[XNA/Monogame] Getting the bone rotations right

jonas

Hello there!

Following this approach, I am trying to apply 2D lightning to a normal mapped spine animation passing each bone's rotation as vertex data to the pixel shader. However, I think I calculate the rotation angle wrong since for some regions the lightning angle is shifted by 90 or 180 degrees. The rotated atlas regions should already be taken into account by checking the region.rotate property.

The angle I am passing in the SkeletonMeshRenderer's draw function is

(slot.Bone.WorldRotation - (region.rotate ? + 90 : 0) ) * (float)Math.PI / 180;

The atlas region of the blinking head is rotated, the shoes are not. Is it right to use the bone's worldrotation? Any insight would be greatly appreciated.

Greetings, Jonas

jonas

Nate

I would get it working without atlas rotation first. I assume your attachment's rotation in the setup pose is the zero rotation for your normal map, so what you need to send to the shader is the difference between this and the attachment's current rotation. Maybe try something like:

(boneSetupWorldRotation + attachmentRotation) - (boneCurrentWorldRotation + attachmentRotation)
// which of course is the same as
boneSetupWorldRotation - boneCurrentWorldRotation

jonas

Thanks for your answer. I got it working now using

float RotationForShader = ((region.rotate ? 90 : 0) - regionAttachment.Rotation - slot.Bone.WorldRotation) * (float)Math.PI / 180;

If anyone is interested in the code, please pm me.