Struct demo_vk::graphics::BindlessTextureAtlas

pub struct BindlessTextureAtlas { /* private fields */ }

Maintains descriptors for a list of texture images. Textures can be accessed by their index in shaders when the descriptor is bound. e.g. “bindless” textures.

The descriptor set provided by the atlas expects the following bindings in shader code for descriptor set 0:

1. [vk_binding(0, 0)] SamplerState samplers[3];
2. [vk_binding(1, 0)] texture2D textures[];

Samplers have the following properties (by index):

1. samplers[0] - Linear filtering, linear mipmaps, no anisotropic filtering
2. samplers[1] - Linear filtering, linear mipmaps, with anisotropic filtering
3. samplers[2] - Nearest filtering, nearest mipmap, no anisotropic filtering

Why Descriptor Set 0?

Because the BindlessTextureAtlas can be bound a single time at the beginning of the renderpass for the frame and ignored after that. If a higher index is used, then switching to different graphics pipelines could require rebinding.

This works only so long as any subsequently bound pipelines have a compatible layout (e.g. they use the BindlessTextureAtlas’s descriptor_set_layout as descriptor 0).

Implementations

impl BindlessTextureAtlas

pub fn new( ctx: Arc<VulkanContext>, max_textures: u32, frames_in_flight: &FramesInFlight, ) -> Result<Self>

Creates a new atlas that can hold up to max_textures total textures.

pub fn add_texture(&mut self, texture: Arc<Texture>) -> u32

Adds a texture to the atlas. The returned texture number can be used to index in to the textures array in a shader.

This function is safe to call at any time. The new texture will be available in the shader in the next frame.

pub fn descriptor_set_layout(&self) -> &DescriptorSetLayout

Borrows the descriptor set layout for the atlas. Useful when creating pipelines.

pub fn bind_frame_descriptor(&mut self, frame: &Frame) -> Result<()>

Binds the descriptor for the given frame.

Conditionally updates the descriptor if any new textures have been added since the last frame.