用C++初始化一個GLfloats的多維數組

Question

我現在正在腦海裏結一個關於如何正確初始化GLFloats的一個數組，逐行。 據我所知，一個陣列可以這樣寫：

int a[2][2] = {{1,2},{3,4}} 

在我的情況，我有數組

GLfloat targetVertices[10][72]; 

爲立方體的六個面的頂點（萬個立方，準確地說）。立方座標存儲在

float targetX[10], targetY[10], targetZ[10]; 

數組中。我想初始化它是這樣的：

for(iii = 0; iii <= 9; iii++) { 
    targetVertices[iii] = {     /*Side 1*/ 
          targetX[iii]-1, targetY[iii]-1, targetZ[iii]-1, 
          targetX[iii]-1, targetY[iii]-1, targetZ[iii]+1, 
          targetX[iii]-1, targetY[iii]+1, targetZ[iii]+1, 
          targetX[iii]-1, targetY[iii]+1, targetZ[iii]-1, 
              /*Side 2*/ 
          targetX[iii]+1, targetY[iii]-1, targetZ[iii]-1, 
          targetX[iii]+1, targetY[iii]-1, targetZ[iii]+1, 
          targetX[iii]+1, targetY[iii]+1, targetZ[iii]+1, 
          targetX[iii]+1, targetY[iii]+1, targetZ[iii]-1, 
              /*Side 3*/ 
          targetX[iii]-1, targetY[iii]-1, targetZ[iii]-1, 
          targetX[iii]-1, targetY[iii]-1, targetZ[iii]+1, 
          targetX[iii]+1, targetY[iii]-1, targetZ[iii]+1, 
          targetX[iii]+1, targetY[iii]-1, targetZ[iii]-1, 
              /*Side 4*/ 
          targetX[iii]-1, targetY[iii]+1, targetZ[iii]-1, 
          targetX[iii]-1, targetY[iii]+1, targetZ[iii]+1, 
          targetX[iii]+1, targetY[iii]+1, targetZ[iii]+1, 
          targetX[iii]+1, targetY[iii]+1, targetZ[iii]-1, 
              /*Side 5*/ 
          targetX[iii]-1, targetY[iii]-1, targetZ[iii]-1, 
          targetX[iii]-1, targetY[iii]+1, targetZ[iii]-1, 
          targetX[iii]+1, targetY[iii]+1, targetZ[iii]-1, 
          targetX[iii]+1, targetY[iii]-1, targetZ[iii]-1, 
              /*Side 6*/ 
          targetX[iii]-1, targetY[iii]-1, targetZ[iii]+1, 
          targetX[iii]-1, targetY[iii]+1, targetZ[iii]+1, 
          targetX[iii]+1, targetY[iii]+1, targetZ[iii]+1, 
          targetX[iii]+1, targetY[iii]-1, targetZ[iii]+1 
          }; 
} 

不幸的是，我總是告訴關於第一個波浪支架語法錯誤（C2059和C2143，但那些沒有任何意義，我在那裏） 。 我希望我的問題很清楚，有人可以幫助我。我還沒有在這個或任何其他網站上發現任何類似於我的問題。

在此先感謝！

Answer 1

你的語法問題是說targetVertices [iii]你指的是數組的iith索引，而不是整列。二維數組存儲爲一維數組，但爲簡單訪問提供[] []。您可以將它們稱爲單維或二維。

這是一個更可重用的方法來解決這個問題。

void addVertex(std::vector<GLfloat> &data, GLfloat x, GLfloat y, GLfloat z) 
{ 
    data.push_back(x); 
    data.push_back(y); 
    data.push_back(z); 
} 

---

void addCube(std::vector<GLfloat> &data, GLfloat x, GLfloat y, GLfloat z) 
{ 
    addVertex(data, x-1, y-1, z-1); 
    addVertex(data, x-1, y-1, z+1); 
    addVertex(data, x-1, y+1, z+1); 
    addVertex(data, x-1, y+1, z-1); 

    addVertex(data, x+1, y-1, z-1); 
    addVertex(data, x+1, y-1, z+1); 
    addVertex(data, x+1, y+1, z+1); 
    addVertex(data, x+1, y+1, z-1); 

    addVertex(data, x-1, y-1, z-1); 
    addVertex(data, x-1, y-1, z+1); 
    addVertex(data, x+1, y-1, z+1); 
    addVertex(data, x+1, y-1, z-1); 

    addVertex(data, x-1, y+1, z-1); 
    addVertex(data, x-1, y+1, z+1); 
    addVertex(data, x+1, y+1, z+1); 
    addVertex(data, x+1, y+1, z-1); 

    addVertex(data, x-1, y-1, z-1); 
    addVertex(data, x-1, y+1, z-1); 
    addVertex(data, x+1, y+1, z-1); 
    addVertex(data, x+1, y-1, z-1); 

    addVertex(data, x-1, y-1, z+1); 
    addVertex(data, x-1, y+1, z+1); 
    addVertex(data, x+1, y+1, z+1); 
    addVertex(data, x+1, y-1, z+1); 
} 

---

void makeCubes(std::vector<GLfloat> &data) 
{ 
    float targetX[10], targetY[10], targetZ[10]; 
      data.clear(); 
      data.reserve(720); 

    //...initialize the above arrays... 

    for (int i=0; i<10; i++) 
    { 
     std::vector<GLfloat> newData; 
     addCube(newData, targetX[i], targetY[i], targetZ[i]); 
     data.insert(data.begin(), newData.begin(), newData.end()); 
    } 
} 

---

你可以很容易通過採取參照第一元件將其轉換爲一個C-數組：

std::vector<GLfloat> data; 
makeCubes(data); 
GLfloat *cArray = &data[0]; 

的呼叫到glBufferData c應該是這樣的：

glBufferData(GL_ARRAY_BUFFER, 
      data.size()*sizeof(GLfloat), 
      &data[0], 
      GL_STREAM_DRAW);