HeightFIeld divided into parts - PhysX - c++

Question

I have a terrain with a specific length and width, which take the information from he file bmp. With Shade of grey i can modify my terrain. Fine, it works great.
Here comes the problem.
I need my terrain divided into physically smaller parts, joined together create the original terrain.
How can i do this? I know that its possible. Any sugestions? Where, why there?
Mys file:
HeightField.cpp
#include "HeightField.h"
HeightField::HeightField(Terrain terrain, PxPhysics& sdk, PxMaterial &material, int width, int height)
{
this->nrVertices = terrain.NumVertices;
this->terrain = terrain;
this->width = width;
this->height = height;
this->fillSamples();
this->fillDesc();
this->aHeightField = sdk.createHeightField(hfDesc);
this->hfGeom = new PxHeightFieldGeometry(aHeightField, PxMeshGeometryFlags(), this->terrain.dy / 255.0, this->terrain.dx, this->terrain.dz);
this->terrainPos = new PxTransform(PxVec3(-this->terrain.dx*(this->width - 1) / 2, 0.0f, this->terrain.dz*(this->height - 1) / 2), PxQuat(3.1415 / 2.0, PxVec3(0, 1, 0)));
this->g_pxHeightField = sdk.createRigidDynamic(*this->terrainPos);
this->g_pxHeightField->setRigidDynamicFlag(PxRigidDynamicFlag::eKINEMATIC, true);
PxShape* aHeightFieldShape = this->g_pxHeightField->createShape(*(this->hfGeom), material);
}
HeightField::~HeightField()
{
}
void HeightField::fillSamples()
{
this->samples = (PxHeightFieldSample*)malloc(sizeof(PxHeightFieldSample)*(this->nrVertices));
for (int i = 0; i < this->nrVertices; i++)
{
samples[i].height = this->terrain.hminfo.heightMap[i].y;
samples[i].clearTessFlag();
}
}
void HeightField::fillDesc()
{
this->hfDesc.format = PxHeightFieldFormat::eS16_TM;
this->hfDesc.nbColumns = this->width;
this->hfDesc.nbRows = this->height;
this->hfDesc.samples.data = this->samples;
this->hfDesc.samples.stride = sizeof(PxHeightFieldSample);
}
Terrain.cpp
#include "Terrain.h"
Terrain::Terrain(void)
{
v = NULL;
indices = NULL;
dx = dz = 1000; //odleg³oœæ miêdzy punktami grid'a
dy = 1000; //maksymalna wysokoϾ terenu
}
Terrain::~Terrain(void)
{
if (v != NULL) delete [] v;
if (indices != NULL) delete indices;
if (hminfo.heightMap != NULL) delete [] hminfo.heightMap;
}
bool Terrain::HeightMapLoad(char* filename, float sx, float sz, float maxy)
{
FILE *filePtr; // Point to the current position in the file
BITMAPFILEHEADER bitmapFileHeader; // Structure which stores information about file
BITMAPINFOHEADER bitmapInfoHeader; // Structure which stores information about image
int imageSize, index;
unsigned char height;
// Open the file
filePtr = fopen(filename,"rb");
if (filePtr == NULL)
return 0;
dx = sz;
dz = sz;
dy = maxy;
// Get the width and height (width and length) of the image
hminfo.terrainWidth = bitmapInfoHeader.biWidth;
hminfo.terrainHeight = bitmapInfoHeader.biHeight;
// Initialize the heightMap array (stores the vertices of our terrain)
hminfo.heightMap = new IntV3[hminfo.terrainWidth * hminfo.terrainHeight];
// We use a greyscale image, so all 3 rgb values are the same, but we only need one for the height
// So we use this counter to skip the next two components in the image data (we read R, then skip BG)
int k=0;
// Read the image data into our heightMap array
for(int j=0; j< hminfo.terrainHeight; j++)
{
for(int i=0; i< hminfo.terrainWidth; i++)
{
height = bitmapImage[k];
index = ( hminfo.terrainWidth * (hminfo.terrainHeight - 1 - j)) + i;
hminfo.heightMap[index].x = i - (hminfo.terrainWidth - 1)/2;
hminfo.heightMap[index].y = height;
hminfo.heightMap[index].z = j - (hminfo.terrainHeight - 1)/2;
k+=3;
}
k++;
}
int cols = hminfo.terrainWidth;
int rows = hminfo.terrainHeight;
//Create the grid
NumVertices = 2 * rows * cols;
NumFaces = (rows-1)*(cols-1)*2;
v = new struct HeightFieldVertex[NumVertices];
for(DWORD i = 0; i < rows; ++i)
{
for(DWORD j = 0; j < cols; ++j)
{
v[i*cols+j].pos.x = hminfo.heightMap[i*cols+j].x * dx;
v[i*cols+j].pos.y = (float(hminfo.heightMap[i*cols+j].y)/255.0) * dy;
v[i*cols+j].pos.z = hminfo.heightMap[i*cols+j].z * dz;
v[i*cols+j].texCoord = D3DXVECTOR2(j, i);
}
}
indices = new DWORD[NumFaces * 3];
k = 0;
for(DWORD i = 0; i < rows-1; i++)
{
for(DWORD j = 0; j < cols-1; j++)
{
indices[k] = i*cols+j; // Bottom left of quad
indices[k+1] = i*cols+j+1; // Bottom right of quad
indices[k+2] = (i+1)*cols+j; // Top left of quad
indices[k+3] = (i+1)*cols+j; // Top left of quad
indices[k+4] = i*cols+j+1; // Bottom right of quad
indices[k+5] = (i+1)*cols+j+1; // Top right of quad
k += 6; // next quad
}
}
//normals & tangents
std::vector<D3DXVECTOR3> tempNormal;
//normalized and unnormalized normals
D3DXVECTOR3 unnormalized(0.0f, 0.0f, 0.0f);
//tangent stuff
std::vector<D3DXVECTOR3> tempTangent;
D3DXVECTOR3 tangent(0.0f, 0.0f, 0.0f);
float tcU1, tcV1, tcU2, tcV2;
//Used to get vectors (sides) from the position of the verts
float vecX, vecY, vecZ;
//Two edges of our triangle
D3DXVECTOR3 edge1(0.0f, 0.0f, 0.0f);
D3DXVECTOR3 edge2(0.0f, 0.0f, 0.0f);
//Compute face normals
//And Tangents
for(int i = 0; i < NumFaces; ++i)
{
//Get the vector describing one edge of our triangle (edge 0,2)
vecX = v[indices[(i*3)+1]].pos.x - v[indices[(i*3)]].pos.x;
vecY = v[indices[(i*3)+1]].pos.y - v[indices[(i*3)]].pos.y;
vecZ = v[indices[(i*3)+1]].pos.z - v[indices[(i*3)]].pos.z;
edge1 = D3DXVECTOR3(vecX, vecY, vecZ); //Create our first edge
//Get the vector describing another edge of our triangle (edge 2,1)
vecX = v[indices[(i*3)+2]].pos.x - v[indices[(i*3)]].pos.x;
vecY = v[indices[(i*3)+2]].pos.y - v[indices[(i*3)]].pos.y;
vecZ = v[indices[(i*3)+2]].pos.z - v[indices[(i*3)]].pos.z;
edge2 = D3DXVECTOR3(vecX, vecY, vecZ); //Create our second edge
//Cross multiply the two edge vectors to get the un-normalized face normal
D3DXVec3Cross(&unnormalized, &edge1, &edge2);
tempNormal.push_back(unnormalized);
//Find first texture coordinate edge 2d vector
tcU1 = v[indices[(i*3)+1]].texCoord.x - v[indices[(i*3)]].texCoord.x;
tcV1 = v[indices[(i*3)+1]].texCoord.y - v[indices[(i*3)]].texCoord.y;
//Find second texture coordinate edge 2d vector
tcU2 = v[indices[(i*3)+2]].texCoord.x - v[indices[(i*3)]].texCoord.x;
tcV2 = v[indices[(i*3)+2]].texCoord.y - v[indices[(i*3)]].texCoord.y;
//Find tangent using both tex coord edges and position edges
tangent.x = (tcV2 * edge1.x - tcV1 * edge2.x) / (tcU1 * tcV2 - tcU2 * tcV1);
tangent.y = (tcV2 * edge1.y - tcV1 * edge2.y) / (tcU1 * tcV2 - tcU2 * tcV1);
tangent.z = (tcV2 * edge1.z - tcV1 * edge2.z) / (tcU1 * tcV2 - tcU2 * tcV1);
tempTangent.push_back(tangent);
}
//Compute vertex normals (normal Averaging)
D3DXVECTOR4 normalSum(0.0f, 0.0f, 0.0f, 0.0f);
D3DXVECTOR4 tangentSum(0.0f, 0.0f, 0.0f, 0.0f);
int facesUsing = 0;
float tX, tY, tZ; //temp axis variables
//Go through each vertex
for(int i = 0; i < NumVertices; ++i)
{
//Check which triangles use this vertex
for(int j = 0; j < NumFaces; ++j)
{
if(indices[j*3] == i ||
indices[(j*3)+1] == i ||
indices[(j*3)+2] == i)
{
tX = normalSum.x + tempNormal[j].x;
tY = normalSum.y + tempNormal[j].y;
tZ = normalSum.z + tempNormal[j].z;
normalSum = D3DXVECTOR4(tX, tY, tZ, 0.0f); //If a face is using the vertex, add the unormalized face normal to the normalSum
facesUsing++;
}
}
//Get the actual normal by dividing the normalSum by the number of faces sharing the vertex
normalSum = normalSum / facesUsing;
facesUsing = 0;
//Check which triangles use this vertex
for(int j = 0; j < NumFaces; ++j)
{
if(indices[j*3] == i ||
indices[(j*3)+1] == i ||
indices[(j*3)+2] == i)
{
//We can reuse tX, tY, tZ to sum up tangents
tX = tangentSum.x + tempTangent[j].x;
tY = tangentSum.y + tempTangent[j].y;
tZ = tangentSum.z + tempTangent[j].z;
tangentSum = D3DXVECTOR4(tX, tY, tZ, 0.0f); //sum up face tangents using this vertex
facesUsing++;
}
}
//Get the actual normal by dividing the normalSum by the number of faces sharing the vertex
tangentSum = tangentSum / facesUsing;
//Normalize the normalSum vector and tangent
D3DXVec4Normalize(&normalSum, &normalSum);
D3DXVec4Normalize(&tangentSum, &tangentSum);
//Store the normal and tangent in our current vertex
v[i].normal.x = normalSum.x;
v[i].normal.y = normalSum.y;
v[i].normal.z = normalSum.z;
v[i].tangent.x = tangentSum.x;
v[i].tangent.y = tangentSum.y;
v[i].tangent.z = tangentSum.z;
D3DXVECTOR3 bit;
D3DXVec3Cross(&bit, &v[i].normal, &v[i].tangent);
v[i].bitangent = -1.0 * bit;
//Clear normalSum, tangentSum and facesUsing for next vertex
normalSum = D3DXVECTOR4(0.0f, 0.0f, 0.0f, 0.0f);
tangentSum = D3DXVECTOR4(0.0f, 0.0f, 0.0f, 0.0f);
facesUsing = 0;
}
////terrain AABB
//MinX = -1.0 * dx * (hminfo.terrainWidth - 1)/2;
//MinY = 0.0;
//MinZ = -1.0 * dz * (hminfo.terrainHeight - 1)/2;
//MaxX = dx * (hminfo.terrainWidth - 1)/2;
//MaxY = dy;
//MaxZ = dz * (hminfo.terrainHeight - 1)/2;
return true;
}
Fragment of Base.cpp
HeightField *hf = new HeightField(g_Terrain, *g_PhysicsSDK, *material, g_Terrain.hminfo.terrainWidth, g_Terrain.hminfo.terrainHeight);
g_PxScene->addActor(*(hf->g_pxHeightField));
I want to get something similar, but in order to work correctly
PVD - simulation Terrain

Answer 1

If you are familiar with the website rastertek for working with DirectX 10 or 11 in c++ within his updated DirectX 11 Terrain Series or version 2 a similar construct was created in tutorial 9 in which he calls Terrain Cells. The direct link to that tutorial can be found here: DirectX 11: Terrain Series2: Tutorial 9 - Terrain Cells. This should provide an excellent reference that I think is related toward the topic at hand and your initial question.