From f7909cac2884683c0bfe6fbb0e50375a1f79f615 Mon Sep 17 00:00:00 2001
From: staphen <staphen@gmail.com>
Date: Mon, 30 Jun 2025 21:57:12 -0400
Subject: [PATCH] Add benchmark for Lightmap::build()

---
 Source/levels/gendung.h                       |   2 +-
 test/CMakeLists.txt                           |   2 +
 .../light_render_benchmark/dLight.dmp         | Bin 0 -> 12544 bytes
 test/light_render_benchmark.cpp               |  64 ++++++++++++++++++
 4 files changed, 67 insertions(+), 1 deletion(-)
 create mode 100644 test/fixtures/light_render_benchmark/dLight.dmp
 create mode 100644 test/light_render_benchmark.cpp

diff --git a/Source/levels/gendung.h b/Source/levels/gendung.h
index d8ad32b3f..15c5401b2 100644
--- a/Source/levels/gendung.h
+++ b/Source/levels/gendung.h
@@ -181,7 +181,7 @@ extern DVL_API_FOR_TEST MICROS DPieceMicros[MAXTILES];
 /** Specifies the transparency at each coordinate of the map. */
 extern DVL_API_FOR_TEST int8_t dTransVal[MAXDUNX][MAXDUNY];
 /** Current realtime lighting. Per tile. */
-extern uint8_t dLight[MAXDUNX][MAXDUNY];
+extern DVL_API_FOR_TEST uint8_t dLight[MAXDUNX][MAXDUNY];
 /** Precalculated static lights. dLight uses this as a base before applying lights. Per tile. */
 extern uint8_t dPreLight[MAXDUNX][MAXDUNY];
 /** Holds various information about dungeon tiles, @see DungeonFlag */
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index cfbc160ce..4d72e5921 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -59,6 +59,7 @@ set(benchmarks
   clx_render_benchmark
   crawl_benchmark
   dun_render_benchmark
+  light_render_benchmark
   palette_blending_benchmark
   path_benchmark
 )
@@ -106,6 +107,7 @@ target_link_dependencies(dun_render_benchmark PRIVATE libdevilutionx_so)
 target_link_dependencies(file_util_test PRIVATE libdevilutionx_file_util app_fatal_for_testing)
 target_link_dependencies(format_int_test PRIVATE libdevilutionx_format_int language_for_testing)
 target_link_dependencies(ini_test PRIVATE libdevilutionx_ini app_fatal_for_testing)
+target_link_dependencies(light_render_benchmark PRIVATE libdevilutionx_so)
 target_link_dependencies(palette_blending_test PRIVATE libdevilutionx_palette_blending DevilutionX::SDL libdevilutionx_strings GTest::gmock app_fatal_for_testing)
 target_link_dependencies(palette_blending_benchmark PRIVATE libdevilutionx_palette_blending DevilutionX::SDL app_fatal_for_testing)
 target_link_dependencies(parse_int_test PRIVATE libdevilutionx_parse_int)
diff --git a/test/fixtures/light_render_benchmark/dLight.dmp b/test/fixtures/light_render_benchmark/dLight.dmp
new file mode 100644
index 0000000000000000000000000000000000000000..31879837edc83e362bde0917f0a4081974594cf9
GIT binary patch
literal 12544
zcmeHMiIRgL46RiwqT>Jm?Is*bs9G<wv)y!Nr|Ke)_i_<Bj`9%&L;+Di6c7det^#Jj
zkKrO<hE8kUaRHh^w@Rs2GXV}=+thX4wB5j>=%7_ymSwFpBi@4<Px#&DOWgj+9e*Qp
zei;FfHGkgb2}=_(b78g>w=Z(Xn$&_NpFaQ0>iNC34x*29ui~SRZ7&wFW7*vPv*>fB
z;&bUcT~cWD`BL$*bvR#Ai2XvTaIM2S%P{UldlC63ZdzO@y4GQxWf*s&y@-}-FKydk
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zQ$se(054pypNBJM==;$0S<BG|Ffuc|LGQwf4}2pUH0+^Jpl60_*Kj6`2-^cVVW{c5
zPPfPl3q{w1MQH<{S}e9^m}LJq&;vNt;K$*CzT|)+*mkn#{>c|cdbk(F`O5?P1|l56
zr2G~p+5ZUWA-h*yRh0wm;T(i8OzgLR?xm4nJ#ZC(gSbOLv>*r?Taex@O>*EF;z2s8
z%4hKez(yfn!icavF!$2X39on*GhT>Be*|;QBMIz;NBH?{bB{;9;l0`KR*xib;E9oc
zg85nv{+Za1zH#wxjz4#31_|bRj@($&lwVxsLwcB$Nru^Y{rJDYV{HEPHLtf@-y1zL
zT@etB>qGuiR$KotXR|dDpq}N(aA@rfWq{=Ro-;MU`TNun9crjV=jUB{Gfn*tKHrZ4
zNh0y^`TQnHlpa3cj{(Wn#KY%1EKm8lI+X8#<hS{`oo+_^(XDiL|KyIpw?daWzkJtO
f{7Mp)$D)8JAPR^AqJStM3Wx%tfG8jeuq*HbtYy5+

literal 0
HcmV?d00001

diff --git a/test/light_render_benchmark.cpp b/test/light_render_benchmark.cpp
new file mode 100644
index 000000000..7d7720bbd
--- /dev/null
+++ b/test/light_render_benchmark.cpp
@@ -0,0 +1,64 @@
+#include <cstddef>
+
+#include <benchmark/benchmark.h>
+
+#include "engine/render/light_render.hpp"
+#include "engine/surface.hpp"
+#include "lighting.h"
+#include "utils/log.hpp"
+#include "utils/paths.h"
+#include "utils/sdl_wrap.h"
+
+namespace devilution {
+namespace {
+
+void BM_BuildLightmap(benchmark::State &state)
+{
+	std::string benchmarkDataPath = paths::BasePath() + "test/fixtures/light_render_benchmark/dLight.dmp";
+	FILE *lightFile = std::fopen(benchmarkDataPath.c_str(), "rb");
+	if (lightFile != nullptr) {
+		std::fread(&dLight[0][0], sizeof(uint8_t), MAXDUNX * MAXDUNY, lightFile);
+		std::fclose(lightFile);
+	}
+
+	SDLSurfaceUniquePtr sdl_surface = SDLWrap::CreateRGBSurfaceWithFormat(
+	    /*flags=*/0, /*width=*/640, /*height=*/480, /*depth=*/8, SDL_PIXELFORMAT_INDEX8);
+	if (sdl_surface == nullptr) {
+		LogError("Failed to create SDL Surface: {}", SDL_GetError());
+		exit(1);
+	}
+	Surface out = Surface(sdl_surface.get());
+
+	Point tilePosition { 48, 44 };
+	Point targetBufferPosition { 0, -17 };
+	int viewportWidth = 640;
+	int viewportHeight = 352;
+	int rows = 25;
+	int columns = 10;
+	const uint8_t *outBuffer = out.at(0, 0);
+	uint16_t outPitch = out.pitch();
+	const uint8_t *lightTables = LightTables[0].data();
+	size_t lightTableSize = LightTables[0].size();
+
+	size_t numViewportTiles = rows * columns;
+	size_t numPixels = viewportWidth * viewportHeight;
+	size_t numBytesProcessed = 0;
+	size_t numItemsProcessed = 0;
+	for (auto _ : state) {
+		Lightmap lightmap = Lightmap::build(tilePosition, targetBufferPosition,
+		    viewportWidth, viewportHeight, rows, columns,
+		    outBuffer, outPitch, lightTables, lightTableSize);
+
+		uint8_t lightLevel = *lightmap.getLightingAt(outBuffer + outPitch * 120 + 120);
+		benchmark::DoNotOptimize(lightLevel);
+		numItemsProcessed += numViewportTiles;
+		numBytesProcessed += numPixels;
+	}
+	state.SetBytesProcessed(numBytesProcessed);
+	state.SetItemsProcessed(numItemsProcessed);
+}
+
+BENCHMARK(BM_BuildLightmap);
+
+} // namespace
+} // namespace devilution