[英]Creating a fractal tree in opengl
在opengl中创建分形有些麻烦。 这是我当前的代码
void generateTree(){
Point3f startPoint({0.0f,0.0f,0.0f});
Point3f endPoint({1.0f,0.0f,0.0f});
float rotation = 90.0f;
glutWireSphere(0.05, 4, 4);
_generateTreeBranches(startPoint,1.0f,rotation,0);
}
void _generateTreeBranches(const Point3f& newPosition,
float length,
float rotation,
const int depth)
{
if(depth > MAX_DEPTH) return;
cout << "at depth = " << depth << endl;
if(depth == 0){
glColor3f(1.0f,1.0f,1.0f);
}else if(depth == 1){
glColor3f(1.0f,0.0f,0.0f);
}else{
glColor3f(0.0f,1.0f,0.0f);
}
glTranslatef(newPosition.x,newPosition.y,newPosition.z);
glRotatef(rotation, 0.0f, 0.0f, 1.0f);
drawLine(length);
glRotatef(-rotation, 0.0f, 0.0f, 1.0f);
glTranslatef(-newPosition.x,-newPosition.y,-newPosition.z);
const float newLength = length * BRANCH_LENGTH_DECREASE_FACTOR;
int nextDepth = depth + 1;
Point3f nextPosition = {newPosition.x+length, newPosition.y, newPosition.z};
float leftRotation = rotation + CHILD_BRANCH_ANGLE * nextDepth;
_generateTreeBranches(nextPosition,newLength,leftRotation,nextDepth);
float rightRotation = rotation - CHILD_BRANCH_ANGLE * nextDepth;
_generateTreeBranches(nextPosition,newLength,rightRotation,nextDepth);
}
定位不正确,尽管旋转似乎正确。 从父级分支的端点开始绘制新的分支。 有人可以帮我解决这个问题。 在此处查看完整代码
nextPosition的公式不正确,因为它没有考虑当前分支所面向的方向
Point3f nextPosition = {newPosition.x+length, newPosition.y, newPosition.z};
应该是这样的(请仔细检查):
Point3f nextPosition = {newPosition.x+length*cos(rotation), newPosition.y+length*sin(rotation), newPosition.z};
另外,请使用glLoadIdentity()立即重置矩阵,如下所示:
glTranslatef(newPosition.x,newPosition.y,newPosition.z);
glRotatef(rotation, 0.0f, 0.0f, 1.0f);
drawLine(length);
glLoadIdentity();
这将比您要尝试的要清楚得多。
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