3 replies to this topic

[Waaayoff]

I think i read somewhere that if you generate a normal map from the heightmap you don't need normal, binormal and tangent vectors per vertex to transform into object space? I'm not sure but i want to use normal maps to do lighting in my terrain.

[gnomgrol]

Here is the code I use to to this:

for(int z = 0; z<terrainHeight; z++){   
	   for(int x = 0; x<terrainWidth; x++){
    indexNm = z*terrainWidth+x;

    if(z > terrainHeight-1){ //aboth
	   nmOffset = terrainWidth;
    }else{
    nmOffset = 0;
    }
    D3DXVECTOR3 N1 = D3DXVECTOR3(x, heightMap[indexNm+nmOffset],z+1);

    if(x > 0){ //left
	   nmOffset = -1;
    }else{
    nmOffset = 0;
    }
    D3DXVECTOR3 N2 = D3DXVECTOR3(x-1, heightMap[indexNm+nmOffset],z);

    if(x > terrainWidth-1){ //right
	   nmOffset = 1;
    }else{
    nmOffset = 0;
    }
    D3DXVECTOR3 N3 = D3DXVECTOR3(x+1, heightMap[indexNm+nmOffset],z);

    if(z > 0){//below
	   nmOffset = -terrainWidth;
    }else{
    nmOffset = 0;
    }
    D3DXVECTOR3 N4 = D3DXVECTOR3(x, heightMap[indexNm+nmOffset],z-1);
			 D3DXVec3Cross(&normalMap[indexNm], &(N2 - N3), &(N1 - N4)); // cross and done!
    D3DXVec3Normalize(&normalMap[indexNm], &normalMap[indexNm]);
    }
  }

[Waaayoff]

Thanks, but do i have to use tangents/binormals?

[gnomgrol]

No, you don't. Just look up a terrain lightning tutorial. It's mostly the same like with any other object.