//Creates a full patch for one frequency. Calculates gradientpoints, and interpolates values for all pixels between them
vector<float> PerlinPatchGenerator::createPatch(int frequency, int gradientPoints, float amplitude){
float s,t,u,v,diffX,diffY,a,b,z;
int gradientX, gradientY;
vector<float> finalGrid;
float sVec[2], tVec[2], uVec[2], vVec[2];
vector<vector<float>> gradients;
gradients = createGradients(gradientPoints);
//Number of pixels included between each gradient point
int numberOfPixels = gridSize/frequency;
//Loop over all pixels in patch
for(int row = 0; row < gridSize; row++) {
//Calculate distance from pixel to closest gradient point in Y-axis
diffY = (float)(row % numberOfPixels)/(float)numberOfPixels;
for(int col = 0; col < gridSize; col++) {
//Calculate distance from pixel to closest gradient point in X-axis
diffX = (float)(col % numberOfPixels)/(float)numberOfPixels;
//Check what gradientpoints we should interpolate values from
gradientX = floor(col/numberOfPixels);
gradientY = floor(row/numberOfPixels);
//Calculate vectors from each gradientpoint to the pixel
sVec[0] = diffX;
sVec[1] = diffY;
tVec[0] = diffX-1;
tVec[1] = diffY;
uVec[0] = diffX;
uVec[1] = diffY-1;
vVec[0] = diffX-1;
vVec[1] = diffY-1;
//Calculate values to interpolate between for each pixel
s = dotProduct(gradients.at(gradientY*gradientPoints + gradientX),sVec);
t = dotProduct(gradients.at(gradientY*gradientPoints + gradientX+1),tVec);
u = dotProduct(gradients.at((gradientY+1)*gradientPoints + gradientX),uVec);
v = dotProduct(gradients.at((gradientY+1)*gradientPoints + gradientX+1),vVec);
//Interpolate in x-axis and y-axis
a = interpolateValues(s,t,diffX);
b = interpolateValues(u,v,diffX);
z = interpolateValues(a,b,diffY);;
finalGrid.push_back(z * amplitude);
}
}
return finalGrid;
}
// Private functions
void Blender::initCornerWeight(){
// Fill cornerWeight with zeros
// There are four corners, hence i < 4
vector<float> tempZeros (overlap*overlap,0.0);
for(int i = 0; i<4; i++){
cornerWeight.push_back(tempZeros);
}
for(int i = 0; i<overlap;i++){
for(int j = 0; j<overlap; j++){
float diffX = ((float)i)/((float)overlap-1);
float diffY = ((float)j)/((float)overlap-1);
float interpX = interpolateValues(1,0,diffX);
cornerWeight.at(0).at(overlap*i + j) = interpolateValues(interpX,0,diffY);
interpX = interpolateValues(0,1,diffX);
cornerWeight.at(1).at(overlap*i + j) = interpolateValues(interpX,0,diffY);
interpX = interpolateValues(1,0,diffX);
cornerWeight.at(2).at(overlap*i + j) = interpolateValues(0,interpX,diffY);
interpX = interpolateValues(0,1,diffX);
cornerWeight.at(3).at(overlap*i + j) = interpolateValues(0,interpX,diffY);
}
}
}
vector<float> PerlinPatchGenerator::createPatch(int gridSize, int frequency, int gradientPoints, float amplitude){
cout << "createPatch begin\n";
vector<vector<float>> gradients;
gradients = createGradients(gradientPoints);
int numberOfPixels = gridSize/frequency;
float s,t,u,v,diffX,diffY,Sx,Sy,a,b,z,ft,f;
int gradientX, gradientY;
vector<float> finalGrid;
for(int row = 0; row < gridSize; row++) {
diffY = (float)(row % numberOfPixels)/(float)numberOfPixels;
for(int col = 0; col < gridSize; col++) {
diffX = (float)(col % numberOfPixels)/(float)numberOfPixels;
gradientX = floor(col/numberOfPixels);
gradientY = floor(row/numberOfPixels);
vector<float> sVec, tVec, uVec, vVec;
sVec.push_back(diffX);
sVec.push_back(diffY);
tVec.push_back(diffX-1);
tVec.push_back(diffY);
uVec.push_back(diffX);
uVec.push_back(diffY-1);
vVec.push_back(diffX-1);
vVec.push_back(diffY-1);
s = dotProduct(gradients.at(gradientY*gradientPoints + gradientX),sVec);
t = dotProduct(gradients.at(gradientY*gradientPoints + gradientX+1),tVec);
u = dotProduct(gradients.at((gradientY+1)*gradientPoints + gradientX),uVec);
v = dotProduct(gradients.at((gradientY+1)*gradientPoints + gradientX+1),vVec);
a = interpolateValues(s,t,diffX);
b = interpolateValues(u,v,diffX);
z = interpolateValues(a,b,diffY);;
finalGrid.push_back(z * amplitude);
}
}
cout << "createPatch end\n";
return finalGrid;
}
void Blender::blendHors(TerrainPatch* patchWest,TerrainPatch* patchEast){
int patchSize = patchWest->size;
int jWest; // jEast is always = j
for(int i=overlap; i<patchSize-overlap; i++){
for(int j=0; j<overlap; j++){
jWest = j + patchSize - overlap;
float diff = ((float)j)/(overlap-1);
float weight = interpolateValues(0,1,diff);
float interp =
weight*patchEast->rawHeightMap.at(patchSize*i + j) +
(1-weight)*patchWest->rawHeightMap.at(patchSize*i + jWest);
patchWest->blendedHeightMap.at(patchSize*i + jWest) = interp;
patchEast->blendedHeightMap.at(patchSize*i + j) = interp;
}
}
}
void Blender::blendVert(TerrainPatch* patchNorth,TerrainPatch* patchSouth){
int patchSize = patchNorth->size;
int iNorth; // iSouth is always = i
for(int i=0; i<overlap; i++){
float diff = ((float)i)/(overlap-1);
float weight = interpolateValues(0,1,diff);
for(int j=overlap; j<patchSize-overlap; j++){
iNorth = i + patchSize - overlap;
float interp =
weight*patchSouth->rawHeightMap.at(patchSize*i + j) +
(1-weight)*patchNorth->rawHeightMap.at(patchSize*iNorth + j);
patchNorth->blendedHeightMap.at(patchSize*iNorth + j) = interp;
patchSouth->blendedHeightMap.at(patchSize*i + j) = interp;
}
}
}
