Add a render buffer cache to reuse stencil buffers
Bug #7146141
This new cache is used in a similar way to LayerCache. It helps
reuse already allocated stencil buffers and thus avoid churning
memory on every frame.
Change-Id: I19551d72da52c40039e65904563600e492c8b193
diff --git a/libs/hwui/RenderBufferCache.h b/libs/hwui/RenderBufferCache.h
new file mode 100644
index 0000000..af8060f
--- /dev/null
+++ b/libs/hwui/RenderBufferCache.h
@@ -0,0 +1,130 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * 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.
+ */
+
+#ifndef ANDROID_HWUI_RENDER_BUFFER_CACHE_H
+#define ANDROID_HWUI_RENDER_BUFFER_CACHE_H
+
+#include <GLES2/gl2.h>
+
+#include "RenderBuffer.h"
+#include "utils/SortedList.h"
+
+namespace android {
+namespace uirenderer {
+
+class RenderBufferCache {
+public:
+ RenderBufferCache();
+ ~RenderBufferCache();
+
+ /**
+ * Returns a buffer with the exact specified dimensions. If no suitable
+ * buffer can be found, a new one is created and returned. If creating a
+ * new buffer fails, NULL is returned.
+ *
+ * When a buffer is obtained from the cache, it is removed and the total
+ * size of the cache goes down.
+ *
+ * The returned buffer is always allocated and bound
+ * (see RenderBuffer::isAllocated()).
+ *
+ * @param format The desired render buffer format
+ * @param width The desired width of the buffer
+ * @param height The desired height of the buffer
+ */
+ RenderBuffer* get(GLenum format, const uint32_t width, const uint32_t height);
+
+ /**
+ * Adds the buffer to the cache. The buffer will not be added if there is
+ * not enough space available. Adding a buffer can cause other buffer to
+ * be removed from the cache.
+ *
+ * @param buffer The render buffer to add to the cache
+ *
+ * @return True if the buffer was added, false otherwise.
+ */
+ bool put(RenderBuffer* buffer);
+ /**
+ * Clears the cache. This causes all layers to be deleted.
+ */
+ void clear();
+
+ /**
+ * Sets the maximum size of the cache in bytes.
+ */
+ void setMaxSize(uint32_t maxSize);
+ /**
+ * Returns the maximum size of the cache in bytes.
+ */
+ uint32_t getMaxSize();
+ /**
+ * Returns the current size of the cache in bytes.
+ */
+ uint32_t getSize();
+
+private:
+ struct RenderBufferEntry {
+ RenderBufferEntry():
+ mBuffer(NULL), mWidth(0), mHeight(0) {
+ }
+
+ RenderBufferEntry(GLenum format, const uint32_t width, const uint32_t height):
+ mBuffer(NULL), mFormat(format), mWidth(width), mHeight(height) {
+ }
+
+ RenderBufferEntry(RenderBuffer* buffer):
+ mBuffer(buffer), mFormat(buffer->getFormat()),
+ mWidth(buffer->getWidth()), mHeight(buffer->getHeight()) {
+ }
+
+ static int compare(const RenderBufferEntry& lhs, const RenderBufferEntry& rhs);
+
+ bool operator==(const RenderBufferEntry& other) const {
+ return compare(*this, other) == 0;
+ }
+
+ bool operator!=(const RenderBufferEntry& other) const {
+ return compare(*this, other) != 0;
+ }
+
+ friend inline int strictly_order_type(const RenderBufferEntry& lhs,
+ const RenderBufferEntry& rhs) {
+ return RenderBufferEntry::compare(lhs, rhs) < 0;
+ }
+
+ friend inline int compare_type(const RenderBufferEntry& lhs,
+ const RenderBufferEntry& rhs) {
+ return RenderBufferEntry::compare(lhs, rhs);
+ }
+
+ RenderBuffer* mBuffer;
+ GLenum mFormat;
+ uint32_t mWidth;
+ uint32_t mHeight;
+ }; // struct RenderBufferEntry
+
+ void deleteBuffer(RenderBuffer* buffer);
+
+ SortedList<RenderBufferEntry> mCache;
+
+ uint32_t mSize;
+ uint32_t mMaxSize;
+}; // class RenderBufferCache
+
+}; // namespace uirenderer
+}; // namespace android
+
+#endif // ANDROID_HWUI_RENDER_BUFFER_CACHE_H