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Zeblar Nagrim

Normal problem

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Hello! My d3d8 normals for my 3ds object are so fu*k*ng wrong! Here is some code:


// Name: CreateVertexBuffer()

// Desc: Create vertexbuffer from vertex and texcoord arrarys


bool CD3DMesh::CreateVertexBuffer(LPDIRECT3DDEVICE8 device, int NumVertices, float *pfVertices, float *pfTexcoords)
    m_iNumFaces = NumVertices/3;

    if(FAILED(device->CreateVertexBuffer( NumVertices*sizeof(CUSTOMVERTEX),
        0, D3DFVF_CUSTOMVERTEX, D3DPOOL_DEFAULT, &m_lpVertexBuffer ))) return false;

    CUSTOMVERTEX *pVertices;
    if(FAILED(m_lpVertexBuffer->Lock( 0, 0, (BYTE**)&pVertices, 0 ))) return false;

    float *pfNormals = new float[NumVertices*3];
    GenerateFaceNormals(NumVertices, pfVertices, pfNormals);

    for(int i=0; i<NumVertices; i++)
        pVertices[i].p.x = pfVertices[i*3];
        pVertices[i].p.y = pfVertices[i*3+1];
        pVertices[i].p.z = pfVertices[i*3+2];

        pVertices[i].n.x = pfNormals[i*3];
        pVertices[i].n.y = pfNormals[i*3+1];
        pVertices[i].n.z = pfNormals[i*3+2];

            pVertices[i].tu = pfTexcoords[i*2];
            pVertices[i].tv = pfTexcoords[i*2+1];
            pVertices[i].tu = 0.0f;
            pVertices[i].tv = 0.0f;


    delete[] pfNormals;

    return true;


// Name: GenerateNormals()

// Desc: 


void CD3DMesh::GenerateFaceNormals(int NumVertex, float *pdVertexData, float *pfNormalData)
    D3DXVECTOR3 vertex1, vertex2, vertex3, normal, vector1, vector2;

    for(int i=0; i<NumVertex/3; i++)
        vertex1 = D3DXVECTOR3(pdVertexData[i*9+0], pdVertexData[i*9+1] , pdVertexData[i*9+2]);
        vertex2 = D3DXVECTOR3(pdVertexData[i*9+3], pdVertexData[i*9+4] , pdVertexData[i*9+5]);
        vertex3 = D3DXVECTOR3(pdVertexData[i*9+6], pdVertexData[i*9+7] , pdVertexData[i*9+8]);

        vector1 = vertex2 - vertex1;
        vector2 = vertex3 - vertex1;

        D3DXVec3Cross(&normal, &vector1, &vector2);
        D3DXVec3Normalize(&normal, &normal);
        normal = -normal;

        pfNormalData[i*9+0] = normal.x;
        pfNormalData[i*9+1] = normal.x;
        pfNormalData[i*9+2] = normal.x;

        pfNormalData[i*9+3] = normal.y;
        pfNormalData[i*9+4] = normal.y;
        pfNormalData[i*9+5] = normal.y;

        pfNormalData[i*9+6] = normal.z;
        pfNormalData[i*9+7] = normal.z;
        pfNormalData[i*9+8] = normal.z;

Please! If somebody can see what I have done wrong this time, please respond. Zeblar Nagrim, Lord of Chaos

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I think you're making a mistake in your renderloop. In the code you use i as the base index for your vertex/normals (as in i+0 gives x, i+1 gives y and i+2 gives z). Then for the next vertex you have to add 3, but in stead i is incremented by 1! Change it to this:

int index = 0;

for(int i = 0; i < NumVertices; i++)
pVertices.p.x = pfVertices[index*3];
pVertices[i].p.y = pfVertices[index*3+1];
pVertices[i].p.z = pfVertices[index*3+2];
pVertices[i].n.x = pfNormals[index*3];
pVertices[i].n.y = pfNormals[index*3+1];
pVertices[i].n.z = pfNormals[index*3+2];


index += 3;

This should work.

Edited by - sysmark on July 28, 2001 9:00:58 PM

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