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cw4:tutorials:rotation_conversion

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cw4:tutorials:rotation_conversion [2021/01/09 14:02] – created Karsten75cw4:tutorials:rotation_conversion [2025/02/14 14:57] (current) – external edit 127.0.0.1
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 +<=[[4rpl:start|Index]] \\
 +<=[[cw4:Tutorials]]
 +
 ====== Converting between different kinds of rotation ====== ====== Converting between different kinds of rotation ======
  
-Many objects in CW4 have a rotation which can either be obtained or set through 4RPL commands. This includes the rotation of the camera, units and the individual objects custom unit is made up of. These rotations are defined in degrees, whereas the trigonometric functions of 4rpl use radians. Even though 4RPL has built in function to convert between degrees and radians, you'll still notice that a downward angle you calculated will make the camera look upwards instead. This is because the game uses a rotation system specific to the Unity engine that doesn't match with how rotations are usually calculated along axes in maths.+Many objects in CW4 have a rotation which can either be obtained or set through 4RPL commands. This includes the rotation of the camera, units and the individual objects custom units are made up of. These rotations are defined in degrees, whereas the trigonometric functions of 4rpl use radians. Even though 4RPL has built in function to convert between degrees and radians, you'll still notice that a downward angle you calculated will make the camera look upwards instead. This is because the game uses a rotation system specific to the Unity engine that doesn't match with how rotations are usually calculated along axes in maths.
  
 This page will show you how the different types of rotations in this game work and how to convert between them This page will show you how the different types of rotations in this game work and how to convert between them
 +
 +----
  
 ===== Radians and degrees ===== ===== Radians and degrees =====
  
-{{ :4rpl:tutorials:simple_math_rotation.png?300&nolink}}You're probably at least a little familiar with a coordinate grid as show here, with an X and Y axis. An arbitrary angle is usually defined by the distance in radians or degrees from the positive side of the X-axis. You can define the same angle with both a positive or negative value, 30° is the same as -330°. (in radians: ⅙π and -1⅚π)+{{ :4rpl:tutorials:simple_math_rotation.png?300&nolink|Basic coordinate grid with an angle}}You're probably at least a little familiar with a coordinate grid with an X and Y axis, as shown here. An arbitrary angle is usually defined by the distance in radians or degrees from the positive side of the  horizontal axis. You can define the same angle with both a positive or negative value, 30° is the same as -330°. (in radians: ⅙π and -1⅚π)
  
 The trigonometry functions of 4RPL such as sin, cos, tan, atan2, etc. all use or return radian values, but other parts of the game use degrees, which is why you'll have to convert between them. The trigonometry functions of 4RPL such as sin, cos, tan, atan2, etc. all use or return radian values, but other parts of the game use degrees, which is why you'll have to convert between them.
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 <-degAngle deg2rad * ->radAngle <-degAngle deg2rad * ->radAngle
 </code> </code>
 +
 +----
  
 ===== The difference between Unity rotation and mathematical rotation ===== ===== The difference between Unity rotation and mathematical rotation =====
  
-**TLDR; Rotations along the X and Y axes are inverted.**+**TLDR; In Unity, rotations along the X and Y axes are inverted.**
  
-Even though units are normally locked to the grid, the game allows us to rotate them by any amount. Lets try to give a unit a Y rotation of 30°, which should make them point slightly up and to the right, just like the image above here.+Even though units are normally locked to the grid, the game allows us to rotate them by any amount. Lets try to give a unit a Y rotation of 30°, which should make them point slightly up and to the right, just like the image of the section above.
  
 <code 4rpl> <code 4rpl>
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 </code> </code>
  
-What we see when we run this however, is that the unit faces //down //and to the right instead, we only get the result we originally expected when we use the //negative //value -30°. This means that rotations along the Y-axis is inverted. It turns out the the same is true for the X-axis. The Z axis on the other hand is fine and works as we would expect.+What we see when we run this however, is that the unit faces //down //and to the right instead, we only get the result we originally expected when we use the //negative //value -30°. This means that rotations along the Y-axis is inverted.
  
-{{:4rpl:tutorials:unit_rotation_30.png?200&nolink}} {{:4rpl:tutorials:unit_rotation_0.png?200&nolink}} {{:4rpl:tutorials:unit_rotation_-30.png?200&nolink}} Rotating along the Y-axis is inverted+{{:4rpl:tutorials:unit_rotation_0.png?200&nolink|A cannon rotated 0° on the Y-axis}} {{:4rpl:tutorials:unit_rotation_30.png?200&nolink|A cannon rotated 30° on the Y-axis}} {{:4rpl:tutorials:unit_rotation_-30.png?200&nolink|A cannon rotated -30° on the Y-axis}} Rotating along the Y-axis is inverted
  
-So, if you work out some kind of angle within the map's coordinate system and you want to to use that angle to modify a unit in some way, make sure to invert the X and Y axes before doing so, or your unit will turn in exactly the opposite way. The easiest way to invert the X and Y angles of a vector is as follows: ''<-rotVector V3(-1 -1 1) * ->rotVector ''+It turns out the the same is true for the X-axis (rotating by a negative value will make units face upwards instead of downwards). The Z axis on the other hand is not inverted and works as we would expect. 
 + 
 +So, if you use conventional math to calculate a rotation within the coordinate system of a map, make sure to invert the X and Y axes of the rotation before applying it to a unit, or your unit will turn in exactly the opposite way. The easiest way to invert both X and Y values of a vector is as follows: ''<-rotVector V3(-1 -1 1) * ->rotVector''. For inverting a single value the [[4rpl:commands:neg]] function can be used. 
 + 
 +This way of calculating rotations is tied to the engine, and therefore used in any and all game objects that can have some kind of rotation. That includes units, their individual component objects and notably, the camera. 
 + 
 +----
  
 ===== Camera rotation ===== ===== Camera rotation =====
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 To account for this, we'll have to turn our angle 90° to the right before setting the camera. Similarly, when we want to convert the angle back into something that works in the map's coordinate system, you'll have to turn 90° left first. Below are some functions made for converting from and to camera orientation. To account for this, we'll have to turn our angle 90° to the right before setting the camera. Similarly, when we want to convert the angle back into something that works in the map's coordinate system, you'll have to turn 90° left first. Below are some functions made for converting from and to camera orientation.
 +
 +----
  
 ===== Converting rotations using 4RPL ===== ===== Converting rotations using 4RPL =====
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     deg2rad *      deg2rad * 
 </code> </code>
 +
 +<=[[4rpl:tutorials| Tutorials]]
  
  
cw4/tutorials/rotation_conversion.1610200956.txt.gz · Last modified: 2025/02/14 14:56 (external edit)

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