关于协调规划的思考
Section outline
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Reflec tions in Video Games
::视频游戏中的反思Reflections may not seem to play as big a role in video games as other rigid motion s do , but reflections play a large role behind the scenes in determining how objects look and interact within an environment. In 2-dimensional video games, reflections are used to simulate some 3-dimensional movements like reversing direction. In 3-dimensional video games, reflections are used to recreate physical reflections in objects like mirrors and water. They can also be used to simulate events like a ball bouncing.
::反射似乎不像其他僵硬动作那样在电子游戏中扮演大的角色,但反射在幕后决定物体在环境中的外观和互动作用很大。在二维电子游戏中,反射被用来模拟一些三维运动,如反向方向。在三维电子游戏中,反射被用来在镜子和水等物体中重建物理反射。它们也可以用来模拟球弹跳等事件。See the interactive below to explore how reflections might be used in a video game setting.
::见下文互动内容,探讨如何在视频游戏环境中利用反思。
Reflecting on Reflections
::反思反思Remember that reflections describe 'flipping' an image over a mirror line so that every point of the flipped image is the same distance from the mirror line as the original shape. In math, reflections are commonly explored using a coordinate grid , with the reflections taking place across the x axis and/or y axis.
::记住反射会描述“ 翻转” 图像在反射线上的位置, 这样翻转图像的每个点与反射线的距离与原始形状的距离相同。 在数学中, 反射通常使用坐标网格进行探索, 反射在 x 轴和/ 或 y 轴之间进行 。Use the interactive below to explore how vertical and horizontal reflections are related to the x and y coordinates of a point.
::利用下面的交互作用来探讨垂直和水平反射如何与点的x和y坐标相关。Discussion Question
::讨论问题Create a custom mirror line that runs at a 45° angle . Can you come up with a rule or set of rules you could use to predict the location of the mirrored point for any starting point? A 45° angle is perfectly diagonal and halfway between 0° and 90°.
::创建以 45 ° 角度运行的自定义镜像线。 您能否提出一套规则或规则来预测任何起点的镜像点位置? 45 ° 角度完全对角, 介于 0 ° 到 90 ° 之间 。
Reflecting Shapes
::反映形状Suppose you translate a shape instead of a point. Every point in the shape will undergo a reflection over the same axis . If the reflection is over the x axis, the y coordinate of every point in the shape will be multiplied by negative 1. If the reflection is over the y axis, the x coordinate of every point in the shape will be multiplied by negative 1.
::假设您翻译了一个形状而不是一个点。 形状中的每个点都会在同一轴上进行反射。 如果反射在 x 轴上方, 形状中每个点的 Y 坐标将乘以负 1 。 如果反射在 y 轴上方, 形状中每个点的 x 坐标将乘以负 1 。Use the interactive below and practice predicting the new location of A B C ( A ′ B ′ C ′ ) for each reflection.
::使用下文中的交互式数据,并使用预测每部反射的ABC新位置(A_B_C})的做法。Discussion Question
::讨论问题How does reflecting on the coordinate plane differ from the reflecting you have practiced before? How is it the same? Think about your answers in terms of the .
::协调平面上的反射与你以前所练习的反射有何不同? 如何相同? 考虑一下你的答案。
Reflection Notation
::反射符号To reflect an object on a coordinate plane , first identify where the mirror line is. To reflect over the x axis, simply multiply the y coordinate of the point by -1. Use the notation A ( x , y ) → A ′ ( x , − y ) . To reflect over the y axis , just multiply the x coordinate of the point by -1. U se the notation A ( x , y ) → A ′ ( − x , y ) .
::要在坐标平面上反射对象, 请先确定镜像线的位置。 要在 x 轴上反射, 请简单地将点的 Y 坐标乘以-1。 使用 符号 A( x,y) {A}}A}} (x,- y) 。 要在 y 轴上反射, 请将点的 x 坐标乘以 - 1. 。 请使用 符号 A( x,y) {A} (- x,y) A} (- x) 。Use the interactive questions below to practice this.
::使用下面的交互式问题来实践这一点。Summary
::摘要-
Every point of a flipped image is the same distance from the mirror line as the original shape.
::翻转图像的每个点与镜像线的距离与原始形状相同。 -
To reflect a given point over the
x
-
axis, simply multiply the
y
coordinate of the point by -1.
::要在 x 轴上反映给定点,只需将点的 Y 坐标乘以-1 即可。 -
To reflect over the
y
-
axis, just multiply the
x
coordinate of the point by -1.
::要在 Y 轴上反射,只需将点的 x 坐标乘以-1 即可。
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Every point of a flipped image is the same distance from the mirror line as the original shape.