From 717433e2aab78c9804a634e824c4ca17574cdb5f Mon Sep 17 00:00:00 2001
From: Stanislaw Halik <sthalik@misaki.pl>
Date: Mon, 27 Feb 2023 12:23:38 +0100
Subject: test: add bitmask benchmark

---
 src/anim-atlas.cpp | 14 ++++++++++----
 src/anim-atlas.hpp |  1 +
 test/bitmask.cpp   | 37 ++++++++++++++++++++++++++++++++-----
 3 files changed, 43 insertions(+), 9 deletions(-)

diff --git a/src/anim-atlas.cpp b/src/anim-atlas.cpp
index ffade2d6..c6193b5b 100644
--- a/src/anim-atlas.cpp
+++ b/src/anim-atlas.cpp
@@ -127,15 +127,14 @@ auto anim_atlas::frame_quad(const Vector3& center, rotation r, std::size_t i) co
     }};
 }
 
-BitArray anim_atlas::make_bitmask(const ImageView2D& tex)
+void anim_atlas::make_bitmask_(const ImageView2D& tex, BitArray& array)
 {
     const auto pixels = tex.pixels();
     const auto size   = pixels.size();
-    const auto width = size[1], height = size[0], dest_len = width*height,
+    const auto width = size[1], height = size[0],
                stride = (std::size_t)pixels.stride()[0], width0 = width & ~7u;
     const auto* const data = (const unsigned char*)pixels.data();
-    auto* const dest = new unsigned char[(dest_len+7)>>3];
-    auto array = BitArray{dest, 0, dest_len, {}};
+    auto* const dest = (unsigned char*)array.data();
 
     fm_assert(tex.pixelSize() == 4);
     fm_assert(pixels.stride()[1] == 4);
@@ -165,6 +164,13 @@ BitArray anim_atlas::make_bitmask(const ImageView2D& tex)
             array.set((height-j-1)*width + i, alpha >= amin);
         }
     }
+}
+
+BitArray anim_atlas::make_bitmask(const ImageView2D& tex)
+{
+    const auto size = tex.pixels().size();
+    auto array = BitArray{NoInit, size[0]*size[1]};
+    make_bitmask_(tex, array);
     return array;
 }
 
diff --git a/src/anim-atlas.hpp b/src/anim-atlas.hpp
index eaddef21..e5446c82 100644
--- a/src/anim-atlas.hpp
+++ b/src/anim-atlas.hpp
@@ -48,6 +48,7 @@ struct anim_atlas final
 
     fm_DECLARE_DELETED_COPY_ASSIGNMENT(anim_atlas);
 
+    static void make_bitmask_(const ImageView2D& tex, BitArray& array);
     static BitArray make_bitmask(const ImageView2D& tex);
 
 private:
diff --git a/test/bitmask.cpp b/test/bitmask.cpp
index f7d12dc2..4deeca6e 100644
--- a/test/bitmask.cpp
+++ b/test/bitmask.cpp
@@ -1,13 +1,15 @@
 #include "app.hpp"
 #include "compat/assert.hpp"
 #include "src/anim-atlas.hpp"
+#include "loader/loader.hpp"
+#include <iterator>
+#include <Corrade/Containers/ArrayView.h>
 #include <Magnum/Magnum.h>
 #include <Magnum/Math/Vector4.h>
+#include <Magnum/Trade/ImageData.h>
 #include <Magnum/ImageView.h>
-#include <Magnum/Image.h>
-#include <Corrade/Containers/ArrayView.h>
 #include <Magnum/PixelFormat.h>
-#include <iterator>
+#include <chrono>
 
 namespace floormat {
 
@@ -38,9 +40,26 @@ constexpr bool result[] = {
 
 };
 
-} // namespace
+[[maybe_unused]] void bitmask_benchmark()
+{
+    std::chrono::high_resolution_clock clock;
+    auto img = loader.texture(loader.SCENERY_PATH, "door-close"_s);
+    auto bitmask = anim_atlas::make_bitmask(img);
+    constexpr int runs = 10, warmup = 100, cycles = 1000;
+    for (int i = 0; i < runs; i++)
+    {
+        for (int i = 0; i < warmup; i++)
+            anim_atlas::make_bitmask_(img, bitmask);
+        auto time0 = clock.now();
+        for (int i = 0; i < cycles; i++)
+            (void)anim_atlas::make_bitmask_(img, bitmask);
+        std::chrono::duration<double, std::milli> time = clock.now() - time0;
 
-void test_app::test_bitmask()
+        fm_log("[BENCH] bitmask %d/%d took %.1f ms", i, runs, time.count());
+    }
+}
+
+void bitmask_test()
 {
     constexpr auto size = std::size(img_data), width = 4_uz, height = size/4;
     static_assert(size % 4 == 0);
@@ -53,4 +72,12 @@ void test_app::test_bitmask()
             fm_abort("wrong value at bit %zu, should be %s", i, result[i] ? "true" : "false");
 }
 
+} // namespace
+
+void test_app::test_bitmask()
+{
+    bitmask_test();
+    //bitmask_benchmark();
+}
+
 } // namespace floormat
-- 
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