rockbox/apps/plugins/sdl/progs/wolf3d/wl_floorceiling.c
Franklin Wei 3f59fc8b77 Wolfenstein 3-D!
This is a port of Wolf4SDL, which is derived from the original id
software source release. The port runs on top of the SDL plugin
runtime and is loaded as an overlay.

Licensing of the game code is not an issue, as discussed below
(essentially, the Debian project treats Wolf4SDL as GPLv2, with an
email from John Carmack backing it up):

  http://forums.rockbox.org/index.php?topic=52872

Included is a copy of MAME's Yamaha OPL sound chip emulator
(fmopl_gpl.c).  This file was not part of the original Wolf4SDL source
(which includes a non-GPL'd version), but was rather rebased from from
a later MAME source which had been relicensed to GPLv2.

Change-Id: I64c2ba035e0be7e2f49252f40640641416613439
2019-07-09 11:20:55 -04:00

87 lines
3.4 KiB
C

#include "version.h"
#ifdef USE_FLOORCEILINGTEX
#include "wl_def.h"
#include "wl_shade.h"
// Textured Floor and Ceiling by DarkOne
// With multi-textured floors and ceilings stored in lower and upper bytes of
// according tile in third mapplane, respectively.
void DrawFloorAndCeiling(byte *vbuf, unsigned vbufPitch, int min_wallheight)
{
fixed dist; // distance to row projection
fixed tex_step; // global step per one screen pixel
fixed gu, gv, du, dv; // global texture coordinates
int u, v; // local texture coordinates
byte *toptex, *bottex;
unsigned lasttoptex = 0xffffffff, lastbottex = 0xffffffff;
int halfheight = viewheight >> 1;
int y0 = min_wallheight >> 3; // starting y value
if(y0 > halfheight)
return; // view obscured by walls
if(!y0) y0 = 1; // don't let division by zero
unsigned bot_offset0 = vbufPitch * (halfheight + y0);
unsigned top_offset0 = vbufPitch * (halfheight - y0 - 1);
// draw horizontal lines
for(int y = y0, bot_offset = bot_offset0, top_offset = top_offset0;
y < halfheight; y++, bot_offset += vbufPitch, top_offset -= vbufPitch)
{
dist = (heightnumerator / (y + 1)) << 5;
gu = viewx + FixedMul(dist, viewcos);
gv = -viewy + FixedMul(dist, viewsin);
tex_step = (dist << 8) / viewwidth / 175;
du = FixedMul(tex_step, viewsin);
dv = -FixedMul(tex_step, viewcos);
gu -= (viewwidth >> 1) * du;
gv -= (viewwidth >> 1) * dv; // starting point (leftmost)
#ifdef USE_SHADING
byte *curshades = shadetable[GetShade(y << 3)];
#endif
for(int x = 0, bot_add = bot_offset, top_add = top_offset;
x < viewwidth; x++, bot_add++, top_add++)
{
if(wallheight[x] >> 3 <= y)
{
int curx = (gu >> TILESHIFT) & (MAPSIZE - 1);
int cury = (-(gv >> TILESHIFT) - 1) & (MAPSIZE - 1);
unsigned curtex = MAPSPOT(curx, cury, 2);
if(curtex)
{
unsigned curtoptex = curtex >> 8;
if (curtoptex != lasttoptex)
{
lasttoptex = curtoptex;
toptex = PM_GetTexture(curtoptex);
}
unsigned curbottex = curtex & 0xff;
if (curbottex != lastbottex)
{
lastbottex = curbottex;
bottex = PM_GetTexture(curbottex);
}
u = (gu >> (TILESHIFT - TEXTURESHIFT)) & (TEXTURESIZE - 1);
v = (gv >> (TILESHIFT - TEXTURESHIFT)) & (TEXTURESIZE - 1);
unsigned texoffs = (u << TEXTURESHIFT) + (TEXTURESIZE - 1) - v;
#ifdef USE_SHADING
if(curtoptex)
vbuf[top_add] = curshades[toptex[texoffs]];
if(curbottex)
vbuf[bot_add] = curshades[bottex[texoffs]];
#else
if(curtoptex)
vbuf[top_add] = toptex[texoffs];
if(curbottex)
vbuf[bot_add] = bottex[texoffs];
#endif
}
}
gu += du;
gv += dv;
}
}
}
#endif