Added 3 color correction profiles, added color correction setting to Cocoa GUI, improved cross-platform and cross-frontend save-state compatibility

Cocoa/AppDelegate.m

@@ -30,7 +30,8 @@
                                                               @"GBTurbo": @(kVK_Space),
 
                                                               @"GBFilter": @"NearestNeighbor",
-                                                              @"GBHighpassFilter": @(GB_HIGHPASS_REMOVE_DC_OFFSET),
+                                                              @"GBColorCorrection": @(GB_COLOR_CORRECTION_EMULATE_HARDWARE),
+                                                              @"GBHighpassFilter": @(GB_HIGHPASS_REMOVE_DC_OFFSET)
                                                               }];
 }
 

Cocoa/Document.m

@@ -145,6 +145,7 @@ static void printImage(GB_gameboy_t *gb, uint32_t *image, uint8_t height,
     GB_set_log_callback(&gb, (GB_log_callback_t) consoleLog);
     GB_set_input_callback(&gb, (GB_input_callback_t) consoleInput);
     GB_set_async_input_callback(&gb, (GB_input_callback_t) asyncConsoleInput);
+    GB_set_color_correction_mode(&gb, (GB_color_correction_mode_t) [[NSUserDefaults standardUserDefaults] integerForKey:@"GBColorCorrection"]);
     GB_set_rgb_encode_callback(&gb, rgbEncode);
     GB_set_camera_get_pixel_callback(&gb, cameraGetPixel);
     GB_set_camera_update_request_callback(&gb, cameraRequestUpdate);
@@ -302,6 +303,11 @@ static void printImage(GB_gameboy_t *gb, uint32_t *image, uint8_t height,
                                                  name:@"GBHighpassFilterChanged"
                                                object:nil];
     
+    [[NSNotificationCenter defaultCenter] addObserver:self
+                                             selector:@selector(updateColorCorrectionMode)
+                                                 name:@"GBColorCorrectionChanged"
+                                               object:nil];
+    
     if ([[NSUserDefaults standardUserDefaults] boolForKey:@"EmulateDMG"]) {
         [self initDMG];
     }
@@ -1287,4 +1293,11 @@ static void printImage(GB_gameboy_t *gb, uint32_t *image, uint8_t height,
     }
 }
 
+- (void) updateColorCorrectionMode
+{
+    if (GB_is_inited(&gb)) {
+        GB_set_color_correction_mode(&gb, (GB_color_correction_mode_t) [[NSUserDefaults standardUserDefaults] integerForKey:@"GBColorCorrection"]);
+    }
+}
+
 @end

Cocoa/GBPreferencesWindow.h

@@ -5,4 +5,5 @@
 @property IBOutlet NSPopUpButton *graphicsFilterPopupButton;
 @property (strong) IBOutlet NSButton *aspectRatioCheckbox;
 @property (strong) IBOutlet NSPopUpButton *highpassFilterPopupButton;
+@property (strong) IBOutlet NSPopUpButton *colorCorrectionPopupButton;
 @end

Cocoa/GBPreferencesWindow.m

@@ -10,6 +10,7 @@
 
     NSPopUpButton *_graphicsFilterPopupButton;
     NSPopUpButton *_highpassFilterPopupButton;
+    NSPopUpButton *_colorCorrectionPopupButton;
     NSButton *_aspectRatioCheckbox;
 }
 
@@ -52,6 +53,18 @@
     return _highpassFilterPopupButton;
 }
 
+- (void)setColorCorrectionPopupButton:(NSPopUpButton *)colorCorrectionPopupButton
+{
+    _colorCorrectionPopupButton = colorCorrectionPopupButton;
+    NSInteger mode = [[NSUserDefaults standardUserDefaults] integerForKey:@"GBColorCorrection"];
+    [_colorCorrectionPopupButton selectItemAtIndex:mode];
+}
+
+- (NSPopUpButton *)colorCorrectionPopupButton
+{
+    return _colorCorrectionPopupButton;
+}
+
 - (void)setHighpassFilterPopupButton:(NSPopUpButton *)highpassFilterPopupButton
 {
     _highpassFilterPopupButton = highpassFilterPopupButton;
@@ -128,6 +141,14 @@
     [[NSNotificationCenter defaultCenter] postNotificationName:@"GBAspectChanged" object:nil];
 }
 
+- (IBAction)colorCorrectionChanged:(id)sender
+{
+    [[NSUserDefaults standardUserDefaults] setObject:@([sender indexOfSelectedItem])
+                                              forKey:@"GBColorCorrection"];
+    [[NSNotificationCenter defaultCenter] postNotificationName:@"GBColorCorrectionChanged" object:nil];
+
+}
+
 - (NSButton *)aspectRatioCheckbox
 {
     return _aspectRatioCheckbox;

Cocoa/Preferences.xib

@@ -1,8 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="12121" systemVersion="16F73" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" customObjectInstantitationMethod="direct">
+<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="13196" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" customObjectInstantitationMethod="direct">
     <dependencies>
         <deployment identifier="macosx"/>
-        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="12121"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="13196"/>
         <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
     </dependencies>
     <objects>
@@ -17,14 +17,14 @@
             <windowStyleMask key="styleMask" titled="YES" closable="YES"/>
             <windowCollectionBehavior key="collectionBehavior" fullScreenAuxiliary="YES"/>
             <windowPositionMask key="initialPositionMask" leftStrut="YES" rightStrut="YES" topStrut="YES" bottomStrut="YES"/>
-            <rect key="contentRect" x="196" y="240" width="292" height="378"/>
+            <rect key="contentRect" x="196" y="240" width="292" height="426"/>
             <rect key="screenRect" x="0.0" y="0.0" width="2560" height="1417"/>
             <view key="contentView" id="EiT-Mj-1SZ">
-                <rect key="frame" x="0.0" y="0.0" width="292" height="378"/>
+                <rect key="frame" x="0.0" y="0.0" width="292" height="426"/>
                 <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                 <subviews>
-                    <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" allowsCharacterPickerTouchBarItem="NO" translatesAutoresizingMaskIntoConstraints="NO" id="T91-rh-rRp">
+                    <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="T91-rh-rRp">
-                        <rect key="frame" x="18" y="341" width="256" height="17"/>
+                        <rect key="frame" x="18" y="389" width="256" height="17"/>
                         <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
                         <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Graphics Filter:" id="pXg-WY-8Q5">
                             <font key="font" metaFont="system"/>
@@ -33,7 +33,7 @@
                         </textFieldCell>
                     </textField>
                     <popUpButton verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="6pP-kK-EEC">
-                        <rect key="frame" x="30" y="309" width="245" height="26"/>
+                        <rect key="frame" x="30" y="357" width="245" height="26"/>
                         <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
                         <popUpButtonCell key="cell" type="push" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" borderStyle="borderAndBezel" imageScaling="proportionallyDown" inset="2" id="I1w-05-lGl">
                             <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
@@ -66,6 +66,36 @@
                             <action selector="graphicFilterChanged:" target="QvC-M9-y7g" id="n87-t4-fbV"/>
                         </connections>
                     </popUpButton>
+                    <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="Wc3-2K-6CD">
+                        <rect key="frame" x="18" y="335" width="256" height="17"/>
+                        <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
+                        <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Color Correction:" id="5Si-hz-EK3">
+                            <font key="font" metaFont="system"/>
+                            <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
+                            <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
+                        </textFieldCell>
+                    </textField>
+                    <popUpButton verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="VEz-N4-uP6">
+                        <rect key="frame" x="30" y="303" width="245" height="26"/>
+                        <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
+                        <popUpButtonCell key="cell" type="push" title="Disabled" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" imageScaling="proportionallyDown" inset="2" selectedItem="D2J-wV-1vu" id="fNJ-Fi-yOm">
+                            <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
+                            <font key="font" metaFont="menu"/>
+                            <menu key="menu" id="6go-Lb-a4m">
+                                <items>
+                                    <menuItem title="Disabled" state="on" id="D2J-wV-1vu">
+                                        <modifierMask key="keyEquivalentModifierMask"/>
+                                    </menuItem>
+                                    <menuItem title="Correct Color Curves" id="B3Q-x1-VRl"/>
+                                    <menuItem title="Emulate Hardware" id="XBL-hS-7ke"/>
+                                    <menuItem title="Preserve Brightness" id="tlx-WB-Bkw"/>
+                                </items>
+                            </menu>
+                        </popUpButtonCell>
+                        <connections>
+                            <action selector="colorCorrectionChanged:" target="QvC-M9-y7g" id="Oq4-B5-nO6"/>
+                        </connections>
+                    </popUpButton>
                     <popUpButton verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="T69-6N-dhT">
                         <rect key="frame" x="30" y="223" width="245" height="26"/>
                         <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
@@ -87,7 +117,7 @@
                         </connections>
                     </popUpButton>
                     <button fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="Vfj-tg-7OP">
-                        <rect key="frame" x="18" y="285" width="256" height="18"/>
+                        <rect key="frame" x="18" y="278" width="256" height="18"/>
                         <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
                         <buttonCell key="cell" type="check" title="Keep Aspect Ratio" bezelStyle="regularSquare" imagePosition="left" state="on" inset="2" id="lsj-rC-Eo6">
                             <behavior key="behavior" changeContents="YES" doesNotDimImage="YES" lightByContents="YES"/>
@@ -97,7 +127,7 @@
                             <action selector="changeAspectRatio:" target="QvC-M9-y7g" id="mQG-Ib-1jN"/>
                         </connections>
                     </button>
-                    <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" allowsCharacterPickerTouchBarItem="NO" translatesAutoresizingMaskIntoConstraints="NO" id="Utu-t4-cLx">
+                    <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="Utu-t4-cLx">
                         <rect key="frame" x="18" y="201" width="256" height="17"/>
                         <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
                         <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Button configuration:" id="YqW-Ds-VIC">
@@ -106,7 +136,7 @@
                             <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
                         </textFieldCell>
                     </textField>
-                    <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" allowsCharacterPickerTouchBarItem="NO" translatesAutoresizingMaskIntoConstraints="NO" id="WU3-oV-KHO">
+                    <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="WU3-oV-KHO">
                         <rect key="frame" x="18" y="255" width="256" height="17"/>
                         <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
                         <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="High-pass Filter:" id="YLF-RL-b2D">
@@ -177,12 +207,13 @@
             </view>
             <connections>
                 <outlet property="aspectRatioCheckbox" destination="Vfj-tg-7OP" id="Yw0-xS-DBr"/>
+                <outlet property="colorCorrectionPopupButton" destination="VEz-N4-uP6" id="EO2-Vt-JFJ"/>
                 <outlet property="controlsTableView" destination="UDd-IJ-fxX" id="a1D-Md-yXv"/>
                 <outlet property="delegate" destination="-2" id="ASc-vN-Zbq"/>
                 <outlet property="graphicsFilterPopupButton" destination="6pP-kK-EEC" id="LS7-HY-kHC"/>
                 <outlet property="highpassFilterPopupButton" destination="T69-6N-dhT" id="0p6-4m-hb1"/>
             </connections>
-            <point key="canvasLocation" x="179" y="474"/>
+            <point key="canvasLocation" x="179" y="498"/>
         </window>
     </objects>
 </document>

Core/display.c

@@ -222,21 +222,77 @@ static void display_vblank(GB_gameboy_t *gb)
 
 static inline uint8_t scale_channel(uint8_t x)
 {
-    x &= 0x1f;
     return (x << 3) | (x >> 2);
 }
 
+static inline uint8_t scale_channel_with_curve(uint8_t x)
+{
+    return (uint8_t[]){0,2,4,7,12,18,25,34,42,52,62,73,85,97,109,121,134,146,158,170,182,193,203,213,221,230,237,243,248,251,253,255,}[x];
+}
+
+uint32_t GB_convert_rgb15(GB_gameboy_t *gb, uint16_t color)
+{
+    uint8_t r = (color) & 0x1F;
+    uint8_t g = (color >> 5) & 0x1F;
+    uint8_t b = (color >> 10) & 0x1F;
+    
+    if (gb->color_correction_mode == GB_COLOR_CORRECTION_DISABLED) {
+        r = scale_channel(r);
+        g = scale_channel(g);
+        b = scale_channel(b);
+    }
+    else {
+        r = scale_channel_with_curve(r);
+        g = scale_channel_with_curve(g);
+        b = scale_channel_with_curve(b);
+        
+        if (gb->color_correction_mode != GB_COLOR_CORRECTION_CORRECT_CURVES) {
+            uint8_t new_g = (g * 3 + b) / 4;
+            uint8_t new_r = r, new_b = b;
+            if (gb->color_correction_mode == GB_COLOR_CORRECTION_PRESERVE_BRIGHTNESS) {
+                uint8_t old_max = MAX(r, MAX(g, b));
+                uint8_t new_max = MAX(new_r, MAX(new_g, new_b));
+                
+                if (new_max != 0) {
+                    new_r = new_r * old_max / new_max;
+                    new_g = new_g * old_max / new_max;
+                    new_b = new_b * old_max / new_max;
+                }
+                
+                uint8_t old_min = MIN(r, MIN(g, b));
+                uint8_t new_min = MIN(new_r, MIN(new_g, new_b));
+                
+                if (new_min != 0xff) {
+                    new_r = 0xff - (0xff - new_r) * (0xff - old_min) / (0xff - new_min);
+                    new_g = 0xff - (0xff - new_g) * (0xff - old_min) / (0xff - new_min);
+                    new_b = 0xff - (0xff - new_b) * (0xff - old_min) / (0xff - new_min);;
+                }
+            }
+            r = new_r;
+            g = new_g;
+            b = new_b;
+        }
+    }
+    
+    return gb->rgb_encode_callback(gb, r, g, b);
+}
+
 void GB_palette_changed(GB_gameboy_t *gb, bool background_palette, uint8_t index)
 {
+    if (!gb->rgb_encode_callback) return;
     uint8_t *palette_data = background_palette? gb->background_palettes_data : gb->sprite_palettes_data;
     uint16_t color = palette_data[index & ~1] | (palette_data[index | 1] << 8);
 
-    // No need to &, scale channel does that.
+    (background_palette? gb->background_palettes_rgb : gb->sprite_palettes_rgb)[index / 2] = GB_convert_rgb15(gb, color);
-    uint8_t r = scale_channel(color);
+}
-    uint8_t g = scale_channel(color >> 5);
+
-    uint8_t b = scale_channel(color >> 10);
+void GB_set_color_correction_mode(GB_gameboy_t *gb, GB_color_correction_mode_t mode)
-    assert (gb->rgb_encode_callback);
+{
-    (background_palette? gb->background_palettes_rgb : gb->sprite_palettes_rgb)[index / 2] = gb->rgb_encode_callback(gb, r, g, b);
+    gb->color_correction_mode = mode;
+    for (unsigned i = 0; i < 32; i++) {
+        GB_palette_changed(gb, false, i * 2);
+        GB_palette_changed(gb, true, i * 2);
+    }
 }
 
 /*

Core/display.h

@@ -34,8 +34,16 @@ typedef struct {
     bool obscured_by_line_limit;
 } GB_oam_info_t;
 
+typedef enum {
+    GB_COLOR_CORRECTION_DISABLED,
+    GB_COLOR_CORRECTION_CORRECT_CURVES,
+    GB_COLOR_CORRECTION_EMULATE_HARDWARE,
+    GB_COLOR_CORRECTION_PRESERVE_BRIGHTNESS,
+} GB_color_correction_mode_t;
+
 void GB_draw_tileset(GB_gameboy_t *gb, uint32_t *dest, GB_palette_type_t palette_type, uint8_t palette_index);
 void GB_draw_tilemap(GB_gameboy_t *gb, uint32_t *dest, GB_palette_type_t palette_type, uint8_t palette_index, GB_map_type_t map_type, GB_tileset_type_t tileset_type);
 uint8_t GB_get_oam_info(GB_gameboy_t *gb, GB_oam_info_t *dest, uint8_t *sprite_height);
-
+uint32_t GB_convert_rgb15(GB_gameboy_t *gb, uint16_t color);
+void GB_set_color_correction_mode(GB_gameboy_t *gb, GB_color_correction_mode_t mode);
 #endif /* display_h */

Core/gb.h

@@ -162,6 +162,14 @@ typedef enum {
 #define DIV_CYCLES (0x100)
 #define INTERNAL_DIV_CYCLES (0x40000)
 #define FRAME_LENGTH 16742706 // in nanoseconds
+
+#if !defined(MIN)
+#define MIN(A,B)    ({ __typeof__(A) __a = (A); __typeof__(B) __b = (B); __a < __b ? __a : __b; })
+#endif
+
+#if !defined(MAX)
+#define MAX(A,B)    ({ __typeof__(A) __a = (A); __typeof__(B) __b = (B); __a < __b ? __b : __a; })
+#endif
 #endif
 
 typedef void (*GB_vblank_callback_t)(GB_gameboy_t *gb);
@@ -361,8 +369,6 @@ struct GB_gameboy_internal_s {
         uint8_t oam[0xA0];
         uint8_t background_palettes_data[0x40];
         uint8_t sprite_palettes_data[0x40];
-        uint32_t background_palettes_rgb[0x20];
-        uint32_t sprite_palettes_rgb[0x20];
         int16_t previous_lcdc_x;
         bool stat_interrupt_line;
         uint8_t effective_scx;
@@ -405,6 +411,9 @@ struct GB_gameboy_internal_s {
 
         /* I/O */
         uint32_t *screen;
+        uint32_t background_palettes_rgb[0x20];
+        uint32_t sprite_palettes_rgb[0x20];
+        GB_color_correction_mode_t color_correction_mode;
         bool keys[GB_KEY_MAX];
                
         /* Timing */

Core/save_state.c

@@ -213,6 +213,11 @@ int GB_load_state(GB_gameboy_t *gb, const char *path)
         gb->rumble_callback(gb, gb->rumble_state);
     }
     
+    for (unsigned i = 0; i < 32; i++) {
+        GB_palette_changed(gb, false, i * 2);
+        GB_palette_changed(gb, true, i * 2);
+    }
+
 error:
     fclose(f);
     return errno;