KERBAL SPACE PROGRAM 2 DEV DIARY FULL

The entire universe also orbits around the craft when it is below the inverse rotation altitude threshold, which means that PhysX is doing physics in the co-rotating reference frame. Pretty sure that the floating origin moves with the craft now every frame. The fix is to use homogeneous texture coordinates. What's less obvious is that this problem is present to a lesser extent in every quad on the sphere, because the triangle with the horizontal edge nearer the pole is smaller than the other, so half of the texture is stretched and half is shrunk.

Then when you texture map that 'quad' with a square texture, half of the texture is not shown, and you get visible seams (Google Earth suffers from this artifact, or at least it did in the past). However, at the poles, one of the triangles has zero area because two of its vertices are the same, the pole. Of course the quads are split into two triangles for rendering. So you have to make sure that you do calculations needing high precision on the CPU in double precision and only send the GPU coordinates it can handle, or your 3D models will get crunched by precision errors.Īnother one is that a planet sphere renderer will often tesselate the sphere into quads in lat-lon space. Another one is that single precision floating point doesn't have enough precision to represent both planet scale and human scale in the same coordinate system (let alone solar system scale or galaxy scale), yet GPUs don't support double precision well.

KERBAL SPACE PROGRAM 2 DEV DIARY FULL

Space rendering is full of interesting problems like this.

Kerbal space program 2 dev diary