From a779011b9048cdda04887c77e20ee8936f332a7a Mon Sep 17 00:00:00 2001
From: Kai Stevenson <kai@kaistevenson.com>
Date: Tue, 25 Aug 2026 00:32:16 -0700
Subject: vfx pipeline

---
 src/content/entities/entity_bullet_emitter.rs | 17 +++++++++++++---
 src/content/mod.rs                            |  1 +
 src/content/vfx/mod.rs                        | 29 +++++++++++++++++++++++++++
 3 files changed, 44 insertions(+), 3 deletions(-)
 create mode 100644 src/content/vfx/mod.rs

(limited to 'src/content')

diff --git a/src/content/entities/entity_bullet_emitter.rs b/src/content/entities/entity_bullet_emitter.rs
index c014e8c..3788dd9 100644
--- a/src/content/entities/entity_bullet_emitter.rs
+++ b/src/content/entities/entity_bullet_emitter.rs
@@ -2,7 +2,7 @@ use glam::{IVec2, Vec2};
 use rapier2d::dynamics::RigidBodyBuilder;
 
 use crate::{
-    content::materials::MaterialId,
+    content::{materials::MaterialId, vfx::VfxMaterialId},
     input::Input,
     sim::{
         cell::Cell,
@@ -10,6 +10,7 @@ use crate::{
         lib::force::apply_bullet,
         sim_manager::SimCtx,
     },
+    vfx::VfxLine,
 };
 
 struct BulletEmitterEntityBehaviour {
@@ -27,11 +28,21 @@ impl EntityBehaviour for BulletEmitterEntityBehaviour {
         if let Some(target) = self.target {
             let pos = update_ctx.entity_data.transform(ctx).unwrap().0;
             let dir = (target - pos).normalize();
+            let from = pos + (dir * 4.0);
 
             self.shot_timer -= delta_time;
             if self.shot_timer <= 0.0 {
-                apply_bullet(ctx, pos + (dir * 4.0), target, 70);
-                self.shot_timer = 0.1;
+                apply_bullet(ctx, from, target, 70);
+                // 0.1 seconds to travel 200 cells
+                let lifetime = (target - from).length() / 1000.0;
+                ctx.vfx_writer.write_vfx_line(VfxLine::new(
+                    from,
+                    target,
+                    1.3,
+                    VfxMaterialId::Tracer,
+                    lifetime,
+                ));
+                self.shot_timer = 0.2;
             }
 
             self.life -= delta_time;
diff --git a/src/content/mod.rs b/src/content/mod.rs
index 2044048..ee2f47c 100644
--- a/src/content/mod.rs
+++ b/src/content/mod.rs
@@ -1,2 +1,3 @@
 pub mod entities;
 pub mod materials;
+pub mod vfx;
diff --git a/src/content/vfx/mod.rs b/src/content/vfx/mod.rs
new file mode 100644
index 0000000..8843bf1
--- /dev/null
+++ b/src/content/vfx/mod.rs
@@ -0,0 +1,29 @@
+#[repr(u8)]
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+pub enum VfxMaterialId {
+    Tracer = 0,
+}
+
+pub struct VfxMaterialDef {
+    pub name: &'static str,
+    pub color: (u8, u8, u8, u8),
+    pub length: f32,
+}
+
+static MATERIALS: [VfxMaterialDef; 1] = [VfxMaterialDef {
+    name: "Tracer",
+    color: (0xFF, 0xAA, 0xAA, 0xFF),
+    length: 15.0,
+}];
+
+impl VfxMaterialId {
+    pub const ALL: [VfxMaterialId; 1] = [VfxMaterialId::Tracer];
+    #[inline]
+    pub fn def(self) -> &'static VfxMaterialDef {
+        &MATERIALS[self as usize]
+    }
+
+    pub fn from_index(idx: u8) -> VfxMaterialId {
+        VfxMaterialId::ALL[idx as usize]
+    }
+}
-- 
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