Add SSBO and compute shader support to gl wrappers

gl/ssbo.cpp

@@ -0,0 +1,49 @@
+#include "stdafx.h"
+#include "ssbo.h"
+
+gl::ssbo::ssbo(GLsizeiptr size, GLuint index) : m_index(index)
+{
+	create(size);
+}
+
+gl::ssbo::~ssbo()
+{
+	glDeleteBuffers(1, *this);
+}
+
+void gl::ssbo::create(GLsizeiptr size)
+{
+	glCreateBuffers(1, *this);
+	// written only through glNamedBufferSubData and by shaders
+	glNamedBufferStorage(*this, size, nullptr, GL_DYNAMIC_STORAGE_BIT);
+	m_size = size;
+}
+
+void gl::ssbo::bind_base() const
+{
+	glBindBuffersBase(GL_SHADER_STORAGE_BUFFER, m_index, 1, *this);
+}
+
+void gl::ssbo::resize(GLsizeiptr size)
+{
+	if (size == m_size)
+		return;
+
+	glDeleteBuffers(1, *this);
+	create(size);
+}
+
+void gl::ssbo::update(const void *data, GLintptr offset, GLsizeiptr size)
+{
+	glNamedBufferSubData(*this, offset, size, data);
+}
+
+void gl::ssbo::download(void *data, GLintptr offset, GLsizeiptr size) const
+{
+	glGetNamedBufferSubData(*this, offset, size, data);
+}
+
+void gl::memory_barrier(GLbitfield barriers)
+{
+	glMemoryBarrier(barriers);
+}