From bde5939b2f1eb5c04c1ab429a79fa799c3bfee28 Mon Sep 17 00:00:00 2001
From: Stanislaw Halik <sthalik@misaki.pl>
Date: Mon, 26 Feb 2024 18:46:21 +0100
Subject: implement printing fractions for corrade's Debug{}

---
 compat/debug.cpp     | 16 ++++++++++++++++
 compat/debug.hpp     | 12 ++++++++++++
 src/chunk-region.cpp |  5 ++---
 3 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/compat/debug.cpp b/compat/debug.cpp
index 0a77d298..0c7a6fd1 100644
--- a/compat/debug.cpp
+++ b/compat/debug.cpp
@@ -1,11 +1,16 @@
 #include "debug.hpp"
 #include "compat/strerror.hpp"
 #include <cerrno>
+#include <cstdio>
 #include <Corrade/Containers/StringView.h>
 
 // Error{} << "error" << colon() << "can't open file" << colon() << quoted("foo") << error_string(EINVAL);
 // ===> "error: can't open file 'foo': Invalid argument"
 
+#ifdef __clang__
+#pragma clang diagnostic ignored "-Wformat-nonliteral"
+#endif
+
 namespace floormat::detail::corrade_debug {
 
 Debug& operator<<(Debug& dbg, Colon box)
@@ -46,6 +51,15 @@ Debug& quoted_end(Debug& dbg, Debug::Flags flags, char c)
 
 template struct Quoted<StringView>;
 
+Debug& operator<<(Debug& dbg, Fraction f)
+{
+    char fmt[8], buf[56];
+    std::snprintf(fmt, sizeof fmt, "%%.%hhuf", f.decimal_points);
+    std::snprintf(buf, sizeof buf, fmt, (double)f.value);
+    dbg << buf;
+    return dbg;
+}
+
 } // namespace floormat::detail::corrade_debug
 
 namespace floormat {
@@ -56,4 +70,6 @@ Colon colon(char c) { return Colon{c}; }
 ErrorString error_string(int error) { return { error }; }
 ErrorString error_string() { return { errno }; }
 
+Fraction fraction(float value, uint8_t decimal_points) { return Fraction { value, decimal_points }; }
+
 } // namespace floormat
diff --git a/compat/debug.hpp b/compat/debug.hpp
index cb36e612..1fdd9a7e 100644
--- a/compat/debug.hpp
+++ b/compat/debug.hpp
@@ -40,6 +40,16 @@ template<typename T> Debug& operator<<(Debug& dbg, Quoted<T> box)
     return quoted_end(dbg, flags, box.c);
 }
 
+// ***** float *****
+
+struct Fraction
+{
+    float value;
+    uint8_t decimal_points;
+};
+
+Debug& operator<<(Debug& dbg, Fraction frac);
+
 } // namespace floormat::detail::corrade_debug
 
 // ***** api *****
@@ -52,6 +62,8 @@ floormat::detail::corrade_debug::Colon colon(char c = ':');
 floormat::detail::corrade_debug::ErrorString error_string(int error);
 floormat::detail::corrade_debug::ErrorString error_string();
 
+floormat::detail::corrade_debug::Fraction fraction(float value, uint8_t decimal_points = 1);
+
 template<DebugPrintable T>
 auto quoted(T&& value, char c = '\'')
 {
diff --git a/src/chunk-region.cpp b/src/chunk-region.cpp
index 0006285d..5b15b7e2 100644
--- a/src/chunk-region.cpp
+++ b/src/chunk-region.cpp
@@ -3,6 +3,7 @@
 #include "world.hpp"
 #include "collision.hpp"
 #include "object.hpp"
+#include "compat/debug.hpp"
 #include "compat/function2.hpp"
 #include <bit>
 #include <array>
@@ -183,9 +184,7 @@ auto chunk::make_pass_region(const pred& f, bool debug) -> pass_region
     if (debug) [[unlikely]]
     {
         const auto time = timeline.currentFrameTime();
-        char buf[32];
-        std::snprintf(buf, sizeof buf, "%.3f", 1e3*(double)time);
-        DBG_nospace << "region: generating for " << _coord << " took " << buf << " ms";
+        DBG_nospace << "region: generating for " << _coord << " took " << fraction(1e3f*time, 3) << " ms";
     }
 
     return ret;
-- 
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