As understood, I am busy with GLES 2.0 and mostly oriented to 2D.
I am trying to setup a performant template to convert/split a png file into 2 ETC1 files one includes rgb, other includes alpha. MipMap included to call texture with offsets (because no preset in godot shaders regarding nearest/linear/bilinear/trilinear options. i do not know the performance effects with these calls) later.
Maybe mipmapped series can be added into ECT1 couples. So, maybe more than 2 Sampler2D required for one image.
What i am looking for are listed below.
110 figure out ETC1 format properties
120 import ETC1 as mentioned above
120a in editor manually
120b on the fly with for multiple images
130 texture function implementation pretending texel fetch (a separate help request will be for this one)
I have checked some documentation
1100
https://registry.khronos.org/DataFormat/specs/1.1/dataformat.1.1.html#ETC1
little bit confused. if you reply the other options it will be clearer.
1200
https://docs.godotengine.org/en/stable/tutorials/rendering/gles2_gles3_differences.html#texture-compression
https://docs.godotengine.org/en/3.5/tutorials/assets_pipeline/importing_images.html#importing-textures
1200a - If you fill a sample for this one it will be perfect.
https://docs.godotengine.org/en/stable/classes/class_image.html
1200b - sample code will be perfect
Thanks in advance.