feat: Add stepping and exact input value control to animation system

[Rhuagh]

Needs rebase when #567 is merged.

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This change is 

[Rhuagh]

Rebased, ready now.

[torkleyy]

Reviewed 5 of 5 files at r1.
Review status: all files reviewed at latest revision, all discussions resolved.

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amethyst_animation/src/resources.rs, line 328 at r1 (raw file):

/// Used when doing animation stepping (i.e only move forward/backward to discrete input values)
#[derive(Clone, Debug)]
pub enum StepDirection {

Can you make the repr to i8 and set Forward to +1 and Backward to -1? That might make the code above shorter.

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Comments from Reviewable

[Rhuagh]

Review status: all files reviewed at latest revision, 1 unresolved discussion.

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amethyst_animation/src/resources.rs, line 328 at r1 (raw file):

Previously, torkleyy (Thomas Schaller) wrote…

Can you make the repr to i8 and set Forward to +1 and Backward to -1? That might make the code above shorter.

Not sure, still need to do edge case handling individually so the index don't overflow/underflow.

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Comments from Reviewable

[Rhuagh]

Review status: all files reviewed at latest revision, 1 unresolved discussion.

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amethyst_animation/src/resources.rs, line 328 at r1 (raw file):

Previously, Rhuagh (Simon Rönnberg) wrote…

Not sure, still need to do edge case handling individually so the index don't overflow/underflow.

It would remove one line, that's about it.

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Comments from Reviewable

[Rhuagh]

r? @Xaeroxe @omni-viral

[torkleyy]

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Review status: all files reviewed at latest revision, all discussions resolved, all commit checks successful.

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Comments from Reviewable

[Xaeroxe]

LGTM!

bors r+

[bors]

Build succeeded

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