From 3d3864171785c589872bf23faaaa3a421f56ee4e Mon Sep 17 00:00:00 2001
From: Jon Santmyer <jon@jonsantmyer.com>
Date: Wed, 22 Apr 2026 10:51:13 -0400
Subject: complete orbit camera. add most large solar bodies

---
 src/tacmap/render.rs | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

(limited to 'src/tacmap/render.rs')

diff --git a/src/tacmap/render.rs b/src/tacmap/render.rs
index 0f6b409..26d6977 100644
--- a/src/tacmap/render.rs
+++ b/src/tacmap/render.rs
@@ -9,7 +9,7 @@ use crate::{solar_system::{SolarSystem, SystemId}, timeman::Second, vertex::{sel
 
 struct BodyInstance
 {
-    position: cgmath::Point3<Kilometers>,
+    position: cgmath::Vector3<Kilometers>,
     radius: f32
 }
 
@@ -36,6 +36,7 @@ pub struct BodyRenderer
 {
     needs_rebuild: bool,
     last_time: Option<Second>,
+    last_pos: Option<cgmath::Vector3<Kilometers>>,
 
     pipeline: wgpu::RenderPipeline,
 
@@ -73,6 +74,7 @@ impl BodyRenderer
         Self {
             needs_rebuild: true,
             last_time: None,
+            last_pos: None,
             pipeline: render_pipeline,
             body_vertex_buffer,
             body_instance_buffer: None
@@ -113,6 +115,7 @@ impl BodyRenderer
         );
 
         self.last_time = None;
+        self.last_pos = None;
         self.body_instance_buffer = Some((bodies.len(), buffer));
     }
 
@@ -120,21 +123,21 @@ impl BodyRenderer
         &mut self,
         wgpuctx: &WgpuCtx,
         solar_system: &SolarSystem,
+        camera: &Camera,
         time: Second)
     -> Result<(), Box<dyn Error>>
     {
         //If the last updated time is the same, we don't need to update
         //the positions of all the bodies.
-        match self.last_time {
-            Some(last_time) => {
-                if last_time == time {
-                    return Ok(());
-                }
+        if self.last_time.is_some_and(|last_time| { last_time == time }) {
+            if self.last_pos.is_some_and(|last_pos| { last_pos == camera.get_abs_position() }) {
+                return Ok(())
             }
-            None => {}
         }
 
         self.last_time = Some(time);
+        self.last_pos = Some(camera.get_abs_position());
+
         let (_, bodies_buffer) = match &self.body_instance_buffer {
             Some(tuple) => tuple,
             None => return Err(Box::new(NeedsRebuildError))
@@ -142,9 +145,9 @@ impl BodyRenderer
 
         let bodies = solar_system.bodies();
         let body_instances = bodies.iter().map(|body| {
-            let position = body.position();
+            let position = solar_system.body_position(body);
             BodyInstance {
-                position: position,
+                position: (position - self.last_pos.unwrap()),
                 radius: body.radius()
             }.raw()
         }).collect::<Vec<_>>();
-- 
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