Shader Texture Atlas Support

[MackeyK24]

1 hour ago, Pryme8 said:

https://mtnphil.wordpress.com/2011/09/26/terrain-texture-atlas-construction/

see how it uses a "buffer" of data around the actual texture, its kinda a oddball thing to wrap your head around but this explains it decently.

and here is some discussion on to mip or not to mip
https://blogs.msdn.microsoft.com/shawnhar/2009/09/14/texture-filtering-mipmaps/

So how many mip maps does the GLSL system create when noMipmap = false ... So I can know how big to make the gutter?

And also when swapping the corners... How do only swap left AND right CORNERS or top AND bottom corners?

 How can you swap all 4 corners left and right and top and bottom...

I see how you can take the left gutter of original and make right gutter on scaled down version and make the right gutter on original  the left gutter on scaled down version... Same thing with top and bottom... But how to handle CORNERS ???

[Pryme8]

It will generate as many steps as it’s needed to reduce the image to a 1x1

[MackeyK24]

Yo @Pryme8 ... I am trying to under stand the corner swiping when preparing the texture atlas tiles...

it says to take edges from opposite sides of the original image... I get the for the left, right, top and bottom... they just swap...

But what about corners... if that goes swaps left and right and top and bottom I think that just swaps them DIAGONALLY...

Is that high for the edges... The TOP-LEFT corner from source image should go to BOTTOM-RIGHT corner of destination image and

the BOTTOM-LEFT corner should go to the TOP-RIGHT corner ???

 

[MackeyK24]

Yo @Pryme8 ... Just for debugging the edge seams for now (I am however writing code to do all the border swapping and 9 image 3 x 3 center cropping).

But just for debugging I actually paint ALL sub textures with just a solid color... because within the texture size (512 x 512 for example) the gutter, body and edges ... everything is one solid color.

But I still get edge seams when mip mapping. Here is shot of solid color Texture Atlas:

 

And here is Output:

So mip level selection is off...

I was reading something about manual mip selection and someone about half pixel correction... Any ideals about that ?

 

[Pryme8]

With a solid color like that you would never need mips, effectively you could get away with a 4px by 4px image to do what your demonstrating above.

I would recommend just turning off mips for now and continuing development with the NEAREST and no mips method.

The whole point of the mip maps is for getting rid of texture artifacts and sharpness at a distance (and to save memory) but if you use like a fog pass or some secondary pass you can clean up the "choas" on the texture at a distance.  Just move on and worry about it more once your really finishing stuff up.