void AreaShader::shadeArea(Surface& s, const Area* ar) const
{
WFMath::Polygon<2> clipped = ar->clipToSegment(s.m_segment);
assert(clipped.isValid());
if (clipped.numCorners() == 0) return;
Point2 segOrigin = s.m_segment.getRect().lowCorner();
clipped.shift(Point2(0,0) - segOrigin);
scanConvert(clipped, s);
}
static void scanConvert(const WFMath::Polygon<2>& inPoly, Surface& sf)
{
if (!inPoly.isValid()) return;
std::list<Edge> pending;
std::vector<Edge> active;
Point2 lastPt = inPoly.getCorner(inPoly.numCorners() - 1);
for (std::size_t p=0; p < inPoly.numCorners(); ++p) {
Point2 curPt = inPoly.getCorner(p);
// skip horizontal edges
if (curPt.y() != lastPt.y())
pending.emplace_back(lastPt, curPt);
lastPt = curPt;
}
if (pending.empty()) return;
// sort edges by starting (lowest) z value
pending.sort();
active.push_back(pending.front());
pending.pop_front();
// advance to the row of the first z value, and ensure z sits in the
// middle of sample rows - we do this by offseting by 1/2 a row height
// if you don't do this, you'll find alternating rows are over/under
// sampled, producing a charming striped effect.
WFMath::CoordType z = std::floor(active.front().start().y()) + ROW_HEIGHT * 0.5f;
for (; !pending.empty() || !active.empty(); z += ROW_HEIGHT)
{
while (!pending.empty() && (pending.front().start().y() <= z)) {
active.push_back(pending.front());
pending.pop_front();
}
// sort by x value - note active will be close to sorted anyway
std::sort(active.begin(), active.end(), EdgeAtZ(z));
// delete finished edges
for (unsigned int i=0; i< active.size(); ) {
if (active[i].end().y() <= z)
active.erase(active.begin() + i);
else
++i;
}
// draw pairs of active edges
for (unsigned int i=1; i < active.size(); i += 2)
span(sf, z, active[i - 1].xValueAtZ(z), active[i].xValueAtZ(z));
} // of active edges loop
}
WFMath::Polygon<2> sutherlandHodgmanKernel(const WFMath::Polygon<2>& inpoly, Clip clipper)
{
WFMath::Polygon<2> outpoly;
if (!inpoly.isValid()) return inpoly;
std::size_t points = inpoly.numCorners();
if (points < 3) return outpoly; // i.e an invalid result
Point2 lastPt = inpoly.getCorner(points - 1);
bool lastInside = clipper.inside(lastPt);
for (std::size_t p = 0; p < points; ++p) {
Point2 curPt = inpoly.getCorner(p);
bool inside = clipper.inside(curPt);
if (lastInside) {
if (inside) {
// emit curPt
outpoly.addCorner(outpoly.numCorners(), curPt);
} else {
// emit intersection of edge with clip line
outpoly.addCorner(outpoly.numCorners(), clipper.clip(lastPt, curPt));
}
} else {
if (inside) {
// emit both
outpoly.addCorner(outpoly.numCorners(), clipper.clip(lastPt, curPt));
outpoly.addCorner(outpoly.numCorners(), curPt);
} else {
// don't emit anything
}
} // last was outside
lastPt = curPt;
lastInside = inside;
}
return outpoly;
}
void Area::setShape(const WFMath::Polygon<2>& p)
{
assert(p.isValid());
m_shape = p;
m_box = p.boundingBox();
}
int main(int argc, char* argv[])
{
Mercator::Area* a1 = new Mercator::Area(1, false);
WFMath::Polygon<2> p;
p.addCorner(p.numCorners(), Point2(3, 4));
p.addCorner(p.numCorners(), Point2(10, 10));
p.addCorner(p.numCorners(), Point2(-1, 18));
p.addCorner(p.numCorners(), Point2(-8, 11));
a1->setShape(p);
Mercator::Terrain terrain(Mercator::Terrain::SHADED, seg_size);
Mercator::AreaShader* ashade = new Mercator::AreaShader(1);
terrain.addShader(ashade, 0);
terrain.setBasePoint(-2, -1, 5);
terrain.setBasePoint(-2, 0, 2);
terrain.setBasePoint(-2, 1, 19);
terrain.setBasePoint(-1, -1, 4);
terrain.setBasePoint(-1, 0, 6);
terrain.setBasePoint(-1, 1, 10);
terrain.setBasePoint(0, -1, 2);
terrain.setBasePoint(0, 0, -1);
terrain.setBasePoint(0, 1, 8);
terrain.setBasePoint(0, 2, 11);
terrain.setBasePoint(1, -1, 7);
terrain.setBasePoint(1, 0, 2);
terrain.setBasePoint(1, 1, 11);
terrain.setBasePoint(1, 2, 9);
terrain.setBasePoint(2, -1, 3);
terrain.setBasePoint(2, 0, 8);
terrain.setBasePoint(2, 1, 2);
terrain.setBasePoint(3, -1, 6);
terrain.setBasePoint(3, 0, 7);
terrain.setBasePoint(3, 1, 9);
terrain.addArea(a1);
Mercator::Segment* seg = terrain.getSegment(0,0);
assert(seg->getAreas().size() == 1);
assert(seg->getAreas().count(1) == 1);
assert(a1->checkIntersects(*seg));
seg = terrain.getSegment(1,0);
assert(seg->getAreas().size() == 0);
assert(seg->getAreas().count(1) == 0);
assert(a1->checkIntersects(*seg) == false);
WFMath::Polygon<2> clipped = a1->clipToSegment(*seg);
assert(clipped.isValid());
seg = terrain.getSegment(-1,0);
assert(seg->getAreas().size() == 1);
assert(seg->getAreas().count(1) == 1);
assert(a1->checkIntersects(*seg));
clipped = a1->clipToSegment(*seg);
assert(clipped.isValid());
seg = terrain.getSegment(0,1);
assert(seg->getAreas().size() == 1);
assert(seg->getAreas().count(1) == 1);
assert(a1->checkIntersects(*seg));
clipped = a1->clipToSegment(*seg);
assert(clipped.isValid());
seg = terrain.getSegment(2,0);
assert(seg->getAreas().size() == 0);
assert(seg->getAreas().count(1) == 0);
assert(a1->checkIntersects(*seg) == false);
p.clear();
p.addCorner(p.numCorners(), Point2(3 + seg_size, 4));
p.addCorner(p.numCorners(), Point2(10 + seg_size, 10));
p.addCorner(p.numCorners(), Point2(-1 + seg_size, 18));
p.addCorner(p.numCorners(), Point2(-8 + seg_size, 11));
a1->setShape(p);
terrain.updateArea(a1);
seg = terrain.getSegment(0,0);
assert(seg->getAreas().size() == 1);
assert(seg->getAreas().count(1) == 1);
assert(a1->checkIntersects(*seg));
seg = terrain.getSegment(1,0);
assert(seg->getAreas().size() == 1);
assert(seg->getAreas().count(1) == 1);
assert(a1->checkIntersects(*seg));
clipped = a1->clipToSegment(*seg);
assert(clipped.isValid());
seg = terrain.getSegment(-1,0);
assert(seg->getAreas().size() == 0);
assert(seg->getAreas().count(1) == 0);
assert(a1->checkIntersects(*seg) == false);
seg = terrain.getSegment(0,1);
assert(seg->getAreas().size() == 1);
assert(seg->getAreas().count(1) == 1);
assert(a1->checkIntersects(*seg));
clipped = a1->clipToSegment(*seg);
assert(clipped.isValid());
seg = terrain.getSegment(2,0);
assert(seg->getAreas().size() == 0);
assert(seg->getAreas().count(1) == 0);
assert(a1->checkIntersects(*seg) == false);
clipped = a1->clipToSegment(*seg);
assert(clipped.isValid());
terrain.removeArea(a1);
seg = terrain.getSegment(0,0);
assert(seg->getAreas().size() == 0);
assert(seg->getAreas().count(1) == 0);
seg = terrain.getSegment(1,0);
assert(seg->getAreas().size() == 0);
assert(seg->getAreas().count(1) == 0);
seg = terrain.getSegment(-1,0);
assert(seg->getAreas().size() == 0);
assert(seg->getAreas().count(1) == 0);
seg = terrain.getSegment(0,1);
assert(seg->getAreas().size() == 0);
assert(seg->getAreas().count(1) == 0);
testAreaShader();
testAddToSegment();
return EXIT_SUCCESS;
}