From 2abf3de6656b2ad1c1956a4124fbd04729bed48b Mon Sep 17 00:00:00 2001
From: Stephen Seo <seo.disparate@gmail.com>
Date: Thu, 28 Mar 2024 16:42:56 +0900
Subject: [PATCH] Vulkan compute: minor refactoring

---
 src/blue_noise.cpp | 16 ++++++++++------
 src/blue_noise.hpp |  2 +-
 2 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/src/blue_noise.cpp b/src/blue_noise.cpp
index 85a8bf2..618a24d 100644
--- a/src/blue_noise.cpp
+++ b/src/blue_noise.cpp
@@ -576,7 +576,7 @@ std::optional<std::pair<int, int>> dither::internal::vulkan_minmax(
     std::array<VkDescriptorSet, 2> minmax_desc_sets, VkBuffer max_in_buf,
     VkBuffer min_in_buf, VkBuffer max_out_buf, VkBuffer min_out_buf,
     VkBuffer state_buf, const int size, const float *const filter_mapped,
-    std::vector<bool> pbp) {
+    const std::vector<bool> &pbp) {
   // ensure minority pixel is "true"
   unsigned int count = 0;
   for (bool value : pbp) {
@@ -584,17 +584,21 @@ std::optional<std::pair<int, int>> dither::internal::vulkan_minmax(
       ++count;
     }
   }
+  bool flip;
   if (count * 2 >= pbp.size()) {
-    // std::cout << "MINMAX flip\n"; // DEBUG
-    for (unsigned int i = 0; i < pbp.size(); ++i) {
-      pbp[i] = !pbp[i];
-    }
+    flip = true;
+  } else {
+    flip = false;
   }
 
   std::vector<FloatAndIndex> fai(size);
   for (int i = 0; i < size; ++i) {
     fai[i].value = filter_mapped[i];
-    fai[i].pbp = pbp[i] ? 1 : 0;
+    if (flip) {
+      fai[i].pbp = pbp[i] ? 0 : 1;
+    } else {
+      fai[i].pbp = pbp[i] ? 1 : 0;
+    }
     fai[i].idx = i;
   }
 
diff --git a/src/blue_noise.hpp b/src/blue_noise.hpp
index 43f9f44..0a9f896 100644
--- a/src/blue_noise.hpp
+++ b/src/blue_noise.hpp
@@ -162,7 +162,7 @@ std::optional<std::pair<int, int>> vulkan_minmax(
     std::array<VkDescriptorSet, 2> minmax_desc_sets, VkBuffer max_in_buf,
     VkBuffer min_in_buf, VkBuffer max_out_buf, VkBuffer min_out_buf,
     VkBuffer state_buf, const int size, const float *const filter_mapped,
-    std::vector<bool> pbp);
+    const std::vector<bool> &pbp);
 
 #endif