GPU: Add base functionality for GL streaming buffers

src/common/common.vcxproj

@@ -40,6 +40,7 @@
     <ClInclude Include="cd_image.h" />
     <ClInclude Include="fifo_queue.h" />
     <ClInclude Include="gl_program.h" />
+    <ClInclude Include="gl_stream_buffer.h" />
     <ClInclude Include="gl_texture.h" />
     <ClInclude Include="heap_array.h" />
     <ClInclude Include="jit_code_buffer.h" />
@@ -53,6 +54,7 @@
     <ClCompile Include="cd_image_bin.cpp" />
     <ClCompile Include="cd_image_cue.cpp" />
     <ClCompile Include="gl_program.cpp" />
+    <ClCompile Include="gl_stream_buffer.cpp" />
     <ClCompile Include="gl_texture.cpp" />
     <ClCompile Include="jit_code_buffer.cpp" />
     <ClCompile Include="state_wrapper.cpp" />

src/common/common.vcxproj.filters

@@ -12,6 +12,7 @@
     <ClInclude Include="audio_stream.h" />
     <ClInclude Include="cd_xa.h" />
     <ClInclude Include="heap_array.h" />
+    <ClInclude Include="gl_stream_buffer.h" />
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="jit_code_buffer.cpp" />
@@ -23,6 +24,7 @@
     <ClCompile Include="cd_xa.cpp" />
     <ClCompile Include="cd_image_cue.cpp" />
     <ClCompile Include="cd_image_bin.cpp" />
+    <ClCompile Include="gl_stream_buffer.cpp" />
   </ItemGroup>
   <ItemGroup>
     <Natvis Include="bitfield.natvis" />

src/common/gl_stream_buffer.cpp

@@ -0,0 +1,53 @@
+#include "gl_stream_buffer.h"
+
+namespace GL {
+
+StreamBuffer::StreamBuffer(GLenum target, GLuint buffer_id, u32 size)
+  : m_target(target), m_buffer_id(buffer_id), m_size(size), m_cpu_buffer(size)
+{
+}
+
+StreamBuffer::~StreamBuffer()
+{
+  glDeleteBuffers(1, &m_buffer_id);
+}
+
+void StreamBuffer::Bind()
+{
+  glBindBuffer(m_target, m_buffer_id);
+}
+
+StreamBuffer::MappingResult StreamBuffer::Map(u32 alignment, u32 min_size)
+{
+  return MappingResult{static_cast<void*>(m_cpu_buffer.data()), 0, m_size / alignment};
+}
+
+void StreamBuffer::Unmap(u32 used_size)
+{
+  if (used_size == 0)
+    return;
+
+  glBindBuffer(m_target, m_buffer_id);
+  glBufferSubData(m_target, 0, used_size, m_cpu_buffer.data());
+}
+
+std::unique_ptr<StreamBuffer> StreamBuffer::Create(GLenum target, u32 size)
+{
+  glGetError();
+
+  GLuint buffer_id;
+  glGenBuffers(1, &buffer_id);
+  glBindBuffer(target, buffer_id);
+  glBufferData(target, size, nullptr, GL_STREAM_DRAW);
+
+  GLenum err = glGetError();
+  if (err != GL_NO_ERROR)
+  {
+    glDeleteBuffers(1, &buffer_id);
+    return {};
+  }
+
+  return std::unique_ptr<StreamBuffer>(new StreamBuffer(target, buffer_id, size));
+}
+
+} // namespace GL

src/common/gl_stream_buffer.h

@@ -0,0 +1,42 @@
+#pragma once
+#include "types.h"
+#include <glad.h>
+#include <memory>
+#include <tuple>
+#include <vector>
+
+namespace GL {
+// TODO: Persistent mapping-based implementation
+class StreamBuffer
+{
+public:
+  ~StreamBuffer();
+
+  ALWAYS_INLINE GLuint GetGLBufferId() const { return m_buffer_id; }
+  ALWAYS_INLINE GLenum GetGLTarget() const { return m_target; }
+  ALWAYS_INLINE u32 GetSize() const { return m_size; }
+
+  void Bind();
+
+  struct MappingResult
+  {
+    void* pointer;
+    u32 index_aligned; // offset / alignment, suitable for base vertex
+    u32 space_aligned; // remaining space / alignment
+  };
+
+  MappingResult Map(u32 alignment, u32 min_size);
+  void Unmap(u32 used_size);
+
+  static std::unique_ptr<StreamBuffer> Create(GLenum target, u32 size);
+
+private:
+  StreamBuffer(GLenum target, GLuint buffer_id, u32 size);
+
+  GLenum m_target;
+  GLuint m_buffer_id;
+  u32 m_size;
+
+  std::vector<u8> m_cpu_buffer;
+};
+} // namespace GL