Opengl 免費凸輪（來自 Learnopengl）到第三個凸輪

Question

我正在學習 opengl 並按照 learnopengl 網站 ( https://learnopengl.com/ ) 上的教程進行操作

有人可以幫我把這個相機從 learnopengl 教程轉換成第三人稱嗎？

我試過把物體（角色）的值放進去，但是我不能讓相機圍繞玩家旋轉。 只有物體走在相機前面，如果我轉向側面，物體就會跟着轉，看起來像FPS相機，物體（角色）就是武器。

走的代碼（鍵盤）：

void processKeyboard(Camera_Movement direction, float deltaTime)
{
    frontY = Front.y;//para tirar o freeCamera
    if (cameraStyle == FPS_CAMERA) {
        Front.y = 0;
    }       

    float velocity = MovementSpeed * deltaTime;

    if (direction == FORWARD)
        Position += Front * velocity;
    if (direction == BACKWARD)
        Position -= Front * velocity;
    if (direction == LEFT)
        Position -= Right * velocity;
    if (direction == RIGHT)
        Position += Right * velocity;

    Front.y = frontY;
}

鼠標事件：

void processMouseMovement(float xoffset, float yoffset, GLboolean constrainPitch = true)
{
    xoffset *= MouseSensitivity;
    yoffset *= MouseSensitivity;

    Yaw += xoffset;
    Pitch += yoffset;

    // Make sure that when pitch is out of bounds, screen doesn't get flipped
    if (constrainPitch)
    {
        if (Pitch > 89.0f)
            Pitch = 89.0f;
        if (Pitch < -89.0f)
            Pitch = -89.0f;
    }

    // Update Front, Right and Up Vectors using the updated Euler angles
    updateCameraVectors();
}

要更新值：

void updateCameraVectors()
{
    // Calculate the new Front vector
    glm::vec3 front;
    front.x = cos(glm::radians(Yaw)) * cos(glm::radians(Pitch));
    front.y = sin(glm::radians(Pitch));
    front.z = sin(glm::radians(Yaw)) * cos(glm::radians(Pitch));
    Front = glm::normalize(front);
    // Also re-calculate the Right and Up vector
    Right = glm::normalize(glm::cross(Front, WorldUp));  // Normalize the vectors, because their length gets closer to 0 the more you look up or down which results in slower movement.
    Up = glm::normalize(glm::cross(Right, Front));
}

並使用：

glm::vec3 playerPosition = glm::vec3(Position.x, terrainY, Position.z) + glm::vec3(1, -0.06f, 1)

有沒有人經歷過這個，誰能幫助我？ 謝謝

Answer 1

這是我用來創建第三人稱相機的代碼：

float pitch = -Pitch;
// I use a 90.0f offset
// but you can play around with that value to suit your needs
float yaw = Yaw - 90.0f;

// constrain pitch so you don't look from below ground level
if (pitch < 0.0) {
    pitch = 0.0;
}
    
// algorithm from ThinMatrix video on third person cameras
float distance = 20.0f;
float x = distance * cos(glm::radians(pitch)) * sin(radians(-yaw));
float y = distance * sin(glm::radians(pitch));
float z = distance * cos(glm::radians(pitch)) * cos(glm::radians(yaw));

glm::vec3 tpCamPos = playerPosition + vec3(-x, y, -z);