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 RenderPolygonTransparency(BlendingMode currentTransparency, BSPFaceRef bspRef,
UnlitTintedShaderDescription shader)
{
// Blending mode switcher.
// Note that modes above 2 aren't explicitly used in TR textures, only for
// internal particle processing. Theoretically it's still possible to use
// them if you will force type via TRTextur utility.
var refe = bspRef.Polygon;
var p = refe.Polygon;
if(currentTransparency != p.BlendMode)
{
currentTransparency = p.BlendMode;
switch (p.BlendMode)
{
case BlendingMode.Multiply: // Classic PC alpha
GL.BlendFunc(BlendingFactorSrc.One, BlendingFactorDest.One);
break;
case BlendingMode.InvertSrc: // Inversion by src (PS darkness) - SAME AS IN TR3-TR5
GL.BlendFunc(BlendingFactorSrc.Zero, BlendingFactorDest.OneMinusSrcAlpha);
break;
case BlendingMode.InvertDst: // Inversion by dest
GL.BlendFunc(BlendingFactorSrc.OneMinusSrcColor, BlendingFactorDest.OneMinusSrcAlpha);
break;
case BlendingMode.Screen: // Screen (smoke, etc.)
GL.BlendFunc(BlendingFactorSrc.One, BlendingFactorDest.OneMinusSrcAlpha);
break;
case BlendingMode.AnimatedTexture:
GL.BlendFunc(BlendingFactorSrc.One, BlendingFactorDest.Zero);
break;
}
}
var mvp = Camera.GLViewProjMat.MultiplyByTransform(bspRef.Transform);
GL.UniformMatrix4(shader.ModelViewProjection, false, ref mvp);
refe.UsedVertexArray.Bind();
GL.BindTexture(TextureTarget.Texture2D, World.Textures[p.TexIndex]);
GL.DrawElements(PrimitiveType.Triangles, (int)refe.Count, DrawElementsType.UnsignedInt, (int)(sizeof(uint) * refe.FirstIndex));
}