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I am having trouble building a c++ algorithm to remove the duplicate vertices when I am building the index array. What I am working on is model after http://www.robtheblo...e/ObjLoader.zip but his example was written in c using pointer arrays and malloc and realloc. the section of his code I am using is the convertmeshto function which can be found in objLoader7 and up.
The problem I have is when I am comparing my current face data to data I may have gotten before. apart form creating a new set of for loops I dont see how to get around it. In the code that follows I
-loop for the total of faces the mesh may have, then i loop for a count of 3 to represent a triangle. then loop for the total count of my Index Array I am building.
in my loop for a count of 3, using the current face i get the reference it has to the normal, vertex, and uv data. put each in a temp 3 float array.
The trouble I am having, Now i want to go and check the VBO I am building if it has any of this data in it already. if it does use the same index for it other wise its a new index. Short from creating for loops to go back through the vbo I have built, I dont see how to get around this, now the code example from that site doesnt have another loop, but reading through the source example he has a global loop counter called "j" that is incremented with the loop for 3.
so I have worked it out as at face 0 j is 0
then j incremented 3 times as its the first face
next face j is at 3, j is the reference to get the vertex,normal and uv data we may have in the VBO, yet i dont see how it compares past data.
in my code I am concerned with having the variable "index" read the right data to do the correct compare. an example, verts gets the right data that I compare next to see if I have it already or need it. does it mean more loops>
Vertex Verts = currentMesh.meshData->vertexList[index];
unsigned int index = 0;
for(unsigned int currentFace= 0; currentFace < currentMesh.meshData->numFaces; currentFace++)
{
bool hasNormal =false; bool hasUV = false;
//short hand reference
pf = currentMesh.meshData->faceList[currentFace];
//did we count normals and uv's when reading the mesh data
if(currentMesh.meshData->numNormals > 0)
hasNormal = true;
if(currentMesh.meshData->numUV > 0)
hasUV = true;
//check for duplicate vertices,normals and uv
/*Here we use K to represent 3 points of a triangle
We use index to move along the currentFace and reference the actual data of a uv,normal,or vertex
*/
for(int k = 0; k < 3; k++, index++)
{
//temp data
float verts[3]={0},norms[3]={0},uvs[2]={0};
//at least we will have 3 vertices to make up a triangle verts[0] = pVT[ pf.vertIndices[k] ].x ;
verts[1] = pVT[ pf.vertIndices[k] ].y ;
verts[2] = pVT[ pf.vertIndices[k] ].z ;
tempVerts = pVT[ pf.vertIndices[k] ];
if(hasNormal)
{
norms[0] = pNT[ pf.normalIndices[k] ].x ;
norms[1] = pNT[ pf.normalIndices[k] ].y ;
norms[2] = pNT[ pf.normalIndices[k] ].z ;
tempNorm = pNT[ pf.normalIndices[k] ];
}
if(hasUV)
{
uvs[0] = pUT[ pf.uvIndices[k] ].u ;
uvs[1] = pUT[ pf.uvIndices[k] ].v ;
tempUV = pUT[ pf.uvIndices[k] ];
}
//verts norms uvs now have the current triangle data.
//test for reoccurrence
//if we have incremented the IBO we check against the indices and vertex we have crossed referenced
//with the other vertex data of the obj.
int ib = 0;
while(ib < ActualVertexArraySize;++ib)
{
//loop through all the triangle data we may have stored
//compare if we added this vertex yet
Vertex Verts = currentMesh.meshData->vertexList[index];
//test if the vertex exsist already if not add it as a new VBO data reference
// wrong comparrison need to check normalList.
if(FLOATCOMPARE(tempVerts.x,Verts.x)&&
FLOATCOMPARE(tempVerts.y,Verts.y)&&
FLOATCOMPARE(tempVerts.z,Verts.z) )
{
//comparison true so we reuse this vertex
if(hasNormal)
{
//short form
Vertex Norm = currentMesh.meshData->normalList[index];
//test if the vertex exsist already if not add it as a new VBO data reference
// wrong comparrison need to check normalList.
if(FLOATCOMPARE(tempNorm.x,Norm.x)&&
FLOATCOMPARE(tempNorm.y,Norm.y)&&
FLOATCOMPARE(tempNorm.z,Norm.z) )
{
//test if UV's exsist
if(hasUV)
{
goto douv;
}
else
{
//comparison true so we reuse this vertex
goto reuse;
}
}//compare normals
}//end had normals
//no normals so just UV coords maybe
else if(hasUV)
{
//goto douv;
douv:
{
//short form
TexUV UV = currentMesh.meshData->uvList[index];
if(FLOATCOMPARE(tempUV.u,UV.u)&&
FLOATCOMPARE(tempUV.v,UV.v))
{
goto reuse;
}
}//end goto label
}//else if has UV only
else
{
goto reuse;
}
}//if compare duplicate vertex
}//end while actualVertexArraySize has a count
//the first data for actualVertexArraySize hence we start at 1 in the loop but ensure we do have a element in the vertex count
//procedual steps, the element was unique so add it as a new vertexsize, jump and increment the index buffer.
currentMesh.triangleIndexBuffer[IBcount]= ActualVertexArraySize++;
goto endElement;
//jumped here, it is a old index, so reuse it, then increment the new index place
reuse:
currentMesh.triangleIndexBuffer[IBcount]= ib;
newElement:
IBcount++; //next indices position
}//end loop per trangle
