dreamwell_engine/

material.rs

//! Material descriptor types shared between engine and GPU crates.
//!
//! These are CPU-side descriptions — the GPU crate translates them
//! into pipeline-specific bind group data.

use serde::{Deserialize, Serialize};

/// Alpha blending mode for materials.
#[derive(Debug, Clone, Copy, PartialEq, Default, Serialize, Deserialize)]
pub enum AlphaMode {
    /// Fully opaque. No blending.
    #[default]
    Opaque,
    /// Alpha-tested with cutoff threshold. Fragments below cutoff are discarded.
    Mask { cutoff: f32 },
    /// Alpha-blended. Requires sorted draw order.
    Blend,
}

/// Classification of material pipeline variants.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
pub enum MaterialClass {
    PbrLit,
    PbrLitUntextured,
    PbrEmissive,
    PbrMasked,
    PbrTransparent,
    Unlit,
    SpriteLit2D,
    SpriteUnlit2D,
}

/// Ray tracing quality preset for SceneDreamMode::PbrRayTraced.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
pub enum RtQuality {
    /// Full RT GI + RT shadows (highest quality, ~2x GPU cost).
    Full,
    /// RT shadows only (moderate cost, significant visual improvement).
    ShadowsOnly,
    /// RT GI only (high quality ambient, keep CSM shadows).
    GiOnly,
}

impl Default for RtQuality {
    fn default() -> Self {
        Self::Full
    }
}

/// Scene-wide rendering mode that controls which pipeline features are active.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
pub enum SceneDreamMode {
    /// Full PBR with all texture slots, HDR post-processing, shadows.
    PbrDefault,
    /// PBR with reduced texture slots (no occlusion, no emissive). Lower VRAM.
    PbrLightweight,
    /// No lighting. Flat color / texture only. Fastest.
    Unlit,
    /// 2D sprites with normal-mapped PBR lighting.
    SpriteLit2D,
    /// 2D sprites, no lighting. Standard 2D game mode.
    SpriteUnlit2D,
    /// PBR with native ray-traced global illumination and/or shadows.
    /// Requires GPU with EXPERIMENTAL_RAY_QUERY support. Falls back to PbrDefault without RT hardware.
    PbrRayTraced(RtQuality),
    /// User-provided shader pipeline. Engine provides frame lifecycle only.
    Custom,
}

impl Default for SceneDreamMode {
    fn default() -> Self {
        Self::PbrDefault
    }
}

/// HDR tonemapping operator applied during post-processing.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum TonemapOperator {
    /// ACES fitted (BakingLab). Default. Best color fidelity.
    AcesFilmic,
    /// Uncharted 2 filmic (Hable). Warmer, cinematic look.
    Uncharted2,
    /// Reinhard. Simple x/(x+1). Useful for debugging.
    Reinhard,
    /// No tonemapping. Linear HDR passthrough.
    None,
}

impl Default for TonemapOperator {
    fn default() -> Self {
        Self::AcesFilmic
    }
}

/// PBR lit material descriptor.
/// Texture references are optional `u32` handles resolved by the GPU store.
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub struct PbrMaterial {
    /// Base color (RGBA linear).
    pub base_color: [f32; 4],
    /// Emissive color (RGB linear).
    pub emissive: [f32; 3],
    /// Roughness [0..1]. 0 = mirror, 1 = diffuse.
    pub roughness: f32,
    /// Metallic [0..1]. 0 = dielectric, 1 = metal.
    pub metallic: f32,
    /// Optional base color texture handle.
    pub base_color_tex: Option<u32>,
    /// Optional normal map texture handle.
    pub normal_tex: Option<u32>,
    /// Optional emissive texture handle.
    pub emissive_tex: Option<u32>,
    /// Optional roughness-metalness texture handle (R=metallic, G=roughness, glTF convention).
    pub roughness_metalness_tex: Option<u32>,
    /// Optional occlusion texture handle.
    pub occlusion_tex: Option<u32>,
    /// Occlusion strength [0..1]. 1.0 = full effect.
    pub occlusion_strength: f32,
    /// Normal map scale factor. 1.0 = unmodified normals.
    pub normal_scale: f32,
    /// Emissive strength multiplier. 1.0 = use emissive color as-is.
    pub emissive_strength: f32,
    /// Alpha blending mode.
    pub alpha_mode: AlphaMode,
    /// Render both front and back faces.
    pub double_sided: bool,
}

/// Backward compatibility alias.
pub type LitMaterialDesc = PbrMaterial;

// ═══════════════════════════════════════════════════════════════════════
// Dream Lighting — unified GI + reflection + shadow quality presets
// ═══════════════════════════════════════════════════════════════════════

/// Dream Lighting quality preset — controls the entire lighting pipeline.
/// Maps to a fixed parameter matrix for all GI, shadow, reflection, and
/// post-processing subsystems.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
pub enum DreamLightingQuality {
    /// Screen-space GI only, no RT. SSAO + TAA. Minimal VRAM.
    Low,
    /// Screen-space GI, CSM shadows, SSAO + SSR + TAA. Moderate VRAM.
    Medium,
    /// SHaRC RT GI + RT shadows, full screen-space stack, screen traces. ~150 MB.
    High,
    /// SHaRC RT GI (high density) + RT shadows, all effects, Hi-Z. ~250 MB.
    Ultra,
    /// Maximum quality: Dream TSR, 4-bounce GI, all effects at max settings.
    Cinematic,
}

impl Default for DreamLightingQuality {
    fn default() -> Self {
        Self::Medium
    }
}

impl DreamLightingQuality {
    /// Auto-detect quality from GPU capabilities (spec §4.3).
    pub fn auto_detect(ray_tracing: bool, max_storage_bytes: u64, max_tlas_instances: u32) -> Self {
        if !ray_tracing {
            if max_storage_bytes >= 64 * 1024 * 1024 {
                return Self::Medium;
            }
            return Self::Low;
        }
        // RT-capable GPU — select based on TLAS instance capacity
        if max_tlas_instances >= 16_000_000 {
            Self::Ultra
        } else {
            Self::High
        }
    }
}

/// Full Dream Lighting configuration — all 21 parameters from the lighting spec.
/// Created via `for_quality()` or manually tuned.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct DreamLightingConfig {
    // ── RT features ──
    pub rt_gi_enabled: bool,
    pub rt_shadows_enabled: bool,
    // ── Screen-space effects ──
    pub ssgi_enabled: bool,
    pub ssao_enabled: bool,
    pub ssr_enabled: bool,
    pub taa_enabled: bool,
    pub screen_traces_enabled: bool,
    // ── SHaRC radiance cache ──
    pub sharc_hash_capacity: u32,
    pub sharc_sparse_rate: f32,
    pub sharc_max_bounces: u32,
    pub sharc_grid_log_base: f32,
    // ── Denoiser ──
    pub denoiser_enabled: bool,
    pub denoiser_temporal_alpha: f32,
    // ── Occlusion & motion ──
    pub hiz_enabled: bool,
    pub motion_vectors_enabled: bool,
    // ── Shadows ──
    pub csm_cascades: u32,
    // ── Reflections ──
    pub reflection_max_roughness: f32,
    // ── IBL ──
    pub ibl_resolution: u32,
    // ── Atmospheric ──
    pub volumetric_fog_enabled: bool,
    // ── DOF ──
    pub dof_enabled: bool,
    // ── TSR ──
    pub dream_tsr_enabled: bool,
}

impl Default for DreamLightingConfig {
    fn default() -> Self {
        Self::for_quality(DreamLightingQuality::Medium)
    }
}

impl DreamLightingConfig {
    /// Create a config for a specific quality preset.
    pub fn for_quality(quality: DreamLightingQuality) -> Self {
        match quality {
            // Spec §4.2: IBL ambient only. No RT, no screen traces, no SSGI.
            DreamLightingQuality::Low => Self {
                rt_gi_enabled: false,
                rt_shadows_enabled: false,
                ssgi_enabled: false,
                ssao_enabled: false,
                ssr_enabled: false,
                taa_enabled: false,
                screen_traces_enabled: false,
                sharc_hash_capacity: 0,
                sharc_sparse_rate: 0.0,
                sharc_max_bounces: 0,
                sharc_grid_log_base: 2.0,
                denoiser_enabled: false,
                denoiser_temporal_alpha: 0.0,
                hiz_enabled: false,
                motion_vectors_enabled: false,
                csm_cascades: 2,
                reflection_max_roughness: 0.0,
                ibl_resolution: 32,
                volumetric_fog_enabled: false,
                dof_enabled: false,
                dream_tsr_enabled: false,
            },
            // Spec §4.2: SSGI + SSAO + SSR + TAA. No RT.
            DreamLightingQuality::Medium => Self {
                rt_gi_enabled: false,
                rt_shadows_enabled: false,
                ssgi_enabled: true,
                ssao_enabled: true,
                ssr_enabled: true,
                taa_enabled: true,
                screen_traces_enabled: false,
                sharc_hash_capacity: 0,
                sharc_sparse_rate: 0.0,
                sharc_max_bounces: 0,
                sharc_grid_log_base: 2.0,
                denoiser_enabled: false,
                denoiser_temporal_alpha: 0.0,
                hiz_enabled: false,
                motion_vectors_enabled: true,
                csm_cascades: 4,
                reflection_max_roughness: 0.3,
                ibl_resolution: 64,
                volumetric_fog_enabled: false,
                dof_enabled: false,
                dream_tsr_enabled: false,
            },
            // Spec §4.2: Screen traces + SHaRC + RT shadows.
            DreamLightingQuality::High => Self {
                rt_gi_enabled: true,
                rt_shadows_enabled: true,
                ssgi_enabled: false,
                ssao_enabled: true,
                ssr_enabled: true,
                taa_enabled: true,
                screen_traces_enabled: true,
                sharc_hash_capacity: 1 << 18, // 262K
                sharc_sparse_rate: 0.02,
                sharc_max_bounces: 2,
                sharc_grid_log_base: 2.5,
                denoiser_enabled: true,
                denoiser_temporal_alpha: 0.80,
                hiz_enabled: true,
                motion_vectors_enabled: true,
                csm_cascades: 0, // RT shadows replace CSM
                reflection_max_roughness: 0.4,
                ibl_resolution: 128,
                volumetric_fog_enabled: false,
                dof_enabled: false,
                dream_tsr_enabled: false,
            },
            // Spec §4.2: Full Dream Lighting with multi-bounce + denoiser.
            DreamLightingQuality::Ultra => Self {
                rt_gi_enabled: true,
                rt_shadows_enabled: true,
                ssgi_enabled: false,
                ssao_enabled: true,
                ssr_enabled: true,
                taa_enabled: true,
                screen_traces_enabled: true,
                sharc_hash_capacity: 1 << 20, // 1M
                sharc_sparse_rate: 0.04,
                sharc_max_bounces: 3,
                sharc_grid_log_base: 2.0,
                denoiser_enabled: true,
                denoiser_temporal_alpha: 0.85,
                hiz_enabled: true,
                motion_vectors_enabled: true,
                csm_cascades: 0, // RT shadows replace CSM
                reflection_max_roughness: 0.5,
                ibl_resolution: 128,
                volumetric_fog_enabled: true,
                dof_enabled: false,
                dream_tsr_enabled: false,
            },
            // Spec §4.2: Maximum quality with Dream TSR + 5 bounces.
            DreamLightingQuality::Cinematic => Self {
                rt_gi_enabled: true,
                rt_shadows_enabled: true,
                ssgi_enabled: false,
                ssao_enabled: true,
                ssr_enabled: true,
                taa_enabled: false, // replaced by Dream TSR
                screen_traces_enabled: true,
                sharc_hash_capacity: 1 << 22, // 4M
                sharc_sparse_rate: 0.08,
                sharc_max_bounces: 5,
                sharc_grid_log_base: 1.5,
                denoiser_enabled: true,
                denoiser_temporal_alpha: 0.90,
                hiz_enabled: true,
                motion_vectors_enabled: true,
                csm_cascades: 0, // RT shadows replace CSM
                reflection_max_roughness: 0.6,
                ibl_resolution: 256,
                volumetric_fog_enabled: true,
                dof_enabled: true,
                dream_tsr_enabled: true,
            },
        }
    }

    /// The quality preset this config most closely matches (if any).
    pub fn infer_quality(&self) -> DreamLightingQuality {
        if self.dream_tsr_enabled {
            DreamLightingQuality::Cinematic
        } else if self.rt_gi_enabled && self.sharc_hash_capacity >= (1 << 20) {
            DreamLightingQuality::Ultra
        } else if self.rt_gi_enabled {
            DreamLightingQuality::High
        } else if self.ssgi_enabled {
            DreamLightingQuality::Medium
        } else {
            DreamLightingQuality::Low
        }
    }
}

impl Default for PbrMaterial {
    fn default() -> Self {
        Self {
            base_color: [1.0, 1.0, 1.0, 1.0],
            emissive: [0.0, 0.0, 0.0],
            roughness: 0.5,
            metallic: 0.0,
            base_color_tex: None,
            normal_tex: None,
            emissive_tex: None,
            roughness_metalness_tex: None,
            occlusion_tex: None,
            occlusion_strength: 1.0,
            normal_scale: 1.0,
            emissive_strength: 1.0,
            alpha_mode: AlphaMode::Opaque,
            double_sided: false,
        }
    }
}

impl PbrMaterial {
    pub fn painted_metal() -> Self {
        Self {
            roughness: 0.4,
            metallic: 1.0,
            base_color: [0.8, 0.1, 0.1, 1.0],
            ..Default::default()
        }
    }

    pub fn brushed_steel() -> Self {
        Self {
            roughness: 0.3,
            metallic: 1.0,
            base_color: [0.7, 0.7, 0.7, 1.0],
            ..Default::default()
        }
    }

    pub fn matte_plastic() -> Self {
        Self {
            roughness: 0.9,
            metallic: 0.0,
            base_color: [0.8, 0.8, 0.8, 1.0],
            ..Default::default()
        }
    }

    pub fn glossy_ceramic() -> Self {
        Self {
            roughness: 0.15,
            metallic: 0.0,
            base_color: [0.95, 0.95, 0.9, 1.0],
            ..Default::default()
        }
    }

    pub fn rough_wood() -> Self {
        Self {
            roughness: 0.85,
            metallic: 0.0,
            base_color: [0.55, 0.35, 0.2, 1.0],
            ..Default::default()
        }
    }

    pub fn polished_marble() -> Self {
        Self {
            roughness: 0.2,
            metallic: 0.0,
            base_color: [0.95, 0.93, 0.88, 1.0],
            ..Default::default()
        }
    }

    pub fn wet_stone() -> Self {
        Self {
            roughness: 0.3,
            metallic: 0.0,
            base_color: [0.4, 0.4, 0.4, 1.0],
            ..Default::default()
        }
    }

    pub fn gold() -> Self {
        Self {
            roughness: 0.25,
            metallic: 1.0,
            base_color: [1.0, 0.76, 0.33, 1.0],
            ..Default::default()
        }
    }

    pub fn copper() -> Self {
        Self {
            roughness: 0.3,
            metallic: 1.0,
            base_color: [0.95, 0.64, 0.54, 1.0],
            ..Default::default()
        }
    }

    pub fn rubber() -> Self {
        Self {
            roughness: 0.95,
            metallic: 0.0,
            base_color: [0.15, 0.15, 0.15, 1.0],
            ..Default::default()
        }
    }

    pub fn glass() -> Self {
        Self {
            roughness: 0.05,
            metallic: 0.0,
            alpha_mode: AlphaMode::Blend,
            base_color: [1.0, 1.0, 1.0, 0.3],
            ..Default::default()
        }
    }

    pub fn fabric() -> Self {
        Self {
            roughness: 0.8,
            metallic: 0.0,
            base_color: [0.6, 0.5, 0.4, 1.0],
            ..Default::default()
        }
    }

    pub fn skin() -> Self {
        Self {
            roughness: 0.5,
            metallic: 0.0,
            base_color: [0.9, 0.7, 0.6, 1.0],
            ..Default::default()
        }
    }

    pub fn emissive_panel() -> Self {
        Self {
            emissive: [5.0, 5.0, 5.0],
            emissive_strength: 2.0,
            base_color: [0.1, 0.1, 0.1, 1.0],
            ..Default::default()
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn alpha_mode_default_opaque() {
        assert_eq!(AlphaMode::default(), AlphaMode::Opaque);
    }

    #[test]
    fn pbr_material_default() {
        let m = PbrMaterial::default();
        assert_eq!(m.base_color, [1.0, 1.0, 1.0, 1.0]);
        assert_eq!(m.roughness, 0.5);
        assert_eq!(m.metallic, 0.0);
        assert!(!m.double_sided);
    }

    #[test]
    fn alpha_mask_cutoff() {
        let mode = AlphaMode::Mask { cutoff: 0.5 };
        if let AlphaMode::Mask { cutoff } = mode {
            assert_eq!(cutoff, 0.5);
        } else {
            panic!("expected Mask");
        }
    }

    #[test]
    fn serde_roundtrip() {
        let m = PbrMaterial {
            roughness: 0.8,
            metallic: 1.0,
            alpha_mode: AlphaMode::Blend,
            ..Default::default()
        };
        let json = serde_json::to_string(&m).unwrap();
        let back: PbrMaterial = serde_json::from_str(&json).unwrap();
        assert_eq!(m, back);
    }

    #[test]
    fn pbr_material_new_fields_default() {
        let m = PbrMaterial::default();
        assert_eq!(m.roughness_metalness_tex, None);
        assert_eq!(m.occlusion_tex, None);
        assert_eq!(m.occlusion_strength, 1.0);
        assert_eq!(m.normal_scale, 1.0);
        assert_eq!(m.emissive_strength, 1.0);
    }

    #[test]
    fn scene_dream_mode_default() {
        assert_eq!(SceneDreamMode::default(), SceneDreamMode::PbrDefault);
    }

    #[test]
    fn rt_quality_default() {
        assert_eq!(RtQuality::default(), RtQuality::Full);
    }

    #[test]
    fn scene_dream_mode_ray_traced() {
        let mode = SceneDreamMode::PbrRayTraced(RtQuality::Full);
        assert_ne!(mode, SceneDreamMode::PbrDefault);
        let mode2 = SceneDreamMode::PbrRayTraced(RtQuality::ShadowsOnly);
        assert_ne!(mode, mode2);
    }

    #[test]
    fn serde_roundtrip_rt_quality() {
        let q = RtQuality::GiOnly;
        let json = serde_json::to_string(&q).unwrap();
        let back: RtQuality = serde_json::from_str(&json).unwrap();
        assert_eq!(q, back);
    }

    #[test]
    fn serde_roundtrip_pbr_ray_traced() {
        let mode = SceneDreamMode::PbrRayTraced(RtQuality::Full);
        let json = serde_json::to_string(&mode).unwrap();
        let back: SceneDreamMode = serde_json::from_str(&json).unwrap();
        assert_eq!(mode, back);
    }

    #[test]
    fn tonemap_operator_default() {
        assert_eq!(TonemapOperator::default(), TonemapOperator::AcesFilmic);
    }

    #[test]
    fn material_class_variants() {
        let variants = [
            MaterialClass::PbrLit,
            MaterialClass::PbrLitUntextured,
            MaterialClass::PbrEmissive,
            MaterialClass::PbrMasked,
            MaterialClass::PbrTransparent,
            MaterialClass::Unlit,
            MaterialClass::SpriteLit2D,
            MaterialClass::SpriteUnlit2D,
        ];
        assert_eq!(variants.len(), 8);
    }

    #[test]
    fn preset_painted_metal() {
        let m = PbrMaterial::painted_metal();
        assert_eq!(m.roughness, 0.4);
        assert_eq!(m.metallic, 1.0);
        assert_eq!(m.base_color, [0.8, 0.1, 0.1, 1.0]);
    }

    #[test]
    fn preset_glass_is_blend() {
        let m = PbrMaterial::glass();
        assert_eq!(m.alpha_mode, AlphaMode::Blend);
        assert_eq!(m.base_color[3], 0.3);
    }

    #[test]
    fn serde_roundtrip_scene_dream_mode() {
        let mode = SceneDreamMode::SpriteLit2D;
        let json = serde_json::to_string(&mode).unwrap();
        let back: SceneDreamMode = serde_json::from_str(&json).unwrap();
        assert_eq!(mode, back);
    }

    #[test]
    fn serde_roundtrip_tonemap() {
        let op = TonemapOperator::Uncharted2;
        let json = serde_json::to_string(&op).unwrap();
        let back: TonemapOperator = serde_json::from_str(&json).unwrap();
        assert_eq!(op, back);
    }

    #[test]
    fn serde_roundtrip_material_class() {
        let cls = MaterialClass::PbrEmissive;
        let json = serde_json::to_string(&cls).unwrap();
        let back: MaterialClass = serde_json::from_str(&json).unwrap();
        assert_eq!(cls, back);
    }

    // ── Dream Lighting tests ──

    #[test]
    fn dream_lighting_quality_default() {
        assert_eq!(DreamLightingQuality::default(), DreamLightingQuality::Medium);
    }

    #[test]
    fn dream_lighting_config_default_matches_medium() {
        let config = DreamLightingConfig::default();
        let medium = DreamLightingConfig::for_quality(DreamLightingQuality::Medium);
        assert_eq!(config.rt_gi_enabled, medium.rt_gi_enabled);
        assert_eq!(config.ssao_enabled, medium.ssao_enabled);
        assert_eq!(config.csm_cascades, medium.csm_cascades);
        assert!(!config.hiz_enabled); // spec §4.2: Medium has no Hi-Z
        assert_eq!(config.ibl_resolution, 64); // spec §4.2
        assert!((config.reflection_max_roughness - 0.3).abs() < 0.01);
    }

    #[test]
    fn quality_preset_low_no_rt() {
        let config = DreamLightingConfig::for_quality(DreamLightingQuality::Low);
        assert!(!config.rt_gi_enabled);
        assert!(!config.rt_shadows_enabled);
        assert!(!config.ssgi_enabled);
        assert!(!config.ssao_enabled); // spec §4.2: Low has no SSAO
        assert!(!config.taa_enabled); // spec §4.2: Low has no TAA
        assert_eq!(config.ibl_resolution, 32);
        assert_eq!(config.csm_cascades, 2);
    }

    #[test]
    fn quality_preset_high_has_rt() {
        let config = DreamLightingConfig::for_quality(DreamLightingQuality::High);
        assert!(config.rt_gi_enabled);
        assert!(config.rt_shadows_enabled);
        assert!(config.screen_traces_enabled);
        assert_eq!(config.sharc_hash_capacity, 1 << 18); // spec: 262K
        assert_eq!(config.sharc_max_bounces, 2); // spec: 2
        assert_eq!(config.csm_cascades, 0); // spec: RT replaces CSM
        assert!((config.sharc_sparse_rate - 0.02).abs() < 0.001);
        assert!((config.sharc_grid_log_base - 2.5).abs() < 0.01);
        assert!((config.denoiser_temporal_alpha - 0.80).abs() < 0.01);
        assert_eq!(config.ibl_resolution, 128);
    }

    #[test]
    fn quality_preset_cinematic_has_tsr() {
        let config = DreamLightingConfig::for_quality(DreamLightingQuality::Cinematic);
        assert!(config.dream_tsr_enabled);
        assert!(!config.taa_enabled); // TSR replaces TAA
        assert_eq!(config.sharc_max_bounces, 5); // spec: 5
        assert_eq!(config.sharc_hash_capacity, 1 << 22);
        assert_eq!(config.csm_cascades, 0); // spec: RT replaces CSM
        assert_eq!(config.ibl_resolution, 256);
        assert!((config.sharc_grid_log_base - 1.5).abs() < 0.01);
        assert!((config.denoiser_temporal_alpha - 0.90).abs() < 0.01);
        assert!((config.reflection_max_roughness - 0.6).abs() < 0.01);
    }

    #[test]
    fn auto_detect_no_rt_64mb_returns_medium() {
        let q = DreamLightingQuality::auto_detect(false, 64 * 1024 * 1024, 0);
        assert_eq!(q, DreamLightingQuality::Medium);
    }

    #[test]
    fn auto_detect_no_rt_low_storage_returns_low() {
        let q = DreamLightingQuality::auto_detect(false, 32 * 1024 * 1024, 0);
        assert_eq!(q, DreamLightingQuality::Low);
    }

    #[test]
    fn auto_detect_rt_16m_tlas_returns_ultra() {
        let q = DreamLightingQuality::auto_detect(true, 512 * 1024 * 1024, 16_000_000);
        assert_eq!(q, DreamLightingQuality::Ultra);
    }

    #[test]
    fn auto_detect_rt_below_16m_returns_high() {
        let q = DreamLightingQuality::auto_detect(true, 256 * 1024 * 1024, 100_000);
        assert_eq!(q, DreamLightingQuality::High);
    }

    #[test]
    fn infer_quality_roundtrip() {
        for quality in [
            DreamLightingQuality::Low,
            DreamLightingQuality::Medium,
            DreamLightingQuality::High,
            DreamLightingQuality::Ultra,
            DreamLightingQuality::Cinematic,
        ] {
            let config = DreamLightingConfig::for_quality(quality);
            assert_eq!(
                config.infer_quality(),
                quality,
                "infer_quality failed for {:?}",
                quality
            );
        }
    }

    #[test]
    fn serde_roundtrip_dream_lighting_quality() {
        let q = DreamLightingQuality::Cinematic;
        let json = serde_json::to_string(&q).unwrap();
        let back: DreamLightingQuality = serde_json::from_str(&json).unwrap();
        assert_eq!(q, back);
    }

    #[test]
    fn serde_roundtrip_dream_lighting_config() {
        let config = DreamLightingConfig::for_quality(DreamLightingQuality::Ultra);
        let json = serde_json::to_string(&config).unwrap();
        let back: DreamLightingConfig = serde_json::from_str(&json).unwrap();
        assert_eq!(config.rt_gi_enabled, back.rt_gi_enabled);
        assert_eq!(config.sharc_hash_capacity, back.sharc_hash_capacity);
        assert_eq!(config.dream_tsr_enabled, back.dream_tsr_enabled);
    }
}