Struct FogParams 

#[repr(C)]
pub struct FogParams {

    pub inv_vp: [[f32; 4]; 4],
    pub color: [f32; 4],
    pub cam_pos: [f32; 3],
    pub _pad0: f32,
    pub sun_dir: [f32; 3],
    pub _pad1: f32,
    pub sun_color: [f32; 3],
    pub _pad2: f32,
    pub density: f32,
    pub height_falloff: f32,
    pub height_reference: f32,
    pub max_distance: f32,
    pub phase_g: f32,
    pub ambient: f32,
    pub viewport: [f32; 2],
    pub inv_max_distance: f32,
    pub _pad3: [f32; 3],
}

Per-frame uniform consumed by the volumetric-fog ray-march. Carries the clamped authored tunables plus the view inputs the shader needs to reconstruct world positions from depth and integrate sun-aligned scattering. Pushed verbatim to the fog fragment shader, so the layout must stay in sync with FogParams in metal/shaders/fog.metal. 176 bytes.

Fields

inv_vp: [[f32; 4]; 4]

Inverse view-projection: reconstructs world position from depth.

color: [f32; 4]

Linear-space fog tint (RGB); alpha unused.

cam_pos: [f32; 3]

World-space camera position. The marcher starts here and walks the view ray to the scene point. _pad keeps cam_pos 16-byte aligned inside MSL.

_pad0: f32

Padding so the field layout matches the shader-side struct.

sun_dir: [f32; 3]

First directional light’s world-space direction (toward the light), used for the Henyey-Greenstein phase and the per-step sun radiance.

_pad1: f32

Padding so the field layout matches the shader-side struct.

sun_color: [f32; 3]

First directional light’s colour pre-multiplied with its intensity. Drives the per-step sun in-scatter alongside the phase function.

_pad2: f32

Padding so the field layout matches the shader-side struct.

density: f32

Base density at height_reference (per world unit).

height_falloff: f32

Exponential height-falloff rate; 0 = homogeneous medium.

height_reference: f32

World-space Y at which density equals density.

max_distance: f32

Ray-march cap in world units.

phase_g: f32

Henyey-Greenstein anisotropy in (-0.95, 0.95).

ambient: f32

Ambient (sky-side) scattering term added each step.

viewport: [f32; 2]

Width / height of the HDR resolve target in pixels: drives the screen→NDC conversion in the fragment shader.

inv_max_distance: f32

Pre-computed reciprocal of max_distance; the shader uses it to skip a per-step 1 / max_distance divide.

_pad3: [f32; 3]

Padding so the field layout matches the shader-side struct.

Trait Implementations

impl Clone for FogParams

fn clone(&self) -> FogParams

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for FogParams

impl Debug for FogParams

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl NoUninit for FogParams