From b075a2f68ded65e3828d18e972e9a0fd0a24d596 Mon Sep 17 00:00:00 2001
From: Jamie Bray <jamie@jamiebray.xyz>
Date: Thu, 7 Oct 2021 00:05:01 +0800
Subject: [PATCH] 6.14ms -> 5.38 ms. Prefer logic benchmark speed over app
 speed.

---
 results/benchmark.txt |  4 ++--
 src/board/board.h     |  5 ++---
 src/board/next.cpp    | 19 ++++++-------------
 src/board/sdl.cpp     | 16 +++++++++++++++-
 4 files changed, 25 insertions(+), 19 deletions(-)

diff --git a/results/benchmark.txt b/results/benchmark.txt
index 520c08b..0cc2493 100644
--- a/results/benchmark.txt
+++ b/results/benchmark.txt
@@ -1,5 +1,5 @@
 ---------------------------------------------------------------------------------------------
 Benchmark                                                   Time             CPU   Iterations
 ---------------------------------------------------------------------------------------------
-BM_NextBoard/min_time:2.000/process_time/real_time       6.14 ms         24.0 ms          451
-BM_RenderBoard/process_time/real_time                    7.12 ms         6.97 ms           91
+BM_NextBoard/min_time:2.000/process_time/real_time       5.38 ms         20.6 ms          516
+BM_RenderBoard/process_time/real_time                    11.9 ms         11.9 ms           53
diff --git a/src/board/board.h b/src/board/board.h
index 7c61be0..b8f89ad 100644
--- a/src/board/board.h
+++ b/src/board/board.h
@@ -4,9 +4,8 @@
 #include <memory>
 #include <tuple>
 
-using Cell = unsigned int;  // Should match SDL::Uint32, otherwise the rendering
-                            // will not work as intended
-const Cell ALIVE = UINT32_MAX;  // Should match SDL::SDL_UINT32_MAX, "
+using Cell = unsigned int;
+const Cell ALIVE = 1;
 const Cell DEAD = 0;
 
 using Board = std::tuple<Cell*, unsigned int, unsigned int>;
diff --git a/src/board/next.cpp b/src/board/next.cpp
index 53876d6..c835272 100644
--- a/src/board/next.cpp
+++ b/src/board/next.cpp
@@ -19,10 +19,6 @@ void setThreads(unsigned int n) {
   THREAD_COUNT = std::max(n, (unsigned int)1);
 }
 
-inline const auto maxToOne(Cell n) {
-  return (1 - (n + 1));
-}
-
 void nextBoardSection(
     const unsigned int startY,
     const unsigned int endY,
@@ -38,7 +34,7 @@ void nextBoardSection(
   const auto endI = endY * width;
   for (unsigned int i = startY * width; i < endI; i++) {
     const unsigned int x = i % width;
-    auto currentStateBool = maxToOne(input[i]);
+    auto currentStateBool = input[i];
 
     // Slide neighbours
     if (x == 0) {
@@ -61,18 +57,15 @@ void nextBoardSection(
     if (neighbours[0] == UINT32_MAX) {
       const auto previousX = (x - 1 + width) % width;
 
-      neighbours[0] = maxToOne(input[yBelowBase + previousX]) +
-                      maxToOne(input[yBase + previousX]) +
-                      maxToOne(input[yAboveBase + previousX]);
+      neighbours[0] = input[yBelowBase + previousX] + input[yBase + previousX] +
+                      input[yAboveBase + previousX];
     }
     if (neighbours[1] == UINT32_MAX) {
-      neighbours[1] =
-          maxToOne(input[yBelowBase + x]) + maxToOne(input[yAboveBase + x]);
+      neighbours[1] = input[yBelowBase + x] + input[yAboveBase + x];
     }
     const auto nextX = (x + 1) % width;
-    neighbours[2] = maxToOne(input[yBelowBase + nextX]) +
-                    maxToOne(input[yBase + nextX]) +
-                    maxToOne(input[yAboveBase + nextX]);
+    neighbours[2] = input[yBelowBase + nextX] + input[yBase + nextX] +
+                    input[yAboveBase + nextX];
 
     // Compute new cell state
     const auto totalNeighbours = neighbours[0] + neighbours[1] + neighbours[2];
diff --git a/src/board/sdl.cpp b/src/board/sdl.cpp
index 318d57a..ffa2e19 100644
--- a/src/board/sdl.cpp
+++ b/src/board/sdl.cpp
@@ -1,5 +1,6 @@
 #include "sdl.h"
 #include <vector>
+#include <cstring>
 #include "../util/profile.h"
 #include "generate.h"
 
@@ -20,7 +21,18 @@ void renderBoardSdl(
     const Board board,
     SDL_Renderer* renderer,
     SDL_Texture* texture) {
-  const auto& [input, width, height] = board;
+  const auto& [rawInput, width, height] = board;
+  Cell* input = new Cell[width*height];
+
+  // I would LOVE it if someone could figure out how to create a "bool" pixel
+  // format to use with SDL. Then I wouldn't need to do this memcpy trash.
+  std::memcpy(input, rawInput, width*height*sizeof(Cell));
+
+  for (unsigned int i = 0; i < width * height; i ++) {
+    if (input[i] == ALIVE) {
+      input[i] = UINT32_MAX;
+    }
+  }
 
   static_assert(sizeof(input[0]) == sizeof(Uint32));
   SDL_UpdateTexture(
@@ -28,4 +40,6 @@ void renderBoardSdl(
 
   SDL_RenderCopy(renderer, texture, nullptr, nullptr);
   SDL_RenderPresent(renderer);
+
+  delete[] input;
 }