我在理解相机的翻译时遇到麻烦。我已经可以成功旋转相机了,但是我仍然对平移相机感到困惑。我包含有关如何旋转相机的代码,因为平移和旋转需要使用lookat函数。作业说平移相机意味着眼睛和中心都应该移动相同的量。我知道我可以更改lookat函数中的参数以实现此目的。
lookat函数的定义如下:
Lookat(cameraPos, center, up)
glm::vec3 cameraPos = glm::vec3(0.0f, 0.0f, 10.0f);
glm::vec3 center(0.0f, 0.0f, 0.0f);
glm::vec3 cameraUp = glm::vec3(0.0f, 1.0f, 0.0f);
modelViewProjectionMatrix.Perspective(glm::radians(fov), float(width) / float(height), 0.1f, 100.0f);
modelViewProjectionMatrix.LookAt(cameraPos, center, cameraUp);
void CursorPositionCallback(GLFWwindow* lWindow, double xpos, double ypos)
{
int state = glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_LEFT);
if (state == GLFW_PRESS)
{
if (firstMouse)
{
lastX = xpos;
lastY = ypos;
firstMouse = false;
}
float xoffset = xpos - lastX;
float yoffset = lastY- ypos;
lastX = xpos;
lastY = ypos;
yaw += xoffset;
pitch += yoffset;
glm::vec3 front;
front.x = center[0] + 5.0f*cos(glm::radians(yaw)) * cos(glm::radians(pitch));
front.y = center[1] + 5.0f*sin(glm::radians(pitch));
front.z = center[1] + 5.0f*sin(glm::radians(yaw)) * cos(glm::radians(pitch));
cameraPos = front;
}
}
[如果要平移摄影机偏移量,则必须将相同的向量(glm::vec3 offset
)添加到摄影机位置(cameraPos
)和摄影机目标(center
):
center = center + offset;
cameraPos = cameraPos + offset;
[当您以center
和pitch
角计算摄像机的新目标(yaw
)时,也必须更新摄像机的向上矢量(cameraUp
):
glm::vec3 front(
cos(glm::radians(pitch)) * cos(glm::radians(yaw)),
sin(glm::radians(pitch)),
cos(glm::radians(pitch)) * sin(glm::radians(yaw))
);
glm::vec3 up(
-sin(glm::radians(pitch)) * cos(glm::radians(yaw)),
cos(glm::radians(pitch)),
-sin(glm::radians(pitch)) * sin(glm::radians(yaw))
);
cameraPos = center + front * 5.0f;
cameraUp = up;
要在视空间中沿x轴(从左到右)平移相机,您必须通过将矢量的Cross product移至目标(front
)和向上的矢量([[ C0]或cameraUp
):
up
视图空间中的y轴(从下到上)是向上矢量。
要转换标量(glm::vec3 right = glm::cross(front, up);
)和(float trans_x
),必须将缩放后的trans_y
和right
向量添加到摄像机位置(up
)和摄像机目标(cameraPos
):
center
使用操纵向量设置视图矩阵:
center = center + right * trans_x + up * trans_y;
cameraPos = cameraPos + right * trans_x + up * trans_y;