bool TerrainBlock::castRayBlock(const Point3F &pStart, const Point3F &pEnd, const Point2I &aBlockPos, U32 aLevel, F32 invDeltaX, F32 invDeltaY, F32 aStartT, F32 aEndT, RayInfo *info, bool collideEmpty)
{
F32 invBlockSize = 1 / F32(BlockSquareWidth);
static TerrLOSStackNode stack[BlockShift * 3 + 1];
U32 stackSize = 1;
stack[0].startT = aStartT;
stack[0].endT = aEndT;
stack[0].blockPos = aBlockPos;
stack[0].level = aLevel;
if(!mTile && !aBlockPos.isZero())
return false;
while(stackSize--)
{
TerrLOSStackNode *sn = stack + stackSize;
U32 level = sn->level;
F32 startT = sn->startT;
F32 endT = sn->endT;
Point2I blockPos = sn->blockPos;
GridSquare *sq = findSquare(level, Point2I(blockPos.x & BlockMask, blockPos.y & BlockMask));
F32 startZ = startT * (pEnd.z - pStart.z) + pStart.z;
F32 endZ = endT * (pEnd.z - pStart.z) + pStart.z;
F32 minHeight = fixedToFloat(sq->minHeight);
if(startZ <= minHeight && endZ <= minHeight)
{
//drawLineTest(startT, sn->endT, false);
continue;
}
F32 maxHeight = fixedToFloat(sq->maxHeight);
if(startZ >= maxHeight && endZ >= maxHeight)
{
//drawLineTest(startT, endT, false);
continue;
}
if (!collideEmpty && (sq->flags & GridSquare::Empty) &&
blockPos.x == (blockPos.x & BlockMask) && blockPos.y == (blockPos.y & BlockMask))
{
//drawLineTest(startT, endT, false);
continue;
}
if(level == 0)
{
F32 xs = blockPos.x * invBlockSize;
F32 ys = blockPos.y * invBlockSize;
F32 zBottomLeft = fixedToFloat(getHeight(blockPos.x, blockPos.y));
F32 zBottomRight= fixedToFloat(getHeight(blockPos.x + 1, blockPos.y));
F32 zTopLeft = fixedToFloat(getHeight(blockPos.x, blockPos.y + 1));
F32 zTopRight = fixedToFloat(getHeight(blockPos.x + 1, blockPos.y + 1));
PlaneF p1, p2;
PlaneF divider;
Point3F planePoint;
if(sq->flags & GridSquare::Split45)
{
p1.set(zBottomLeft - zBottomRight, zBottomRight - zTopRight, invBlockSize);
p2.set(zTopLeft - zTopRight, zBottomLeft - zTopLeft, invBlockSize);
planePoint.set(xs, ys, zBottomLeft);
divider.x = 1;
divider.y = -1;
divider.z = 0;
}
else
{
p1.set(zTopLeft - zTopRight, zBottomRight - zTopRight, invBlockSize);
p2.set(zBottomLeft - zBottomRight, zBottomLeft - zTopLeft, invBlockSize);
planePoint.set(xs + invBlockSize, ys, zBottomRight);
divider.x = 1;
divider.y = 1;
divider.z = 0;
}
p1.setPoint(planePoint);
p2.setPoint(planePoint);
divider.setPoint(planePoint);
F32 t1 = p1.intersect(pStart, pEnd);
F32 t2 = p2.intersect(pStart, pEnd);
F32 td = divider.intersect(pStart, pEnd);
F32 dStart = divider.distToPlane(pStart);
F32 dEnd = divider.distToPlane(pEnd);
// see if the line crosses the divider
if((dStart >= 0 && dEnd < 0) || (dStart < 0 && dEnd >= 0))
{
if(dStart < 0)
{
F32 temp = t1;
t1 = t2;
t2 = temp;
}
if(t1 >= startT && t1 && t1 <= td && t1 <= endT)
{
info->t = t1;
info->normal = p1;
return true;
}
if(t2 >= td && t2 >= startT && t2 <= endT)
{
info->t = t2;
info->normal = p2;
return true;
}
}
else
{
F32 t;
if(dStart >= 0) {
t = t1;
info->normal = p1;
}
else {
t = t2;
info->normal = p2;
}
if(t >= startT && t <= endT)
{
info->t = t;
return true;
}
}
continue;
}
int subSqWidth = 1 << (level - 1);
F32 xIntercept = (blockPos.x + subSqWidth) * invBlockSize;
F32 xInt = calcInterceptX(pStart.x, invDeltaX, xIntercept);
F32 yIntercept = (blockPos.y + subSqWidth) * invBlockSize;
F32 yInt = calcInterceptY(pStart.y, invDeltaY, yIntercept);
F32 startX = startT * (pEnd.x - pStart.x) + pStart.x;
F32 startY = startT * (pEnd.y - pStart.y) + pStart.y;
if(xInt < startT)
xInt = MAX_FLOAT;
if(yInt < startT)
yInt = MAX_FLOAT;
U32 x0 = (startX > xIntercept) * subSqWidth;
U32 y0 = (startY > yIntercept) * subSqWidth;
U32 x1 = subSqWidth - x0;
U32 y1 = subSqWidth - y0;
U32 nextLevel = level - 1;
// push the items on the stack in reverse order of processing
if(xInt > endT && yInt > endT)
{
// only test the square the point started in:
stack[stackSize].blockPos.set(blockPos.x + x0, blockPos.y + y0);
stack[stackSize].level = nextLevel;
stackSize++;
}
else if(xInt < yInt)
{
F32 nextIntersect = endT;
if(yInt <= endT)
{
stack[stackSize].blockPos.set(blockPos.x + x1, blockPos.y + y1);
stack[stackSize].startT = yInt;
stack[stackSize].endT = endT;
stack[stackSize].level = nextLevel;
nextIntersect = yInt;
stackSize++;
}
stack[stackSize].blockPos.set(blockPos.x + x1, blockPos.y + y0);
stack[stackSize].startT = xInt;
stack[stackSize].endT = nextIntersect;
stack[stackSize].level = nextLevel;
stack[stackSize+1].blockPos.set(blockPos.x + x0, blockPos.y + y0);
stack[stackSize+1].startT = startT;
stack[stackSize+1].endT = xInt;
stack[stackSize+1].level = nextLevel;
stackSize += 2;
}
else if(yInt < xInt)
{
F32 nextIntersect = endT;
if(xInt <= endT)
{
stack[stackSize].blockPos.set(blockPos.x + x1, blockPos.y + y1);
stack[stackSize].startT = xInt;
stack[stackSize].endT = endT;
stack[stackSize].level = nextLevel;
nextIntersect = xInt;
stackSize++;
}
stack[stackSize].blockPos.set(blockPos.x + x0, blockPos.y + y1);
stack[stackSize].startT = yInt;
stack[stackSize].endT = nextIntersect;
stack[stackSize].level = nextLevel;
stack[stackSize+1].blockPos.set(blockPos.x + x0, blockPos.y + y0);
stack[stackSize+1].startT = startT;
stack[stackSize+1].endT = yInt;
stack[stackSize+1].level = nextLevel;
stackSize += 2;
}
else
{
stack[stackSize].blockPos.set(blockPos.x + x1, blockPos.y + y1);
stack[stackSize].startT = xInt;
stack[stackSize].endT = endT;
stack[stackSize].level = nextLevel;
stack[stackSize+1].blockPos.set(blockPos.x + x0, blockPos.y + y0);
stack[stackSize+1].startT = startT;
stack[stackSize+1].endT = xInt;
stack[stackSize+1].level = nextLevel;
stackSize += 2;
}
}
return false;
}
