我正在玩 Xcode 4.5 中的 OpenGL ES 模板。我在 Google Sketchup 中绘制了一个立方体并导出到 collada。我将顶点和法线数据复制到 Xcode 中的 open gl 模板中，如下所示：
GLfloat gCubeVertexData[] =
{
// Data layout for each line below is:
// positionX, positionY, positionZ, normalX, normalY, normalZ,
// 0.5f, -0.5f, -0.5f, 1.0f, 0.0f, 0.0f,
// 0.5f, 0.5f, -0.5f, 1.0f, 0.0f, 0.0f,
// 0.5f, -0.5f, 0.5f, 1.0f, 0.0f, 0.0f,
// 0.5f, -0.5f, 0.5f, 1.0f, 0.0f, 0.0f,
// 0.5f, 0.5f, -0.5f, 1.0f, 0.0f, 0.0f,
// 0.5f, 0.5f, 0.5f, 1.0f, 0.0f, 0.0f,
//
// 0.5f, 0.5f, -0.5f, 0.0f, 1.0f, 0.0f,
// -0.5f, 0.5f, -0.5f, 0.0f, 1.0f, 0.0f,
// 0.5f, 0.5f, 0.5f, 0.0f, 1.0f, 0.0f,
// 0.5f, 0.5f, 0.5f, 0.0f, 1.0f, 0.0f,
// -0.5f, 0.5f, -0.5f, 0.0f, 1.0f, 0.0f,
// -0.5f, 0.5f, 0.5f, 0.0f, 1.0f, 0.0f,
//
// -0.5f, 0.5f, -0.5f, -1.0f, 0.0f, 0.0f,
// -0.5f, -0.5f, -0.5f, -1.0f, 0.0f, 0.0f,
// -0.5f, 0.5f, 0.5f, -1.0f, 0.0f, 0.0f,
// -0.5f, 0.5f, 0.5f, -1.0f, 0.0f, 0.0f,
// -0.5f, -0.5f, -0.5f, -1.0f, 0.0f, 0.0f,
// -0.5f, -0.5f, 0.5f, -1.0f, 0.0f, 0.0f,
//
// -0.5f, -0.5f, -0.5f, 0.0f, -1.0f, 0.0f,
// 0.5f, -0.5f, -0.5f, 0.0f, -1.0f, 0.0f,
// -0.5f, -0.5f, 0.5f, 0.0f, -1.0f, 0.0f,
// -0.5f, -0.5f, 0.5f, 0.0f, -1.0f, 0.0f,
// 0.5f, -0.5f, -0.5f, 0.0f, -1.0f, 0.0f,
// 0.5f, -0.5f, 0.5f, 0.0f, -1.0f, 0.0f,
//
// 0.5f, 0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
// -0.5f, 0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
// 0.5f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
// 0.5f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
// -0.5f, 0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
// -0.5f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
//
// 0.5f, -0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
// -0.5f, -0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
// 0.5f, 0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
// 0.5f, 0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
// -0.5f, -0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
// -0.5f, 0.5f, -0.5f, 0.0f, 0.0f, -1.0f
9.8425197/9.8425197, 9.8425197/9.8425197, 0.0000000/9.8425197, 0.0000000, 0.0000000, -1.0000000,
0.0000000/9.8425197, 0.0000000/9.8425197, 0.0000000/9.8425197, 0.0000000, 0.0000000, -1.0000000,
0.0000000/9.8425197, 9.8425197/9.8425197, 0.0000000/9.8425197, 0.0000000, 0.0000000, -1.0000000,
9.8425197/9.8425197, 0.0000000/9.8425197, 0.0000000/9.8425197, 0.0000000, 0.0000000, -1.0000000,
0.0000000/9.8425197, 9.8425197/9.8425197, 8.2677165/9.8425197, -1.0000000, 0.0000000, 0.0000000,
0.0000000/9.8425197, 0.0000000/9.8425197, 0.0000000/9.8425197, -1.0000000, 0.0000000, 0.0000000,
0.0000000/9.8425197, 0.0000000/9.8425197, 8.2677165/9.8425197, -1.0000000, 0.0000000, 0.0000000,
0.0000000/9.8425197, 9.8425197/9.8425197, 0.0000000/9.8425197, -1.0000000, 0.0000000, 0.0000000,
0.0000000/9.8425197, 9.8425197/9.8425197, 8.2677165/9.8425197, -0.0000000, 1.0000000, 0.0000000,
9.8425197/9.8425197, 9.8425197/9.8425197, 0.0000000/9.8425197, -0.0000000, 1.0000000, 0.0000000,
0.0000000/9.8425197, 9.8425197/9.8425197, 0.0000000/9.8425197, -0.0000000, 1.0000000, 0.0000000,
9.8425197/9.8425197, 9.8425197/9.8425197, 8.2677165/9.8425197, -0.0000000, 1.0000000, 0.0000000,
9.8425197/9.8425197, 9.8425197/9.8425197, 0.0000000/9.8425197, 1.0000000, 0.0000000, 0.0000000,
9.8425197/9.8425197, 0.0000000/9.8425197, 8.2677165/9.8425197, 1.0000000, 0.0000000, 0.0000000,
9.8425197/9.8425197, 0.0000000/9.8425197, 0.0000000/9.8425197, 1.0000000, 0.0000000, 0.0000000,
9.8425197/9.8425197, 9.8425197/9.8425197, 8.2677165/9.8425197, 1.0000000, 0.0000000, 0.0000000,
9.8425197/9.8425197, 0.0000000/9.8425197, 8.2677165/9.8425197, -0.0000000, -1.0000000, -0.0000000,
0.0000000/9.8425197, 0.0000000/9.8425197, 0.0000000/9.8425197, -0.0000000, -1.0000000, -0.0000000,
9.8425197/9.8425197, 0.0000000/9.8425197, 0.0000000/9.8425197, -0.0000000, -1.0000000, -0.0000000,
0.0000000/9.8425197, 0.0000000/9.8425197, 8.2677165/9.8425197, -0.0000000, -1.0000000, -0.0000000,
9.8425197/9.8425197, 0.0000000/9.8425197, 8.2677165/9.8425197, 0.0000000, 0.0000000, 1.0000000,
0.0000000/9.8425197, 9.8425197/9.8425197, 8.2677165/9.8425197, 0.0000000, 0.0000000, 1.0000000,
0.0000000/9.8425197, 0.0000000/9.8425197, 8.2677165/9.8425197, 0.0000000, 0.0000000, 1.0000000,
9.8425197/9.8425197, 9.8425197/9.8425197, 8.2677165/9.8425197, 0.0000000, 0.0000000, 1.0000000
};
当我运行时，我在下面有渲染的立方体，所以有些不对劲。
=======
看起来如果我使用法线，我不需要提供索引来渲染 3D 对象。但在我的情况下，顶点数据或正常数据似乎有问题......有人知道这两个数据在collada中是如何排列的吗？我通读了文档，但找不到答案...谢谢