From 449089e80cd294cbf2016ca8b76ba2a14c6637ab Mon Sep 17 00:00:00 2001
From: Isaac Clayton
Date: Sat, 22 Jan 2022 10:13:03 +0100
Subject: working on writing quadtree to texture

---
 src/ctx.rs    |  4 ++++
 src/main.rs   |  5 +++++
 src/quad.rs   | 37 +++++++++++++++++++++++++++++++++++++
 src/render.rs | 10 ++++++++--
 4 files changed, 54 insertions(+), 2 deletions(-)

diff --git a/src/ctx.rs b/src/ctx.rs
index 38aa4ae..3eebbec 100644
--- a/src/ctx.rs
+++ b/src/ctx.rs
@@ -20,6 +20,10 @@ impl Ctx {
         todo!("Turn Base Cell into a vector B");
     }
 
+    pub fn color_base<A>(&mut self, base: &A) -> [u8; 4] {
+        todo!();
+    }
+
     /// Compresses a single node into a vector representation.
     /// Returns `None` if node has already been compressed and trimmed from tree.
     /// To recover a trimmed node, use `expand` on the compressed representation.
diff --git a/src/main.rs b/src/main.rs
index 735c25d..aa5a312 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -5,6 +5,11 @@ mod render;
 
 fn main() {
     println!("Warming up...");
+
+    // let mut ctx = ctx::Ctx::new_empty();
+    // let quad: quad::Node<u8, u8> = quad::Node::new_empty(&mut ctx);
+
     render::graphics();
+
     println!("Hello!");
 }
diff --git a/src/quad.rs b/src/quad.rs
index 25fda47..640b1f9 100644
--- a/src/quad.rs
+++ b/src/quad.rs
@@ -14,6 +14,7 @@ pub enum Quad<A: Default, B: Copy> {
 
 /// Represends a node in a quadtree.
 /// Has a depth denoting the number of nodes below it.
+/// The base node has a depth of 0
 /// Nodes should only be siblings of nodes with the same depth.
 /// Data stored inside a quadtree node, including children, are in `data`.
 pub struct Node<A: Default, B: Copy> {
@@ -23,6 +24,42 @@ pub struct Node<A: Default, B: Copy> {
 }
 
 impl<A: Default, B: Copy> Node<A, B> {
+    /// Bytes must be of size (2**depth)**2 * 4
+    pub fn write_rgba8(
+        self,
+        ctx: &mut Ctx,
+        bytes: &mut [u8],
+        depth: usize,
+        x: usize,
+        y: usize,
+    ) -> Self {
+        let mut expanded = ctx.expand(self);
+        expanded.data = match expanded.data {
+            // Base cell in grid.
+            Quad::Base(base) => {
+                let mut color = ctx.color_base(&base);
+                let idx = ((1 << depth) * y + x) * 4;
+                bytes[idx..(idx + 4)].swap_with_slice(&mut color);
+                Quad::Base(base)
+            },
+            // Node with 4 children.
+            Quad::Node(children) => {
+                let size = 1 << expanded.depth;
+                let half = size / 2;
+                let c = [
+                    children[0].write_rgba8(ctx, bytes, depth, x,        y       ),
+                    children[1].write_rgba8(ctx, bytes, depth, x + half, y       ),
+                    children[2].write_rgba8(ctx, bytes, depth, x,        y + half),
+                    children[3].write_rgba8(ctx, bytes, depth, x + half, y + half),
+                ];
+                todo!()
+            },
+            // Children may be generated from Node.
+            Cached => { unreachable!(); },
+        };
+        expanded
+    }
+
     /// Creates a new tree from a single base node
     pub fn new_base(base: A, ctx: &mut Ctx) -> Self {
         Node {
diff --git a/src/render.rs b/src/render.rs
index 964a022..6939ee8 100644
--- a/src/render.rs
+++ b/src/render.rs
@@ -14,6 +14,7 @@ struct Vertex {
 struct Stage {
     pipeline: Pipeline,
     bindings: Bindings,
+    texture:  Texture,
 }
 
 impl Stage {
@@ -51,12 +52,17 @@ impl Stage {
             shader,
         );
 
-        Stage { pipeline, bindings }
+        Stage { pipeline, bindings, texture }
     }
 }
 
 impl EventHandler for Stage {
-    fn update(&mut self, _ctx: &mut Context) {}
+    fn update(&mut self, ctx: &mut Context) {
+        let t = date::now();
+        let bright = t.sin()*0.5+0.5;
+        let bytes = [(bright * 255.0) as u8; 512*512*4];
+        self.texture.update(ctx, &bytes)
+    }
 
     fn draw(&mut self, ctx: &mut Context) {
         ctx.begin_default_pass(Default::default());
-- 
cgit v1.2.3-70-g09d2