DirectX texture arrays

Question

I want to do batch-rendering with OpenGL and DirectX.
I have this glsl code for the fragment(pixel) shader:

#version 450 core

out vec4 FSOutFragColor;

in vec2 VSOutTexCoords;
in flat uint VSOutTexIndex;

uniform sampler2D[16] u_Textures;

void main()
{
FSOutFragColor = texture(u_Textures[VSOutTexIndex], VSOutTexCoords);
}

But if I try to do the same thing with hlsl's Texture2D it gives me:
X3512: sampler array index must be a literal expression. (I know what the error is saying)
I searched the web and didn't find any clear answers, can someone help me with this ^_^

Answer 1

Alright, so I figured it out (I asked chili on discord).
" You can't dynamically index into different texture resources. The array syntax is just a convenience, the compiler has to generate hard-coded lookups for each fetch. If you want full dynamic access you either need to use texture arrays as Nik02 suggests, use a texture atlas, or use some combination of the two.
so you either have to generate those hard-coded lookups yourself or use something more dynamic like a kind of atlas ".

So I need to use Texture2DArray in hlsl and sampler2DArray in glsl and all the textures have to be the same size ( so I'll need to use texture atlases ).