CODEWITHSUNDEEP
xnabeziercurves
Not Szwagi
Not Szwagi

Reputation: 81

Drawing Curves using XNA

I've been making progress in a fan-replicated game I'm coding, but I'm stuck with this problem. Right now I'm drawing a texture pixel by pixel on the curve path, but this cuts down frames per second from 4000 to 50 on curves with long lengths. I need to store pixel by pixel Vector2 + length data anyway, so I can produce static speed movement along it, looping through it to draw the curve as well.

Curves I need to be able to draw are Bezier, Circular and Catmull.

enter image description here

Any ideas of how to make it more efficient?

Upvotes: 1

Views: 847

Answers (2)

Stefan Agartsson
Stefan Agartsson

Reputation: 441

Maybe I have misunderstood the question but I did this once:

Create the curve and sample x points on it. (Red dots) Create a mesh from it by calculating the cross vector of each point. (Green lines) Build a quad between all of these. So basically 5 of them in my picture.

Set the U coordinate to be on the perpendicular plane and V coordinate follows the curve length. So 0 at the start an 1 at the end of it. You can of course scale V if you want you texture to repeat. enter image description here

Upvotes: 1

user585968
user585968

Reputation:

Any ideas of how to make it more efficient?

Assuming the texture needs to be dynamic, draw the texture on the GPU-side using a shader. Drawing it on the CPU-side is not only slow, but bogs down both the CPU and GPU when you need to send it back to the GPU every frame. Much better to draw it GPU-side.

I need to store pixel by pixel Vector2 + length data anyway

The shader can store additional information into the texture. e.g. even though you may allocate a RGBA texture, it doesn't mean that it needs to store color information when it is your shaders that will interpret the data.

Upvotes: 0

Related Questions