Question

我正在尝试在开放空间中旋转单个多维数据集。首先，它从静止开始，然后在按键时，应该在特定按键上的特定访问中提高旋转速度。

我的初始代码如下：

model = glm::rotate(model, glm::radians(rotationAngle.x * glfwGetTime()), glm::vec3(1.0f, 0.0f, 0.0f));
model = glm::rotate(model, glm::radians(rotationAngle.y * glfwGetTime())), glm::vec3(0.0f, 1.0f, 0.0f));
model = glm::rotate(model, glm::radians(rotationAngle.z * glfwGetTime())), glm::vec3(0.0f, 0.0f, 1.0f)

在普通按键上说A，代码如下：

if(glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS){
    rotationAngle.x += 0.01;
}

这会提高旋转速度，但是由于glfwGetTime()不断增加，因此当我按住键时，旋转会非常快，然后在按下键时，它将恢复到正常旋转速度。

我可能做错了什么？

Answer 1

您可能要使用增量时间（自上一帧以来的时间变化）而不是时间。我不确定GLFW是否具有特定功能，但是您可以这样做：

time = glfwGetTime();
delta = time - lastTime;

// do stuff with delta ...

lastTime = time;

Answer 2

从描述中，我看到代码是这样的

while(condition)
{
    model = glm::rotate(model, glm::radians(rotationAngle.x * glfwGetTime()), glm::vec3(1.0f, 0.0f, 0.0f));
    model = glm::rotate(model, glm::radians(rotationAngle.y * glfwGetTime())), glm::vec3(0.0f, 1.0f, 0.0f));
    model = glm::rotate(model, glm::radians(rotationAngle.z * glfwGetTime())), glm::vec3(0.0f, 0.0f, 1.0f));

    if(glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS)
    {
        rotationAngle.x += 0.01;
    }
}

按住键时，旋转角度每次增加0.01，并且每次循环迭代时，旋转功能都会在每个循环中旋转更大的角度。为了防止这种情况发生，if语句仅应在从“未按下”变为“按下”时激活。我们可以用一个标志来做到这一点。

while(condition)
{
    static bool keyDown = false;

    model = glm::rotate(model, glm::radians(rotationAngle.x * glfwGetTime()), glm::vec3(1.0f, 0.0f, 0.0f));
    model = glm::rotate(model, glm::radians(rotationAngle.y * glfwGetTime())), glm::vec3(0.0f, 1.0f, 0.0f));
    model = glm::rotate(model, glm::radians(rotationAngle.z * glfwGetTime())), glm::vec3(0.0f, 0.0f, 1.0f));

    if(glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS)
    {
        // We don't combine !keyDown in the outer if statement because
        // we don't want the else statement to be activated whenever either 
        // statement is false.

        // If key was not previously pressed, then activate. Otherwise, 
        // key is already down and we ignore this.
        if(!keyDown)
        {
            rotationAngle.x += 0.01;
            keyDown = true;
        }
    }
    // Once you let go of the key, this part activates and resets the flag 
    // as well as the rotation angle.
    else
    {
        rotationAngle.x = 0.0;
        keydown = false;
    }
}

看起来应该差不多。我不知道glfwGetKey的详细信息，因此您可能需要更多条件来检查密钥状态。

增加按键上模型的加速度？

2 个答案: