Basic knowledge of trigonometric functions

1. Conversion of angles and radians

180 degrees =π radians

1 radians = 180/π degrees

1 degrees =π/180 radians

2. Vectors

Direction and size (these two values can express a variety of physical properties, such as Force and motion)

Direction: x, y coordinates of the circle selected counterclockwise

The size of the vector: the hypotenuse is obtained by the Pythagorean theorem

X, y =x/hypotenuse of the unit vector, y/hypotenuse

Addition and subtraction of vectors:

Dot product: Var dotproduct=vectorone.x * vectortwo.x+ Vectorone.y * VECTORTWO.Y

The meaning of dot product:

The technical term for dot product is called scalar or pure quantity, if the dot product is greater than 0, then the two vectors are roughly in the same direction (quadrant), and if equal to 0, the two vectors are perpendicular.

Determines whether the end point of two vectors is roughly in the same direction and is a key technique for responding to collisions between objects

3. Achieve time-based motion effects

Pixel/frame = (X * Y)/1000

X = frame rate represented by milliseconds/frame

Y = speed expressed in pixels per second

Basic knowledge of trigonometric functions