3 files changed, 58 insertions, 0 deletions
diff --git a/test/app.hpp b/test/app.hpp
index b3787826..894401c8 100644
--- a/test/app.hpp
+++ b/test/app.hpp
@@ -29,5 +29,6 @@ struct test_app final : private FM_APPLICATION
     static void test_serializer();
     static void test_entity();
     static void test_loader();
+    static void test_bitmask();
 };
 } // namespace floormat
diff --git a/test/bitmask.cpp b/test/bitmask.cpp
new file mode 100644
index 00000000..f7d12dc2
--- /dev/null
+++ b/test/bitmask.cpp
@@ -0,0 +1,56 @@
+#include "app.hpp"
+#include "compat/assert.hpp"
+#include "src/anim-atlas.hpp"
+#include <Magnum/Magnum.h>
+#include <Magnum/Math/Vector4.h>
+#include <Magnum/ImageView.h>
+#include <Magnum/Image.h>
+#include <Corrade/Containers/ArrayView.h>
+#include <Magnum/PixelFormat.h>
+#include <iterator>
+
+namespace floormat {
+
+namespace {
+
+constexpr Vector4ub
+    red(0xff, 0x00, 0x00, 0x20), green(0x00, 0x00, 0xff, 0x20), blue(0xff, 0x00, 0x00, 0x20),
+    red0(0xff, 0x00, 0x00, 0x1f), green0(0x00, 0x00, 0xff, 0x1f), blue0(0xff, 0x00, 0x00, 0x1f),
+    none0(0xff, 0xff, 0xff, 0x1f), white(0xff, 0xff, 0xff, 0xff);
+
+constexpr Vector4ub img_data[] = {
+    red,   green0, blue0, white,
+    red0,  green,  blue,  none0,
+    none0, green,  blue0, blue,
+    red0,  green0, blue,  green,
+    red,   green,  blue,  none0,
+    red,   green0, blue0, red,
+};
+
+constexpr bool result[] = {
+    // inverse row order, use tac(1)
+    true,  false, false, true,
+    true,  true,  true,  false,
+    false, false, true,  true,
+    false, true,  false, true,
+    false, true,  true,  false,
+    true,  false, false, true,
+
+};
+
+} // namespace
+
+void test_app::test_bitmask()
+{
+    constexpr auto size = std::size(img_data), width = 4_uz, height = size/4;
+    static_assert(size % 4 == 0);
+    static_assert(size == std::size(result));
+    ImageView2D img{PixelFormat::RGBA8Unorm, {width, height}, img_data};
+    auto bitmask = anim_atlas::make_bitmask(img);
+    fm_assert(img.size().product() == std::size(result));
+    for (auto i = 0_uz; i < size; i++)
+        if (bitmask[i] != result[i])
+            fm_abort("wrong value at bit %zu, should be %s", i, result[i] ? "true" : "false");
+}
+
+} // namespace floormat
diff --git a/test/main.cpp b/test/main.cpp
index c01f09f0..2187ba21 100644
--- a/test/main.cpp
+++ b/test/main.cpp
@@ -25,6 +25,7 @@ int test_app::exec()
     test_serializer();
     test_entity();
     test_loader();
+    test_bitmask();
     return 0;
 }