Set MSRV to 1.51

Reason: --features on a workspace level is not supported before.
Further complicating CI scripts, while we already have Rust 1.57, is questionable.

Also removes the custom-built clamp(), which was introduced as f32::clamp() in Rust 1.50.

.github/workflows/full-ci.yml

@@ -105,7 +105,7 @@ jobs:
           - rust: { toolchain: 'nightly' }
             testflags: '-- --skip ui_tests'
           - os: { id: ubuntu-latest, name: linux }
-            rust: { toolchain: '1.48', postfix: ' (msrv 1.48)' }
+            rust: { toolchain: '1.51', postfix: ' (msrv 1.51)' }
             testflags: '-- --skip ui_tests'
     runs-on: ${{ matrix.os.id }}
     steps:
@@ -233,17 +233,21 @@ jobs:
       fail-fast: false # cancel all jobs as soon as one fails?
       matrix:
         include:
+          # Latest Godot with different Rust versions
           - rust: stable
             godot: "3.4.1"
             postfix: ''
           - rust: nightly
             godot: "3.4.1"
             postfix: ' (nightly)'
-          - rust: '1.48'
+          - rust: '1.51'
             godot: "3.4.1"
-            postfix: ' (msrv 1.48)'
+            postfix: ' (msrv 1.51)'
+
+          # Test with older engine version
+          # Note: headless versions of Godot <= 3.3 may crash with a bug, see feature description in lib.rs
           - rust: stable
-            godot: "3.2"
+            godot: "3.3.1"
             postfix: ''
             build_args: '--features custom-godot'
 

gdnative-core/src/core_types/geom/transform2d.rs

@@ -1,21 +1,5 @@
 use crate::core_types::Vector2;
 
-/// Clamp method for f32.
-/// NOTE: This method was copied as-is from std. This was done to avoid compatibility issues
-/// with newer rustc versions and should be removed in favor of f32::clamp once that is stable.
-#[inline]
-fn clamp(num: f32, min: f32, max: f32) -> f32 {
-    assert!(min <= max);
-    let mut x = num;
-    if x < min {
-        x = min;
-    }
-    if x > max {
-        x = max;
-    }
-    x
-}
-
 /// Affine 2D transform (2x3 matrix).
 ///
 /// Represents transformations such as translation, rotation, or scaling.
@@ -228,7 +212,7 @@ impl Transform2D {
         // slerp rotation
         let v1 = Vector2::new(f32::cos(r1), f32::sin(r1));
         let v2 = Vector2::new(f32::cos(r2), f32::sin(r2));
-        let dot = clamp(v1.dot(v2), -1.0, 1.0);
+        let dot = v1.dot(v2).clamp(-1.0, 1.0);
 
         let v = if dot > 0.9995 {
             //linearly interpolate to avoid numerical precision issues