PR #1/5 Astolfo feature/builtin-scalar

godot-core/src/builtin/math.rs

@@ -0,0 +1,110 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+pub const CMP_EPSILON: f32 = 0.00001;
+
+pub fn lerp(a: f32, b: f32, t: f32) -> f32 {
+    a + ((b - a) * t)
+}
+
+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
+}
+
+pub fn is_zero_approx(s: f32) -> bool {
+    s.abs() < CMP_EPSILON
+}
+
+pub fn fposmod(x: f32, y: f32) -> f32 {
+    let mut value = x % y;
+    if ((value < 0.0) && (y > 0.0)) || ((value > 0.0) && (y < 0.0)) {
+        value += y;
+    }
+    value += 0.0;
+    value
+}
+
+pub fn snapped(mut value: f32, step: f32) -> f32 {
+    if step != 0.0 {
+        value = ((value / step + 0.5) * step).floor()
+    }
+    value
+}
+
+pub fn bezier_derivative(start: f32, control_1: f32, control_2: f32, end: f32, t: f32) -> f32 {
+    let omt = 1.0 - t;
+    let omt2 = omt * omt;
+    let t2 = t * t;
+    (control_1 - start) * 3.0 * omt2
+        + (control_2 - control_1) * 6.0 * omt * t
+        + (end - control_2) * 3.0 * t2
+}
+
+pub fn bezier_interpolate(start: f32, control_1: f32, control_2: f32, end: f32, t: f32) -> f32 {
+    let omt = 1.0 - t;
+    let omt2 = omt * omt;
+    let omt3 = omt2 * omt;
+    let t2 = t * t;
+    let t3 = t2 * t;
+    start * omt3 + control_1 * omt2 * t * 3.0 + control_2 * omt * t2 * 3.0 + end * t3
+}
+
+pub fn cubic_interpolate(from: f32, to: f32, pre: f32, post: f32, weight: f32) -> f32 {
+    0.5 * ((from * 2.0)
+        + (-pre + to) * weight
+        + (2.0 * pre - 5.0 * from + 4.0 * to - post) * (weight * weight)
+        + (-pre + 3.0 * from - 3.0 * to + post) * (weight * weight * weight))
+}
+
+pub fn cubic_interpolate_in_time(
+    from: f32,
+    to: f32,
+    pre: f32,
+    post: f32,
+    weight: f32,
+    to_t: f32,
+    pre_t: f32,
+    post_t: f32,
+) -> f32 {
+    let t = lerp(0.0, to_t, weight);
+    let a1 = lerp(
+        pre,
+        from,
+        if pre_t == 0.0 {
+            0.0
+        } else {
+            (t - pre_t) / -pre_t
+        },
+    );
+    let a2 = lerp(from, to, if to_t == 0.0 { 0.5 } else { t / to_t });
+    let a3 = lerp(
+        to,
+        post,
+        if post_t - to_t == 0.0 {
+            1.0
+        } else {
+            (t - to_t) / (post_t - to_t)
+        },
+    );
+    let b1 = lerp(
+        a1,
+        a2,
+        if to_t - pre_t == 0.0 {
+            0.0
+        } else {
+            (t - pre_t) / (to_t - pre_t)
+        },
+    );
+    let b2 = lerp(a2, a3, if post_t == 0.0 { 1.0 } else { t / post_t });
+    lerp(b1, b2, if to_t == 0.0 { 0.5 } else { t / to_t })
+}