Render R2: persist named render setups without re-evaluating geometry (#667)

render.settings.set saves validated named render setups (camera, output size, exposure, environment) as one undo step, and render.settings.get reads them back without applying a camera. When validated render settings are the only change, the engine keeps the evaluated model instead of rebuilding it. Setups are saved under design format 21; format-20 designs read as having none. Fixes #658; refs #620.

Contributed by @0xlillith.

Co-authored-by: lillith <35337584+0xlillith@users.noreply.github.com>

crates/doc/src/render_settings.rs

@@ -0,0 +1,257 @@
+//! Saved render intent, independent of runtime backend availability and GPU resources.
+
+use std::collections::BTreeMap;
+
+use serde::{Deserialize, Serialize};
+use solidcraft_geom::Vec3;
+use solidcraft_render::{BackendId, Camera, RenderFormat, RenderLimits, RenderMode, UpAxis};
+
+use crate::{DocError, Result};
+
+pub const MAX_RENDER_SETUPS: usize = 32;
+pub const MAX_SETUP_NAME_BYTES: usize = 128;
+
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(default, deny_unknown_fields)]
+pub struct RenderSetup {
+    pub backend: BackendId,
+    pub mode: RenderMode,
+    #[serde(deserialize_with = "SavedCamera::deserialize")]
+    pub camera: Camera,
+    pub width: u32,
+    pub height: u32,
+    pub format: RenderFormat,
+    pub exposure_ev: f64,
+    /// Procedural environment orientation, in radians. No HDRI is loaded in R2.
+    pub environment_rotation: f64,
+    pub environment_intensity: f64,
+    /// sRGB background. Alpha/output colour management belong to rendering phases.
+    pub background: [u8; 3],
+}
+
+// Reuse Camera's representation and defaults, but reject misspelled saved fields. A remote
+// derive constructs Camera itself, so adding a Camera field requires updating this adapter.
+// Navigation/named-view deserialization keeps its existing compatibility policy.
+#[derive(Deserialize)]
+#[serde(remote = "Camera", deny_unknown_fields)]
+struct SavedCamera {
+    target: Vec3,
+    yaw: f64,
+    pitch: f64,
+    #[serde(default)]
+    roll: f64,
+    distance: f64,
+    fov: f64,
+    #[serde(default)]
+    up: UpAxis,
+}
+
+impl Default for RenderSetup {
+    fn default() -> Self {
+        // The built-in descriptor owns the canonical default backend identifier.
+        Self {
+            backend: solidcraft_render::builtin_backend().id,
+            mode: RenderMode::Preview,
+            camera: Camera::default(),
+            width: 1024,
+            height: 768,
+            format: RenderFormat::Png,
+            exposure_ev: 0.0,
+            environment_rotation: 0.0,
+            environment_intensity: 1.0,
+            background: [236, 240, 245],
+        }
+    }
+}
+
+impl RenderSetup {
+    pub fn validate(&self) -> Result<()> {
+        let limits = RenderLimits::default();
+        if self.width == 0
+            || self.height == 0
+            || u64::from(self.width) > limits.max_dimension
+            || u64::from(self.height) > limits.max_dimension
+            || u64::from(self.width) * u64::from(self.height) > limits.max_pixels
+        {
+            return Err(DocError::Invalid("render output exceeds the dimension/pixel limits".into()));
+        }
+        let camera = &self.camera;
+        if !camera.is_valid()
+            || [camera.target.x, camera.target.y, camera.target.z, camera.distance].into_iter().any(|x| x.abs() > 1e9)
+            || [camera.yaw, camera.pitch, camera.roll].into_iter().any(|x| x.abs() > 1e6)
+            || !camera.fov.is_finite()
+            || !(0.0..std::f64::consts::PI).contains(&camera.fov)
+        {
+            return Err(DocError::Invalid("invalid render camera (finite mm/radians, positive distance, 0 <= fov < pi required)".into()));
+        }
+        if !self.exposure_ev.is_finite() || !(-32.0..=32.0).contains(&self.exposure_ev) {
+            return Err(DocError::Invalid("render exposure must be finite and between -32 and 32 EV".into()));
+        }
+        if !self.environment_rotation.is_finite() || self.environment_rotation.abs() > 1e6 {
+            return Err(DocError::Invalid("render environment rotation must be finite, bounded radians".into()));
+        }
+        if !self.environment_intensity.is_finite() || !(0.0..=100.0).contains(&self.environment_intensity) {
+            return Err(DocError::Invalid("render environment intensity must be finite and between 0 and 100".into()));
+        }
+        // Desired mode/format/backend may be unavailable on this host. Saving intent is not preflight.
+        Ok(())
+    }
+}
+
+#[derive(Clone, Debug, Default, PartialEq, Serialize, Deserialize)]
+#[serde(try_from = "UncheckedSettings")]
+pub struct RenderSettings {
+    pub setups: BTreeMap<String, RenderSetup>,
+}
+
+#[derive(Default, Deserialize)]
+#[serde(default, deny_unknown_fields)]
+struct UncheckedSettings {
+    setups: BTreeMap<String, RenderSetup>,
+}
+
+impl TryFrom<UncheckedSettings> for RenderSettings {
+    type Error = DocError;
+    fn try_from(value: UncheckedSettings) -> Result<Self> {
+        let settings = Self { setups: value.setups };
+        settings.validate()?;
+        Ok(settings)
+    }
+}
+
+impl RenderSettings {
+    pub fn is_empty(&self) -> bool {
+        self.setups.is_empty()
+    }
+
+    pub fn validate_name(name: &str) -> Result<()> {
+        if name.trim().is_empty() || name != name.trim() || name.len() > MAX_SETUP_NAME_BYTES || name.chars().any(char::is_control) {
+            return Err(DocError::Invalid("render setup name must be trimmed, nonempty, at most 128 bytes and contain no control characters".into()));
+        }
+        Ok(())
+    }
+
+    pub fn validate(&self) -> Result<()> {
+        if self.setups.len() > MAX_RENDER_SETUPS {
+            return Err(DocError::Invalid("too many render setups (maximum 32)".into()));
+        }
+        for (name, setup) in &self.setups {
+            Self::validate_name(name)?;
+            setup.validate()?;
+        }
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::Document;
+    use std::sync::Arc;
+
+    #[test]
+    fn camera_fields_are_strict_without_changing_existing_camera_defaults() {
+        let mut camera = serde_json::to_value(Camera::default()).unwrap();
+        camera["fov_degrees"] = serde_json::json!(45);
+        let saved = serde_json::json!({"setups":{"Studio":{"camera":camera}}});
+        let mut doc = serde_json::to_value(Document::default()).unwrap();
+        doc["render"] = saved.clone();
+        assert!(Document::from_json(&doc.to_string()).is_err());
+        assert!(serde_json::from_value::<RenderSettings>(saved).is_err());
+        camera.as_object_mut().unwrap().remove("fov_degrees");
+        camera.as_object_mut().unwrap().remove("roll");
+        camera.as_object_mut().unwrap().remove("up");
+        let setup: RenderSetup = serde_json::from_value(serde_json::json!({"camera":camera})).unwrap();
+        assert_eq!(setup.camera, Camera::default());
+    }
+
+    #[test]
+    fn legacy_and_named_setups_round_trip_without_changing_other_data() {
+        let old = Document::new("Legacy");
+        let mut json = serde_json::to_value(&old).unwrap();
+        json["format"] = serde_json::json!("solidcraft/16");
+        json.as_object_mut().unwrap().remove("render");
+        let mut loaded = Document::from_json(&json.to_string()).unwrap();
+        assert!(loaded.render.is_empty());
+        assert_eq!(loaded.format, crate::format::format_string(crate::format::FORMAT));
+        // Upstream owns 19 for editable offsets; saved render intent needs 20.
+        for version in [17, 18, 19] {
+            json["format"] = serde_json::json!(crate::format::format_string(version));
+            assert_eq!(Document::from_json(&json.to_string()).unwrap(), loaded);
+        }
+        let before = loaded.clone();
+        let setup = RenderSetup {
+            backend: serde_json::from_value(serde_json::json!("future-backend")).unwrap(),
+            exposure_ev: 2.5,
+            mode: RenderMode::Final,
+            format: RenderFormat::Exr,
+            camera: Camera { up: solidcraft_render::UpAxis::Y, ..Default::default() },
+            ..Default::default()
+        };
+        Arc::make_mut(&mut loaded.render).setups.insert("Studio".into(), setup);
+        assert!(loaded.differs_only_in_render(&before));
+        assert_eq!(Document::from_json(&loaded.to_json()).unwrap(), loaded);
+        let mut previous_draft = serde_json::to_value(&loaded).unwrap();
+        previous_draft["format"] = serde_json::json!("solidcraft/17");
+        assert_eq!(Document::from_json(&previous_draft.to_string()).unwrap(), loaded);
+        loaded.units = "in".into();
+        assert!(!loaded.differs_only_in_render(&before));
+    }
+
+    #[test]
+    fn mixed_document_changes_never_qualify_as_render_only() {
+        let before = Document::default();
+        let mut render_only = before.clone();
+        Arc::make_mut(&mut render_only.render).setups.insert("Studio".into(), RenderSetup::default());
+        assert!(render_only.differs_only_in_render(&before));
+        for (key, value) in [
+            ("marker", serde_json::json!(0)),
+            ("materials", serde_json::json!({"Body1":"Steel"})),
+            ("visibility", serde_json::json!({"hidden_bodies":["Body1"]})),
+            ("body_components", serde_json::json!({"Body1":1})),
+            ("next_id", serde_json::json!(99)),
+        ] {
+            let mut json = serde_json::to_value(&render_only).unwrap();
+            json[key] = value;
+            let mixed: Document = serde_json::from_value(json).unwrap();
+            assert!(!mixed.differs_only_in_render(&before), "{key}");
+        }
+    }
+
+    #[test]
+    fn invalid_saved_intent_is_rejected_at_deserialization() {
+        for patch in [
+            serde_json::json!({"width":0}),
+            serde_json::json!({"width":4097}),
+            serde_json::json!({"width":4096,"height":4096}),
+            serde_json::json!({"exposure_ev":33}),
+            serde_json::json!({"environment_rotation":1000001}),
+            serde_json::json!({"environment_intensity":-1}),
+            serde_json::json!({"background":[256,0,0]}),
+            serde_json::json!({"unknown":1}),
+        ] {
+            let json = serde_json::json!({"setups":{"Studio":patch}});
+            assert!(serde_json::from_value::<RenderSettings>(json).is_err());
+        }
+        for name in ["", " padded", "line\nfeed"] {
+            assert!(RenderSettings::validate_name(name).is_err());
+        }
+        let mut settings = RenderSettings::default();
+        for i in 0..=MAX_RENDER_SETUPS {
+            settings.setups.insert(i.to_string(), RenderSetup::default());
+        }
+        assert!(serde_json::from_value::<RenderSettings>(serde_json::to_value(settings).unwrap()).is_err());
+        let mut setup = RenderSetup::default();
+        setup.camera.fov = f64::NAN;
+        assert!(setup.validate().is_err());
+        for field in ["yaw", "pitch", "roll", "distance", "fov"] {
+            let mut value = serde_json::to_value(RenderSetup::default()).unwrap();
+            value["camera"][field] = serde_json::json!(1e12);
+            let setup: RenderSetup = serde_json::from_value(value).unwrap();
+            assert!(setup.validate().is_err(), "{field}");
+        }
+        setup.camera = Camera::default();
+        setup.environment_intensity = f64::INFINITY;
+        assert!(setup.validate().is_err());
+    }
+}