自从我编写 C/C++ 以来已经有几年了,现在我面临一个我似乎无法靠自己解决的问题。
给定以下结构:
struct InputData
{
float diameter;
float length;
int vertIndex;
struct InputData *parent;
vector<InputData*> children;
bool deadEnd;
InputData(float dia, float lngth)
{
diameter = dia;
length = lngth;
vertIndex = NULL;
parent = NULL;
deadEnd = false;
}
};
我首先定义了一些节点,以及它们的父/子关系:
InputData i0 = InputData(3.0f, 3.0f);
InputData i1 = InputData(2.0f, 2.0f);
InputData i2 = InputData(1.0f, 1.0f);
InputData i3 = InputData(1.0f, 1.0f);
InputData i4 = InputData(1.0f, 1.0f);
InputData i5 = InputData(1.01f, 0.5f);
i0.children.push_back(&i1);
i1.children.push_back(&i2);
i2.children.push_back(&i3);
i3.children.push_back(&i4);
i4.children.push_back(&i5);
i1.parent = &i0;
i2.parent = &i1;
i3.parent = &i2;
i4.parent = &i3;
i5.parent = &i4;
请注意, i5 作为唯一节点没有任何子节点。
然后我继续使用这些数据做一些工作(从 main() 调用 BuildMeshVertices(&i0, &vertices)),最后将一个子级添加到 i5:
void BuildMeshVertices(InputData* current, vector<SimpleVertex> *vertices)
{
//Do work
if(current->children.size() == 1)
{
BuildMeshVertices(current->children[0], vertices);
}
else if(current->children.size() == 0 && current->deadEnd == false)
{
InputData iDeadEnd = InputData(1.01f, 0.5f);
iDeadEnd.deadEnd = true;
iDeadEnd.parent = current;
current->children.push_back(&iDeadEnd);
BuildMeshVertices(&iDeadEnd, vertices);
}
}
之后一切都很好。i0 有一个孩子 (i1),i1 有一个孩子 (i2),依此类推,i5 现在也有一个孩子。
我调用了另一个函数(BuildMeshIndices()),突然在这个函数的几行(第 63 行)中,新添加到 i5 的子节点的数据被覆盖了。i5 仍然指向正确的孩子,但是这个孩子的数据突然乱码。
这是之前和之后的屏幕截图(对不起链接,但我不被允许使用 IMG 标签)
我不知道为什么会发生这种情况,但我感觉这与我糟糕的内存管理有关?
更新也不必这样做。例如,如果将子向量更改为值向量是首选的 C++ 方式,我更愿意这样做。我试图对答案发表评论,但我不确定你们是否看到了评论(根据常见问题解答,您需要 50 声望才能发表评论)?
下面是完整的源代码(去掉了所有不必要的东西,但足以重现错误):
#include "stdafx.h"
#include <vector>
using std::vector;
struct InputData
{
float diameter;
float length;
int vertIndex;
struct InputData *parent;
vector<InputData*> children;
bool deadEnd;
InputData(float dia, float lngth)
{
diameter = dia;
length = lngth;
vertIndex = NULL;
parent = NULL;
deadEnd = false;
}
};
//--------------------------------------------------------------------------------------
// Vertex types
//--------------------------------------------------------------------------------------
struct SimpleVertex
{
float Pos;
SimpleVertex(float Position)
{
Pos = Position;
}
};
void BuildMeshVertices(InputData* current, vector<SimpleVertex> *vertices)
{
current->vertIndex = vertices->size();
//Add vertices..
if(current->children.size() == 1)
{
BuildMeshVertices(current->children[0], vertices);
}
else if(current->children.size() == 0 && current->deadEnd == false)
{
InputData iDeadEnd = InputData(1.01f, 0.5f);
iDeadEnd.deadEnd = true;
iDeadEnd.parent = current;
current->children.push_back(&iDeadEnd);
BuildMeshVertices(&iDeadEnd, vertices);
}
}
void BuildMeshIndices(InputData* current, vector<unsigned long> *indices)
{
indices->push_back(current->vertIndex+2);
indices->push_back(current->vertIndex+0);
indices->push_back(current->vertIndex+1);
indices->push_back(current->vertIndex+3);
indices->push_back(current->vertIndex+0);
indices->push_back(current->vertIndex+2);
InputData *parent = current->parent;
unsigned long vOffset;
if(parent != NULL && parent->children.size() == 1)
{
vOffset = (unsigned long)current->vertIndex;
indices->push_back(vOffset+7);
indices->push_back(vOffset+5);
indices->push_back(vOffset+4);
indices->push_back(vOffset+6);
indices->push_back(vOffset+5);
indices->push_back(vOffset+7);
indices->push_back(vOffset+10);
indices->push_back(vOffset+8);
indices->push_back(vOffset+9);
indices->push_back(vOffset+11);
indices->push_back(vOffset+8);
indices->push_back(vOffset+10);
indices->push_back(vOffset+15);
indices->push_back(vOffset+13);
indices->push_back(vOffset+12);
indices->push_back(vOffset+14);
indices->push_back(vOffset+13);
indices->push_back(vOffset+15);
indices->push_back(vOffset+18);
indices->push_back(vOffset+16);
indices->push_back(vOffset+17);
indices->push_back(vOffset+19);
indices->push_back(vOffset+16);
indices->push_back(vOffset+18);
}
if(current->children.size() == 1 && current->deadEnd == false)
{
BuildMeshIndices(current->children[0], indices);
}
}
int _tmain(int argc, _TCHAR* argv[])
{
InputData i0 = InputData(3.0f, 3.0f);
InputData i1 = InputData(2.0f, 2.0f);
InputData i2 = InputData(1.0f, 1.0f);
InputData i3 = InputData(1.0f, 1.0f);
InputData i4 = InputData(1.0f, 1.0f);
InputData i5 = InputData(1.01f, 0.5f);
i0.children.push_back(&i1);
i1.children.push_back(&i2);
i2.children.push_back(&i3);
i3.children.push_back(&i4);
i4.children.push_back(&i5);
i1.parent = &i0;
i2.parent = &i1;
i3.parent = &i2;
i4.parent = &i3;
i5.parent = &i4;
// Create vertex buffer
vector<SimpleVertex> vertices;
BuildMeshVertices(&i0, &vertices);
// Create index buffer
vector<unsigned long> indices;
BuildMeshIndices(&i0, &indices);
return 0;
}