Adjust library for new go lang 1.15+

* where TypedArrayOf was removed & replaced with other techniques
* the conversion was inspired & copied from issue golang/go#32402

Author: misak113

go.mod

@@ -1 +1,3 @@
 module github.com/nuberu/webgl
+
+go 1.15

js.go

@@ -0,0 +1,114 @@
+package webgl
+
+import (
+	"fmt"
+	"reflect"
+	"runtime"
+	"syscall/js"
+	"unsafe"
+)
+
+func sliceToByteSlice(s interface{}) []byte {
+	switch s := s.(type) {
+	case []int8:
+		h := (*reflect.SliceHeader)(unsafe.Pointer(&s))
+		return *(*[]byte)(unsafe.Pointer(h))
+	case []int16:
+		h := (*reflect.SliceHeader)(unsafe.Pointer(&s))
+		h.Len *= 2
+		h.Cap *= 2
+		return *(*[]byte)(unsafe.Pointer(h))
+	case []int32:
+		h := (*reflect.SliceHeader)(unsafe.Pointer(&s))
+		h.Len *= 4
+		h.Cap *= 4
+		return *(*[]byte)(unsafe.Pointer(h))
+	case []int64:
+		h := (*reflect.SliceHeader)(unsafe.Pointer(&s))
+		h.Len *= 8
+		h.Cap *= 8
+		return *(*[]byte)(unsafe.Pointer(h))
+	case []uint8:
+		return s
+	case []uint16:
+		h := (*reflect.SliceHeader)(unsafe.Pointer(&s))
+		h.Len *= 2
+		h.Cap *= 2
+		return *(*[]byte)(unsafe.Pointer(h))
+	case []uint32:
+		h := (*reflect.SliceHeader)(unsafe.Pointer(&s))
+		h.Len *= 4
+		h.Cap *= 4
+		return *(*[]byte)(unsafe.Pointer(h))
+	case []uint64:
+		h := (*reflect.SliceHeader)(unsafe.Pointer(&s))
+		h.Len *= 8
+		h.Cap *= 8
+		return *(*[]byte)(unsafe.Pointer(h))
+	case []float32:
+		h := (*reflect.SliceHeader)(unsafe.Pointer(&s))
+		h.Len *= 4
+		h.Cap *= 4
+		return *(*[]byte)(unsafe.Pointer(h))
+	case []float64:
+		h := (*reflect.SliceHeader)(unsafe.Pointer(&s))
+		h.Len *= 8
+		h.Cap *= 8
+		return *(*[]byte)(unsafe.Pointer(h))
+	default:
+		panic(fmt.Sprintf("jsutil: unexpected value at sliceToBytesSlice: %T", s))
+	}
+}
+func TypedArrayOf(s interface{}) js.Value {
+	switch s := s.(type) {
+	case []int8:
+		a := js.Global().Get("Uint8Array").New(len(s))
+		js.CopyBytesToJS(a, sliceToByteSlice(s))
+		runtime.KeepAlive(s)
+		buf := a.Get("buffer")
+		return js.Global().Get("Int8Array").New(buf, a.Get("byteOffset"), a.Get("byteLength"))
+	case []int16:
+		a := js.Global().Get("Uint8Array").New(len(s) * 2)
+		js.CopyBytesToJS(a, sliceToByteSlice(s))
+		runtime.KeepAlive(s)
+		buf := a.Get("buffer")
+		return js.Global().Get("Int16Array").New(buf, a.Get("byteOffset"), a.Get("byteLength").Int()/2)
+	case []int32:
+		a := js.Global().Get("Uint8Array").New(len(s) * 4)
+		js.CopyBytesToJS(a, sliceToByteSlice(s))
+		runtime.KeepAlive(s)
+		buf := a.Get("buffer")
+		return js.Global().Get("Int32Array").New(buf, a.Get("byteOffset"), a.Get("byteLength").Int()/4)
+	case []uint8:
+		a := js.Global().Get("Uint8Array").New(len(s))
+		js.CopyBytesToJS(a, s)
+		runtime.KeepAlive(s)
+		return a
+	case []uint16:
+		a := js.Global().Get("Uint8Array").New(len(s) * 2)
+		js.CopyBytesToJS(a, sliceToByteSlice(s))
+		runtime.KeepAlive(s)
+		buf := a.Get("buffer")
+		return js.Global().Get("Uint16Array").New(buf, a.Get("byteOffset"), a.Get("byteLength").Int()/2)
+	case []uint32:
+		a := js.Global().Get("Uint8Array").New(len(s) * 4)
+		js.CopyBytesToJS(a, sliceToByteSlice(s))
+		runtime.KeepAlive(s)
+		buf := a.Get("buffer")
+		return js.Global().Get("Uint32Array").New(buf, a.Get("byteOffset"), a.Get("byteLength").Int()/4)
+	case []float32:
+		a := js.Global().Get("Uint8Array").New(len(s) * 4)
+		js.CopyBytesToJS(a, sliceToByteSlice(s))
+		runtime.KeepAlive(s)
+		buf := a.Get("buffer")
+		return js.Global().Get("Float32Array").New(buf, a.Get("byteOffset"), a.Get("byteLength").Int()/4)
+	case []float64:
+		a := js.Global().Get("Uint8Array").New(len(s) * 8)
+		js.CopyBytesToJS(a, sliceToByteSlice(s))
+		runtime.KeepAlive(s)
+		buf := a.Get("buffer")
+		return js.Global().Get("Float64Array").New(buf, a.Get("byteOffset"), a.Get("byteLength").Int()/8)
+	default:
+		panic(fmt.Sprintf("jsutil: unexpected value at SliceToTypedArray: %T", s))
+	}
+}