From ef88325fc85637b972cf52bf838c35076f6d3eb6 Mon Sep 17 00:00:00 2001
From: Paul Mathieu <paul@ponteilla.net>
Date: Tue, 18 Oct 2022 14:01:02 -0700
Subject: [PATCH] geometry: sample pixels from their centers

---
 geometry.js | 24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/geometry.js b/geometry.js
index d930c2a..9d0a067 100644
--- a/geometry.js
+++ b/geometry.js
@@ -1,18 +1,22 @@
 import { memoize } from "./memoize";
 
 function _makeTextureFace(texture) {
-    const textMul = 0.0625;
-    const textOff = texture.map(x => x * textMul);
+    const textureWidth = 16;
+    const texturesPerAtlas = 16; 
+    const textMul = 1 / texturesPerAtlas;
+    const halfPixel = 1 / texturesPerAtlas / textureWidth / 2;
+    const textOff = texture.map(x => x * textMul + halfPixel);
+    const a = textMul / textureWidth * (textureWidth - 1);
     const textuv = [
-        [0.99, 0.99],
-        [0.01, 0.99],
-        [0.01, 0.01],
-        [0.99, 0.99],
-        [0.01, 0.01],
-        [0.99, 0.01],
+        [1, 1],
+        [0, 1],
+        [0, 0],
+        [1, 1],
+        [0, 0],
+        [1, 0],
     ];
 
-    const textures = textuv.map(uv => uv.map((x, j) => textMul * x + textOff[j]));
+    const textures = textuv.map(uv => uv.map((x, j) => a * x + textOff[j]));
 
     return textures;
 }
@@ -124,4 +128,4 @@ export function makeBufferFromFaces(gl, faces) {
         numVertices,
         delete: () => gl.deleteBuffer(glBuffer),
     };
-}
\ No newline at end of file
+}