From 11fb586a206d7bbc6ed2405fa8abb8ae4a98c679 Mon Sep 17 00:00:00 2001
From: Sam Hocevar <sam@hocevar.net>
Date: Mon, 7 Nov 2011 00:36:28 +0000
Subject: [PATCH] gpu: start implementing a vertex buffer object.

---
 src/Makefile.am |   1 +
 src/core.h      |   1 +
 src/gpu/vbo.cpp | 100 ++++++++++++++++++++++++++++++++++++++++++++++++
 src/gpu/vbo.h   |  45 ++++++++++++++++++++++
 4 files changed, 147 insertions(+)
 create mode 100644 src/gpu/vbo.cpp
 create mode 100644 src/gpu/vbo.h

diff --git a/src/Makefile.am b/src/Makefile.am
index 4435cacd..9de31693 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -22,6 +22,7 @@ liblol_a_SOURCES = \
     $(sdl_sources) \
     \
     shader/shader.cpp shader/shader.h \
+    gpu/vbo.cpp gpu/vbo.h \
     \
     image/image.cpp image/image.h image/image-private.h \
     image/codec/android-image.cpp \
diff --git a/src/core.h b/src/core.h
index b95d5db3..45fdce5d 100644
--- a/src/core.h
+++ b/src/core.h
@@ -96,6 +96,7 @@ static inline int isnan(float f)
 #include "dict.h"
 #include "map.h"
 #include "layer.h"
+#include "gpu/vbo.h"
 #include "shader/shader.h"
 #include "image/image.h"
 #include "application/application.h"
diff --git a/src/gpu/vbo.cpp b/src/gpu/vbo.cpp
new file mode 100644
index 00000000..baee78cb
--- /dev/null
+++ b/src/gpu/vbo.cpp
@@ -0,0 +1,100 @@
+//
+// Lol Engine
+//
+// Copyright: (c) 2010-2011 Sam Hocevar <sam@hocevar.net>
+//   This program is free software; you can redistribute it and/or
+//   modify it under the terms of the Do What The Fuck You Want To
+//   Public License, Version 2, as published by Sam Hocevar. See
+//   http://sam.zoy.org/projects/COPYING.WTFPL for more details.
+//
+
+#if defined HAVE_CONFIG_H
+#   include "config.h"
+#endif
+
+#include "core.h"
+#include "lolgl.h"
+#include "gpu/vbo.h"
+
+using namespace std;
+
+namespace lol
+{
+
+/*
+ * GpuVbo implementation class
+ */
+
+class GpuVboData
+{
+    friend class GpuVbo;
+
+    size_t elemsize, elemcount;
+    uint8_t *alloc_buffer;
+
+    static size_t const GPU_ALIGN = 128;
+};
+
+/*
+ * Public GpuVbo class
+ */
+
+GpuVbo::GpuVbo()
+  : data(new GpuVboData())
+{
+    data->elemsize = 0;
+    data->elemcount = 0;
+    data->alloc_buffer = 0;
+}
+
+void GpuVbo::SetSize(size_t elemsize, size_t elemcount)
+{
+    size_t oldsize = data->elemsize * data->elemcount;
+    size_t newsize = elemsize * elemcount;
+
+    if (newsize == oldsize)
+        return;
+
+    if (oldsize)
+        delete[] data->alloc_buffer;
+    data->alloc_buffer = NULL;
+    if (newsize)
+        data->alloc_buffer = new uint8_t[newsize + GpuVboData::GPU_ALIGN - 1];
+
+    data->elemsize = elemsize;
+    data->elemcount = elemcount;
+}
+
+size_t GpuVbo::GetSize()
+{
+    return data->elemsize * data->elemcount;
+}
+
+uint8_t *GpuVbo::GetData()
+{
+    return (uint8_t *)(((uintptr_t)data->alloc_buffer)
+                        & ~((uintptr_t)GpuVboData::GPU_ALIGN - 1));
+}
+
+uint8_t const *GpuVbo::GetData() const
+{
+    return (uint8_t const *)(((uintptr_t)data->alloc_buffer)
+                              & ~((uintptr_t)GpuVboData::GPU_ALIGN - 1));
+}
+
+void GpuVbo::Bind()
+{
+}
+
+void GpuVbo::Unbind()
+{
+}
+
+GpuVbo::~GpuVbo()
+{
+    delete[] data->alloc_buffer;
+    delete data;
+}
+
+} /* namespace lol */
+
diff --git a/src/gpu/vbo.h b/src/gpu/vbo.h
new file mode 100644
index 00000000..4f8b0c5e
--- /dev/null
+++ b/src/gpu/vbo.h
@@ -0,0 +1,45 @@
+//
+// Lol Engine
+//
+// Copyright: (c) 2010-2011 Sam Hocevar <sam@hocevar.net>
+//   This program is free software; you can redistribute it and/or
+//   modify it under the terms of the Do What The Fuck You Want To
+//   Public License, Version 2, as published by Sam Hocevar. See
+//   http://sam.zoy.org/projects/COPYING.WTFPL for more details.
+//
+
+//
+// The GpuVbo class
+// ----------------
+//
+
+#if !defined __LOL_VBO_H__
+#define __LOL_VBO_H__
+
+namespace lol
+{
+
+class GpuVboData;
+
+class GpuVbo
+{
+public:
+    GpuVbo();
+    ~GpuVbo();
+
+    void SetSize(size_t elemsize, size_t elemcount);
+    size_t GetSize();
+    uint8_t *GetData();
+    uint8_t const *GetData() const;
+
+    void Bind();
+    void Unbind();
+
+private:
+    GpuVboData *data;
+};
+
+} /* namespace lol */
+
+#endif // __LOL_VBO_H__
+