OpenGL模型加载器问题

终于让我的模型加载器工作起来了（基于前面的问题）。存储所有值都很好，运行glDrawElemts很好，但它不运行glDrawArrays。

是的，你首先要说的是"glDrawArrays显然写得不对"。这就是问题所在——我99%肯定是这样。

代码如下：

bool modelLoader(string fileName,vector<GLfloat>& vertices, vector<GLushort>& indices)
{
fstream objFile;
vector<GLfloat> localVertices;
string dataLine;
stringstream mystream;
GLfloat x, y, z;
GLushort ind1, ind2, ind3;
char c, d; 
vertices.clear();
indices.clear();
for (int i = 0; i < 3; i++)
{
    vertices.push_back(0);
}

for (int i = 0; i < 3; i++)
{
    localVertices.push_back(0);
}

objFile.open(fileName);
if (!objFile.good())
{
    printf("Error with loader");
    return false; 
}
while (!objFile.eof())
{
    getline(objFile, dataLine);
    if (dataLine == "") 
    {                                                                  
        mystream.clear();                                              
        continue;                                                      
    }                                                                  
    mystream.clear();                                                  
    mystream.str(dataLine);                                            
    c = dataLine[0];                                                   
    d = dataLine[1];
    mystream.ignore(2);
    switch (c)
    {
    case 'v':
        {
            switch (d)
            {
            case 'n':
                { /* for normals */ break;}
            case ' ':
                mystream >> x >> y >> z;
                localVertices.push_back(x);
                localVertices.push_back(y);
                localVertices.push_back(z);
                printf("nVertices: %f, %f, %f", x, y, z);
                break;
            default:
                {break;}
            }                                                                                                    
            break;                                                                                               
        }                                                                                                        
    case 'f':                                                                                                    
        {                                                                                                        
            //printf("F entered");                                                                               
            mystream >> ind1 >> ind2 >> ind3;                                                                    
            vertices.push_back(localVertices[ind1* 3 + 0]);                                                      
            vertices.push_back(localVertices[ind1* 3 + 1]);                                                      
            vertices.push_back(localVertices[ind1* 3 + 2]);                                                      
            vertices.push_back(localVertices[ind2* 3 + 0]);                                                      
            vertices.push_back(localVertices[ind2* 3 + 1]);                                                      
            vertices.push_back(localVertices[ind2* 3 + 2]);                                                      
            vertices.push_back(localVertices[ind3* 3 + 0]);                                                      
            vertices.push_back(localVertices[ind3* 3 + 1]);                                                     
            vertices.push_back(localVertices[ind3* 3 + 2]);
            indices.push_back(ind1);
            indices.push_back(ind2);
            indices.push_back(ind3);
            printf("nIndices: %d, %d, %d", ind1, ind2, ind3);
            break;
        }
    case !'v' || !'f':
        {
            break;
        }
    default:
        {break;}
    }
    mystream.clear();
}
objFile.close(); 
return true;
 }

从这里我继续调用主函数中的以下内容：

vector<GLfloat> vertices;
vector<GLushort> indices;

if (!modelLoader("triangles.obj", vertices, indices))
{
    cout << "FAILED TO RUN: MODEL LOADER";
    return 1;
}

插入一堆关于设置模型视图矩阵、运行循环以更新每次迭代的其他陈词滥调。。。

int size = vertices.size()-3;
glDrawArrays(GL_TRIANGLES, 3, (GLsizei)size);

哦，triangles.obj文件是：

v -10.0 10.0 10.0
v -10.0 -10.0 10.0
v 10.0 -10.0 10.0
v 10.0 10.0 10.0
v 20.0 10.0 10.0
v 20.0 -10.0 10.0
f 1 2 3
f 4 5 6

一点快乐都没有。正如我所说，使用DrawElements可以很好地做到这一点，但当我尝试绘制任何其他.obj文件时会导致异常错误。

关于我哪里出了问题，有什么线索吗？