Check the flat qualifier from the correct member

[libs/gl.git] / source / core / buffer.h

diff --git a/source/core/buffer.h b/source/core/buffer.h
index b642738e0e96ef370a5e748701be071998e2de54..9b1293615832a615318cf0212400c08b3af10961 100644 (file)
--- a/source/core/buffer.h
+++ b/source/core/buffer.h
@@ -15,6 +15,12 @@ public:
        virtual ~buffer_too_small() throw() { }
 };
 
+enum BufferUsage
+{
+       STATIC,
+       STREAMING
+};
+
 /**
 Stores data in GPU memory.
 
@@ -22,6 +28,10 @@ Memory must be allocated for the buffer by calling storage().  Contents can
 then be modified either synchronously with the data() and sub_data() functions,
 or asynchronously by memory-mapping the buffer.
 
+Buffers can have a static or streaming usage pattern.  Streaming buffers can be
+memory mapped for less update overhead, but memory space is more limited.  If
+the buffer is updated only rarely, static is recommended.
+
 Applications normally don't need to deal with Buffers directly.  They're
 managed by other classes such as Mesh and ProgramData.
 */
@@ -29,13 +39,47 @@ class Buffer: public BufferBackend
 {
        friend BufferBackend;
 
+public:
+       /**
+       An RAII handle for asynchronously writing data into a buffer.
+       */
+       class AsyncTransfer: public NonCopyable
+       {
+               friend BufferBackend;
+               friend class Buffer;
+
+       private:
+               Buffer *buffer = 0;
+               std::size_t offset = 0;
+               std::size_t size = 0;
+               void *dest_addr = 0;
+
+               AsyncTransfer(Buffer &, std::size_t, std::size_t);
+       public:
+               AsyncTransfer() = default;
+               AsyncTransfer(AsyncTransfer &&);
+               AsyncTransfer &operator=(AsyncTransfer &&);
+               ~AsyncTransfer();
+
+       private:
+               void allocate();
+               void finalize();
+
+       public:
+               /** Returns an address for writing the data.  It should not be used
+               beyond the lifetime of the object. */
+               void *get_address() { return dest_addr; }
+       };
+
 private:
        std::size_t size = 0;
+       BufferUsage usage = STATIC;
+       bool mapped = false;
 
 public:
-       /** Sets the storage size and allocates memory for the buffer.  Size cannot
-       be changed once set. */
-       void storage(std::size_t);
+       /** Sets storage size and usage pattern and allocates memory for the buffer.
+       Size and usage cannot be changed once set. */
+       void storage(std::size_t, BufferUsage);
 
        /** Replaces contents of the entire buffer.  Allocated storage must exist.
        The data must have size matching the defined storage. */
@@ -45,12 +89,24 @@ public:
        The range must be fully inside the buffer. */
        void sub_data(std::size_t, std::size_t, const void *);
 
+       /** Creates an asynchronous transfer for writing data to a range of bytes in
+       the buffer.  While the transfer is pending, the state of the buffer region
+       is indeterminate. */
+       AsyncTransfer sub_data_async(std::size_t, std::size_t);
+
+private:
+       void check_sub_data(std::size_t, std::size_t, const char *);
+
+public:
        std::size_t get_size() const { return size; }
+       using BufferBackend::get_multiplicity;
+       std::size_t get_total_size() const { return size*get_multiplicity(); }
+       BufferUsage get_usage() const { return usage; }
 
        void require_size(std::size_t) const;
 
-       using BufferBackend::map;
-       using BufferBackend::unmap;
+       void *map();
+       bool unmap();
 
        using BufferBackend::set_debug_name;
 };