private void addPolygon(ref BSPNode root, BSPFaceRef face, Polygon transformed)
{
if(root == null) root = new BSPNode();
if(root.PolygonsFront.Count == 0)
{
// We though root.Front == null && root.Back == null
root.Plane = transformed.Plane;
root.PolygonsFront = new List<BSPFaceRef> { face };
return;
}
var positive = 0;
var negative = 0;
var inPlane = 0;
foreach(var v in transformed.Vertices)
{
var dist = root.Plane.Distance(v.Position);
if (dist > SPLIT_EPSILON)
positive++;
else if (dist < -SPLIT_EPSILON)
negative++;
else
inPlane++;
}
if(positive > 0 && negative == 0) // SPLIT_FRONT
{
addPolygon(ref root.Front, face, transformed);
}
else if(positive == 0 && negative > 0) // SPLIT_BACK
{
addPolygon(ref root.Back, face, transformed);
}
else // SPLIT_IN_PLANE
{
if(transformed.Plane.Normal.Dot(root.Plane.Normal) > 0.9)
{
root.PolygonsFront.Add(face);
}
else
{
root.PolygonsBack.Add(face);
}
}
}
public void RenderBSPBackToFront(BlendingMode currentTransparency, BSPNode root,
UnlitTintedShaderDescription shader)
{
var d = root.Plane.Distance(EngineCamera.Position);
if (d >= 0)
{
if (root.Back != null)
{
RenderBSPBackToFront(currentTransparency, root.Back, shader);
}
foreach (var p in root.PolygonsBack)
{
RenderPolygonTransparency(currentTransparency, p, shader);
}
foreach (var p in root.PolygonsFront)
{
RenderPolygonTransparency(currentTransparency, p, shader);
}
if (root.Front != null)
{
RenderBSPBackToFront(currentTransparency, root.Front, shader);
}
}
else
{
if (root.Front != null)
{
RenderBSPBackToFront(currentTransparency, root.Front, shader);
}
foreach (var p in root.PolygonsFront)
{
RenderPolygonTransparency(currentTransparency, p, shader);
}
foreach (var p in root.PolygonsBack)
{
RenderPolygonTransparency(currentTransparency, p, shader);
}
if (root.Back != null)
{
RenderBSPBackToFront(currentTransparency, root.Back, shader);
}
}
}
public void Reset()
{
Root = new BSPNode();
}