Struct HdrGpuContext 

pub struct HdrGpuContext {
    pub device: Device,
    pub queue: Queue,
    pub color_texture: Texture,
    pub color_view: TextureView,
    pub width: u32,
    pub height: u32,
}

A headless GPU context backed by an Rgba16Float offscreen texture.

Unlike crate::GpuContext (which uses Rgba8Unorm for byte-exact readback), HdrGpuContext uses Rgba16Float so fragment shaders can output linear-light values in [0, +∞). Readback returns raw f16 bytes; use a half-to-float conversion to get the actual float values.

HDR capability requires the adapter to support Rgba16Float as a render attachment. The from_device constructor validates this and returns UiError::Unsupported if the format is not supported.

Fields

device: Device

The logical GPU device.

queue: Queue

The command queue.

color_texture: Texture

The Rgba16Float offscreen texture.

color_view: TextureView

View over color_texture.

width: u32

Target width in physical pixels.

height: u32

Target height in physical pixels.

Implementations

impl HdrGpuContext

pub fn headless(width: u32, height: u32) -> Result<Self, UiError>

Create a headless HDR context.

Errors

• UiError::Unsupported if no GPU adapter is available, if the dimensions are zero, or if the adapter does not support Rgba16Float as a render attachment.
• UiError::Backend if device creation fails.

pub fn readback_f16(&self) -> Result<Vec<u8>, UiError>

Read back the HDR texture as raw bytes.

The returned buffer contains width * height * 8 bytes (4 channels × 2 bytes per channel, f16 little-endian), tightly packed (row padding stripped).

Errors

Returns UiError::Render if the GPU poll or buffer mapping fails.