TextureAtlas actually not separating pieces. When you get region from atlas its just saying that this is the area you gonna use (u,v,u2,v2) and this is original reference to whole texture.
This is why batch.draw(Texture) and batch.draw(TextureRegion) are not same in use.
However taking part of picture as texture is possible.
It may be quite expensive due to your Textureatlas size.
- You can use framebuffer.
Create FBbuilder and build new frame buffer.Draw texture region to this buffer and get texture from it.
Problem here is the sizes of texture will be same as viewport/screen sizes.I guess you can create new camera to change it to sizes you want.
GLFrameBuffer.FrameBufferBuilder frameBufferBuilder = new GLFrameBuffer.FrameBufferBuilder(widthofBox, heightofBox);
frameBufferBuilder.addColorTextureAttachment(GL30.GL_RGBA8, GL30.GL_RGBA, GL30.GL_UNSIGNED_BYTE);
frameBuffer = frameBufferBuilder.build();
OrthographicCamera c = new OrthographicCamera(widthofBox, heightofBox);
c.up.set(0, 1, 0);
c.direction.set(0, 0, -1);
c.position.set(widthofBox / 2, heightofBox / 2, 0f);
Texture texturefbo = frameBuffer.getColorBufferTexture();
Texturefbo will be y flipped. You can fix this with texture draw method by setting scaleY to -1 or You can scale scaleY to -1 while drawing on framebuffer or can change camera like this
up.set(0, -1, 0);
direction.set(0, 0, 1);
to flip to camera on y axis.
Last thing came to my mind is mipmapping this texture.Its also not so hard.