Add Clamp

README.md

@@ -20,6 +20,8 @@ gglm currently has the following:
 
 ## Installation
 
+Note: gglm requires Go 1.18 or higher.
+
 `go get github.com/bloeys/gglm`
 
 ## Usage

gglm/scalar.go

@@ -1,6 +1,10 @@
 package gglm
 
-import "math"
+import (
+	"math"
+
+	"golang.org/x/exp/constraints"
+)
 
 // EqF32 true if abs(f1-f2) <= F32Epsilon
 func EqF32(f1, f2 float32) bool {
@@ -52,3 +56,21 @@ func Abs32(x float32) float32 {
 func Sqrt32(x float32) float32 {
 	return float32(math.Sqrt(float64(x)))
 }
+
+// Clamp returns:
+//
+//	min if x<min
+//	max if x>max
+//	x   if x>=min && x<=max
+func Clamp[T constraints.Ordered](x, min, max T) T {
+
+	if x < min {
+		return min
+	}
+
+	if x > max {
+		return max
+	}
+
+	return x
+}

gglm/scalar_test.go

@@ -0,0 +1,64 @@
+package gglm_test
+
+import (
+	"testing"
+
+	"github.com/bloeys/gglm/gglm"
+)
+
+func TestClamp(t *testing.T) {
+
+	x := 5
+	ans := 5
+	if gglm.Clamp(x, 0, 10) != ans {
+		t.Errorf("Got: %v; Expected: %v", x, ans)
+	}
+
+	x = 10
+	ans = 10
+	if gglm.Clamp(x, 0, 10) != ans {
+		t.Errorf("Got: %v; Expected: %v", x, ans)
+	}
+
+	x = 20
+	ans = 10
+	if gglm.Clamp(x, 0, 10) != ans {
+		t.Errorf("Got: %v; Expected: %v", x, ans)
+	}
+
+	x = -10
+	ans = 0
+	if gglm.Clamp(x, 0, 10) != ans {
+		t.Errorf("Got: %v; Expected: %v", x, ans)
+	}
+
+	xf := 1.5
+	ansf := 1.5
+	if gglm.Clamp(xf, 0, 10) != ansf {
+		t.Errorf("Got: %v; Expected: %v", xf, ansf)
+	}
+
+	xf = 15
+	ansf = 10
+	if gglm.Clamp(xf, 0, 10) != ansf {
+		t.Errorf("Got: %v; Expected: %v", xf, ansf)
+	}
+
+	xf = -1.5
+	ansf = 0
+	if gglm.Clamp(xf, 0, 10) != ansf {
+		t.Errorf("Got: %v; Expected: %v", xf, ansf)
+	}
+
+	xf = 2
+	ansf = 1.5
+	if gglm.Clamp(xf, 0.5, 1.5) != ansf {
+		t.Errorf("Got: %v; Expected: %v", xf, ansf)
+	}
+
+	xf = 1.2
+	ansf = 1.2
+	if gglm.Clamp(xf, 0.5, 1.5) != ansf {
+		t.Errorf("Got: %v; Expected: %v", xf, ansf)
+	}
+}

go.mod

@@ -1,3 +1,5 @@
 module github.com/bloeys/gglm
 
-go 1.17
+go 1.18
+
+require golang.org/x/exp v0.0.0-20240506185415-9bf2ced13842

go.sum

@@ -0,0 +1,2 @@
+golang.org/x/exp v0.0.0-20240506185415-9bf2ced13842 h1:vr/HnozRka3pE4EsMEg1lgkXJkTFJCVUX+S/ZT6wYzM=
+golang.org/x/exp v0.0.0-20240506185415-9bf2ced13842/go.mod h1:XtvwrStGgqGPLc4cjQfWqZHG1YFdYs6swckp8vpsjnc=