Add explanation of converting between floating and fixed point #21
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AntonioND
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This is useful in many situations, like when generating fixed point constants, or when printing fixed point values for debugging (or non debugging) purposes. Also, fix some qualifiers (`extern` isn't needed, `const` is nice to use).
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| // 1 and 5/8, written verbosely for demonstration purposes | ||
| int player_speed = 8 + 5; | ||
| int player_speed = (1 << player_fp) + ((5 << player_fp) / 8); |
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Shouldn't this bitwise expanded a bit? Like shift 1 by 3 position will effectively multiply 1 for 2^3 and same for the 5/8
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This is correct: 1 << 3 is 8, so the first part of the addition is correct. The second one is just 5 * 8 / 8, but at least this way it's more clear that the intention is to have 5/8 in fixed point, rather than just a random 5.
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Or maybe I've misunderstood your suggestion.
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Yeah I wasn't discussing the correctness, just to expand a bit more explaining the shift
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I see what you mean, but I'm not sure how to change the explanation to make it more clear. I think that the shift itself doesn't need to be understood as a multiplication, more like "making room for decimals".
In any case, if the rest of the PR is ok, we can merge it and that can be improved later, all I wanted with this change is explain a bit better where "5" was coming from, and now it's just using the general formula for any number, so...
Co-authored-by: Antonio Vivace <avivace4@gmail.com>
This is useful in many situations, like when generating fixed point
constants, or when printing fixed point values for debugging (or non
debugging) purposes.
Also, fix some qualifiers (
externisn't needed,constis nice touse).