void TreeStem::buildSegment(TreeGeneralParams generalParams, TreeSegment* prevSeg, int segIndex,
float splitAngle, float divergeAngle, float rotateYAngle, LevelContext& context)
{
_Assert(segIndex < mLevelParams.curveRes);
static int dbNumSegs[4];
dbNumSegs[mLevelParams.level]++;
ConsolePrint(L"current numSegs: (0-%d),(1-%d),(2-%d),(3-%d)\n", dbNumSegs[0], dbNumSegs[1], dbNumSegs[2], dbNumSegs[3]);
int numSegs = mLevelParams.curveRes;
float segLength = mLength / numSegs;
TreeSegment* seg = New TreeSegment;
float curveDelta = 0;
if(segIndex != 0)
{
if(mLevelParams.curveBack == 0)
{
curveDelta = mLevelParams.curve / mLevelParams.curveRes;
}
else
{
if(segIndex < (mLevelParams.curveRes + 1) / 2)
curveDelta = 2 * mLevelParams.curve / mLevelParams.curveRes;
else
curveDelta = -2 * mLevelParams.curveBack / mLevelParams.curveRes;
}
curveDelta += RandomVariation(0, mLevelParams.curveV) / mLevelParams.curveRes;
}
Vector3 basePos;
if(prevSeg == NULL)
basePos = Vector3::Zero;
else
basePos = Vector3(0, segLength, 0);
seg->mPos = basePos;
seg->mOrient = Quaternion(0, DEGREE_TO_RAD(divergeAngle), DEGREE_TO_RAD(curveDelta + splitAngle));
seg->mSegIndex = segIndex;
seg->mParent = prevSeg;
seg->mStem = this;
Quaternion parentOrientWorld;
if(prevSeg)
{
prevSeg->mChildren.push_back(seg);
parentOrientWorld = prevSeg->mOrientWorld;
}
else
{
mFirstSeg = seg;
parentOrientWorld = mOrient;
}
// divergeAngle是绕世界的y轴旋转
seg->mOrientWorld = Quaternion(0, DEGREE_TO_RAD(rotateYAngle), 0) * (parentOrientWorld * seg->mOrient);
seg->mOrient = WorldRotationToLocal(parentOrientWorld.Difference(seg->mOrientWorld), parentOrientWorld);
// create seg vb ...
std::vector<float> segRadius;
{
float offset = (float)segIndex / numSegs;
float offsetDelta = 1.0f / numSegs / mLevelParams.segSegsH;
for(int i = 0; i <= mLevelParams.segSegsH; ++i)
{
segRadius.push_back(GetStemRadius(offset));
offset += offsetDelta;
}
}
bool closeTop = true;
bool closeBottom = true;
//if(segIndex == 0)
// closeBottom = true;
//if(segIndex == numSegs - 1)
// closeTop = true;
seg->mGeo = New TreeSegGeo(segLength, mLevelParams.segSegsW, mLevelParams.segSegsH, segRadius,
Quaternion(0, 0, DEGREE_TO_RAD(curveDelta + splitAngle)), closeTop, closeBottom);
seg->mGeo->CalculateNormals();
seg->mGeo->BuildGeometry(XYZ_N);
// branches
if(seg->mStem->GetNumBranches() != 0 && mLevelParams.level < generalParams.levels - 1)
{
float baseOffset = 0;
if(mLevelParams.level == 0)
{
float baseLength = generalParams.baseSize * mLength;
baseOffset = baseLength - segIndex * segLength;
}
float offset = 0;
if(baseOffset <= 0)
{
offset = mBranchInterval - context.branchDistError;
}
else if(baseOffset < segLength)
{
offset = baseOffset + mBranchInterval;
}
else
{
offset = segLength + mBranchInterval;
}
while(offset < segLength - 0.0001f)
{
TreeStem* branch = New TreeStem(mTree, mLevelParams.level + 1);
branch->Build(seg, offset, generalParams, mTree->GetLevelParams(mLevelParams.level + 1), context);
seg->mBranches.push_back(branch);
offset += mBranchInterval;
}
context.branchDistError = segLength - (offset - mBranchInterval);
}
// splits
if(segIndex == numSegs - 1)
return;
int numSplits = 0;
if(mLevelParams.level == 0 && segIndex == 0)
{
numSplits = generalParams.baseSplits;
}
else
{
numSplits = (int)(mLevelParams.segSplits + context.splitError);
context.splitError = mLevelParams.segSplits + context.splitError - numSplits;
}
if(numSplits < 1) // no splits
{
buildSegment(generalParams, seg, segIndex + 1, 0, 0, 0, context);
}
else
{
Vector3 vecUp = Vector3(0, 1, 0) * seg->mOrientWorld;
float declination = VectorAngle(Vector3(0, 1, 0), vecUp);
float splitAngleFactor = 1.0f; // 调整此算法来使splitAngle随枝干的水平角度加成变化
splitAngleFactor = fabs(declination - PI/2) / (PI/2);
float childSplitAngle = max(0, splitAngleFactor * RandomVariation(mLevelParams.splitAngle, mLevelParams.splitAngleV));
for(int i = 0; i <= numSplits; ++i)
{
float childDivergeAngle = 0;
float childRotateYAngle = 0;
childDivergeAngle = ((float)i / (numSplits + 1)) * 360;
if(mLevelParams.level == 0 && segIndex == 0)
{
childRotateYAngle = 0;
}
else
{
float rf = RandomFloat(0, 1.0f);
int s = sign(RandomFloat(-1.0f, 1.0f));
childRotateYAngle = s * (20 + 0.75f * (30 + fabs(declination - 90)) * pow(rf, 2));
}
buildSegment(generalParams, seg, segIndex + 1, childSplitAngle, childDivergeAngle, childRotateYAngle, context);
}
}
}
