From f463db316fc9eae9f26a83605d1c05f662b6e7de Mon Sep 17 00:00:00 2001
From: Roz K <roz@rozk.net>
Date: Wed, 4 Jan 2023 15:24:18 +0100
Subject: [PATCH] Fix signed integers normalisation.

---
 cpp/render/render_opengles.cpp | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/cpp/render/render_opengles.cpp b/cpp/render/render_opengles.cpp
index 39c87c3..a31fc23 100644
--- a/cpp/render/render_opengles.cpp
+++ b/cpp/render/render_opengles.cpp
@@ -421,6 +421,12 @@ static void rk_buckets_alloc(
     }
 }
 
+#define rk_pack_short_norm(_f) (static_cast<rk_int>((_f) * 32767.f) & 65536)
+// #define rk_pack_short_norm(_f) (((static_cast<rk_int>((_f) * 32767.f) - 1) / 2) & 65535)
+
+#define rk_pack_int10_norm(_f) (static_cast<rk_int>((_f) * 511.f) & 1023)
+// #define rk_pack_int10_norm(_f) (((static_cast<rk_int>((_f) * 1023.f) - 1) / 2) & 1023)
+
 static void rk_pack_vec3_float(
     unsigned const count,
     rk_instance_index const * const __restrict indices,
@@ -459,7 +465,7 @@ static void rk_pack_vec3_short_norm(
     rk_instance_index const * const last_index = indices + count;
     rk_vec3_short * __restrict dst = reinterpret_cast<rk_vec3_short *>(_dst);
     rk_vec3_float const * const __restrict src = reinterpret_cast<rk_vec3_float const *>(_src);
-    #define _convert(s) (static_cast<rk_short>((s) * ((s) < 0.f ? 32768.f : 32767.f)))
+    #define _convert(s) rk_pack_short_norm(s)
     for (rk_instance_index const * __restrict index = indices; index < last_index; ++index, ++dst) {
         rk_vec3_float const & input = src[*index];
         dst->x = _convert(input.x);
@@ -494,7 +500,7 @@ static void rk_pack_vec3_int10_norm(
     rk_instance_index const * const last_index = indices + count;
     rk_vec3_int10 * __restrict dst = reinterpret_cast<rk_vec3_int10 *>(_dst);
     rk_vec3_float const * const __restrict src = reinterpret_cast<rk_vec3_float const *>(_src);
-    #define _convert(s) (static_cast<rk_int>((s) * ((s) < 0.f ? 512.f : 511.f)) & 1023)
+    #define _convert(s) rk_pack_int10_norm(s)
     for (rk_instance_index const * __restrict index = indices; index < last_index; ++index, ++dst) {
         rk_vec3_float const & input = src[*index];
         *dst = _convert(input.x) | (_convert(input.y) << 10) | (_convert(input.z) << 20);
@@ -542,7 +548,7 @@ static void rk_pack_mat3_int10_norm(
     rk_instance_index const * const last_index = indices + count;
     rk_mat3_int10 * __restrict dst = reinterpret_cast<rk_mat3_int10 *>(_dst);
     rk_mat3_float const * const __restrict src = reinterpret_cast<rk_mat3_float const *>(_src);
-    #define _convert(s) (static_cast<rk_int>((s) * ((s) < 0.f ? 512.f : 511.f)) & 1023)
+    #define _convert(s) rk_pack_int10_norm(s)
     for (rk_instance_index const * __restrict index = indices; index < last_index; ++index, ++dst) {
         rk_mat3_float const & input = src[*index];
         dst->x = _convert(input.x.x) | (_convert(input.x.y) << 10) | (_convert(input.x.z) << 20);