kolibrios-fun/contrib/games/wolf3d/wl_floorceiling.cpp

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#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