web: implement difficulty abstraction for stdev

4 files changed, 59 insertions, 24 deletions

diff --git a/web/static/index.html b/web/static/index.html
index 2ed654b..472247d 100644
--- a/web/static/index.html
+++ b/web/static/index.html
@@ -17,7 +17,7 @@
 			<div id="titlebar">
 				<div>dartboat™</div>
 				<div title="Delay between computer's darts (ms)" class="input first"><label for="delay" class="icon">&#xf597;</label><input id="delay" data-opt="delay" maxlength="4" value=""></div>
-				<div title="Computer's accuracy (lower is more accurate)" class="input"><label for="stdev" class="icon">&#xf1de;</label><input id="stdev" data-opt="stdev" maxlength="4" value=""></div>
+				<div title="Difficulty (precision of computer's throws)" class="input"><label for="difficulty" class="icon">&#xf1de;</label><input id="difficulty" data-opt="difficulty" maxlength="2" value=""></div>
 				<div title="Toggle controls side" class="button icon" id="flip-controls-button">&#xf1c3;</div>
 				<div title="Help and info" class="button icon" data-modal="help-modal">&#xf50b;</div>
 			</div>
@@ -75,8 +75,8 @@
 				<h2>dartboat</h2>
 				<p>dartboat uses an internal representation of a specification dartboard. Darts are thrown following a normal distribution, with the resultant coordinates used to calculate the segments in which they land. The idea is that this provides a more realistic opponent than picking points at random.</p>
 				<h2>Settings</h2>
-				<p><span class="icon">&#xf597;</span> <em>(delay)</em> — milliseconds it takes the computer to throw each dart.</p>
-				<p><span class="icon">&#xf1de;</span> <em>(stdev)</em> — the standard deviation of the computer's throws in millimetres. A value of 24 translates to a three-dart average of roughly 35. A value of 13 would be a 65 average, and a value of 8 a 95 average.</p>
+				<p><span class="icon">&#xf597;</span> <em>(delay: 0-9999)</em> — milliseconds it takes the computer to throw each dart.</p>
+				<p><span class="icon">&#xf1de;</span> <em>(difficulty: 0-99)</em> — precision of the computer's throws. Starting with a three-dart average of 10 points at difficulty 0, every difficulty increase of 8 corresponds to an average points increase of 10, e.g. difficulty 32 would be a 50-point average. (The rate of increase quickly increases upon reaching an average of 120 points.)</em></p>
 				<h2>Interface</h2>
 				<p>To avoid destructive actions being a misclick away, certain actions require two presses—one to activate the button and another to trigger it.</p>
 				<p>The controls are designed to be keyboard-friendly. The keys should be fairly intuitive for the most part.</p>
diff --git a/web/static/style.css b/web/static/style.css
index 852cffd..f0f4b2f 100644
--- a/web/static/style.css
+++ b/web/static/style.css
@@ -144,6 +144,10 @@ body {
 	border: 0;
 }
 
+#titlebar input#difficulty {
+	width: 2ch;
+}
+
 #titlebar div.button {
 	background-color: #3d2466;
 	font-weight: 700;
diff --git a/web/static/sw.js b/web/static/sw.js
index bf1d818..7576286 100644
--- a/web/static/sw.js
+++ b/web/static/sw.js
@@ -1,5 +1,5 @@
 const CACHE_PREFIX = 'dartboat-'
-const CACHE_VERSION = '5';
+const CACHE_VERSION = '6';
 const CACHE_NAME = `${CACHE_PREFIX}${CACHE_VERSION}`;
 
 const CACHE_FILES = [
diff --git a/web/web_opts.c b/web/web_opts.c
index 553e05d..e1c5eb5 100644
--- a/web/web_opts.c
+++ b/web/web_opts.c
@@ -13,17 +13,53 @@
 #define PREFIX "dartboat_"
 
 int delay_ms = 1000;
+static int difficulty = 32;
+
+struct { int diff; double stdev; } DIFF_PRESETS[] = {
+	{ 0, 66.80}, // 10
+	{ 8, 40.24}, // 20
+	{16, 28.14}, // 30
+	{24, 21.35}, // 40
+	{32, 17.20}, // 50
+	{40, 14.34}, // 60
+	{48, 12.15}, // 70
+	{56, 10.36}, // 80
+	{64,  8.83}, // 90
+	{72,  7.48}, // 100
+	{80,  6.32}, // 110
+	{88,  5.34}, // 120
+	{99,  0.00}, // 167
+};
+#define NUM_DIFF_PRESETS (sizeof(DIFF_PRESETS) / sizeof(*DIFF_PRESETS))
 
 void set_delay(char *val)
 {
 	delay_ms = atoi(val);
 }
 
-void set_stdev(char *val)
+void set_stdev(int diff)
 {
-	double stdev = strtod(val, NULL);
-	if (isfinite(stdev))
-		horizontal_stdev = vertical_stdev = stdev;
+	if (diff < DIFF_PRESETS[0].diff)
+		diff = DIFF_PRESETS[0].diff;
+	else if (diff > DIFF_PRESETS[NUM_DIFF_PRESETS - 1].diff)
+		diff = DIFF_PRESETS[NUM_DIFF_PRESETS - 1].diff;
+
+	size_t ind = 1;
+	while (ind < NUM_DIFF_PRESETS - 1 && DIFF_PRESETS[ind].diff <= diff)
+		ind++;
+
+	double step = (DIFF_PRESETS[ind - 1].stdev - DIFF_PRESETS[ind].stdev) /
+		(DIFF_PRESETS[ind].diff - DIFF_PRESETS[ind - 1].diff);
+	horizontal_stdev = vertical_stdev = DIFF_PRESETS[ind - 1].stdev -
+		((diff - DIFF_PRESETS[ind - 1].diff) * step);
+}
+
+void set_difficulty(char *val)
+{
+	int diff = atoi(val);
+	difficulty = diff < 0 ? 0 : diff > 99 ? 99 : diff;
+
+	set_stdev(difficulty);
 }
 
 char *prefix_opt(char *opt)
@@ -53,34 +89,29 @@ void read_delay()
 	free(val);
 }
 
-void read_stdev()
+void read_difficulty()
 {
-	char *val = read_opt("stdev");
+	char *val = read_opt("difficulty");
 	if (!val) return;
 
-	set_stdev(val);
+	set_difficulty(val);
 	free(val);
 }
 
 void opts_init()
 {
+	// TODO call only when no stored diff setting
+	set_stdev(difficulty);
+
 	read_delay();
-	read_stdev();
+	read_difficulty();
 
 	char buf[64];
 	sprintf(buf, "%d", delay_ms);
 	dom_set_value("#delay", buf);
 
-	int len = sprintf(buf, "%4.2f", horizontal_stdev);
-	char *dot = strchr(buf, '.');
-	if (dot) {
-		for (char *ptr = buf + len - 1; ptr >= dot; --ptr) {
-			if (*ptr != '0' && *ptr != '.')
-				break;
-			*ptr = 0;
-		}
-	}
-	dom_set_value("#stdev", buf);
+	sprintf(buf, "%d", difficulty);
+	dom_set_value("#difficulty", buf);
 }
 
 void store_opt(char *opt, char  *val)
@@ -95,8 +126,8 @@ void set_opt(char *opt, char *val)
 {
 	if (!strcmp(opt, "delay"))
 		set_delay(val);
-	else if (!strcmp(opt, "stdev"))
-		set_stdev(val);
+	else if (!strcmp(opt, "difficulty"))
+		set_difficulty(val);
 	else
 		return;