Question

我已经在OpenGL中编写了一个3D环境，您可以向前/向后移动并环顾四周（向上/向下/向左/向右）但是我无法确定如何向右侧移动。

我正在使用gluLookAt，我的前进代码是

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);

任何人都知道如何采取行动或看到一个例子？

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

要向侧面移动，您只需沿着相机的右侧向量平移眼睛位置。

要找到正确的向量，请记住两个向量的叉积给出垂直向量。因此，前向向量和向上向量的叉积将给出正确的向量。

你的前向矢量是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];

您还应该注意，Glu库不适用于OpenGL ES，因此您必须重新实现lookat函数，这很简单，但也是另一个问题。

iPhone：移动3D空间（使用gluLookAt侧身踩踏）

1 个答案: