the screen is at the camera position in world space.
first find the local position of each point on 3D object, then convert the position into world space, then calc the distance from camera position.
converting involves matrix calculation that you need to know.

www.cesium.com
it's something like google earth.

Hi everyone,
i released a demo of this on moddb, here is the link.
https://www.moddb.com/games/vehicle-simulation
it is not a fun and fast game, there are a lot of texts to read if you want to fly in it. but you can quickly make something move and see the effects - you need keyboard for that.
the moddb page is new, i haven't spent much time on it. just uploaded the file and share with you guys.

i spent quite some time making a telemetry system, besides drawing curves from rolling data, there are UI, channel management etc.  jpct-ae engine helps me make my wishes come true.

the 2 screenshots show the correct result and wrong result.


problem seems to be that, some part of the screen is not updated, but reverse to older buffered image. when i rotate the camera, part of image is jumping back and forth. the size of unupdated part is not constant.

my app has the machanism that the main scene is rendered into texture then blit the texture on screen. if this is on. AA works correctly. if the scene is rendered directly on screen. AA causes problem.
it is also related to my cloud effect. if the clouds are not drawn, no problem. the clouds are drawn with several passes at different time points and there are some gl state changes, it's quite complicated.

this is a funny thing. i like the effect of the PC game Sniper Elite, so i did this, but without advanced visual effects.

with gif files, i can show you more interesting things.
this one shows the vehicle drifting, when rear tyres have much lower friction coefficient, any vehicle can do this.


the colored polylines is a tool for testing purpose.

with jpct-ae engine i can easily control the render order of multiple Worlds, very flexible - my app uses dozens of RenderScene calls to render the whole scene. i have to thank Egon for providing this engine and his much support.

hope you like these