Add package graphicsdriver; Move opengl to graphicsdriver/opengl

internal/graphicsdriver/opengl/bytes.go

@@ -0,0 +1,42 @@
+// Copyright 2018 The Ebiten Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package opengl
+
+import (
+	"reflect"
+	"unsafe"
+)
+
+func float32sToBytes(v []float32) []byte {
+	f32h := (*reflect.SliceHeader)(unsafe.Pointer(&v))
+
+	var b []byte
+	bh := (*reflect.SliceHeader)(unsafe.Pointer(&b))
+	bh.Data = f32h.Data
+	bh.Len = len(v) * 4
+	bh.Cap = len(v) * 4
+	return b
+}
+
+func uint16sToBytes(v []uint16) []byte {
+	u16h := (*reflect.SliceHeader)(unsafe.Pointer(&v))
+
+	var b []byte
+	bh := (*reflect.SliceHeader)(unsafe.Pointer(&b))
+	bh.Data = u16h.Data
+	bh.Len = len(v) * 2
+	bh.Cap = len(v) * 2
+	return b
+}