cmds concat fmap foldl framebuffer Framebuffer Framebuffers GLSL Keysym KHRONOS Memdiscrete multisample Multisample ndev rasterization Rasterization rasterizer SFLOAT Shaderc shadersrc SRGB Struct subpass Subpass SUBPASS subpasses subresource Subresource swapchain Swapchain SWAPCHAIN swapchains TEXEL unmap viewports vulkan Vulkan