iPhone：在3D空间中移动（使用gluLookAt横向移动）

Question

我已经在OpenGL中编写了一个3D环境，您可以向前/向后移动并环视（上/下左/右）然而，我无法解决您可以如何一步到右边。

我使用gluLookAt和我前进的代码是

GLfloat v[] = {[self centerAtIndex:0] - [self eyeAtIndex:0],[self centerAtIndex:1] - [self eyeAtIndex:1], [self centerAtIndex:2] - [self eyeAtIndex:2]}; 

[self setEye:[self eyeAtIndex:0] + v[0] * SPEED_MOVE atIndex:0]; 
[self setEye:[self eyeAtIndex:2] + v[2] * SPEED_MOVE atIndex:2]; 
[self setCenter: [self centerAtIndex:0] + v[0] * SPEED_MOVE atIndex:0]; 
[self setCenter: [self centerAtIndex:2] + v[2] * SPEED_MOVE atIndex:2]; 

和

gluLookAt(eye[0], eye[1], eye[2],center[0], center[1], center[2], 0.0, 1, 0.0); 

任何人有任何想法，以侧步或如何看到的例子吗？

解决方案

float up[3] = {0, 1, 0}; 
     float forward[3] = { center[0] - eye[0],center[1] - eye[1],center[2] - eye[2] }; 

     float left[3]; 
     left[0] = forward[1] * up[2] - forward[2] * up[1]; 
     left[1] = forward[2] * up[0] - forward[0] * up[2]; 
     left[2] = forward[0] * up[1] - forward[1] * up[0]; 

     // now translate your eye position 
     [self setEye:[self eyeAtIndex:0] - left[0] * SPEED_MOVE atIndex:0]; 
     [self setEye:[self eyeAtIndex:2] - left[2] * SPEED_MOVE atIndex:2]; 
     [self setCenter: [self centerAtIndex:0] - left[0] * SPEED_MOVE atIndex:0]; 
     [self setCenter: [self centerAtIndex:2] - left[2] * SPEED_MOVE atIndex:2]; 


     if (([self eyeAtIndex:2] >= MapSizeZ || [self eyeAtIndex:0] >= MapSizeX || [self eyeAtIndex:2] <= 1 || [self eyeAtIndex:0] <= 1) || [self checkCollisionWithPoint:CGPointMake([self eyeAtIndex:0] ,[self eyeAtIndex:2])]){ 

      [self setEye:[self eyeAtIndex:0] + left[0] * SPEED_MOVE atIndex:0]; 
      [self setEye:[self eyeAtIndex:2] + left[2] * SPEED_MOVE atIndex:2]; 
      [self setCenter: [self centerAtIndex:0] + left[0] * SPEED_MOVE atIndex:0]; 
      [self setCenter: [self centerAtIndex:2] + left[2] * SPEED_MOVE atIndex:2]; 
     } 

Answer 1

侧向移动你只需要翻译沿相机的权矢量眼睛的位置。

要找到正确的矢量，请记住两个矢量的叉积给出垂直矢量。所以，你的向前矢量和向上矢量的叉积将会给出正确的矢量。

你的向前矢量是v [3]，但为了清晰起见，我将在这里使用'forward'。

// find the Right vector. (forward cross product up) 
float right[3]; 
right[0] = forward[1] * up[2] - forward[2] * up[1]; 
right[1] = forward[2] * up[0] - forward[0] * up[2]; 
right[2] = forward[0] * up[1] - forward[1] * up[0]; 

// now translate your eye position 
[self setEye:[self eyeAtIndex:0] + right[0] * SPEED_MOVE atIndex:0]; 
[self setEye:[self eyeAtIndex:2] + right[2] * SPEED_MOVE atIndex:2]; 

你还应该注意的是，谷氨酸库不提供OpenGL ES的，所以你将不得不重新实现LOOKAT功能，这很简单，但也是另一个问题。