spec_v2: migrate TAA

[ecoskey]

Objective

• Migrate TAA to spec_v2

Testing

• Ran anti_aliasing example, seems fine

[NicoZweifel]

Tested the anti_aliasing example locally and it worked fine.

I took a look a the spec_v2 issues and understand that it is about splitting creation and modification of descriptors. However, in this specific example the shader expects:

struct Output {
    @location(0) view_target: vec4<f32>,
    @location(1) history: vec4<f32>,
};

Currently, these targets are set later in specialize using raw indices. But from what I understand about the reasoning behind spec_v2, shouldn't it already have the defaults set, which specialize then modifies?

For the index access I would prefer constants (or an enum), e.g.

const TARGET_VIEW: usize = 0;  
const TARGET_HISTORY: usize = 1;

and

fragment.set_target(TARGET_VIEW, color_target_state.clone());
fragment.set_target(TARGET_HISTORY, color_target_state);

since otherwise it's not exactly clear which target it is without looking at the shader.

This is just a minor nit imo and the example works, so approving.