_t*)p)[0] << 24) | (((const uint8_t*)p)[1] << 16) | (((const uint8_t*)p)[2] << 8) | ((const uint8_t*)p)[3])
+#else
+#define READ_BE_UINT16(p) (*(const uint16_t*)p)
+#define READ_BE_UINT32(p) (*(const uint32_t*)p)
+#endif
+
+/* call this before using any alloc functions or the plugin buffer */
+void init_alloc(void);
+
+void *util_alloc(size_t);
+
+size_t util_alloc_remaining(void);
+
+/* camera_calc_depth(): calculates the camera depth given its FOV by evaluating */
+/* LCD_WIDTH / tan(fov/2) */
+int camera_calc_depth(int fov);
+
+void warning_real(const char *msg, ...);
+
+void error_real(const char *msg, ...);
+
+unsigned short crc16_ccitt(unsigned char *data, size_t length, unsigned short seed, unsigned short final);
+
+#define warning warning_real
+#define error error_real
+/*#define warning(msg, ...) warning_real("in function %s at %s:%d: %s", __func__, __FILE__, __LINE__, msg, ##__VA_ARGS__)
+  #define error(msg, ...) error_real("in function %s at %s:%d: %s", __func__, __FILE__, __LINE__, msg, ##__VA_ARGS__)*/