Robert Kosek:
The procedure expects a pointer type.
I shall try your suggestion. Thanks.

User137:
Well im not really any good with c/c++ and my only experiance with it was a simple hellow world application about 5years ago, but here is the C++ version:

Code:
		*(vp++) = Puff->Position + Corner1 * Puff->Size;
		*(tp++) = v1;
		*(cp++) = ParticleColor;
		
		*(vp++) = Puff->Position + Corner2 * Puff->Size;
		*(tp++) = v2;
		*(cp++) = ParticleColor;
		
		*(vp++) = Puff->Position + Corner3 * Puff->Size;
		*(tp++) = v3;
		*(cp++) = ParticleColor;
		
		*(vp++) = Puff->Position + Corner4 * Puff->Size;
		*(tp++) = v4;
		*(cp++) = ParticleColor;
When the cloud is created, it goes to the manager and randomly chooses a cloud data file (this data file contains information on each puff), it then resizes the vBuffer, etc to the required size to fit with the amount of puffs:

[pascal]
GetMem(vBuffer, SizeOf(TVector3f)*(Length(Puffs)*4));
[/pascal]

Now on every update and render the vBuffer, etc seems to get updated to fit with the position of the camera and sun.

How ever in an attempt to speed things up, i have moved the code to only work in the update, so now it looks like:
[pascal]
procedure AddToMem(Cloud: TVolumetricCloud; Index: Integer; v2: TVector2f; v3: TVector3f; v4a,v4b: TVector4f);
begin
Cloud.vBuffer^[Index] := v3;
// Inc(Cloud.vBuffer^);
Cloud.cBuffer^[Index] := v4a;
// Inc(Cloud.cBuffer^);
Cloud.IcBuffer^[Index] := v4b;
// Inc(Cloud.IcBuffer^);
Cloud.tBuffer^[Index] := v2;
// Inc(Cloud.tBuffer^);
end;

procedure TGLVolumetricClouds.buildArrays(Cloud: TVolumetricCloud; Camera,Sun: TVector3f; Alpha: Single);
var
i,j: Integer;
omega2,costheta,phase: Single;
v1,v2,v3,v4: TVector2f;
iv3,vx,vy,Light,vv3,Omega,Corner1,Corner2,Corner3, Corner4: TVector3f;
pColor,pColor2: TVector4f;
mat: Array [0..15] Of Single;
begin
vv3 := Vector3fMake(Camera[0]-Sun[0], Camera[1]-Sun[1], Camera[2]-Sun[2]);
Light := VectorNormalize(vv3);

glGetFloatv(GL_MODELVIEW_MATRIX, @mat);

vx := Vector3fMake(mat[0], mat[4], mat[8]);
vy := Vector3fMake(mat[1], mat[5], mat[9]);

v1 := Vector2fMake(1, 0);
v2 := Vector2fMake(0, 0);
v3 := Vector2fMake(0, 1);
v4 := Vector2fMake(1, 1);

Corner1 := Vector3fMake(-vx[0]-vy[0], -vx[1]-vy[1], -vx[2]-vy[2]);
Corner2 := Vector3fMake( vx[0]-vy[0], vx[1]-vy[1], vx[2]-vy[2]);
Corner3 := Vector3fMake( vx[0]+vy[0], vx[1]+vy[1], vx[2]+vy[2]);
Corner4 := Vector3fMake( vy[0]-vx[0], vy[1]-vx[1], vy[2]-vx[2]);

j := 0;
For i := 0 To High(Cloud.Puffs) Do
Begin
Omega := Vector3fMake(Cloud.Puffs[i].Position[0]-Camera[0],
Cloud.Puffs[i].Position[1]-Camera[1],
Cloud.Puffs[i].Position[2]-Camera[2]);

omega2 := Omega[0]*Omega[0]+Omega[1]*Omega[1]+Omega[2]*Omega[2];
omega2 := carmack_func(omega2);

//omega2 is now 1 / Mag(Omega)
Omega[0] := Omega[0]*omega2;
Omega[1] := Omega[1]*omega2;
Omega[2] := Omega[2]*omega2;

costheta := VectorDotProduct(Omega, Light);
phase := 0.75*(1.0+costheta*costheta);

// 3D
pColor[0] := (0.3+Cloud.Puffs[i].Color[0]*phase)*Alpha;
pColor[1] := (0.3+Cloud.Puffs[i].Color[1]*phase)*Alpha;
pColor[2] := (0.3+Cloud.Puffs[i].Color[2]*phase)*Alpha;
pColor[3] := Cloud.Puffs[i].Color[3]*Cloud.Puffs[i].Life*Alpha;

// Imposter
pColor2[0] := 0.3+Cloud.Puffs[i].Color[0]*phase;
pColor2[1] := 0.3+Cloud.Puffs[i].Color[1]*phase;
pColor2[2] := 0.3+Cloud.Puffs[i].Color[2]*phase;
pColor2[3] := Cloud.Puffs[i].Color[3]*Cloud.Puffs[i].Life;

iv3 := Vector3fMake(Cloud.Puffs[i].Position[0]+Corner1[0]*Cloud.Puffs[i].Size,
Cloud.Puffs[i].Position[1]+Corner1[1]*Cloud.Puffs[i].Size,
Cloud.Puffs[i].Position[2]+Corner1[2]*Cloud.Puffs[i].Size);
AddToMem(Cloud, j, v1, iv3, pColor, pColor2);
Inc(j);
iv3 := Vector3fMake(Cloud.Puffs[i].Position[0]+Corner2[0]*Cloud.Puffs[i].Size,
Cloud.Puffs[i].Position[1]+Corner2[1]*Cloud.Puffs[i].Size,
Cloud.Puffs[i].Position[2]+Corner2[2]*Cloud.Puffs[i].Size);
AddToMem(Cloud, j, v2, iv3, pColor, pColor2);
Inc(j);
iv3 := Vector3fMake(Cloud.Puffs[i].Position[0]+Corner3[0]*Cloud.Puffs[i].Size,
Cloud.Puffs[i].Position[1]+Corner3[1]*Cloud.Puffs[i].Size,
Cloud.Puffs[i].Position[2]+Corner3[2]*Cloud.Puffs[i].Size);
AddToMem(Cloud, j, v3, iv3, pColor, pColor2);
Inc(j);
iv3 := Vector3fMake(Cloud.Puffs[i].Position[0]+Corner4[0]*Cloud.Puffs[i].Size,
Cloud.Puffs[i].Position[1]+Corner4[1]*Cloud.Puffs[i].Size,
Cloud.Puffs[i].Position[2]+Corner4[2]*Cloud.Puffs[i].Size);
AddToMem(Cloud, j, v4, iv3, pColor, pColor2);
Inc(j);
End;
end;
[/pascal]

Many Thanks
Nic