Add gfx::render_target helper struct

libs/gfx/include/psemek/gfx/render_target.hpp

@@ -0,0 +1,27 @@
+#pragma once
+
+#include <psemek/gfx/framebuffer.hpp>
+
+#include <psemek/geom/box.hpp>
+
+#include <psemek/util/assert.hpp>
+
+namespace psemek::gfx
+{
+
+	struct render_target
+	{
+		gfx::framebuffer const * framebuffer;
+		GLenum draw_buffer;
+		geom::box<int, 2> viewport;
+
+		void bind() const
+		{
+			assert(framebuffer);
+			framebuffer->bind();
+			gl::DrawBuffers(1, &draw_buffer);
+			gl::Viewport(viewport[0].min, viewport[1].min, viewport[0].length(), viewport[1].length());
+		}
+	};
+
+}