From 49cbd3fe075ee95fb02a8a564e0c1d89292477bd Mon Sep 17 00:00:00 2001
From: Emil Ernerfeldt <emilernerfeldt@gmail.com>
Date: Thu, 16 Apr 2020 23:10:05 +0200
Subject: [PATCH] Fix: properly sample white color (was off by half a texel)

---
 emigui/src/fonts.rs  | 10 +++++++---
 emigui/src/mesher.rs |  6 ++++--
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/emigui/src/fonts.rs b/emigui/src/fonts.rs
index b4813895..14435533 100644
--- a/emigui/src/fonts.rs
+++ b/emigui/src/fonts.rs
@@ -69,9 +69,13 @@ impl Fonts {
 
         let mut atlas = TextureAtlas::new(512, 8); // TODO: better default?
 
-        // Make one white pixel for use for various stuff:
-        let pos = atlas.allocate((1, 1));
-        atlas.texture_mut()[pos] = 255;
+        // Make the top left four pixels fully white:
+        let pos = atlas.allocate((2, 2));
+        assert_eq!(pos, (0, 0));
+        atlas.texture_mut()[(0, 0)] = 255;
+        atlas.texture_mut()[(0, 1)] = 255;
+        atlas.texture_mut()[(1, 0)] = 255;
+        atlas.texture_mut()[(1, 1)] = 255;
 
         let atlas = Arc::new(Mutex::new(atlas));
 
diff --git a/emigui/src/mesher.rs b/emigui/src/mesher.rs
index 5bd508c1..a5660880 100644
--- a/emigui/src/mesher.rs
+++ b/emigui/src/mesher.rs
@@ -8,6 +8,8 @@ use crate::{
     types::PaintCmd,
 };
 
+const WHITE_UV: (u16, u16) = (1, 1);
+
 #[derive(Clone, Copy, Debug, Default, Serialize)]
 pub struct Vertex {
     /// Pixel coordinates
@@ -146,7 +148,7 @@ impl Mesher {
         let n = points.len() as u32;
         let vert = |pos, color| Vertex {
             pos,
-            uv: (0, 0),
+            uv: WHITE_UV,
             color,
         };
         let mesh = &mut self.mesh;
@@ -192,7 +194,7 @@ impl Mesher {
 
         let vert = |pos, color| Vertex {
             pos,
-            uv: (0, 0),
+            uv: WHITE_UV,
             color,
         };
         let mesh = &mut self.mesh;