mirror of https://github.com/OpenTTD/OpenTTD.git
Change: Perform unit convert with a double-precision constant.
Unit conversion is only performed for display purposes, this does not affect lock-step mechanics. This replaces the old multiply and shift algorithm which relies on choosing a multipler and shift combination that gets close. Some of these multiply/shift combinations were quite inaccurate. We can just use (close-to) real-world numbers instead.
This commit is contained in:
Peter Nelson
Michael Lutz
parent
644e310506
commit
3c2f87ce1f
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@ -658,8 +658,7 @@ static const char *ParseStringChoice(const char *b, uint form, char **dst, const
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/** Helper for unit conversion. */
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struct UnitConversion {
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int multiplier; ///< Amount to multiply upon conversion.
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int shift; ///< Amount to shift upon conversion.
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double factor; ///< Amount to multiply or divide upon conversion.
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/**
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* Convert value from OpenTTD's internal unit into the displayed value.
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@ -669,7 +668,9 @@ struct UnitConversion {
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*/
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int64 ToDisplay(int64 input, bool round = true) const
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{
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return ((input * this->multiplier) + (round && this->shift != 0 ? 1 << (this->shift - 1) : 0)) >> this->shift;
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return round
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? (int64_t)std::round(input * this->factor)
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: (int64_t)(input * this->factor);
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}
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/**
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@ -681,7 +682,9 @@ struct UnitConversion {
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*/
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int64 FromDisplay(int64 input, bool round = true, int64 divider = 1) const
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{
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return ((input << this->shift) + (round ? (this->multiplier * divider) - 1 : 0)) / (this->multiplier * divider);
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return round
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? (int64_t)std::round(input / this->factor / divider)
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: (int64_t)(input / this->factor / divider);
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}
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};
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@ -701,59 +704,59 @@ struct UnitsLong {
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/** Unit conversions for velocity. */
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static const Units _units_velocity[] = {
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{ { 1, 0}, STR_UNITS_VELOCITY_IMPERIAL, 0 },
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{ { 103, 6}, STR_UNITS_VELOCITY_METRIC, 0 },
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{ { 1831, 12}, STR_UNITS_VELOCITY_SI, 0 },
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{ { 37888, 16}, STR_UNITS_VELOCITY_GAMEUNITS, 1 },
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{ { 7289499, 23}, STR_UNITS_VELOCITY_KNOTS, 0 },
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{ { 1.0 }, STR_UNITS_VELOCITY_IMPERIAL, 0 },
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{ { 1.609344 }, STR_UNITS_VELOCITY_METRIC, 0 },
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{ { 0.44704 }, STR_UNITS_VELOCITY_SI, 0 },
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{ { 0.578125 }, STR_UNITS_VELOCITY_GAMEUNITS, 1 },
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{ { 0.868976 }, STR_UNITS_VELOCITY_KNOTS, 0 },
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};
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/** Unit conversions for power. */
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static const Units _units_power[] = {
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{ { 1, 0}, STR_UNITS_POWER_IMPERIAL, 0 },
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{ {4153, 12}, STR_UNITS_POWER_METRIC, 0 },
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{ {6109, 13}, STR_UNITS_POWER_SI, 0 },
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{ { 1.0 }, STR_UNITS_POWER_IMPERIAL, 0 },
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{ { 1.01387 }, STR_UNITS_POWER_METRIC, 0 },
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{ { 0.745699 }, STR_UNITS_POWER_SI, 0 },
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};
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/** Unit conversions for power to weight. */
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static const Units _units_power_to_weight[] = {
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{ { 29, 5}, STR_UNITS_POWER_IMPERIAL_TO_WEIGHT_IMPERIAL, 1},
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{ { 1, 0}, STR_UNITS_POWER_IMPERIAL_TO_WEIGHT_METRIC, 1},
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{ { 1, 0}, STR_UNITS_POWER_IMPERIAL_TO_WEIGHT_SI, 1},
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{ { 59, 6}, STR_UNITS_POWER_METRIC_TO_WEIGHT_IMPERIAL, 1},
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{ { 65, 6}, STR_UNITS_POWER_METRIC_TO_WEIGHT_METRIC, 1},
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{ { 65, 6}, STR_UNITS_POWER_METRIC_TO_WEIGHT_SI, 1},
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{ { 173, 8}, STR_UNITS_POWER_SI_TO_WEIGHT_IMPERIAL, 1},
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{ { 3, 2}, STR_UNITS_POWER_SI_TO_WEIGHT_METRIC, 1},
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{ { 3, 2}, STR_UNITS_POWER_SI_TO_WEIGHT_SI, 1},
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{ { 0.907185 }, STR_UNITS_POWER_IMPERIAL_TO_WEIGHT_IMPERIAL, 1 },
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{ { 1.0 }, STR_UNITS_POWER_IMPERIAL_TO_WEIGHT_METRIC, 1 },
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{ { 1.0 }, STR_UNITS_POWER_IMPERIAL_TO_WEIGHT_SI, 1 },
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{ { 0.919768 }, STR_UNITS_POWER_METRIC_TO_WEIGHT_IMPERIAL, 1 },
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{ { 1.01387 }, STR_UNITS_POWER_METRIC_TO_WEIGHT_METRIC, 1 },
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{ { 1.01387 }, STR_UNITS_POWER_METRIC_TO_WEIGHT_SI, 1 },
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{ { 0.676487 }, STR_UNITS_POWER_SI_TO_WEIGHT_IMPERIAL, 1 },
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{ { 0.745699 }, STR_UNITS_POWER_SI_TO_WEIGHT_METRIC, 1 },
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{ { 0.745699 }, STR_UNITS_POWER_SI_TO_WEIGHT_SI, 1 },
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};
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/** Unit conversions for weight. */
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static const UnitsLong _units_weight[] = {
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{ {4515, 12}, STR_UNITS_WEIGHT_SHORT_IMPERIAL, STR_UNITS_WEIGHT_LONG_IMPERIAL },
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{ { 1, 0}, STR_UNITS_WEIGHT_SHORT_METRIC, STR_UNITS_WEIGHT_LONG_METRIC },
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{ {1000, 0}, STR_UNITS_WEIGHT_SHORT_SI, STR_UNITS_WEIGHT_LONG_SI },
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{ { 1.102311 }, STR_UNITS_WEIGHT_SHORT_IMPERIAL, STR_UNITS_WEIGHT_LONG_IMPERIAL },
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{ { 1.0 }, STR_UNITS_WEIGHT_SHORT_METRIC, STR_UNITS_WEIGHT_LONG_METRIC },
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{ { 1000.0 }, STR_UNITS_WEIGHT_SHORT_SI, STR_UNITS_WEIGHT_LONG_SI },
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};
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/** Unit conversions for volume. */
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static const UnitsLong _units_volume[] = {
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{ {4227, 4}, STR_UNITS_VOLUME_SHORT_IMPERIAL, STR_UNITS_VOLUME_LONG_IMPERIAL },
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{ {1000, 0}, STR_UNITS_VOLUME_SHORT_METRIC, STR_UNITS_VOLUME_LONG_METRIC },
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{ { 1, 0}, STR_UNITS_VOLUME_SHORT_SI, STR_UNITS_VOLUME_LONG_SI },
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{ { 264.172 }, STR_UNITS_VOLUME_SHORT_IMPERIAL, STR_UNITS_VOLUME_LONG_IMPERIAL },
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{ { 1000.0 }, STR_UNITS_VOLUME_SHORT_METRIC, STR_UNITS_VOLUME_LONG_METRIC },
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{ { 1.0 }, STR_UNITS_VOLUME_SHORT_SI, STR_UNITS_VOLUME_LONG_SI },
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};
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/** Unit conversions for force. */
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static const Units _units_force[] = {
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{ {3597, 4}, STR_UNITS_FORCE_IMPERIAL, 0 },
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{ {3263, 5}, STR_UNITS_FORCE_METRIC, 0 },
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{ { 1, 0}, STR_UNITS_FORCE_SI, 0 },
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{ { 224.809 }, STR_UNITS_FORCE_IMPERIAL, 0 },
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{ { 101.972 }, STR_UNITS_FORCE_METRIC, 0 },
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{ { 1.0 }, STR_UNITS_FORCE_SI, 0 },
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};
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/** Unit conversions for height. */
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static const Units _units_height[] = {
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{ { 3, 0}, STR_UNITS_HEIGHT_IMPERIAL, 0 }, // "Wrong" conversion factor for more nicer GUI values
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{ { 1, 0}, STR_UNITS_HEIGHT_METRIC, 0 },
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{ { 1, 0}, STR_UNITS_HEIGHT_SI, 0 },
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{ { 3.0 }, STR_UNITS_HEIGHT_IMPERIAL, 0 }, // "Wrong" conversion factor for more nicer GUI values
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{ { 1.0 }, STR_UNITS_HEIGHT_METRIC, 0 },
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{ { 1.0 }, STR_UNITS_HEIGHT_SI, 0 },
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};
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/**
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