From 57844df7fc9e24a9e433899b981e36613b2bbe4e Mon Sep 17 00:00:00 2001
From: profi200 <fd3194@gmx.de>
Date: Sat, 28 Nov 2020 17:18:58 +0100
Subject: [PATCH] Added some filter options to the config.

---
 include/util.h      | 10 ++++++++
 source/arm11/main.c | 56 ++++++++++++++++++++++++++++++---------------
 source/util.c       | 29 +++++++++++++++++++++++
 3 files changed, 77 insertions(+), 18 deletions(-)

diff --git a/include/util.h b/include/util.h
index 16809cd..172be90 100644
--- a/include/util.h
+++ b/include/util.h
@@ -47,6 +47,16 @@ NAKED void wait_cycles(u32 cycles);
  */
 size_t safeStrcpy(char *const dst, const char *const src, size_t num);
 
+/**
+ * @brief      Basic string to float conversion.
+ *             Limited to 6 after-decimal digits.
+ *
+ * @param[in]  str   The string.
+ *
+ * @return     The floatingpoint number represented by str.
+ */
+float str2float(const char *str);
+
 // case insensitive string compare function
 int strnicmp(const char *str1, const char *str2, u32 len);
 
diff --git a/source/arm11/main.c b/source/arm11/main.c
index 0c44782..9fc5456 100644
--- a/source/arm11/main.c
+++ b/source/arm11/main.c
@@ -45,9 +45,14 @@
 
 #define OAF_WORK_DIR    "sdmc:/3ds/open_agb_firm"
 #define INI_BUF_SIZE    (1024u)
-#define DEFAULT_CONFIG  "[general]\n"      \
-                        "backlight=32\n"   \
-                        "biosIntro=true\n"
+#define DEFAULT_CONFIG  "[general]\n"        \
+                        "backlight=40\n"     \
+                        "biosIntro=true\n\n" \
+                        "[video]\n"          \
+                        "inGamma=4.0\n"      \
+                        "outGamma=2.8\n"     \
+                        "contrast=1.0\n"     \
+                        "brightness=0.0\n"
 
 
 typedef struct
@@ -57,7 +62,10 @@ typedef struct
 	bool biosIntro;
 
 	// [video]
-	// TODO
+	float inGamma;
+	float outGamma;
+	float contrast;
+	float brightness;
 
 	// [audio]
 	// Maybe?
@@ -65,7 +73,15 @@ typedef struct
 	// [input]
 	// TODO
 } OafConfig;
-static OafConfig g_oafConfig = {32, true};
+static OafConfig g_oafConfig =
+{
+	40,
+	true,
+	4.0f,
+	2.8f,
+	1.0f,
+	0.0f
+};
 
 
 
@@ -400,20 +416,16 @@ end:
 
 static void adjustGammaTableForGba(void)
 {
-	const double inGamma = 4.0;
-	const double outGamma = 2.2;
-	//const double contrast = .74851331406341291833644689906823; // GBA
-	//const double brightness = .25148668593658708166355310093177; // GBA
-	const double contrast = 1.0; // No-op
-	const double brightness = 0.0; // No-op
-	//REG_LCD_PDC0_GTBL_IDX = 0;
+	const float inGamma = g_oafConfig.inGamma;
+	const float outGamma = g_oafConfig.outGamma;
+	const float contrast = g_oafConfig.contrast;
+	const float brightness = g_oafConfig.brightness;
 	for(u32 i = 0; i < 256; i++)
 	{
 		// Credits for this algo go to Extrems.
-		// Originally from Game Boy Interface Standard Edition for the Game Cube.
-		//const u32 x = (i & ~7u) | i>>5;
-		u32 res = pow(pow(contrast, inGamma) * pow((double)i / 255.0f + brightness / contrast, inGamma),
-		              1.0 / outGamma) * 255.0f;
+		// Originally from Game Boy Interface Standard Edition for the GameCube.
+		u32 res = powf(powf(contrast, inGamma) * powf((float)i / 255.0f + brightness / contrast, inGamma),
+		              1.0f / outGamma) * 255.0f;
 		if(res > 255) res = 255;
 
 		// Same adjustment for red/green/blue.
@@ -529,10 +541,18 @@ static int confIniCallback(void* user, const char* section, const char* name, co
 		else if(strcmp(name, "biosIntro") == 0)
 			config->biosIntro = (strcmp(value, "true") == 0 ? true : false);
 	}
-	/*else if(strcmp(section, "video") == 0)
+	else if(strcmp(section, "video") == 0)
 	{
+		if(strcmp(name, "inGamma") == 0)
+			config->inGamma = str2float(value);
+		else if(strcmp(name, "outGamma") == 0)
+			config->outGamma = str2float(value);
+		else if(strcmp(name, "contrast") == 0)
+			config->contrast = str2float(value);
+		else if(strcmp(name, "brightness") == 0)
+			config->brightness = str2float(value);
 	}
-	else if(strcmp(section, "audio") == 0)
+	/*else if(strcmp(section, "audio") == 0)
 	{
 	}
 	else if(strcmp(section, "input") == 0)
diff --git a/source/util.c b/source/util.c
index a2df853..6864372 100644
--- a/source/util.c
+++ b/source/util.c
@@ -51,6 +51,35 @@ size_t safeStrcpy(char *const dst, const char *const src, size_t num)
 	return len;
 }
 
+// Limited to 6 after-decimal places.
+// Based on: https://codereview.stackexchange.com/a/158724
+float str2float(const char *str)
+{
+	for(; isspace((unsigned char)*str) != 0; str++); // Skip whitespaces.
+
+	const float sign = (*str == '-' ? -1.f : 1.f);
+	if(*str == '-' || *str == '+') str++;
+
+	float val = 0.f;
+	while(isdigit((unsigned char)*str) != 0)
+	{
+		val = val * 10.f + (*str - '0');
+		str++;
+	}
+
+	if(*str == '.') str++;
+
+	u32 place = 1;
+	while(isdigit((unsigned char)*str) != 0)
+	{
+		val = val * 10.f + (*str - '0');
+		place *= 10;
+		str++;
+	}
+
+	return val * sign / place;
+}
+
 // case insensitive string compare function
 int strnicmp(const char *str1, const char *str2, u32 len)
 {