create generic gl::buffer, rebase gl::ubo onto it

gl/buffer.cpp

@@ -0,0 +1,67 @@
+#include "buffer.h"
+
+GLenum gl::buffer::glenum_target(gl::buffer::targets target)
+{
+    GLenum mapping[13] =
+    {
+        GL_ARRAY_BUFFER,
+        GL_ATOMIC_COUNTER_BUFFER,
+        GL_COPY_READ_BUFFER,
+        GL_COPY_WRITE_BUFFER,
+        GL_DISPATCH_INDIRECT_BUFFER,
+        GL_DRAW_INDIRECT_BUFFER,
+        GL_ELEMENT_ARRAY_BUFFER,
+        GL_PIXEL_PACK_BUFFER,
+        GL_PIXEL_UNPACK_BUFFER,
+        GL_SHADER_STORAGE_BUFFER,
+        GL_TEXTURE_BUFFER,
+        GL_TRANSFORM_FEEDBACK_BUFFER,
+        GL_UNIFORM_BUFFER
+    };
+    return mapping[target];
+}
+
+void gl::buffer::bind(targets target)
+{
+    if (binding_points[target] == *this)
+        return;
+
+    glBindBuffer(glenum_target(target), *this);
+    binding_points[target] = *this;
+}
+
+void gl::buffer::bind_base(targets target, GLuint index)
+{
+    glBindBufferBase(glenum_target(target), index, *this);
+    binding_points[target] = *this;
+}
+
+void gl::buffer::unbind(targets target)
+{
+    glBindBuffer(glenum_target(target), 0);
+    binding_points[target] = 0;
+}
+
+gl::buffer::buffer()
+{
+    glGenBuffers(1, *this);
+}
+
+gl::buffer::~buffer()
+{
+    glDeleteBuffers(1, *this);
+}
+
+void gl::buffer::allocate(targets target, int size, GLenum hint)
+{
+    bind(target);
+    glBufferData(glenum_target(target), size, nullptr, hint);
+}
+
+void gl::buffer::upload(targets target, const void *data, int offset, int size)
+{
+    bind(target);
+    glBufferSubData(glenum_target(target), offset, size, data);
+}
+
+GLuint gl::buffer::binding_points[13];