Question

OpenGL ES3，C ++ 11，Android，我有一个物体和一个实现第三人称相机的相机，所以当我触摸屏幕时，我想让物体看向相机，所以我有一个物体和视图的变换矩阵相机的矩阵，相机围绕物体旋转，当我触摸屏幕时，我希望物体朝向相机旋转，所以我尝试了以下内容：

glm::vec3 up(0, 1, 0);
glm::vec3 camFor(glm::cross(camera.getRight(), up));
GLfloat theta = glm::angle(glm::vec2(camFor.x, camFor.z), glm::vec2(getDirection().x, getDirection().z));
LOGI("game theta %f", theta);
matrix = glm::rotate(matrix, theta, glm::vec3(0.0, 1.0, 0.0));

我得到了物体前向矢量和相机前向矢量之间的水平角度glm::vec3(matrix[2][0], matrix[2][1], matrix[2][2])，第一次当相机正好在物体后面我得到θ等于pi时那就是我触摸了屏幕触发对象旋转的事件并按预期看向摄像机，θ变为零，如果我围绕对象旋转摄像机并再次触发事件，它会为θ提供意外值。相机的旋转代码是：

void Camera::rotate(GLfloat xoffset, GLfloat yoffset, glm::vec3& c, double& delta, GLboolean constrainpitch) {
    xoffset *= (delta * this->rotSpeed);
    yoffset *= (delta * this->rotSpeed);
    pitch += yoffset;
    yaw += xoffset;
    if (constrainpitch) {
        if (pitch >= maxPitch) {
            pitch = maxPitch;
            yoffset = 0;
        }
        if (pitch <= minPitch) {
            pitch = minPitch;
            yoffset = 0;
        }
    }
    glm::quat Qx(glm::angleAxis(glm::radians(yoffset), glm::vec3(1.0f, 0.0f, 0.0f)));
    glm::quat Qy(glm::angleAxis(glm::radians(xoffset), glm::vec3(0.0f, 1.0f, 0.0f)));
    glm::mat4 rotX = glm::mat4_cast(Qx);
    glm::mat4 rotY = glm::mat4_cast(Qy);
    view = glm::translate(view, c);
    view = rotX * view;
    view = view * rotY;
    view = glm::translate(view, -c);
}

解决方案：

错误在于获取相机矩阵的右矢量这是正确的

glm::vec3& Camera::getRight() {
    right = glm::vec3(view[0][0], view[1][0], view[2][0]);
    return right;
}

Answer 1

错误在于获取相机矩阵的右矢量这是正确的

glm::vec3& Camera::getRight() {
    right = glm::vec3(view[0][0], view[1][0], view[2][0]);
    return right;
}

OpenGL制作物体相机

1 个答案: