Normal map from heightmap?

Graphics and GPU Programming Programming

Started by Waaayoff July 29, 2012 02:04 PM

2 comments, last by gnmgrl 11 years, 8 months ago

952

Author

July 29, 2012 02:04 PM

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.

"Spending your life waiting for the messiah to come save the world is like waiting around for the straight piece to come in Tetris...even if it comes, by that time you've accumulated a mountain of shit so high that you're fucked no matter what you do. "

gnmgrl

699

July 29, 2012 06:16 PM

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]);

    }

  }