ebiten/internal/graphicsdriver/metal/buffer.go
2019-02-05 03:09:40 +09:00

109 lines
2.6 KiB
Go

// Copyright 2019 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.
// +build darwin
package metal
import (
"sort"
"unsafe"
"github.com/hajimehoshi/ebiten/internal/graphicsdriver/metal/mtl"
)
// #cgo LDFLAGS: -framework CoreFoundation
//
// #import <CoreFoundation/CoreFoundation.h>
//
// static int count(void* obj) {
// // TODO: Don't rely on the number of ref counts. CFGetRetainCount should be used only for debugging.
// // Note that checking whether MTLCommandBuffer's status is completed or not does not work, because the
// // CommandBuffer might still be used even in such situation.
// return CFGetRetainCount(obj);
// }
import "C"
type buffer struct {
b mtl.Buffer
len uintptr
}
func (b *buffer) used() bool {
// If the count is 2 or more, the buffer is actually retained outside.
// If the count is 1, the buffer is retained only by the buffer pool.
// The count cannot be 0 since the object is already freed in this case.
return C.count(b.b.Native()) > 1
}
var bufferPool = map[*buffer]struct{}{}
func getBuffer(device mtl.Device, data unsafe.Pointer, lengthInBytes uintptr) *buffer {
for buf := range bufferPool {
if buf.used() {
continue
}
if buf.len < lengthInBytes {
continue
}
buf.b.CopyToContents(data, lengthInBytes)
buf.b.Retain()
return buf
}
gcBufferPool()
buf := &buffer{
b: device.MakeBufferWithBytes(data, lengthInBytes, mtl.ResourceStorageModeManaged),
len: lengthInBytes,
}
buf.b.Retain()
bufferPool[buf] = struct{}{}
return buf
}
func putBuffer(buf *buffer) {
buf.b.Release()
// The buffer will be actually released after all the current command buffers are finished.
gcBufferPool()
}
func gcBufferPool() {
const threshold = 16
if len(bufferPool) < threshold {
return
}
toRemove := []*buffer{}
for buf := range bufferPool {
if buf.used() {
continue
}
toRemove = append(toRemove, buf)
}
sort.Slice(toRemove, func(a, b int) bool {
return toRemove[a].len < toRemove[b].len
})
l := len(toRemove)
if l > len(bufferPool)-threshold {
l = len(bufferPool) - threshold
}
for _, buf := range toRemove[:l] {
buf.b.Release()
delete(bufferPool, buf)
}
}