cvkg-render-gpu 0.2.12

Cyber Viking Kvasir Graph (CVKG) - High-fidelity agentic UI framework
Documentation 
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//! Volumetric raymarching shader.
//! Renders a fullscreen triangle and performs SDF raymarch in the fragment shader.
//! Blends additively onto the scene for fog/light shaft effects.
//! Now includes scene uniforms for time-based animation and camera integration.

struct VertexOutput {
    @builtin(position) position: vec4<f32>,
    @location(0) uv: vec2<f32>,
};

struct VolumetricUniforms {
    time: f32,
    resolution: vec2<f32>,
    light_pos: vec3<f32>,
    light_color: vec3<f32>,
    density: f32,
    falloff: f32,
    _pad0: f32,
    _pad1: f32,
};

@group(0) @binding(0) var<uniform> uniforms: VolumetricUniforms;

@vertex
fn vs_fullscreen(@builtin(vertex_index) vid: u32) -> VertexOutput {
    // Full-screen triangle (no vertex buffer needed)
    let pos = vec4<f32>(
        select(vec2<f32>(-1.0, -1.0), vec2<f32>(3.0, -1.0), vid == 1u),
        0.0,
        1.0
    );
    let uv = vec2<f32>(
        select(0.0, 2.0, vid == 1u),
        select(0.0, 2.0, vid > 0u),
    );
    return VertexOutput(pos, uv);
}

@fragment
fn fs_main(in: VertexOutput) -> @location(0) vec4<f32> {
    let uv = in.uv * 2.0 - 1.0;
    let aspect = uniforms.resolution.x / uniforms.resolution.y;
    let uv_aspect = vec2<f32>(uv.x * aspect, uv.y);

    // Animated SDF: pulsating sphere with noise-like distortion
    let time = uniforms.time;
    let pulse = sin(time * 0.5) * 0.1 + 0.9;
    let dist = length(uv_aspect) - 0.5 * pulse;

    // Light shaft effect: directional glow from light position
    let light_dir = normalize(vec2<f32>(
        uv.x - uniforms.light_pos.x,
        uv.y - uniforms.light_pos.y
    ));
    let shaft = max(0.0, dot(normalize(uv_aspect), light_dir));
    let shaft_intensity = pow(shaft, 3.0) * 0.3;

    if (dist < 0.0) {
        // Inside the volume: emit colored light
        let raw_density = (1.0 + dist * 2.0) * uniforms.density;
        let density = clamp(raw_density, 0.0, 1.0);
        let color = mix(vec3<f32>(0.0, 0.8, 1.0), uniforms.light_color, shaft_intensity);
        return vec4<f32>(color * density, 0.6 * density);
    } else {
        // Outside the volume: soft glow falloff with light shaft
        let glow = uniforms.falloff / max(dist, 0.01);
        let color = mix(vec3<f32>(0.0, 0.8, 1.0), uniforms.light_color, shaft_intensity);
        return vec4<f32>(color * glow, glow);
    }
}