/******************************************************************************
*
* project name:   TICT Tutorial S2P1
* file name:      scaler.c
* initial date:   21/02/2001  (TiCT's first Anniversary ;-)
* author:         thomas.nussbaumer@gmx.net
*
* description:    Demonstration of Texturing Vertical Strips Algorithm
*
* NOTE: This is no raycaster nor is this program capable of rendering
*       images for realtime 3D. Its just a "proof of concept" program for
*       the strips texturing and may be improved heavily. Nevertheless
*       it demonstrates the idea quite well.
*
* $Id: scaler.c,v 1.1 2001/02/22 19:58:28 Thomas Nussbaumer Exp $
*
******************************************************************************/

#define SAVE_SCREEN
#define OPTIMIZE_ROM_CALLS

#include <tigcclib.h>

short _ti92plus;
short _ti89;

//-----------------------------------------------------------------------------
// 64x64 pixels texture (2 planes ==> 4 grays)
//
// converted from BMP to BIN with ImageStudio and converted to hex array
// with TTBin2Hex from TIGCC Tools Suite
//-----------------------------------------------------------------------------
unsigned char wall[2][64*8] = {{
0x00,0x00,0x00,0x34,0x00,0x9f,0xfc,0x00,0x00,0x00,0x00,0x73,0xff,0xb8,0x01,0xff,
0x01,0x00,0x00,0xba,0xaf,0xb8,0x06,0x00,0x09,0x0f,0xff,0x3a,0xff,0x38,0x00,0x00,
0xf9,0x0f,0xfb,0x3d,0xfe,0x38,0xff,0xff,0xf9,0xcf,0xfb,0x39,0xb0,0xf9,0xff,0x7d,
0xb9,0xcf,0xef,0x39,0xf0,0xf9,0xed,0xbb,0xf7,0xcf,0xef,0x3c,0x3f,0xf8,0xea,0xad,
0xf7,0xee,0xeb,0x3f,0xff,0xf8,0x5e,0xfe,0x0f,0xef,0x57,0x3f,0xff,0xfc,0x5e,0x00,
0x0f,0xce,0x35,0x3f,0x80,0x15,0x00,0x7f,0xff,0xc2,0x39,0x3c,0x40,0x96,0x1f,0xff,
0xff,0xe2,0x69,0x3e,0x10,0xbd,0xff,0xff,0xff,0xf7,0x26,0x3e,0x2f,0x3f,0xff,0xff,
0xff,0xe7,0xd7,0x3e,0xd0,0xbf,0xff,0xff,0x00,0xe7,0x75,0x3e,0xb0,0xb9,0xb0,0x00,
0xfe,0xdb,0x24,0x3e,0xff,0x38,0x68,0x00,0x46,0xd7,0xd4,0x3e,0xce,0x38,0xe0,0x00,
0xfe,0xf6,0xc0,0x7f,0x81,0xf9,0x73,0xff,0xfe,0xe8,0x1b,0xfe,0x1f,0xf3,0x77,0xf3,
0xfe,0xef,0xff,0xfc,0xff,0xf3,0x77,0xf3,0xc6,0xef,0xff,0xfe,0x7f,0xfb,0x67,0xfb,
0x0f,0xe0,0xff,0x03,0x9e,0x63,0x67,0xf1,0x09,0xf0,0x76,0x80,0x01,0x63,0x67,0xe3,
0xf1,0xe7,0xfa,0x0d,0x0e,0xe7,0x6a,0x0a,0x81,0xef,0xff,0x37,0xf0,0xe7,0x71,0xc0,
0x0f,0xef,0xaf,0x73,0x30,0xe7,0x5f,0xff,0xff,0xed,0xcf,0x3c,0x3e,0xe6,0x5f,0xff,
0xff,0xed,0xcf,0x50,0x4e,0xe7,0x5f,0xff,0x8f,0x2a,0x8f,0x40,0x40,0xe7,0x5c,0x07,
0x40,0xec,0x4e,0x2a,0x0e,0xe1,0x73,0x3e,0x0f,0xee,0x6e,0x20,0x50,0xe6,0x62,0x06,
0x78,0xeb,0x46,0xb8,0x11,0xe6,0x6d,0xfb,0x76,0xef,0x66,0x14,0xaf,0xe5,0x6b,0x2b,
0x77,0xe2,0xe7,0x12,0x7f,0xe6,0x6f,0xbb,0x7f,0xe3,0xc7,0x15,0x41,0xe9,0xff,0xdb,
0x7f,0xe3,0x27,0x50,0x3f,0xef,0xe4,0x03,0x7e,0xf5,0xa7,0x33,0xff,0xef,0xff,0xff,
0x4f,0xe7,0xa7,0xff,0xff,0xef,0xff,0xff,0x7f,0xe7,0x67,0xff,0xff,0xe0,0x00,0x03,
0x7f,0x36,0x67,0x80,0x00,0x0f,0xff,0xfa,0x7f,0x35,0x27,0xbf,0xff,0xc0,0x00,0x0b,
0x7f,0x36,0xa7,0x80,0x00,0x00,0x00,0x03,0x7e,0x36,0xa7,0x80,0x00,0x07,0xff,0xf3,
0x78,0x37,0xc7,0x8f,0xff,0xfe,0xfb,0xf3,0xf0,0xf5,0xc7,0x82,0xbf,0xfe,0xbf,0xf3,
0xf0,0xfe,0x87,0xc6,0xaf,0x79,0x99,0x53,0xf0,0xf0,0x07,0xe7,0x4f,0x7b,0xd0,0xc3,
0xff,0xf7,0xff,0xe5,0xee,0x7f,0x44,0xc3,0xff,0xff,0xff,0xcc,0xb1,0x54,0x56,0x43,
0x81,0xff,0xff,0xc0,0x01,0x00,0x52,0x03,0xc6,0x1f,0xff,0xdf,0xf0,0x00,0x00,0x07,
0x80,0x20,0x03,0xdf,0xff,0xff,0xff,0xff,0xb8,0x00,0x1f,0x00,0xff,0xff,0xff,0xff,
0xbf,0xc0,0x00,0x06,0xff,0xff,0xff,0xff,0xb9,0xd7,0x6b,0x82,0xd0,0x7f,0xff,0xfe,
0xbf,0xfa,0x25,0x5c,0xfe,0xc1,0x00,0x06,0xb9,0xf9,0x15,0x5c,0xf1,0x09,0x00,0x3a,
0x80,0x00,0x00,0x03,0xf1,0xfa,0x7f,0xf2,0xbf,0xff,0xff,0xff,0xff,0xd2,0xbf,0xea,
0xff,0xff,0xff,0xff,0xff,0x82,0xff,0xe2,0x7f,0xff,0xff,0xff,0xf1,0xfe,0x7f,0xfe,
0x0f,0xff,0xff,0xff,0xf0,0x7e,0x7f,0xfe,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff
},{
0xff,0xc0,0x00,0x38,0x00,0x7f,0xff,0xff,0xff,0xc0,0x00,0x38,0x00,0x7f,0xff,0xff,
0xff,0xc0,0x00,0x71,0x50,0x7c,0x01,0xff,0x07,0xc0,0x00,0xf1,0x00,0xfc,0x00,0x00,
0x07,0xc0,0x04,0xfa,0x01,0xfc,0x00,0x00,0x07,0xc0,0x04,0xfe,0x4f,0xfc,0x00,0x82,
0x47,0xc0,0x10,0xfe,0x0f,0xfc,0x12,0x44,0x0f,0xc0,0x10,0xff,0xff,0xfc,0x15,0x52,
0x0f,0xc1,0x14,0xff,0xff,0xfc,0xa1,0x01,0xff,0xc0,0xa8,0xff,0xff,0xfc,0xa1,0xff,
0xff,0xe1,0xca,0xff,0xff,0xfc,0xff,0xff,0xff,0xe5,0xc6,0xff,0x80,0x7d,0xff,0xff,
0xff,0xe5,0x96,0xfc,0x00,0x7f,0xff,0xff,0xff,0xe0,0xd9,0xfc,0x10,0xff,0xff,0xff,
0xff,0xf0,0x28,0xfc,0x2f,0x7f,0xff,0xff,0xff,0xf0,0x8a,0xfc,0x4f,0x7e,0x7f,0xff,
0x01,0xf0,0xdb,0xfc,0x00,0xfc,0x70,0x00,0x01,0xf8,0x2b,0xfc,0x31,0xf8,0x70,0x00,
0x01,0xf9,0x3f,0xfc,0x7f,0xf8,0xe0,0x00,0x01,0xff,0xff,0xfd,0xff,0xf8,0xe0,0x0c,
0x01,0xff,0xff,0xff,0xff,0xf8,0xe0,0x0c,0x39,0xff,0xff,0xff,0xff,0xf0,0xf0,0x04,
0xf1,0xff,0xff,0xfc,0x01,0xf0,0xf0,0x0e,0xf7,0xe0,0x0f,0x00,0x00,0xf0,0xf0,0x1c,
0x0f,0xe0,0x0f,0x00,0x01,0xf0,0xf5,0xf5,0x7f,0xe0,0x0e,0x08,0x0f,0xf0,0xff,0xff,
0xff,0xe0,0x5e,0x0c,0xcf,0xf0,0xff,0xff,0xff,0xe2,0x3e,0x43,0xc1,0xf1,0xff,0xff,
0xff,0xe2,0x3e,0x2f,0xb1,0xf0,0xff,0xff,0xf0,0xe5,0x7e,0x3f,0xbf,0xf0,0xff,0xff,
0x80,0x23,0xbf,0x15,0xf1,0xf6,0xe0,0xff,0x80,0x21,0x9f,0x1f,0xaf,0xf1,0xec,0x03,
0x87,0x24,0xbf,0x07,0xef,0xf1,0xe2,0x07,0x89,0x20,0x9f,0x8b,0x51,0xf2,0xe4,0xd7,
0x88,0x25,0x1f,0x8d,0x81,0xf1,0xe0,0x47,0x80,0x24,0x3f,0x8a,0xbf,0xf7,0xe0,0x27,
0x80,0x24,0xdf,0x8f,0xff,0xff,0xff,0xff,0x81,0x22,0x5f,0xcf,0xff,0xff,0xff,0xff,
0xb0,0x30,0x5f,0xff,0xff,0xff,0xff,0xff,0x80,0x30,0x9f,0xff,0xff,0xff,0xff,0xff,
0x80,0xf1,0x9f,0xff,0xff,0xf0,0x00,0x07,0x80,0xf2,0xdf,0xc0,0x00,0x00,0x00,0x07,
0x80,0xf1,0x5f,0xc0,0x00,0x00,0x00,0x0f,0x81,0xf1,0x5f,0xc0,0x00,0x00,0x00,0x0f,
0x87,0xf0,0x3f,0xc0,0x00,0x01,0x04,0x0f,0x8f,0xf2,0x3f,0xc5,0x40,0x01,0x40,0x0f,
0x8f,0xf1,0x7f,0xc1,0x50,0x86,0x66,0xaf,0xff,0xff,0xff,0xc0,0xb0,0x84,0x2f,0x3f,
0xff,0xff,0xff,0xc2,0x11,0x80,0xbb,0x3f,0xff,0xff,0xff,0xe3,0x4e,0xab,0xa9,0xbf,
0xff,0xff,0xff,0xff,0xfe,0xff,0xad,0xff,0x81,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
0x80,0x1f,0xff,0xff,0xff,0xff,0xff,0xff,0x80,0x00,0x00,0xff,0xff,0xff,0xff,0xff,
0x80,0x00,0x00,0x01,0xff,0xff,0xff,0xff,0x86,0x28,0x94,0x01,0xff,0xff,0xff,0xff,
0x80,0x05,0xda,0xa3,0xf0,0x3f,0xff,0xff,0x86,0x06,0xea,0xa3,0xf0,0x07,0x00,0x07,
0xff,0xff,0xff,0xff,0xf0,0x07,0x00,0x07,0xff,0xff,0xff,0xff,0xf0,0x2e,0x40,0x17,
0xff,0xff,0xff,0xff,0xff,0xfe,0x00,0x1f,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff}};


//-----------------------------------------------------------------------------
// lookup table to speedup vertical scaling of a texture strip
//
// generated with genlookup.exe (subdirectory tools)
//-----------------------------------------------------------------------------

// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
// NOTE: this is a static definition of an array which consists of arrays of
//       different length. It took my quite a while to figure out how this can
//       be implemented (the correct syntax)
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

unsigned short** lookup_table = (unsigned short *[64]){
(unsigned short [1]){0},
(unsigned short [2]){0,256},
(unsigned short [3]){0,168,176},
(unsigned short [4]){0,128,128,128},
(unsigned short [5]){0,104,104,96,104},
(unsigned short [6]){0,88,80,88,88,80},
(unsigned short [7]){0,72,72,72,80,72,72},
(unsigned short [8]){0,64,64,64,64,64,64,64},
(unsigned short [9]){0,56,56,56,56,64,56,56,56},
(unsigned short [10]){0,48,56,48,56,48,48,56,48,56},
(unsigned short [11]){0,48,48,40,48,48,48,48,48,40,48},
(unsigned short [12]){0,40,48,40,40,48,40,40,48,40,40,48},
(unsigned short [13]){0,40,40,40,40,40,40,32,40,40,40,40,40},
(unsigned short [14]){0,40,32,40,32,40,32,40,40,32,40,32,40,32},
(unsigned short [15]){0,32,40,32,32,32,40,32,32,32,40,32,32,32,40},
(unsigned short [16]){0,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32},
(unsigned short [17]){0,32,32,24,32,32,32,24,32,32,32,24,32,32,32,24,32},
(unsigned short [18]){0,32,24,32,24,32,24,32,24,32,32,24,32,24,32,24,32,24},
(unsigned short [19]){0,24,32,24,24,32,24,32,24,24,32,24,24,32,24,32,24,24,32},
(unsigned short [20]){0,24,24,32,24,24,24,24,32,24,24,24,24,32,24,24,24,24,32,24},
(unsigned short [21]){0,24,24,24,24,24,24,24,24,24,24,32,24,24,24,24,24,24,24,24,24},
(unsigned short [22]){0,24,24,24,24,24,16,24,24,24,24,24,24,24,24,24,24,16,24,24,24,24},
(unsigned short [23]){0,24,24,16,24,24,24,16,24,24,24,24,16,24,24,24,24,16,24,24,24,16,24},
(unsigned short [24]){0,24,16,24,24,16,24,24,16,24,24,16,24,24,16,24,24,16,24,24,16,24,24,16},
(unsigned short [25]){0,24,16,24,16,24,16,24,16,24,24,16,24,16,24,16,24,24,16,24,16,24,16,24,16},
(unsigned short [26]){0,16,24,16,24,16,24,16,24,16,24,16,24,16,16,24,16,24,16,24,16,24,16,24,16,24},
(unsigned short [27]){0,16,24,16,16,24,16,24,16,16,24,16,16,24,16,24,16,16,24,16,16,24,16,24,16,16,24},
(unsigned short [28]){0,16,24,16,16,16,24,16,16,24,16,16,16,24,16,16,24,16,16,16,24,16,16,24,16,16,16,24},
(unsigned short [29]){0,16,16,24,16,16,16,16,24,16,16,16,16,24,16,16,16,24,16,16,16,16,24,16,16,16,16,24,16},
(unsigned short [30]){0,16,16,16,24,16,16,16,16,16,16,16,24,16,16,16,16,16,16,24,16,16,16,16,16,16,16,24,16,16},
(unsigned short [31]){0,16,16,16,16,16,16,16,24,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,24,16,16,16,16,16,16},
(unsigned short [32]){0,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16},
(unsigned short [33]){0,16,16,16,16,16,16,16,16,8,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,8,16,16,16,16,16,16,16},
(unsigned short [34]){0,16,16,16,16,8,16,16,16,16,16,16,16,8,16,16,16,16,16,16,16,16,8,16,16,16,16,16,16,16,8,16,16,16},
(unsigned short [35]){0,16,16,8,16,16,16,16,16,8,16,16,16,16,16,8,16,16,16,16,16,8,16,16,16,16,16,8,16,16,16,16,16,8,16},
(unsigned short [36]){0,16,16,8,16,16,16,8,16,16,16,16,8,16,16,16,8,16,16,16,16,8,16,16,16,8,16,16,16,16,8,16,16,16,8,16},
(unsigned short [37]){0,16,8,16,16,16,8,16,16,16,8,16,16,8,16,16,16,8,16,16,16,8,16,16,16,8,16,16,8,16,16,16,8,16,16,16,8},
(unsigned short [38]){0,16,8,16,16,8,16,16,8,16,16,16,8,16,16,8,16,16,8,16,16,8,16,16,8,16,16,8,16,16,16,8,16,16,8,16,16,8},
(unsigned short [39]){0,16,8,16,16,8,16,8,16,16,8,16,16,8,16,16,8,16,16,8,16,8,16,16,8,16,16,8,16,16,8,16,16,8,16,8,16,16,8},
(unsigned short [40]){0,16,8,16,8,16,16,8,16,8,16,16,8,16,8,16,16,8,16,8,16,16,8,16,8,16,16,8,16,8,16,16,8,16,8,16,16,8,16,8},
(unsigned short [41]){0,16,8,16,8,16,8,16,8,16,16,8,16,8,16,8,16,16,8,16,8,16,8,16,8,16,16,8,16,8,16,8,16,16,8,16,8,16,8,16,8},
(unsigned short [42]){0,16,8,16,8,16,8,16,8,16,8,16,8,16,8,16,8,16,8,16,8,16,16,8,16,8,16,8,16,8,16,8,16,8,16,8,16,8,16,8,16,8},
(unsigned short [43]){0,8,16,8,16,8,16,8,16,8,16,8,16,8,16,8,16,8,16,8,16,8,16,8,16,8,16,8,16,8,16,8,16,8,16,8,16,8,16,8,16,8,16},
(unsigned short [44]){0,8,16,8,16,8,16,8,16,8,16,8,8,16,8,16,8,16,8,16,8,16,8,8,16,8,16,8,16,8,16,8,16,8,8,16,8,16,8,16,8,16,8,16},
(unsigned short [45]){0,8,16,8,16,8,16,8,8,16,8,16,8,8,16,8,16,8,16,8,8,16,8,16,8,16,8,8,16,8,16,8,16,8,8,16,8,16,8,8,16,8,16,8,16},
(unsigned short [46]){0,8,16,8,16,8,8,16,8,16,8,8,16,8,8,16,8,16,8,8,16,8,16,8,8,16,8,16,8,8,16,8,16,8,8,16,8,8,16,8,16,8,8,16,8,16},
(unsigned short [47]){0,8,16,8,8,16,8,16,8,8,16,8,8,16,8,8,16,8,16,8,8,16,8,8,16,8,8,16,8,8,16,8,16,8,8,16,8,8,16,8,8,16,8,16,8,8,16},
(unsigned short [48]){0,8,16,8,8,16,8,8,16,8,8,16,8,8,16,8,8,16,8,8,16,8,8,16,8,8,16,8,8,16,8,8,16,8,8,16,8,8,16,8,8,16,8,8,16,8,8,16},
(unsigned short [49]){0,8,16,8,8,16,8,8,8,16,8,8,16,8,8,16,8,8,16,8,8,8,16,8,8,16,8,8,16,8,8,8,16,8,8,16,8,8,16,8,8,16,8,8,8,16,8,8,16},
(unsigned short [50]){0,8,16,8,8,8,16,8,8,16,8,8,8,16,8,8,8,16,8,8,16,8,8,8,16,8,8,16,8,8,8,16,8,8,16,8,8,8,16,8,8,8,16,8,8,16,8,8,8,16},
(unsigned short [51]){0,8,16,8,8,8,16,8,8,8,16,8,8,8,16,8,8,8,16,8,8,8,16,8,8,8,16,8,8,8,16,8,8,8,16,8,8,8,16,8,8,8,16,8,8,8,16,8,8,8,16},
(unsigned short [52]){0,8,8,16,8,8,8,16,8,8,8,16,8,8,8,8,16,8,8,8,16,8,8,8,16,8,8,8,8,16,8,8,8,16,8,8,8,16,8,8,8,8,16,8,8,8,16,8,8,8,16,8},
(unsigned short [53]){0,8,8,16,8,8,8,8,16,8,8,8,8,16,8,8,8,16,8,8,8,8,16,8,8,8,8,16,8,8,8,8,16,8,8,8,8,16,8,8,8,16,8,8,8,8,16,8,8,8,8,16,8},
(unsigned short [54]){0,8,8,16,8,8,8,8,8,16,8,8,8,8,16,8,8,8,8,16,8,8,8,8,8,16,8,8,8,8,16,8,8,8,8,8,16,8,8,8,8,16,8,8,8,8,16,8,8,8,8,8,16,8},
(unsigned short [55]){0,8,8,8,16,8,8,8,8,8,16,8,8,8,8,8,16,8,8,8,8,8,16,8,8,8,8,8,16,8,8,8,8,8,16,8,8,8,8,8,16,8,8,8,8,8,16,8,8,8,8,8,16,8,8},
(unsigned short [56]){0,8,8,8,16,8,8,8,8,8,8,16,8,8,8,8,8,8,16,8,8,8,8,8,8,16,8,8,8,8,8,8,16,8,8,8,8,8,8,16,8,8,8,8,8,8,16,8,8,8,8,8,8,16,8,8},
(unsigned short [57]){0,8,8,8,8,16,8,8,8,8,8,8,8,16,8,8,8,8,8,8,8,16,8,8,8,8,8,8,8,16,8,8,8,8,8,8,8,16,8,8,8,8,8,8,8,16,8,8,8,8,8,8,8,16,8,8,8},
(unsigned short [58]){0,8,8,8,8,16,8,8,8,8,8,8,8,8,8,16,8,8,8,8,8,8,8,8,8,16,8,8,8,8,8,8,8,8,16,8,8,8,8,8,8,8,8,8,16,8,8,8,8,8,8,8,8,8,16,8,8,8},
(unsigned short [59]){0,8,8,8,8,8,16,8,8,8,8,8,8,8,8,8,8,8,16,8,8,8,8,8,8,8,8,8,8,8,16,8,8,8,8,8,8,8,8,8,8,8,16,8,8,8,8,8,8,8,8,8,8,8,16,8,8,8,8},
(unsigned short [60]){0,8,8,8,8,8,8,8,16,8,8,8,8,8,8,8,8,8,8,8,8,8,8,16,8,8,8,8,8,8,8,8,8,8,8,8,8,8,16,8,8,8,8,8,8,8,8,8,8,8,8,8,8,16,8,8,8,8,8,8},
(unsigned short [61]){0,8,8,8,8,8,8,8,8,8,8,16,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,16,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,16,8,8,8,8,8,8,8,8,8},
(unsigned short [62]){0,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,16,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,16,8,8,8,8,8,8,8,8,8,8,8,8,8,8},
(unsigned short [63]){0,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,16,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8},
(unsigned short [64]){0,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8}
};


unsigned char* backbuffer0 = NULL;   // address to backbuffer for lightgray plane
unsigned char* backbuffer1 = NULL;   // address to backbuffer for darkgray plane
short          display_offset = 0;   // used to center the image on a TI-92plus


//=============================================================================
// draws a single strip ...
//=============================================================================
void RenderStrip(short dest_height,short dest_x,short dest_y,short texture_x) {
    unsigned short* ytable       = lookup_table[dest_height-1];  // fetch lookup table which corresponds to given height
    unsigned char   texture_mask = 0x80 >> (texture_x & 7);      // generate bitmask for texture
    unsigned char   screenx_mask = 0x80 >> (dest_x & 7);         // generate bitmask for display
    unsigned char*  dest0        = backbuffer0+dest_y*30+(dest_x>>3)+display_offset; // byte position in display
    unsigned char*  dest1        = backbuffer1+dest_y*30+(dest_x>>3)+display_offset;
    unsigned char*  src0         = wall[0]+(texture_x>>3);       // byte position in texture
    unsigned char*  src1         = wall[1]+(texture_x>>3);

    short i;

    for (i=0;i<dest_height;i++,dest0+=30,dest1+=30) {
        src0 += *ytable;
        src1 += *ytable++;
        // if bit is set in texture -> set it on screen, too
        if ((*src0) & texture_mask) *dest0 |= screenx_mask;
        if ((*src1) & texture_mask) *dest1 |= screenx_mask;
    }
}


//----------------------------------------------------------------------------
// structure which defines a wall
//----------------------------------------------------------------------------
typedef struct {
    short height_left;   // height at the left side
    short height_right;  // height at the right side
    short start_x;       // screen x position where the wall starts
    short end_x;         // screen x position where the wall ends
} WALL_T;


//=============================================================================
// draw a single wall
//
// NOTE: this function still uses floating point operations which make
//       the rendering slow.
//=============================================================================
void DrawWall(WALL_T* wt) {
    short           hdiff        = wt->height_right-wt->height_left;
    short           width        = wt->end_x - wt->start_x;
    float           hdelta       = (float)hdiff/(float)(width);
    float           height       = wt->height_left;

    unsigned short* xtable   = lookup_table[width-1];
    unsigned short  xtexture = 0;
    short           x;

    for (x=wt->start_x; x<wt->end_x; x++) {
        unsigned short tmp_h = (unsigned short)height;
        xtexture += (*xtable++)/8;
        RenderStrip(tmp_h,x,48-(tmp_h>>1),xtexture);
        height += hdelta;
    }

}


//=============================================================================
// draw some walls ...
//=============================================================================
void DrawSomeWalls(void) {
    WALL_T wt[5] = {
        {64,64,0,32},{64,20,32,64},{20,20,64,84},{20,64,84,116},{64,64,116,159}};

    int i;
    memset(backbuffer0,0,LCD_SIZE*2);
    for (i=0;i<5;i++) DrawWall(&wt[i]);
    memcpy(GetPlane(0),backbuffer0,LCD_SIZE);
    memcpy(GetPlane(1),backbuffer1,LCD_SIZE);
}

//=============================================================================
// where all the fun starts ...
//=============================================================================
void _main(void) {
    LCD_BUFFER lcdbuffer; // we are not using SAVE_SCREEN, because we want put
                          // messages into into the statusline in some cases
    int i,j;

    //-------------------------------------------------------------------------
    // allocate memory for 2 planes for double buffering in one piece !!
    //-------------------------------------------------------------------------
    if (!(backbuffer0 = malloc(LCD_SIZE*2))) {
        ST_showHelp("ERR: out of mem");
        return;
    }
    backbuffer1 = backbuffer0 + LCD_SIZE; // the start address of the second
                                          // plane LCD_SIZE bytes apart from
                                          // the first plane

    //-------------------------------------------------------------------------
    // setup the display offset for TI-92p calculators
    // the output image should be centered on these calcs
    //-------------------------------------------------------------------------
    if (TI89) display_offset = 0;
    else      display_offset = 4 + 14*30;

    //-------------------------------------------------------------------------
    // save original screen content and turn on grayscale graphics
    //-------------------------------------------------------------------------
    LCD_save(lcdbuffer);

    if (!GrayMode(GRAY_ON)) {
        free(backbuffer0);
        return;
    }

    memcpy(GetPlane(0),lcdbuffer,LCD_SIZE);
    DrawSomeWalls();

    FontSetSys(F_6x8);
    for (i=0;i<2;i++) {
        SetPlane(i);
        if (TI89) DrawStrXY(4,90,"Tutorial S2P1 - TiCT 2001",A_REPLACE);
        else      DrawStrXY(4+4*8,90+14,"Tutorial S2P1 - TiCT 2001",A_REPLACE);
    }

    ngetchx();

    //-------------------------------------------------------------------------
    // turn graymode off, free backbuffer and restore previous screen content
    //-------------------------------------------------------------------------
    GrayMode(GRAY_OFF);
    free(backbuffer0);
    LCD_restore(lcdbuffer);
}


//#############################################################################
// Revision History
//#############################################################################
//
// $Log: scaler.c,v $
// Revision 1.1  2001/02/22 19:58:28  Thomas Nussbaumer
// initial version
//
//