Is there a good tutorial anyway on tangant mapping?(C++ tutorial is fine, don't expect there to be any blitz ones ;) )
Here's my attempt at it, ripped from the guts of FMC. But, despite being as far as I can tell, corret, it doesn't work at all.
Local tmx#[16]
tmx[0]=1
tmx[1]=0
tmx[2]=0
tmx[3]=0
tmx[4]=0
tmx[5]=-1
tmx[6]=0
tmx[7]=0
tmx[8]=0
tmx[9]=0
tmx[10]=1
tmx[11]=0
tmx[12]=0
tmx[13]=0
tmx[14]=0
tmx[15]=1
Local lpES#[3]; // light position in Eye space
Local lpOS#[3]; // light position in Object space
Local lv#[3]; // vector from vertex to light
Local lv_ts#[3]; // light vector in tangent space
Local modelViewMatrix#[16];
Local modelViewMatrixInverse#[16]
fillMatrix( sys\cam,modelViewMatrix)
matrixInvert( modelViewMatrix,modelViewMatrixInverse)
If KeyDown(205)
lpes[0]=lx
lpes[1]=ly
lpes[2]=lz
Else
TFormPoint lx,ly,lz,sys\cam,0
lpEs[0]=TFormedX()
lpes[1]=TFormedY()
lpes[2]=TFormedZ()
EndIf
vecMatMult(lpES, modelViewMatrixInverse, lpOS);
Local vert1#[3],vert2#[3],vert3#[3]
Local tvec#[3],bnorm#[3],norm#[3]
Local pnorm#[3],tex1#[2],tex2#[2],tex3#[2]
For b.bump=Each bump
sc=CountSurfaces( b\mesh)
For s=1 To sc
srf=GetSurface( b\mesh,s)
tc=CountTriangles(srf)
For t=1 To tc-1
v1=TriangleVertex(srf,t,1)
v2=TriangleVertex(srf,t,2)
v3=TriangleVertex(srf,t,3)
vector( VertexX(srf,v1),VertexY(srf,v1),VertexZ(srf,v1),vert1)
vector( VertexX(srf,v2),VertexY(srf,v2),VertexZ(srf,v2),vert2)
vector( VertexX(srf,v3),VertexY(srf,v3),VertexZ(srf,v3),vert3)
tex1[0]=VertexU(srf,v1)
tex1[1]=VertexV(srf,v1)
tex2[0]=VertexU(srf,v2)
tex2[1]=VertexV(srf,v2)
tex3[0]=VertexU(srf,v3)
tex3[1]=VertexV(srf,v3)
pnorm[0]=triangleNx( srf,t)
pnorm[1]=triangleNy( srf,t)
pnorm[2]=triangleNz( srf,t)
tang(vert1,vert2,vert3,tex1,tex2,tex3,pnorm,tvec,bnorm,norm)
tmx[0] =tvec[0]
tmx[1] =tvec[1]
tmx[2] =tvec[2]
;tmx[3]
tmx[4] =bnorm[0]
tmx[5] =bnorm[1]
tmx[6] =bnorm[2]
;tmx[7]=
tmx[8] =norm[0]
tmx[9] =norm[1]
tmx[10] =norm[2]
;
For vtt=0 To 2
v=TriangleVertex(srf,t,vtt)
vx#=VertexX(srf,v)
vy#=VertexY(srf,v)
vz#=VertexZ(srf,v)
;
lv[0] = (lx - vx);
lv[1] = (ly - vy);
lv[2] = (lz - vz);
vecNormalize(lv);
vecMat3x3Mult(lv, tmx, lv_ts);
;lv_ts[0] = lv_ts[0] * 0.5 + 0.5;
;lv_ts[1] = lv_ts[1] * 0.5 + 0.5;
;lv_ts[2] = lv_ts[2] * 0.5 + 0.5;
rd#=255
VertexColor srf,v,rd+rd*lv_ts[0],rd+rd*lv_ts[1],rd+rd*lv_ts[2]
Next
Next
Next
Next
Here's the vector lib it uses.(Free feel to use this lib btw.)
Function matrixIdentity(matrix#[16])
matrix[ 0] = 1.0; matrix[ 1] = 0.0; matrix[ 2] = 0.0; matrix[ 3] = 0.0;
matrix[ 4] = 0.0; matrix[ 5] = 1.0; matrix[ 6] = 0.0; matrix[ 7] = 0.0;
matrix[ 8] = 0.0; matrix[ 9] = 0.0; matrix[10] = 1.0; matrix[11] = 0.0;
matrix[12] = 0.0; matrix[13] = 0.0; matrix[14] = 0.0; matrix[15] = 1.0;
End Function
;//////////////////////////
;// Invert a matrix. (Matrix MUST be orhtonormal!)
;// in - Input matrix
;// out - Output matrix
;//////////////////////////
Function matrixInvert(in#[16], out#[16])
; // Transpose rotation
out[ 0] = in[ 0]; out[ 1] = in[ 4]; out[ 2] = in[ 8];
out[ 4] = in[ 1]; out[ 5] = in[ 5]; out[ 6] = in[ 9];
out[ 8] = in[ 2]; out[ 9] = in[ 6]; out[10] = in[10];
; // Clear shearing terms
out[3] = 0.0;f; out[7] = 0.0f; out[11] = 0.0f; out[15] = 1.0f;
; // Translation is minus the dot of tranlation And rotations
out[12] = -(in[12]*in[ 0]) - (in[13]*in[ 1]) - (in[14]*in[ 2]);
out[13] = -(in[12]*in[ 4]) - (in[13]*in[ 5]) - (in[14]*in[ 6]);
out[14] = -(in[12]*in[ 8]) - (in[13]*in[ 9]) - (in[14]*in[10]);
End Function
;//////////////////////////
;// Multiply a vector by a matrix.
;// vecIn - Input vector
;// m - Input matrix
;///////////////////////////
Function vecMatMult(vecIn#[3],m#[16], vecOut#[3])
vecOut[0] = (vecIn[0]*m[ 0]) + (vecIn[1]*m[ 4]) + (vecIn[2]*m[ 8]) + m[12];
vecOut[1] = (vecIn[0]*m[ 1]) + (vecIn[1]*m[ 5]) + (vecIn[2]*m[ 9]) + m[13];
vecOut[2] = (vecIn[0]*m[ 2]) + (vecIn[1]*m[ 6]) + (vecIn[2]*m[10]) + m[14];
End Function
;//////////////////////////
;// Multiply a vector by just the 3x3 portion of a matrix.
;// vecIn - Input vector
;// m - Input matrix
;// vecOut - Output vector
;//////////////////////////
;void
Function vecMat3x3Mult(vecIn#[3], m#[16], vecOut#[3])
vecOut[0] = (vecIn[0]*m[ 0]) + (vecIn[1]*m[ 4]) + (vecIn[2]*m[ 8]);
vecOut[1] = (vecIn[0]*m[ 1]) + (vecIn[1]*m[ 5]) + (vecIn[2]*m[ 9]);
vecOut[2] = (vecIn[0]*m[ 2]) + (vecIn[1]*m[ 6]) + (vecIn[2]*m[10]);
End Function
Function vecCrossProd (vecA#[3], vecB#[3], vecOut#[3])
vecOut[0] = vecA[1]*vecB[2] - vecA[2]*vecB[1];
vecOut[1] = vecA[2]*vecB[0] - vecA[0]*vecB[2];
vecOut[2] = vecA[0]*vecB[1] - vecA[1]*vecB[0];
End Function
Function vecNormalize#(vec#[3])
mag# = Sqr(vec[0]*vec[0] +vec[1]*vec[1] +vec[2]*vec[2]);
;// don't divide by zero
If (mag=0)
vec[0] = 0.0;f;
vec[1] = 0.0;f;
vec[2] = 0.0;f;
Return(0.0);
EndIf
vec[0] =vec[0]/mag;
vec[1] =vec[1]/mag;
vec[2] =vec[2]/mag;
Return(mag);
End Function
Function vecDotProd#(vecA#[3], vecB#[3])
Return(vecA[0]*vecB[0] +vecA[1]*vecB[1] +vecA[2]*vecB[2]);
End Function
Function vecCopy (vecIn#[3], vecOut#[3])
vecOut[0] = vecIn[0];
vecOut[1] = vecIn[1];
vecOut[2] = vecIn[2];
End Function
Function vector( v1#,v2#,v3#,vect#[3])
vect[0]=v1
vect[1]=v2
vect[2]=v3
End Function
Function tang( vertex#[3], vertex2#[3], vertex3#[3],texcoords#[2], texcoords2#[2], texcoords3#[2],polynormal#[3], tangent#[3], binormal#[3], normal#[3] )
Local txb#[3];
Local v1#[3],v2#[3]
VECTOR( vertex2[0] - vertex[0], texcoords2[0] - texcoords[0], texcoords2[1] - texcoords[1],v1 );
VECTOR( vertex3[0] - vertex[0], texcoords3[0] - texcoords[0], texcoords3[1] - texcoords[1],v2 );
crossProduct( v1, v2,txb );
If( Abs( txb[0] ) > EPSILON )
tangent[0] = -txb[1] / txb[0];
binormal[0] = -txb[2] / txb[0];
EndIf
v1[0] = vertex2[1] - vertex[1];
v2[0] = vertex3[1] - vertex[1];
CrossProduct( v1, v2,txb );
If( Abs( txb[0] ) > EPSILON )
tangent[1] = -txb[1] / txb[0];
binormal[1] = -txb[2] / txb[0];
EndIf
v1[0] = vertex2[2] - vertex[2];
v2[0] = vertex3[2] - vertex[2];
CrossProduct( v1, v2,txb);
If( Abs( txb[0] ) > EPSILON )
tangent[2] = -txb[1] / txb[0];
binormal[2] = -txb[2] / txb[0];
EndIf
Normalize( tangent );
Normalize( binormal );
;// Make a normal based on the tangent And binormal b/c it may be different than the poly's
;// normal, this normal being computed here is better
CrossProduct( tangent, binormal,normal);
Normalize( normal );
;// Make tangent space vectors orthogonal by recomputing the binormal with the corrected
;// tangent space normal.
CrossProduct( tangent, normal,biNormal);
Normalize( binormal );
If( vecDotProd( normal, polynormal ) < 0.0 )
normal[0] = -normal[0];
normal[1] = -normal[1];
normal[2] = -normal[2];
EndIf
End Function
Function TriangleNormal#(v1#[3],v2#[3],v3#[3],o#[3])
;SubVector v1,v2,
ux#=VectorX()
uy#=VectorY()
uz#=VectorZ()
;SubVector Cx#,Cy#,Cz#,Bx#,By#,Bz#
vx#=VectorX()
vy#=VectorY()
vz#=VectorZ()
;CrossProduct vx#,vy#,vz#,ux#,uy#,uz#
;Normalize vectorx,vectory,vectorz
;Return Ax#*vectorx+Ay#*vectory+Az#*vectorz
End Function
Function VectorX#()
Return vectorx
End Function
Function VectorY#()
Return vectory
End Function
Function VectorZ#()
Return vectorz
End Function
Function VectorW#()
Return vectorw
End Function
Function SubVector(v1#[3],v2#[3],o#[3])
o[0]=v1[0]-v2[0]
o[1]=v1[1]-v2[1]
o[2]=v1[2]=v2[2]
End Function
Function Normalize(v#[3])
If v[0]=0 And v[1]=0 And v[2]=0 Return
m#=Magnitude(v)
v[0]=v[0]/m#
v[1]=v[1]/m#
v[2]=v[2]/m#
End Function
Function CrossProduct(v1#[3],v2#[3],o#[3])
o[0]=v1[1]*v2[2]-v2[2]*v2[1]
o[1]=v1[2]*v2[0]-v1[0]*v2[2]
o[2]=v1[0]*v2[1]-v1[1]*v2[0]
End Function
Function Magnitude(v#[3])
Return Sqr( (v[0]*v[0]) + (v[1]*v[1]) + (v[2]*v[2]) )
End Function
Function TriangleNX#(surf,tri_no)
v0=TriangleVertex(surf,tri_no,0)
v1=TriangleVertex(surf,tri_no,1)
v2=TriangleVertex(surf,tri_no,2)
ax#=VertexX#(surf,v1)-VertexX#(surf,v0)
ay#=VertexY#(surf,v1)-VertexY#(surf,v0)
az#=VertexZ#(surf,v1)-VertexZ#(surf,v0)
bx#=VertexX#(surf,v2)-VertexX#(surf,v1)
by#=VertexY#(surf,v2)-VertexY#(surf,v1)
bz#=VertexZ#(surf,v2)-VertexZ#(surf,v1)
nx#=(ay#*bz#)-(az#*by#)
Return nx#
End Function
Function TriangleNY#(surf,tri_no)
v0=TriangleVertex(surf,tri_no,0)
v1=TriangleVertex(surf,tri_no,1)
v2=TriangleVertex(surf,tri_no,2)
ax#=VertexX#(surf,v1)-VertexX#(surf,v0)
ay#=VertexY#(surf,v1)-VertexY#(surf,v0)
az#=VertexZ#(surf,v1)-VertexZ#(surf,v0)
bx#=VertexX#(surf,v2)-VertexX#(surf,v1)
by#=VertexY#(surf,v2)-VertexY#(surf,v1)
bz#=VertexZ#(surf,v2)-VertexZ#(surf,v1)
ny#=(az#*bx#)-(ax#*bz#)
Return ny#
End Function
Function TriangleNZ#(surf,tri_no)
v0=TriangleVertex(surf,tri_no,0)
v1=TriangleVertex(surf,tri_no,1)
v2=TriangleVertex(surf,tri_no,2)
ax#=VertexX#(surf,v1)-VertexX#(surf,v0)
ay#=VertexY#(surf,v1)-VertexY#(surf,v0)
az#=VertexZ#(surf,v1)-VertexZ#(surf,v0)
bx#=VertexX#(surf,v2)-VertexX#(surf,v1)
by#=VertexY#(surf,v2)-VertexY#(surf,v1)
bz#=VertexZ#(surf,v2)-VertexZ#(surf,v1)
nz#=(ax#*by#)-(ay#*bx#)
Return nz#
End Function
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