From 5e75c63e7b3cf40d5f3ea1348df90c36bea6e5e6 Mon Sep 17 00:00:00 2001
From: Leo Prikler <leo.prikler@student.tugraz.at>
Date: Tue, 23 Feb 2021 11:37:23 +0100
Subject: [PATCH] beatmap: implement advanced scoring system.

Early and late hits are now only awared a third of a point, just like in osu!
---
 include/beatmap/beatmap.h |  6 ++++++
 include/ui/score.h        |  3 +--
 lib/beatmap/helpers.cc    | 33 +++++++++++++++++++++++++++++++++
 lib/game/tty.cc           | 25 ++++++++-----------------
 lib/ui/score.cc           | 16 +++-------------
 5 files changed, 51 insertions(+), 32 deletions(-)

diff --git a/include/beatmap/beatmap.h b/include/beatmap/beatmap.h
index e552009..9844c36 100644
--- a/include/beatmap/beatmap.h
+++ b/include/beatmap/beatmap.h
@@ -946,6 +946,12 @@ int load_beatmap_headers(const char *path, oshu::beatmap *beatmap);
  */
 void destroy_beatmap(oshu::beatmap *beatmap);
 
+/**
+ * Return a numeric value between 0 (no hits) and 1 (perfect) based on the
+ * player's hit/miss ratio.
+ */
+double score(oshu::beatmap *beatmap);
+
 /** \} */
 
 }
diff --git a/include/ui/score.h b/include/ui/score.h
index b907e02..ce476ec 100644
--- a/include/ui/score.h
+++ b/include/ui/score.h
@@ -26,8 +26,7 @@ struct display;
 struct score_frame {
 	oshu::display *display;
 	oshu::beatmap *beatmap;
-	int good;
-	int bad;
+	double score;
 };
 
 /**
diff --git a/lib/beatmap/helpers.cc b/lib/beatmap/helpers.cc
index dc9185a..8e17739 100644
--- a/lib/beatmap/helpers.cc
+++ b/lib/beatmap/helpers.cc
@@ -7,6 +7,8 @@
  */
 
 #include "beatmap/beatmap.h"
+#include <assert.h>
+#include <limits>
 
 double oshu::hit_end_time(oshu::hit *hit)
 {
@@ -23,3 +25,34 @@ oshu::point oshu::end_point(oshu::hit *hit)
 	else
 		return hit->p;
 }
+
+double oshu::score(oshu::beatmap *beatmap)
+{
+	double score = 0, total = 0;
+	auto leniency = beatmap->difficulty.leniency;
+
+	for (oshu::hit *hit = beatmap->hits; hit; hit = hit->next) {
+		switch (hit->state) {
+		case oshu::GOOD_HIT:
+			if (hit->offset < - leniency / 2)
+				score += 1.0/3;
+			else if (hit->offset > leniency / 2)
+				score += 1.0/3;
+			else
+				score += 1.0;
+			[[fallthrough]];
+		case oshu::MISSED_HIT:
+			++total;
+			break;
+		}
+	}
+
+	score /= total;
+	if (total == 0) {
+		if (!std::isnan(score))
+			score = std::numeric_limits<double>::quiet_NaN();
+	}
+	else
+		assert ((0 <= score) && (score <= 1));
+	return score;
+}
diff --git a/lib/game/tty.cc b/lib/game/tty.cc
index 6f1ba20..34952bc 100644
--- a/lib/game/tty.cc
+++ b/lib/game/tty.cc
@@ -74,22 +74,13 @@ void oshu::congratulate(oshu::game_base *game)
 {
 	/* Clear the status line. */
 	printf("\r                                        \r");
-	/* Compute the score. */
-	int good = 0;
-	int missed = 0;
-	for (oshu::hit *hit = game->beatmap.hits; hit; hit = hit->next) {
-		if (hit->state == oshu::MISSED_HIT)
-			missed++;
-		else if (hit->state == oshu::GOOD_HIT)
-			good++;
-	}
-	double rate = (double) good / (good + missed);
+	double score = oshu::score(&game->beatmap);
+        if (std::isnan(score)) return;
+
+        int score_color = 0;
+        if (score >= 0.9) score_color = 32;
+        else if (score < 0.5) score_color = 31;
 	printf(
-		"  \033[1mScore:\033[0m\n"
-		"  \033[%dm%3d\033[0m good\n"
-		"  \033[%dm%3d\033[0m miss\n"
-		"\n",
-		rate >= 0.9 ? 32 : 0, good,
-		rate < 0.5  ? 31 : 0, missed
-	);
+		"  \033[1mScore: \033[%dm%3.2f\033[0m%%\n\n",
+		score_color, score * 100);
 }
diff --git a/lib/ui/score.cc b/lib/ui/score.cc
index ace2124..25ca5f0 100644
--- a/lib/ui/score.cc
+++ b/lib/ui/score.cc
@@ -17,23 +17,13 @@ int oshu::create_score_frame(oshu::display *display, oshu::beatmap *beatmap, osh
 	memset(frame, 0, sizeof(*frame));
 	frame->display = display;
 	frame->beatmap = beatmap;
-
-	for (oshu::hit *hit = beatmap->hits; hit; hit = hit->next) {
-		if (hit->state == oshu::MISSED_HIT)
-			++frame->bad;
-		else if (hit->state == oshu::GOOD_HIT)
-			++frame->good;
-	}
-
+	frame->score = oshu::score(beatmap);
 	return 0;
 }
 
 void oshu::show_score_frame(oshu::score_frame *frame, double opacity)
 {
-	int notes = frame->good + frame->bad;
-	if (notes == 0)
-		return;
-
+	if (std::isnan(frame->score)) return;
 	SDL_SetRenderDrawBlendMode(frame->display->renderer, SDL_BLENDMODE_BLEND);
 
 	SDL_Rect bar = {
@@ -46,7 +36,7 @@ void oshu::show_score_frame(oshu::score_frame *frame, double opacity)
 	SDL_Rect good = {
 		.x = bar.x,
 		.y = bar.y,
-		.w = (int) ((double) frame->good / notes * bar.w),
+		.w = (int) ((double) frame->score * bar.w),
 		.h = bar.h,
 	};
 	SDL_SetRenderDrawColor(frame->display->renderer, 0, 255, 0, 196 * opacity);