Merge #901

901:  GDscript builtin functions to rust  r=Bromeon a=Haxeil

here is the implementation of the builtin functions in GDscript back to rust, regarding this 
#893 issue.
https://docs.godotengine.org/en/stable/classes/[email protected]#

Co-authored-by: Haxeil <[email protected]>

Author: bors[bot]

gdnative-core/src/globalscope.rs

@@ -0,0 +1,379 @@
+//! `fmod` is `%` operator on `f32`;
+//! ```rust
+//! use std::ops::Rem;
+//! assert_eq!(f32::rem(12.0, 10.0), 2.0);
+//! ```
+
+use std::f32::consts::TAU;
+use std::ops::Rem;
+use std::ops::{Range, RangeInclusive};
+
+const CMP_EPSILON: f32 = 0.00001;
+
+/// Converts a 2D point expressed in the `cartesian` coordinate system (X and Y axis)
+///  to the `polar` coordinate system (a distance from the origin and an angle `(in radians)`).
+#[inline]
+pub fn cartasian2polar(x: f32, y: f32) -> (f32, f32) {
+    ((x * x + y * y).sqrt(), y.atan2(x))
+}
+
+/// Converts from `decibels` to linear energy (audio).
+#[inline]
+pub fn db2linear(db: f32) -> f32 {
+    f32::exp(db * 0.115_129_255)
+}
+
+/// Returns the `position` of the first `non-zero` digit, after the decimal point.
+/// Note that the `maximum` return `value` is `10`, which is a design decision in the implementation.
+/// # Examples:
+/// ```
+/// use gdnative_core::globalscope::step_decimals;
+/// assert_eq!(step_decimals(5.0), 0);
+/// assert_eq!(step_decimals(12.0004), 4);
+/// assert_eq!(step_decimals(0.000000004), 9);
+/// ```
+#[inline]
+pub fn step_decimals(step: f32) -> i32 {
+    const MAXN: usize = 10;
+    const SD: [f32; MAXN] = [
+        0.9999, // somehow compensate for floating point error
+        0.09999,
+        0.009999,
+        0.0009999,
+        0.00009999,
+        0.000009999,
+        0.0000009999,
+        0.00000009999,
+        0.000000009999,
+        0.0000000009999,
+    ];
+
+    let abs = step.abs();
+    let int_abs: i32 = step as i32;
+    let decs: f32 = abs - (int_abs as f32); // strip away integer part;
+    for (i, item) in SD.iter().enumerate().take(MAXN) {
+        if decs >= *item {
+            return i.try_into().unwrap();
+        }
+    }
+    0
+}
+
+/// Moves `range.start()` toward `range.end()` by the `delta` `value`.
+/// Use a negative `delta` value `range.end()` move away.
+/// # Examples:
+/// ```
+/// use gdnative_core::globalscope::move_toward;
+/// assert_eq!(move_toward(10.0..=5.0, 4.), 6.);
+/// assert_eq!(move_toward(10.0..=5.0, -1.5), 11.5);
+/// assert_eq!(move_toward(4.0..=8.0, 1.0), 5.0);
+/// assert_eq!(move_toward(4.0..=8.0, 5.0), 8.0);
+/// assert_eq!(move_toward(8.0..=4.0, 1.0), 7.0);
+/// assert_eq!(move_toward(8.0..=4.0, 5.0), 4.0);
+/// ```
+#[inline]
+pub fn move_toward(range: RangeInclusive<f32>, delta: f32) -> f32 {
+    if (range.end() - range.start()).abs() <= delta {
+        *range.end()
+    } else {
+        range.start() + (range.end() - range.start()).signum() * delta
+    }
+}
+
+/// Returns an "eased" value of x based on an easing function defined with `curve`.
+/// This easing function is based on an `exponent`. The curve can be any floating-point number,
+/// with specific values leading to the following behaviors:
+#[inline]
+pub fn ease(mut s: f32, curve: f32) -> f32 {
+    if s < 0.0 {
+        s = 0.0;
+    } else if s > 1.0 {
+        s = 1.0;
+    }
+    if curve > 0.0 {
+        if curve < 1.0 {
+            1.0 - (1.0 - s).powf(1.0 / curve)
+        } else {
+            s.powf(curve)
+        }
+    } else if curve < 0.0 {
+        //inout ease
+
+        if s < 0.5 {
+            (s * 2.0).powf(-curve) * 0.5
+        } else {
+            (1.0 - (1.0 - (s - 0.5) * 2.0).powf(-curve)) * 0.5 + 0.5
+        }
+    } else {
+        0.0 // no ease (raw)
+    }
+}
+
+/// Linearly interpolates between two values by the factor defined in weight.
+/// To perform interpolation, weight should be between 0.0 and 1.0 (inclusive).
+/// However, values outside this range are allowed and can be used to perform extrapolation.
+/// ```
+/// use gdnative_core::globalscope::lerp;
+/// assert_eq!(lerp(0.0..=4.0, 0.75), 3.0);
+/// ```
+#[inline]
+pub fn lerp(range: RangeInclusive<f32>, weight: f32) -> f32 {
+    range.start() + (range.end() - range.start()) * weight
+}
+
+/// Linearly interpolates between two angles (in radians) by a normalized value.
+/// Similar to lerp, but interpolates correctly when the angles wrap around `TAU`.
+/// To perform eased interpolation with `lerp_angle`, combine it with `ease` or `smoothstep`
+/// use std::f32::consts::{PI, TAU};
+/// use gdnative::globalscope::lerp_angle;
+///
+/// assert_eq!(lerp_angle(-PI..PI, 0.0), -PI);
+/// assert_eq!(lerp_angle(-PI..PI, 1.0), -PI);
+/// assert_eq!(lerp_angle(PI..-PI, 0.0), PI);
+/// assert_eq!(lerp_angle(PI..-PI, 1.0), PI);
+/// assert_eq!(lerp_angle(0.0..TAU, 0.0), 0.0);
+/// assert_eq!(lerp_angle(0.0..TAU, 1.0), 0.0);
+/// assert_eq!(lerp_angle(TAU..0, 0.0), TAU);
+/// assert_eq!(lerp_angle(TAU..0, 1.0), TAU);
+#[inline]
+pub fn lerp_angle(range: Range<f32>, amount: f32) -> f32 {
+    let difference = f32::rem(range.end - range.start, TAU);
+
+    let distance = f32::rem(2.0 * difference, TAU) - difference;
+    range.start + distance * amount
+}
+
+/// Returns the floating-point modulus of `a/b` that wraps equally in `positive` and `negative`.
+/// # Examples:
+/// ```rust
+/// use gdnative_core::globalscope::fposmod;
+/// assert_eq!(fposmod(-1.5, 1.5), 0.0);
+/// assert_eq!(fposmod(-1.0, 1.5), 0.5);
+/// assert_eq!(fposmod(-0.5, 1.5), 1.0);
+/// assert_eq!(fposmod(0.0, 1.5), 0.0);
+/// ```
+#[inline]
+pub fn fposmod(x: f32, y: f32) -> f32 {
+    let mut value = f32::rem(x, y);
+    if ((value < 0.0) && (y > 0.0)) || ((value > 0.0) && (y < 0.0)) {
+        value += y;
+    }
+
+    value += 0.0;
+    value
+}
+
+/// Returns an interpolation or extrapolation factor considering the range specified in `range.start()` and `range.end()`,
+/// and the interpolated value specified in `weight`.
+/// The returned value will be between `0.0` and `1.0` if `weight` is between `range.start()` and `range.end()` (inclusive).
+/// If `weight` is located outside this range,
+/// then an extrapolation factor will be returned (return value lower than `0.0` or greater than `1.0`).
+/// # Examples:
+/// ```rust
+/// use gdnative_core::globalscope::inverse_lerp;
+/// assert_eq!(inverse_lerp(20.0..=30.0, 27.5), 0.75);
+/// ```
+#[inline]
+pub fn inverse_lerp(range: RangeInclusive<f32>, value: f32) -> f32 {
+    (value - range.start()) / (range.end() - range.start())
+}
+
+/// Returns the result of smoothly interpolating the value of `s` between `0` and `1`, based on the where `s` lies with respect to the edges `from` and `to`.
+/// The return value is `0` if `s <= from`, and `1` if `s >= to`. If `s` lies between `from` and `to`, the returned value follows an S-shaped curve that maps `s` between `0` and `1`.
+/// This S-shaped curve is the cubic Hermite interpolator, given by `f(y) = 3*y^2 - 2*y^3` where `y = (x-from) / (to-from)`.
+/// Compared to ease with a curve value of `-1.6521`, smoothstep returns the smoothest possible curve with no sudden changes in the derivative.
+/// If you need to perform more advanced transitions, use Tween or AnimationPlayer.
+/// # Examples:
+/// ```rust
+/// use gdnative_core::globalscope::smoothstep;
+/// assert_eq!(smoothstep(0.0, 2.0, -5.0), 0.0);
+/// assert_eq!(smoothstep(0.0, 2.0, 0.5), 0.15625);
+/// assert_eq!(smoothstep(0.0, 2.0, 1.0), 0.5);
+/// assert_eq!(smoothstep(0.0, 2.0, 2.0), 1.0);
+/// ```
+
+#[inline]
+pub fn smoothstep(from: f32, to: f32, s: f32) -> f32 {
+    if is_equal_approx(from, to) {
+        return from;
+    }
+    let s = ((s - from) / (to - from)).clamp(0.0, 1.0);
+    s * s * (3.0 - 2.0 * s)
+}
+
+/// Returns `true` if `a` and `b` are approximately equal to each other.
+/// Here, approximately equal means that `a` and `sb` are within a small internal epsilon of each other,
+/// which scales with the magnitude of the numbers.
+/// Infinity values of the same sign are considered equal.
+#[inline]
+pub fn is_equal_approx(a: f32, b: f32) -> bool {
+    if a == b {
+        return true;
+    }
+    let mut tolerance = CMP_EPSILON * a.abs();
+    if tolerance < CMP_EPSILON {
+        tolerance = CMP_EPSILON;
+    }
+    (a - b).abs() < tolerance
+}
+
+/// Returns true if s is zero or almost zero.
+/// This method is faster than using is_equal_approx with one value as zero.
+#[inline]
+pub fn is_zero_approx(s: f32) -> bool {
+    s.abs() < CMP_EPSILON
+}
+
+/// Converts from linear energy to decibels (audio).
+/// This can be used to implement volume sliders that behave as expected (since volume isn't linear).
+#[inline]
+pub fn linear2db(nrg: f32) -> f32 {
+    nrg.ln() * 0.115_129_255
+}
+
+/// Returns the nearest equal or larger power of 2 for integer value.
+/// In other words, returns the smallest value a where `a = pow(2, n)` such that `value <= a` for some non-negative integer `n`.
+/// # Examples:
+/// ```rust
+/// use gdnative_core::globalscope::nearest_po2;
+/// assert_eq!(nearest_po2(3), 4);
+/// assert_eq!(nearest_po2(4), 4);
+/// assert_eq!(nearest_po2(5), 8);
+/// assert_eq!(nearest_po2(0), 0);
+/// assert_eq!(nearest_po2(-1), 0);
+/// ```
+#[inline]
+pub fn nearest_po2(value: i32) -> u32 {
+    if value <= 0 {
+        return 0;
+    }
+    (value as u32).next_power_of_two()
+}
+
+/// Converts a 2D point expressed in the polar coordinate system
+/// (a distance from the origin r and an angle th (radians)) to the cartesian coordinate system (X and Y axis).
+#[inline]
+pub fn cartesian2polar(r: f32, th: f32) -> (f32, f32) {
+    (r * th.cos(), r * th.sin())
+}
+
+/// Returns the integer modulus of a/b that wraps equally in positive and negative.
+/// # Examples:
+/// ```rust
+/// use gdnative_core::globalscope::posmod;
+/// const VALS: [i32; 7] = [0, 1, 2, 0, 1, 2, 0];
+/// for i in (-3..4).enumerate() {
+///     assert_eq!(posmod(i.1, 3), VALS[i.0]);
+/// }
+/// ```
+#[inline]
+pub fn posmod(a: i32, b: i32) -> i32 {
+    let mut value = a % b;
+    if ((value < 0) && (b > 0)) || ((value > 0) && (b < 0)) {
+        value += b;
+    }
+    value
+}
+
+/// Maps a value from range `range.from` to `range_to`.
+/// # Example:
+/// ```rust
+/// use gdnative_core::globalscope::range_lerp;
+/// assert_eq!(range_lerp(75.0, 0.0..=100.0, -1.0..=1.0), 0.5);
+/// ```
+#[inline]
+pub fn range_lerp(
+    value: f32,
+    range_from: RangeInclusive<f32>,
+    range_to: RangeInclusive<f32>,
+) -> f32 {
+    lerp(range_to, inverse_lerp(range_from, value))
+}
+
+/// Snaps float value s to a given step.
+/// This can also be used to round a floating point number to an arbitrary number of decimals.
+/// ```rust
+/// use gdnative_core::globalscope::stepify;
+/// assert_eq!(stepify(100.0, 32.0), 96.0);
+/// assert_eq!(stepify(3.14159, 0.01), 3.1399999);
+/// ```
+#[inline]
+pub fn stepify(mut value: f32, step: f32) -> f32 {
+    if step != 0.0 {
+        value = (value / step + 0.5).floor() * step;
+    }
+    value
+}
+
+/// Wraps float value between min and max.
+/// Usable for creating loop-alike behavior or infinite surfaces.
+/// # Examples :
+/// ```rust
+/// use gdnative_core::globalscope::wrapf;
+/// use std::f32::consts::{TAU, PI};
+///
+/// //Infinite loop between 5.0 and 9.9
+/// let value = 1.5;
+/// let angle = 0.70707;
+/// let value = wrapf(value + 0.1, 5.0..10.0);
+/// //Infinite rotation (in radians)
+/// let angle = wrapf(angle + 0.1, 0.0..TAU);
+/// //Infinite rotation (in radians)
+/// let angle = wrapf(angle + 0.1, -PI..PI);
+/// ```
+/// # Tests :
+/// ```rust
+/// use gdnative_core::globalscope::wrapf;
+/// use std::f32::consts::{TAU, PI};
+///
+/// let value = 0.5;
+/// assert_eq!(wrapf(value + 0.1, 5.0..0.0), 5.6);
+/// let angle = PI/4.0;
+/// assert_eq!(wrapf(angle, 0.0..TAU), 0.7853982);
+/// assert_eq!(wrapf(1.0, 0.5..1.5), 1.0);
+/// assert_eq!(wrapf(0.75, -0.5..0.5), -0.25);
+/// ```
+///
+/// # Note:
+/// If min is 0, this is equivalent to fposmod, so prefer using that instead.
+/// wrapf is more flexible than using the fposmod approach by giving the user control over the minimum value.
+#[inline]
+pub fn wrapf(value: f32, range: Range<f32>) -> f32 {
+    let range_diff: f32 = range.end - range.start;
+    if is_zero_approx(range_diff) {
+        return range.start;
+    }
+    value - (range_diff * ((value - range.start / range_diff).floor()))
+}
+
+/// Wraps integer value between min and max.
+/// Usable for creating loop-alike behavior or infinite surfaces.
+/// # Example :
+/// ```rust
+/// use gdnative_core::globalscope::wrapi;
+///
+/// //Infinite loop between 5 and 9
+/// let frame = 10;
+/// let frame = wrapi(frame + 1, 5..10);
+/// //result is -2
+/// let result = wrapi(-6, -5..-1);
+/// ```
+/// # Tests :
+/// ```rust
+/// use gdnative_core::globalscope::wrapi;
+///
+/// assert_eq!(wrapi(1, -1..2), 1);
+/// assert_eq!(wrapi(-1, 2..4), 3);
+/// assert_eq!(wrapi(1, 2..-1), 1);
+/// ```
+/// # Note:
+/// If min is 0, this is equivalent to posmod, so prefer using that instead.
+/// wrapi is more flexible than using the posmod approach by giving the user control over the minimum value.
+#[inline]
+pub fn wrapi(value: i32, range: Range<i32>) -> i32 {
+    let range_diff = range.end - range.start;
+    if range_diff == 0 {
+        return range.start;
+    }
+    range.start + (((value - range.start % range_diff) + range_diff) % range_diff)
+}

gdnative-core/src/lib.rs

@@ -43,6 +43,7 @@ mod macros;
 pub mod core_types;
 
 pub mod export;
+pub mod globalscope;
 pub mod init;
 pub mod log;
 pub mod object;

gdnative/src/lib.rs

@@ -81,7 +81,7 @@
 // Items, which are #[doc(hidden)] in their original crate and re-exported with a wildcard, lose
 // their hidden status. Re-exporting them manually and hiding the wildcard solves this.
 #[doc(inline)]
-pub use gdnative_core::{core_types, export, init, log, object, profiler};
+pub use gdnative_core::{core_types, export, globalscope, init, log, object, profiler};
 
 // Implementation details (e.g. used by macros).
 // However, do not re-export macros (on crate level), thus no wildcard