func Str(str string) *uint8 {
	if !strings.HasSuffix(str, "\x00") {
		panic("str argument missing null terminator: " + str)
	}
	header := (*reflect.StringHeader)(unsafe.Pointer(&str))
	return (*uint8)(unsafe.Pointer(header.Data))
}
Str takes a null-terminated Go string and returns its GL-compatible address.
This function reaches into Go string storage in an unsafe way so the caller
must ensure the string is not garbage collected.
package gl
import (
	"fmt"
	"reflect"
	"strings"
	"unsafe"
)
import "C"
func Ptr(data interface{}) unsafe.Pointer {
	if data == nil {
		return unsafe.Pointer(nil)
	}
	var addr unsafe.Pointer
	v := reflect.ValueOf(data)
	switch v.Type().Kind() {
	case reflect.Ptr:
		e := v.Elem()
		switch e.Kind() {
		case
			reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
			reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64,
			reflect.Float32, reflect.Float64:
			addr = unsafe.Pointer(e.UnsafeAddr())
		default:
			panic(fmt.Errorf("unsupported pointer to type %s; must be a slice or pointer to a singular scalar value or the first element of an array or slice", e.Kind()))
		}
	case reflect.Uintptr:
		addr = unsafe.Pointer(v.Pointer())
	case reflect.Slice:
		addr = unsafe.Pointer(v.Index(0).UnsafeAddr())
	default:
		panic(fmt.Errorf("unsupported type %s; must be a slice or pointer to a singular scalar value or the first element of an array or slice", v.Type()))
	}
	return addr
}
func PtrOffset(offset int) unsafe.Pointer {
	return unsafe.Pointer(uintptr(offset))
}