public void Rasterize()
{
// locate the tile table in memory
System.Diagnostics.Debug.Assert(Memory[TERRAIN_BASE_ADDRESS] == 0xE00);
TileTableBaseAddress = Memory[TERRAIN_BASE_ADDRESS]; // always 0x0E00
Parent.StartRender();
Parent.LoadLightVector();
Parent.LoadViewPosition();
Parent.LoadViewMatrix(0x15);
Rotation = Parent.ViewRotation;
Parent.SetWorldMatrix(ref Parent.Terrain.Rotation);
// determine rendering method (dot/vector/polygon)
switch (Memory[TERRAIN_RENDERING_MODE])
{
case 0x0000: renderMode = Mathbox.RenderMode.Polygon; break;
case 0x0100: renderMode = Mathbox.RenderMode.Vector; break;
default: renderMode = Mathbox.RenderMode.Dot; break;
}
// get address of terrain object buffer
ObjectList = Memory[TERRAIN_OBJECT_LIST_ADDRESS];
Int16 z_max = (Int16)Memory[TERRAIN_Z_MAX];
Int16 z_min = (Int16)Memory[TERRAIN_Z_MIN];
Int16 x = (Int16)Memory[TERRAIN_X];
Int16 z_frac = (Int16)Memory[TERRAIN_Z_FRAC];
Int16 x_offset = (Int16)Memory[TERRAIN_X_OFFSET];
Int16 z_offset = (Int16)Memory[TERRAIN_Z_OFFSET];
// locate left front tile corner (x1,y1,z1)
// +-------+
// / /|
// / / | x2 = x1 + Mathbox.Tile.SIZE_X
// y1-- +-------+ | y2 = y1 + Mathbox.Tile.SIZE_Y
// | | + --z2 z2 = z1 + Mathbox.Tile.SIZE_Z
// | | /
// | |/
// y2-- +-------+ --z1
// | |
// x1 x2
Vector3 corner = new Vector3(
Tile.WIDTH_X - x_offset * 128 - x,
-Parent.ViewPosition.Y,
z_max * 128 - z_frac);
// render each row in the terrain
int row = z_offset / 16 + z_max; // first absolute row to be rendered
Row.Count = z_max - z_min + 1; // number of rows to display
while (Row.Count-- > 0)
{
DrawTerrainRow(row-- & 31, corner);
corner.Z -= Tile.DEPTH_Z; // move to next row along the Z axis
}
Parent.EndRender();
}
/// <summary>
/// Parses the list of objects to render
/// </summary>
/// <param name="address">base address of object list</param>
public void ParseObjectList(UInt16 address)
{
// address+0 Object position.X
// address+1 Object position.Y
// address+2 Object position.Z
// address+3 Object Instruction
// address+4 Address of view matrix
// address+5 Address of rotation matrix (only if specified by instruction)
// address+6 Address of surface list (only if specified by instruction)
// address +5 or + 7 first child object
#if false
Debug.WriteLine($"{Memory[address+0].HexString()} {Memory[address + 1].HexString()} {Memory[address + 2].HexString()} {Memory[address + 3].HexString()} {Memory[address + 4].HexString()} {Memory[address + 5].HexString()} {Memory[address + 6].HexString()}");
#endif
for (; ;)
{
// check for end of list
if (address == 0 || address >= 0x8000)
{
return;
}
// Control word encoding
// 0x8000 = stop flag
// 0x4000 = don't load camera matrix
// 0x1000 = ?
// 0x0800 = don't load base address or rotation matrix
// 0x0400 = x/y/z value is relative offset, not absolute position
Mathbox.ObjectInstruction opcode = Memory[address + 3];
// load camera matrix
if (!opcode.SkipObjectRotation)
{
Parent.LoadViewMatrix(Memory[address + 4]);
}
// Get new primitive list address and rotation matrix if they exist
int childAddr = address + 5;
if (!opcode.UsePreviousObjectPointsAndFaces)
{
PrimitiveListAddress = Memory[address + 6];
if (PrimitiveListAddress >= 0x8000)
{
return;
}
Parent.LoadRotationMatrix(Memory[address + 5]);
childAddr += 2;
}
// Don't render invalid objects
if (PrimitiveListAddress >= 0x8000)
{
return;
}
// Determine position of object
Vector3 pt = Parent.GetVectorAt(address);
if (opcode.ObjectPositionIsRelative)
{
// relative position
Parent.WorldPosition += Vector3.Transform(pt, Parent.ViewRotation);
}
else
{
// absolute position
pt -= Parent.ViewPosition;
Parent.WorldPosition = Vector3.Transform(pt, Parent.ViewRotation);
}
Parent.SetWorldMatrix(ref Parent.WorldPosition, ref Parent.WorldRotation);
#if WIDESCREEN_STARS
if (PrimitiveListAddress >= 0x4AE8 && PrimitiveListAddress <= 0x4B44)
{
for (int n = 0; n < Stars.Length; n++)
{
Vertices[n] = Vector3.Transform(Stars[n], Parent.D3DTS_WORLD);
}
DisplayListManager.AddPrimitive(Mathbox.RenderMode.Dot, Vertices, Stars.Length, Parent.GetColor(7));
return;
}
#endif
// parese the surfaces in this object
ParsePrimitiveList(PrimitiveListAddress);
// parse all child objects
for (; ;)
{
UInt16 child = Memory[childAddr++];
if (child == 0 || child >= 0x8000)
{
return;
}
if (child == 0x0002)
{
address += 8;
break;
}
ParseObjectList(child);
}
}
}