glAllocator revampHEADmain

Remove the map of buffers, now a fat pointer containing the buffer's
name. This is accessible via the container's begin/end iterator. Move
the bulk of the logic out of the template, it's mostly void * from the
mapping anyway. Add allocate_at_least support.

1 files changed, 28 insertions, 0 deletions

diff --git a/lib/glAllocator.cpp b/lib/glAllocator.cpp
new file mode 100644
index 0000000..633f7ab
--- /dev/null
+++ b/lib/glAllocator.cpp
@@ -0,0 +1,28 @@
+#include "glAllocator.h"
+
+namespace Detail {
+	std::pair<void *, GLuint>
+	allocateBuffer(size_t count, size_t objSize)
+	{
+		constexpr static GLbitfield MAPPING_FLAGS
+				= GL_MAP_WRITE_BIT | GL_MAP_READ_BIT | GL_MAP_PERSISTENT_BIT | GL_MAP_COHERENT_BIT;
+		constexpr static GLbitfield STORAGE_FLAGS = GL_DYNAMIC_STORAGE_BIT | MAPPING_FLAGS;
+		GLuint name = 0;
+		glCreateBuffers(1, &name);
+		const auto size = static_cast<GLsizeiptr>(count * objSize);
+		glNamedBufferStorage(name, size, nullptr, STORAGE_FLAGS);
+		const auto data = (glMapNamedBufferRange(name, 0, size, MAPPING_FLAGS));
+		if (!data) {
+			glDeleteBuffers(1, &name);
+			throw std::bad_alloc();
+		}
+		return {data, name};
+	}
+
+	void
+	deallocateBuffer(GLuint name)
+	{
+		glUnmapNamedBuffer(name);
+		glDeleteBuffers(1, &name);
+	}
+}