![]() This is because the game screen has dimensions, and therefore distance in the X or Y direction, measured in pixels.Ī sprite’s ||sprites:vx|| represents the sprite’s velocity on the horizontal axis and is how quickly the sprite’s ||sprites:x|| value is changing in value moving left to right.Ī sprite’s ||sprites:vy||, represents the sprite’s velocity in the vertical axis, and is how quickly the sprite’s ||sprites:y|| changes in value moving up and down. In Arcade, a sprite’s velocity is measured in pixels per second, and stored as a sprite’s ||sprites:vx|| and ||sprites:vy||. This means over the course of an hour at this rate, you will be 60 miles further North than you are currently. In real life, you can think of velocity like being in a train or a car the speed on a highway may be 60 miles per hour, but the velocity would be 60 miles per hour going North. Velocity is the distance at which an object’s position changes, along with its direction, over some period of time. The XML is stored in assets/maps/ with the associated sprite stored in assets/gfx/maps/ PS: Until i get this test working I'm using the trial version of PhysicsEditor. ![]() Launch PhysicsEditor and use the Add Sprites button to open the. It was created in PhysicsEditor by adding sprite, using the shape tracer to get the outline, and export as AndEngine exporter. Velocity is defined as speed in a given direction. game development tool, and then we will be ready to get to collision detection coding. ![]() Acceleration: ||sprites:ax|| and ||sprites:ay||.Velocity: ||sprites:vx|| and ||sprites:vy||.In this activity, students will gain a greater understanding of how exactly a sprite’s velocity and acceleration affect their behavior in a game. ![]() 'Not sure what "PhysicsEngine tool" you are referring to, but do you have a screenshot of the output ? It would be interesting to compare to your manually defined shape ! It could indeed be constrained to convex polygons or primitives, as you're suggesting, since these are easier to deal with for collisions at runtime thus providing better accuracy and eliminating your issues and collision artifacts.Up to this point, we have generally glossed over the exact details of how sprite motion works. Do you think that it is just that the generated shapes are constrained to "simple primitives". I noticed the generated shape is actually many shapes, not just a singe polygon so there is something about shapes that is important but I don't understand what. There must be something wrong with my shape, however, because I tried using the PysicsEngine tool to generate it and it works perfectly. I don't know if you had a look at the example on phaser sandbox but you can see the polygon in debug mode. Since I don't get that error with this shape I assume it is convex. I aslso assume it is closed. Thanks Refeuh, I don't know if my shape is convex but when I was experimenting I tried using several polygons and I got an error that convex shapes had to be counter-clockwise (or something like that) so I reversed the order of the points and stopped getting the error. My general advice would be to ban custom hitcheck wherever possible and approximate complex shapes with hierarchies of physics primitives, especially for animated elements. are even easier as it's possible to use implicit solvers, rather than discrete edges. And primitives like spheres, cylinders, etc. That's the reason collision groups in games are usually a hierarchy of primitives, rather than custom shapes.ītw, is your custom collision polygon closed and convex ? This makes things a lot easier in terms of computations, accuracy, etc. As far as I know this is not supported in all, if any, physics engines in Phaser (arcade vs box2d vs ninja to be confirmed ?) as it quickly becomes very computational and intensive the idea usually works well at reasonable cost for simple primitives (a point swept over time becomes a ray, a sphere swept over time becomes a capsule, etc.) but is almost impossible to do with arbitrary polygons, shapes, volumes and meshes (a swept random mesh becomes. The answer to tunnelling is CCD, continuous collision detection, usually with swept-shapes or swept-volumes. Objects moving "fast" relative to their "size" are likely to pass through each other, depending on update time, as you already found out. ![]()
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