Hi Can I have a go at this issue?

Sure go ahead.

@duncanspumpkin which file should I add string literal code to? I can't find a file similar to Types.hpp

https://github.com/OpenRCT2/OpenRCT2/blob/develop/src/openrct2/common.h would probably be the best location. We have placed the money equivalents of this in there. Tbh we could probably do with changing the money macros to use a literal like this as well.

@michiboo i did a bit more experimenting and i think my code can be slightly improved to provide higher precession. Might be useful for some literals that are harder to represent like 0.33333.

// Note: Only valid for 5 decimal places.
        constexpr uint32_t operator"" _mph(long double speedMph)
        {
            uint32_t wholeNumber = speedMph;
            uint64_t fraction = (speedMph - wholeNumber) * 100000;
            return wholeNumber << 16 | ((fraction << 16) / 100000);
        }

@duncanspumpkin I have some problem trying to build it on ubuntu , is there a build guide somewhere?

https://github.com/OpenRCT2/OpenRCT2/wiki/Building-OpenRCT2-on-Linux is our guide. @janisozaur can help you out if you provide information on what the issue is but please follow the guide first.

@janisozaur Hi i got this error when trying make
/home/oem/Desktop/github/OpenRCT2/src/openrct2/actions/../core/../core/../object/../core/JsonFwd.hpp:12:10: fatal error: nlohmann/json_fwd.hpp: No such file or directory
#include <nlohmann/json_fwd.hpp>

I had tried sudo apt install nlohmann-json-dev already.

Can you please help?

You're probably using outdated version of the package. We require at least 3.6 (if memory serves me right)

Can I give it a try for this issue ?
@duncanspumpkin

Sure. OpenLoco has a great example of this https://github.com/OpenLoco/OpenLoco/blob/master/src/OpenLoco/Speed.hpp we've been using it for quite a while now with no noticable issues. Strongly suggest pretty much copying Speed.hpp and modifying it to follow the coding style of OpenRCT2.

Replacing -0x2C000 in if (velocity > -0x2C000) with -2.75_mph, as per your example, gives the error C4146: unary minus operator applied to unsigned type, result still unsigned
All comparisons give warnings like the warning C4018: '>': signed/unsigned mismatch

Should the _mph code be implemented as int32_t instead, or is there any other solution?

If you look at my final code for OpenLoco I made it a signed value for speed.