The-Powder-Toy/src/air.c
2010-10-04 00:29:37 -04:00

142 lines
4.2 KiB
C

#include <math.h>
#include <air.h>
#include <powder.h>
#include <defines.h>
float kernel[9];
float vx[YRES/CELL][XRES/CELL], ovx[YRES/CELL][XRES/CELL];
float vy[YRES/CELL][XRES/CELL], ovy[YRES/CELL][XRES/CELL];
float pv[YRES/CELL][XRES/CELL], opv[YRES/CELL][XRES/CELL];
float cb_vx[YRES/CELL][XRES/CELL], cb_ovx[YRES/CELL][XRES/CELL];
float cb_vy[YRES/CELL][XRES/CELL], cb_ovy[YRES/CELL][XRES/CELL];
float cb_pv[YRES/CELL][XRES/CELL], cb_opv[YRES/CELL][XRES/CELL];
float fvx[YRES/CELL][XRES/CELL], fvy[YRES/CELL][XRES/CELL];
void make_kernel(void)
{
int i, j;
float s = 0.0f;
for(j=-1; j<2; j++)
for(i=-1; i<2; i++)
{
kernel[(i+1)+3*(j+1)] = expf(-2.0f*(i*i+j*j));
s += kernel[(i+1)+3*(j+1)];
}
s = 1.0f / s;
for(j=-1; j<2; j++)
for(i=-1; i<2; i++)
kernel[(i+1)+3*(j+1)] *= s;
}
void update_air(void)
{
int x, y, i, j;
float dp, dx, dy, f, tx, ty;
for(y=1; y<YRES/CELL; y++)
for(x=1; x<XRES/CELL; x++)
{
dp = 0.0f;
dp += vx[y][x-1] - vx[y][x];
dp += vy[y-1][x] - vy[y][x];
pv[y][x] *= PLOSS;
pv[y][x] += dp*TSTEPP;
}
for(y=0; y<YRES/CELL-1; y++)
for(x=0; x<XRES/CELL-1; x++)
{
dx = dy = 0.0f;
dx += pv[y][x] - pv[y][x+1];
dy += pv[y][x] - pv[y+1][x];
vx[y][x] *= VLOSS;
vy[y][x] *= VLOSS;
vx[y][x] += dx*TSTEPV;
vy[y][x] += dy*TSTEPV;
if(bmap[y][x]==1 || bmap[y][x+1]==1 ||
bmap[y][x]==8 || bmap[y][x+1]==8 ||
(bmap[y][x]==7 && !emap[y][x]) ||
(bmap[y][x+1]==7 && !emap[y][x+1]))
vx[y][x] = 0;
if(bmap[y][x]==1 || bmap[y+1][x]==1 ||
bmap[y][x]==8 || bmap[y+1][x]==8 ||
(bmap[y][x]==7 && !emap[y][x]) ||
(bmap[y+1][x]==7 && !emap[y+1][x]))
vy[y][x] = 0;
}
for(y=0; y<YRES/CELL; y++)
for(x=0; x<XRES/CELL; x++)
{
dx = 0.0f;
dy = 0.0f;
dp = 0.0f;
for(j=-1; j<2; j++)
for(i=-1; i<2; i++)
if(y+j>0 && y+j<YRES/CELL-1 &&
x+i>0 && x+i<XRES/CELL-1 &&
bmap[y+j][x+i]!=1 &&
bmap[y+j][x+i]!=8 &&
(bmap[y+j][x+i]!=7 || emap[y+j][x+i]))
{
f = kernel[i+1+(j+1)*3];
dx += vx[y+j][x+i]*f;
dy += vy[y+j][x+i]*f;
dp += pv[y+j][x+i]*f;
}
else
{
f = kernel[i+1+(j+1)*3];
dx += vx[y][x]*f;
dy += vy[y][x]*f;
dp += pv[y][x]*f;
}
tx = x - dx*0.7f;
ty = y - dy*0.7f;
i = (int)tx;
j = (int)ty;
tx -= i;
ty -= j;
if(i>=2 && i<XRES/CELL-3 &&
j>=2 && j<YRES/CELL-3)
{
dx *= 1.0f - VADV;
dy *= 1.0f - VADV;
dx += VADV*(1.0f-tx)*(1.0f-ty)*vx[j][i];
dy += VADV*(1.0f-tx)*(1.0f-ty)*vy[j][i];
dx += VADV*tx*(1.0f-ty)*vx[j][i+1];
dy += VADV*tx*(1.0f-ty)*vy[j][i+1];
dx += VADV*(1.0f-tx)*ty*vx[j+1][i];
dy += VADV*(1.0f-tx)*ty*vy[j+1][i];
dx += VADV*tx*ty*vx[j+1][i+1];
dy += VADV*tx*ty*vy[j+1][i+1];
}
if(bmap[y][x] == 4)
{
dx += fvx[y][x];
dy += fvy[y][x];
}
if(dp > 256.0f) dp = 256.0f;
if(dp < -256.0f) dp = -256.0f;
if(dx > 256.0f) dx = 256.0f;
if(dx < -256.0f) dx = -256.0f;
if(dy > 256.0f) dy = 256.0f;
if(dy < -256.0f) dy = -256.0f;
ovx[y][x] = dx;
ovy[y][x] = dy;
opv[y][x] = dp;
}
memcpy(vx, ovx, sizeof(vx));
memcpy(vy, ovy, sizeof(vy));
memcpy(pv, opv, sizeof(pv));
}