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Thread: Lightmapping rectangle faces...

  1. #1

    Lightmapping rectangle faces...

    I have finally got my lightmapper working, but i have a bigproblem with it!
    For some reason it doesnt like rectangle (eg. 200 x 100) shaped faces :s it works like a dream if it is square (eg. 100 x 100)..

    I cant see anywhere that it assumes the face to be square :s heres the code im using to calculate the lightmaps ::

    Dimension = 32;
    PolyNormal,ZeroPosition,PlaneNormal: TVector3f;
    UVVector,Vect1,Vect2,Lumel,Tempv: TVector3f;
    Edge1,Edge2,nEdge1,nEdge2: TVector3f;
    i,iX,iY,r,g,b,lm: Integer;
    LightmapBMP: TBitmap;
    Plane: ToxPlane;
    PlaneDistance,Distance,X,Y,Z,uFactor,vFactor: Single;
    PolyPlane: ToxPlaneAlignment;
    lm := Add;
    ZeroPosition := Lightmaps[lm].FindZeroUV;
    Plane := oxPlaneFromPoints(Triangle.Vertex);
    PolyPlane := oxTriangleAlignement(Triangle.Vertex);
    PolyNormal := oxNormal(Triangle.Vertex);

    PlaneNormal := Vector3f(Plane.a, Plane.b, Plane.c);
    PlaneDistance := oxDot(PlaneNormal, Triangle.Vertex[0]);
    With Lightmaps[lm] Do
    Case PolyPlane Of
    paXZ: Begin
    y := -(PolyNormal[0]*uMin+PolyNormal[2]*vMin+PlaneDistance)/PolyNormal[1];
    UVVector := Vector3f(uMin, y, vMin);
    y := -(PolyNormal[0]*uMax+PolyNormal[2]*vMin+PlaneDistance)/PolyNormal[1];
    Vect1 := Vector3f(uMax, y, vMin);
    y := -(PolyNormal[0]*uMin+PolyNormal[2]*vMax+PlaneDistance)/PolyNormal[1];
    Vect2 := Vector3f(uMin, y, vMax);
    paYZ: Begin
    x := -(PolyNormal[2]*uMin+PolyNormal[1]*vMin+PlaneDistance)/PolyNormal[0];
    UVVector := Vector3f(x, uMin, vMin);
    x := -(PolyNormal[2]*uMax+PolyNormal[1]*vMin+PlaneDistance)/PolyNormal[0];
    Vect1 := Vector3f(x, uMin, vMax);
    x := -(PolyNormal[2]*uMin+PolyNormal[1]*vMax+PlaneDistance)/PolyNormal[0];
    Vect2 := Vector3f(x, uMax, vMin);
    paXY: Begin
    z := -(PolyNormal[0]*uMin+PolyNormal[1]*vMin+PlaneDistance)/PolyNormal[2];
    UVVector := Vector3f(uMin, vMin, z);
    z := -(PolyNormal[0]*uMax+PolyNormal[1]*vMin+PlaneDistance)/PolyNormal[2];
    Vect1 := Vector3f(uMax, vMin, z);
    z := -(PolyNormal[0]*uMin+PolyNormal[1]*vMax+PlaneDistance)/PolyNormal[2];
    Vect2 := Vector3f(uMin, vMax, z);

    Edge1 := oxSub(Vect1, UVVector);
    Edge2 := oxSub(Vect2, UVVector);

    LightmapBMP := TBitmap.Create;
    LightmapBMP.Width := Dimension;
    LightmapBMP.Height := Dimension;

    For iX := 0 To Dimension Do
    For iY := 0 To Dimension Do
    r := 0;
    g := 0;
    b := 0;
    uFactor := iX/Dimension;
    vFactor := iY/Dimension;
    nEdge1 := Vector3f(Edge1[0]*uFactor, Edge1[1]*uFactor, Edge1[2]*uFactor);
    nEdge2 := Vector3f(Edge2[0]*vFactor, Edge2[1]*vFactor, Edge2[2]*vFactor);
    TempV := oxAdd(UVVector, nEdge1);
    Lumel := oxAdd(TempV, nEdge2);

    If Lumel[0] < 0 Then Lumel[0] := -lumel[0];
    If Lumel[2] < 0 Then Lumel[2] := -lumel[2];
    If Lumel[1] < 0 Then Lumel[1] := -lumel[1];

    For i := 0 To High(PointLights) Do
    With PointLights[i] Do
    Distance := oxDistance(Lumel, Position);
    If Distance < Radius Then
    If Distance = 0 Then
    Distance := 1 Else
    Distance := (Radius-Distance)/Distance;
    r := r+Round(Distance*Colour[0]);
    g := g+Round(Distance*Colour[1]);
    b := b+Round(Distance*Colour[2]);
    If r > 255 Then r := 255;
    If g > 255 Then g := 255;
    If b > 255 Then b := 255;
    LightmapBMP.Canvas.Pixels[iX, iY] := RGB(r,g,b);
    LightmapBMP.PixelFormat := pf24bit;
    LightmapBMP.SaveToFile(InttoStr(Triangle.LightmapI D)+'.bmp');
    Result := lm;

    Here some screenshots of the results ::
    Square Face ::
    Rectangle Face ::

    I coule be wrong, i have been staring at this code for far too long and im now seeing dots :s

    Thanx for any help...

    Edit ::
    The only thing that i can think that is suggesting its a square is the Bitmap, but if this is the problem how can i solve it??
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  2. #2

    Lightmapping rectangle faces...

    I'll bump this in the (probably vain) hope that I'll find some time to investigate for ya.

    I really wish I had "bullet time" -- use it, answer all the questions on forums, code some, get something to eat, and by the time it's finished I'd still have spare time. Of course, the only problem is that I'd have to kill random thugs to get it. Heh.
    "All paid jobs absorb and degrade the mind."
    <br />-- Aristotle

  3. #3

    Lightmapping rectangle faces...

    Thanx, i think i know where i need to change it but im just guessing again lol

    towards the bottom of the code it is using dimension to size the bitmap and to calculate the edges, i have had a quick try at changing this to the distance of the required points, but it didnt work very well.. i will try again soon and any input will be very welcome ..

    On another note, do you know where i can find some maths for calculating the different light types (Point light, spot light, etc)?

    hehe i know what you mean it seems spare time is getting more and more rarer lol
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