static Mathbox.Mesh TryGetMeshAt(UInt16 address)
{
// don't bother with these addresses
if (address == 0x40DC || address == 0x4344)
{
return(null);
}
if (!ROM.TryRead(address, out UInt16 vertex_base))
{
return(null);
}
if (vertex_base < 0x2000 || vertex_base >= 0x8000)
{
return(null);
}
// at this point we should try and parse an object
// the parsing could fail, in which case the catch block will catch us
try
{
Mesh mesh = new Mathbox.Mesh(address, vertex_base);
return(mesh.IsValid ? mesh : null);
}
catch
{
return(null);
}
}
static internal bool Parse(Mathbox.Mesh mesh, UInt16 address)
{
// scan forever until exit condition reached
for (; ;)
{
// ensure no duplicate surfaces
foreach (Surface p in mesh.mSurfaces)
{
if (p.Address == address)
{
return(true); // everything OK, we just can't add any more polys
}
}
// try and create a new surface object
if (!Surface.TryCreateSurface(ref address, out Surface surface))
{
return(false);
}
/// is this the end of the surface list?
if (surface.VertexOffsetTable == 0x8000)
{
return(true); // end of surface list reached
}
// should the surface be drawn?
if (!surface.Flags.IsCullInstruction || surface.Flags.CullInstruction == CULL.AlwaysBranch)
{
// yes
// scan the vertex index list
int pIndices = surface.VertexOffsetTable;
// read the first offset
if (!ROM.TryRead(pIndices++, out UInt16 offset))
{
return(false);
}
// first vertex specifies the (optional) normal vector
if ((offset & 0x4000) == 0)
{
// normal vector exists
Vector3D normal = mesh.Vector(offset);
normal.Normalize();
surface.Normal = normal;
}
// remaining vertices are the points that make up the surface
while (offset < 0x8000)
{
if (!ROM.TryRead(pIndices++, out offset))
{
return(false);
}
surface.mPoints.Add(mesh.Point(offset));
}
// make sure the surface type matches the number of vertices
switch (surface.mPoints.Count)
{
case 0: return(false);
case 1:
// always set to "DOT"
surface.Flags.Type = TYPE.Dot;
break;
case 2:
// must be dot or vector
if (surface.Type == TYPE.Polygon)
{
surface.Flags.Type = TYPE.Vector;
}
break;
default:
if (surface.Type == TYPE.Vector)
{
surface.mPoints.Add(surface.mPoints[0]); // close the vector list
}
break;
}
// shade certain objects
if (surface.Type == TYPE.Polygon)
{
switch (mesh.Address)
{
case 0x3892: // eyeball
case 0x38A4: // eyeball
case 0x38B6: // eyeball
case 0x38C8: // eyeball
case 0x38DA: // eyeball
if (surface.ColorIndex > 0 && surface.ColorIndex <= 7)
{
surface.Flags.IsShaded = true; // make shaded
}
break;
//case 0x5767: // transporter
//case 0x577B: // transporter
//case 0x5791: // transporter
case 0x5B56: // tanker
case 0x5B68: // spike
case 0x5B6E: // spike
case 0x5B72: // spike
case 0x5B8C: // spike
case 0x5BB5: // spike
case 0x5BE7: // spike
case 0x5C22: // spike
case 0x5F08: // colored "big ball"
case 0x692F: // hand
case 0x730A: // cube
case 0x7318: // cube
case 0x7326: // cube
case 0x7334: // cube
case 0x7342: // cube
case 0x7350: // cube
case 0x735E: // cube
//case 0x755D: // dodecahedron
case 0x77D0: // ring
case 0x7DF4: // viewer killer
surface.Flags.IsShaded = true; // make shaded
break;
}
}
// fix objects
switch (mesh.Address)
{
case 0x2958: // robot visor
case 0x29EE: // robot visor
case 0x2A84: // robot visor
case 0x2B1A: // robot visor
case 0x2C00: // robot visor
if (surface.ColorIndex == 0x38 || surface.ColorIndex == 0x39)
{
for (int n = 0; n < surface.mPoints.Count; n++)
{
surface.mPoints[n] = surface.mPoints[n] + new Vector3D(-0.1, 0, 0);
}
}
break;
case 0x51E0: // bird eye
case 0x5234: // bird eye
case 0x5288: // bird eye
if (surface.ColorIndex == 0x38 || surface.ColorIndex == 0x39)
{
for (int n = 0; n < surface.mPoints.Count; n++)
{
surface.mPoints[n] = new Point3D(
surface.mPoints[n].X * 15f / 18f,
surface.mPoints[n].Y - 6f,
surface.mPoints[n].Z + 3f);
}
}
break;
}
// this is a good surface
// check for duplicates
bool keep = true;
foreach (Surface s in mesh.mSurfaces)
{
if (surface.Equals(s))
{
keep = false;
break;
}
}
// keep surface if it is unique
if (keep)
{
mesh.mSurfaces.Add(surface);
}
}
// manage branching
if (surface.Flags.IsCullInstruction)
{
// find address of branch
UInt16 branch_addr = address;
if (!ROM.TryRead(address++, out UInt16 offset))
{
return(false);
}
branch_addr += offset;
// what type of branch is this
switch (surface.Flags.CullInstruction)
{
case CULL.AlwaysBranch:
address = branch_addr; // take the branch
break;
case CULL.BranchIfVisible: // branch if surface visible
case CULL.BranchIfHidden: // branch if surface hidden
case CULL.BranchAlways: // branch never (never draw)
// parse branch
if (!Parse(mesh, branch_addr))
{
return(false); // something went wrong
}
break; // now continue parsing the original branch
}
}
}
}
