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// worldocull.cpp: occlusion map and occlusion test
#include "cube.h"
#define NUMRAYS 512
float rdist[NUMRAYS];
bool ocull = true;
float odist = 256;
void toggleocull() { ocull = !ocull; };
// constructs occlusion map: cast rays in all directions on the 2d plane and record distance.
// done exactly once per frame.
void computeraytable(float vx, float vy)
if(!ocull) return;
odist = getvar("fog")*1.5f;
float apitch = (float)fabs(player1->pitch);
float af = getvar("fov")/2+apitch/1.5f+3;
float byaw = (player1->yaw-90+af)/360*PI2;
float syaw = (player1->yaw-90-af)/360*PI2;
loopi(NUMRAYS)
{
float angle = i*PI2/NUMRAYS;
if((apitch>45 // must be bigger if fov>120
|| (angle<byaw && angle>syaw)
|| (angle<byaw-PI2 && angle>syaw-PI2)
|| (angle<byaw+PI2 && angle>syaw+PI2))
&& !OUTBORD(vx, vy)
&& !SOLID(S(fast_f2nat(vx), fast_f2nat(vy)))) // try to avoid tracing ray if outside of frustrum
{
float ray = i*8/(float)NUMRAYS;
float dx, dy;
if(ray>1 && ray<3) { dx = -(ray-2); dy = 1; }
else if(ray>=3 && ray<5) { dx = -1; dy = -(ray-4); }
else if(ray>=5 && ray<7) { dx = ray-6; dy = -1; }
else { dx = 1; dy = ray>4 ? ray-8 : ray; };
float sx = vx;
float sy = vy;
for(;;)
{
sx += dx;
sy += dy;
if(SOLID(S(fast_f2nat(sx), fast_f2nat(sy)))) // 90% of time spend in this function is on this line
{
rdist[i] = (float)(fabs(sx-vx)+fabs(sy-vy));
break;
};
};
}
else
{
rdist[i] = 2;
};
};
// test occlusion for a cube... one of the most computationally expensive functions in the engine
// as its done for every cube and entity, but its effect is more than worth it!
inline float ca(float x, float y) { return x>y ? y/x : 2-x/y; };
inline float ma(float x, float y) { return x==0 ? (y>0 ? 2 : -2) : y/x; };
int isoccluded(float vx, float vy, float cx, float cy, float csize) // v = viewer, c = cube to test
{
if(!ocull) return 0;
float nx = vx, ny = vy; // n = point on the border of the cube that is closest to v
if(nx<cx) nx = cx;
else if(nx>cx+csize) nx = cx+csize;
if(ny<cy) ny = cy;
else if(ny>cy+csize) ny = cy+csize;
float xdist = (float)fabs(nx-vx);
float ydist = (float)fabs(ny-vy);
if(xdist>odist || ydist>odist) return 2;
float dist = xdist+ydist-1; // 1 needed?
// ABC
// D E
// FGH
// - check middle cube? BG
// find highest and lowest angle in the occlusion map that this cube spans, based on its most left and right
// points on the border from the viewer pov... I see no easier way to do this than this silly code below
float h, l;
if(cx<=vx) // ABDFG
{
if(cx+csize<vx) // ADF
{
if(cy<=vy) // AD
{
if(cy+csize<vy) { h = ca(-(cx-vx), -(cy+csize-vy))+4; l = ca(-(cx+csize-vx), -(cy-vy))+4; } // A
else { h = ma(-(cx+csize-vx), -(cy+csize-vy))+4; l = ma(-(cx+csize-vx), -(cy-vy))+4; } // D
}
else { h = ca(cy+csize-vy, -(cx+csize-vx))+2; l = ca(cy-vy, -(cx-vx))+2; }; // F
}
else // BG
{
if(cy<=vy)
{
if(cy+csize<vy) { h = ma(-(cy+csize-vy), cx-vx)+6; l = ma(-(cy+csize-vy), cx+csize-vx)+6; } // B
else return 0;
}
else { h = ma(cy-vy, -(cx+csize-vx))+2; l = ma(cy-vy, -(cx-vx))+2; }; // G
};
}
else // CEH
{
if(cy<=vy) // CE
{
if(cy+csize<vy) { h = ca(-(cy-vy), cx-vx)+6; l = ca(-(cy+csize-vy), cx+csize-vx)+6; } // C
else { h = ma(cx-vx, cy-vy); l = ma(cx-vx, cy+csize-vy); }; // E
}
else { h = ca(cx+csize-vx, cy-vy); l = ca(cx-vx, cy+csize-vy); }; // H
};
int si = fast_f2nat(h*(NUMRAYS/8))+NUMRAYS; // get indexes into occlusion map from angles
int ei = fast_f2nat(l*(NUMRAYS/8))+NUMRAYS+1;
if(ei<=si) ei += NUMRAYS;
for(int i = si; i<=ei; i++)
{
if(dist<rdist[i&(NUMRAYS-1)]) return 0; // if any value in this segment of the occlusion map is further away then cube is not occluded
};
return 1; // cube is entirely occluded
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// worldocull.cpp: occlusion map and occlusion test
#include "cube.h"
#define NUMRAYS 512
float rdist[NUMRAYS];
bool ocull = true;
float odist = 256;
void
toggleocull()
{
ocull = !ocull;
};
COMMAND(toggleocull, ARG_NONE);
// constructs occlusion map: cast rays in all directions on the 2d plane and
// record distance. done exactly once per frame.
void
computeraytable(float vx, float vy)
{
if (!ocull)
return;
odist = getvar("fog") * 1.5f;
float apitch = (float)fabs(player1->pitch);
float af = getvar("fov") / 2 + apitch / 1.5f + 3;
float byaw = (player1->yaw - 90 + af) / 360 * PI2;
float syaw = (player1->yaw - 90 - af) / 360 * PI2;
loopi(NUMRAYS)
{
float angle = i * PI2 / NUMRAYS;
if ((apitch > 45 // must be bigger if fov>120
|| (angle < byaw && angle > syaw) ||
(angle < byaw - PI2 && angle > syaw - PI2) ||
(angle < byaw + PI2 && angle > syaw + PI2)) &&
!OUTBORD(vx, vy) &&
!SOLID(S(fast_f2nat(vx),
fast_f2nat(vy)))) // try to avoid tracing ray if outside
// of frustrum
{
float ray = i * 8 / (float)NUMRAYS;
float dx, dy;
if (ray > 1 && ray < 3) {
dx = -(ray - 2);
dy = 1;
} else if (ray >= 3 && ray < 5) {
dx = -1;
dy = -(ray - 4);
} else if (ray >= 5 && ray < 7) {
dx = ray - 6;
dy = -1;
} else {
dx = 1;
dy = ray > 4 ? ray - 8 : ray;
};
float sx = vx;
float sy = vy;
for (;;) {
sx += dx;
sy += dy;
if (SOLID(S(fast_f2nat(sx),
fast_f2nat(
sy)))) // 90% of time spend in this
// function is on this line
{
rdist[i] = (float)(fabs(sx - vx) +
fabs(sy - vy));
break;
};
};
} else {
rdist[i] = 2;
};
};
};
// test occlusion for a cube... one of the most computationally expensive
// functions in the engine as its done for every cube and entity, but its effect
// is more than worth it!
inline float
ca(float x, float y)
{
return x > y ? y / x : 2 - x / y;
};
inline float
ma(float x, float y)
{
return x == 0 ? (y > 0 ? 2 : -2) : y / x;
};
int
isoccluded(float vx, float vy, float cx, float cy,
float csize) // v = viewer, c = cube to test
{
if (!ocull)
return 0;
float
nx = vx,
ny = vy; // n = point on the border of the cube that is closest to v
if (nx < cx)
nx = cx;
else if (nx > cx + csize)
nx = cx + csize;
if (ny < cy)
ny = cy;
else if (ny > cy + csize)
ny = cy + csize;
float xdist = (float)fabs(nx - vx);
float ydist = (float)fabs(ny - vy);
if (xdist > odist || ydist > odist)
return 2;
float dist = xdist + ydist - 1; // 1 needed?
// ABC
// D E
// FGH
// - check middle cube? BG
// find highest and lowest angle in the occlusion map that this cube
// spans, based on its most left and right points on the border from the
// viewer pov... I see no easier way to do this than this silly code
// below
float h, l;
if (cx <= vx) // ABDFG
{
if (cx + csize < vx) // ADF
{
if (cy <= vy) // AD
{
if (cy + csize < vy) {
h = ca(-(cx - vx), -(cy + csize - vy)) +
4;
l = ca(-(cx + csize - vx), -(cy - vy)) +
4;
} // A
else {
h = ma(-(cx + csize - vx),
-(cy + csize - vy)) +
4;
l = ma(-(cx + csize - vx), -(cy - vy)) +
4;
} // D
} else {
h = ca(cy + csize - vy, -(cx + csize - vx)) + 2;
l = ca(cy - vy, -(cx - vx)) + 2;
}; // F
} else // BG
{
if (cy <= vy) {
if (cy + csize < vy) {
h = ma(-(cy + csize - vy), cx - vx) + 6;
l = ma(-(cy + csize - vy),
cx + csize - vx) +
6;
} // B
else
return 0;
} else {
h = ma(cy - vy, -(cx + csize - vx)) + 2;
l = ma(cy - vy, -(cx - vx)) + 2;
}; // G
};
} else // CEH
{
if (cy <= vy) // CE
{
if (cy + csize < vy) {
h = ca(-(cy - vy), cx - vx) + 6;
l = ca(-(cy + csize - vy), cx + csize - vx) + 6;
} // C
else {
h = ma(cx - vx, cy - vy);
l = ma(cx - vx, cy + csize - vy);
}; // E
} else {
h = ca(cx + csize - vx, cy - vy);
l = ca(cx - vx, cy + csize - vy);
}; // H
};
int si = fast_f2nat(h * (NUMRAYS / 8)) +
NUMRAYS; // get indexes into occlusion map from angles
int ei = fast_f2nat(l * (NUMRAYS / 8)) + NUMRAYS + 1;
if (ei <= si)
ei += NUMRAYS;
for (int i = si; i <= ei; i++) {
if (dist < rdist[i & (NUMRAYS - 1)])
return 0; // if any value in this segment of the
// occlusion map is further away then cube is
// not occluded
};
return 1; // cube is entirely occluded
};
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