Color temperature control

Cocoa/Document.m

@@ -689,6 +689,11 @@ static unsigned *multiplication_table_for_frequency(unsigned frequency)
                                                  name:@"GBColorCorrectionChanged"
                                                object:nil];
     
+    [[NSNotificationCenter defaultCenter] addObserver:self
+                                             selector:@selector(updateLightTemperature)
+                                                 name:@"GBLightTemperatureChanged"
+                                               object:nil];
+    
     [[NSNotificationCenter defaultCenter] addObserver:self
                                              selector:@selector(updateFrameBlendingMode)
                                                  name:@"GBFrameBlendingModeChanged"
@@ -1835,6 +1840,14 @@ static unsigned *multiplication_table_for_frequency(unsigned frequency)
     }
 }
 
+- (void) updateLightTemperature
+{
+    if (GB_is_inited(&gb)) {
+        GB_set_light_temperature(&gb, [[NSUserDefaults standardUserDefaults] doubleForKey:@"GBLightTemperature"]);
+    }
+}
+
+
 - (void) updateFrameBlendingMode
 {
     self.view.frameBlendingMode = (GB_frame_blending_mode_t) [[NSUserDefaults standardUserDefaults] integerForKey:@"GBFrameBlendingMode"];

Cocoa/GBPreferencesWindow.h

@@ -17,7 +17,7 @@
 @property (strong) IBOutlet NSMenuItem *bootROMsFolderItem;
 @property (strong) IBOutlet NSPopUpButtonCell *bootROMsButton;
 @property (strong) IBOutlet NSPopUpButton *rumbleModePopupButton;
-
+@property (weak) IBOutlet NSSlider *temperatureSlider;
 @property (weak) IBOutlet NSPopUpButton *dmgPopupButton;
 @property (weak) IBOutlet NSPopUpButton *sgbPopupButton;
 @property (weak) IBOutlet NSPopUpButton *cgbPopupButton;

Cocoa/GBPreferencesWindow.m

@@ -26,6 +26,7 @@
     NSPopUpButton *_dmgPopupButton, *_sgbPopupButton, *_cgbPopupButton;
     NSPopUpButton *_preferredJoypadButton;
     NSPopUpButton *_rumbleModePopupButton;
+    NSSlider *_temperatureSlider;
 }
 
 + (NSArray *)filterList
@@ -91,11 +92,23 @@
     [_colorCorrectionPopupButton selectItemAtIndex:mode];
 }
 
+
 - (NSPopUpButton *)colorCorrectionPopupButton
 {
     return _colorCorrectionPopupButton;
 }
 
+- (void)setTemperatureSlider:(NSSlider *)temperatureSlider
+{
+    _temperatureSlider = temperatureSlider;
+    [temperatureSlider setDoubleValue:[[NSUserDefaults standardUserDefaults] doubleForKey:@"GBLightTemperature"] * 256];
+    temperatureSlider.continuous = YES;
+}
+
+- (NSSlider *)temperatureSlider
+{
+    return _temperatureSlider;
+}
 - (void)setFrameBlendingModePopupButton:(NSPopUpButton *)frameBlendingModePopupButton
 {
     _frameBlendingModePopupButton = frameBlendingModePopupButton;
@@ -284,6 +297,13 @@
     [[NSNotificationCenter defaultCenter] postNotificationName:@"GBColorCorrectionChanged" object:nil];
 }
 
+- (IBAction)lightTemperatureChanged:(id)sender
+{
+    [[NSUserDefaults standardUserDefaults] setObject:@([sender doubleValue] / 256.0)
+                                              forKey:@"GBLightTemperature"];
+    [[NSNotificationCenter defaultCenter] postNotificationName:@"GBLightTemperatureChanged" object:nil];
+}
+
 - (IBAction)franeBlendingModeChanged:(id)sender
 {
     [[NSUserDefaults standardUserDefaults] setObject:@([sender indexOfSelectedItem])

Cocoa/Preferences.xib

@@ -79,15 +79,16 @@
                 <outlet property="rumbleModePopupButton" destination="Ogs-xG-b4b" id="vuw-VN-MTp"/>
                 <outlet property="sgbPopupButton" destination="dza-T7-RkX" id="B0o-Nb-pIH"/>
                 <outlet property="skipButton" destination="d2I-jU-sLb" id="udX-8K-0sK"/>
+                <outlet property="temperatureSlider" destination="G3D-2f-Zcr" id="Etd-U2-wv0"/>
             </connections>
             <point key="canvasLocation" x="183" y="354"/>
         </window>
         <customView id="sRK-wO-K6R">
-            <rect key="frame" x="0.0" y="0.0" width="292" height="323"/>
+            <rect key="frame" x="0.0" y="0.0" width="292" height="378"/>
             <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
             <subviews>
                 <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="T91-rh-rRp">
-                    <rect key="frame" x="18" y="286" width="256" height="17"/>
+                    <rect key="frame" x="18" y="341" 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"/>

Core/display.c

@@ -2,6 +2,7 @@
 #include <stdlib.h>
 #include <assert.h>
 #include <string.h>
+#include <math.h>
 #include "gb.h"
 
 /* FIFO functions */
@@ -208,6 +209,26 @@ static void display_vblank(GB_gameboy_t *gb)
     GB_timing_sync(gb);
 }
 
+static inline void temperature_tint(double temperature, double *r, double *g, double *b)
+{
+    if (temperature >= 0) {
+        *r = 1;
+        *g = pow(1 - temperature, 0.375);
+        if (temperature >= 0.75) {
+            *b = 0;
+        }
+        else {
+            *b = sqrt(0.75 - temperature);
+        }
+    }
+    else {
+        *b = 1;
+        double squared = pow(temperature, 2);
+        *g = 0.125 * squared + 0.3 * temperature + 1.0;
+        *r = 0.21875 * squared + 0.5 * temperature + 1.0;
+    }
+}
+
 static inline uint8_t scale_channel(uint8_t x)
 {
     return (x << 3) | (x >> 2);
@@ -240,13 +261,12 @@ uint32_t GB_convert_rgb15(GB_gameboy_t *gb, uint16_t color, bool for_border)
         g = scale_channel(g);
         b = scale_channel(b);
     }
+    else if (GB_is_sgb(gb) || for_border) {
+        r = scale_channel_with_curve_sgb(r);
+        g = scale_channel_with_curve_sgb(g);
+        b = scale_channel_with_curve_sgb(b);
+    }
     else {
-        if (GB_is_sgb(gb) || for_border) {
-            return gb->rgb_encode_callback(gb,
-                                           scale_channel_with_curve_sgb(r),
-                                           scale_channel_with_curve_sgb(g),
-                                           scale_channel_with_curve_sgb(b));
-        }
         bool agb = gb->model == GB_MODEL_AGB;
         r = agb? scale_channel_with_curve_agb(r) : scale_channel_with_curve(r);
         g = agb? scale_channel_with_curve_agb(g) : scale_channel_with_curve(g);
@@ -301,6 +321,14 @@ uint32_t GB_convert_rgb15(GB_gameboy_t *gb, uint16_t color, bool for_border)
         }
     }
     
+    if (gb->light_temperature) {
+        double light_r, light_g, light_b;
+        temperature_tint(gb->light_temperature, &light_r, &light_g, &light_b);
+        r = round(light_r * r);
+        g = round(light_g * g);
+        b = round(light_b * b);
+    }
+    
     return gb->rgb_encode_callback(gb, r, g, b);
 }
 
@@ -324,6 +352,17 @@ void GB_set_color_correction_mode(GB_gameboy_t *gb, GB_color_correction_mode_t m
     }
 }
 
+void GB_set_light_temperature(GB_gameboy_t *gb, double temperature)
+{
+    gb->light_temperature = temperature;
+    if (GB_is_cgb(gb)) {
+        for (unsigned i = 0; i < 32; i++) {
+            GB_palette_changed(gb, false, i * 2);
+            GB_palette_changed(gb, true, i * 2);
+        }
+    }
+}
+
 /*
  STAT interrupt is implemented based on this finding:
  http://board.byuu.org/phpbb3/viewtopic.php?p=25527#p25531

Core/display.h

@@ -58,5 +58,6 @@ void GB_draw_tilemap(GB_gameboy_t *gb, uint32_t *dest, GB_palette_type_t palette
 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, bool for_border);
 void GB_set_color_correction_mode(GB_gameboy_t *gb, GB_color_correction_mode_t mode);
+void GB_set_light_temperature(GB_gameboy_t *gb, double temperature);
 bool GB_is_odd_frame(GB_gameboy_t *gb);
 #endif /* display_h */

Core/gb.h

@@ -573,6 +573,7 @@ struct GB_gameboy_internal_s {
         uint32_t sprite_palettes_rgb[0x20];
         const GB_palette_t *dmg_palette;
         GB_color_correction_mode_t color_correction_mode;
+        double light_temperature;
         bool keys[4][GB_KEY_MAX];
         GB_border_mode_t border_mode;
         GB_sgb_border_t borrowed_border;

SDL/gui.c

@@ -110,6 +110,7 @@ configuration_t configuration =
     .volume = 100,
     .rumble_mode = GB_RUMBLE_ALL_GAMES,
     .default_scale = 2,
+    .color_temperature = 10,
 };
 
 
@@ -453,6 +454,33 @@ const char *current_color_correction_mode(unsigned index)
         [configuration.color_correction_mode];
 }
 
+const char *current_color_temperature(unsigned index)
+{
+    return (const char *[]){"12000K",
+        "11450K",
+        "10900K",
+        "10350K",
+        "9800K",
+        "9250K",
+        "8700K",
+        "8150K",
+        "7600K",
+        "7050K",
+        "6500K (White)",
+        "5950K",
+        "5400K",
+        "4850K",
+        "4300K",
+        "3750K",
+        "3200K",
+        "2650K",
+        "2100K",
+        "1550K",
+        "1000K"}
+    [configuration.color_temperature];
+}
+
+
 const char *current_palette(unsigned index)
 {
     return (const char *[]){"Greyscale", "Lime (Game Boy)", "Olive (Pocket)", "Teal (Light)"}
@@ -533,6 +561,20 @@ static void cycle_color_correction_backwards(unsigned index)
     }
 }
 
+static void decrease_color_temperature(unsigned index)
+{
+    if (configuration.color_temperature < 20) {
+        configuration.color_temperature++;
+    }
+}
+
+static void increase_color_temperature(unsigned index)
+{
+    if (configuration.color_temperature > 0) {
+        configuration.color_temperature--;
+    }
+}
+
 static void cycle_palette(unsigned index)
 {
     if (configuration.dmg_palette == 3) {
@@ -684,6 +726,7 @@ static const struct menu_item graphics_menu[] = {
     {"Default Window Scale:", cycle_default_scale, current_default_scale, cycle_default_scale_backwards},
     {"Scaling Filter:", cycle_filter, current_filter_name, cycle_filter_backwards},
     {"Color Correction:", cycle_color_correction, current_color_correction_mode, cycle_color_correction_backwards},
+    {"Ambient Light:", decrease_color_temperature, current_color_temperature, increase_color_temperature},
     {"Frame Blending:", cycle_blending_mode, blending_mode_string, cycle_blending_mode_backwards},
     {"Mono Palette:", cycle_palette, current_palette, cycle_palette_backwards},
     {"Display Border:", cycle_border_mode, current_border_mode, cycle_border_mode_backwards},

SDL/gui.h

@@ -110,6 +110,10 @@ typedef struct {
     GB_rumble_mode_t rumble_mode;
 
     uint8_t default_scale;
+    
+    /* v0.14 */
+    unsigned padding;
+    uint8_t color_temperature;
 } configuration_t;
 
 extern configuration_t configuration;

SDL/main.c

@@ -120,6 +120,7 @@ static void open_menu(void)
         GB_audio_set_paused(false);
     }
     GB_set_color_correction_mode(&gb, configuration.color_correction_mode);
+    GB_set_light_temperature(&gb, (configuration.color_temperature - 10.0) / 10.0);
     GB_set_border_mode(&gb, configuration.border_mode);
     update_palette();
     GB_set_highpass_filter_mode(&gb, configuration.highpass_mode);
@@ -496,6 +497,7 @@ restart:
         GB_set_rumble_mode(&gb, configuration.rumble_mode);
         GB_set_sample_rate(&gb, GB_audio_get_frequency());
         GB_set_color_correction_mode(&gb, configuration.color_correction_mode);
+        GB_set_light_temperature(&gb, (configuration.color_temperature - 10.0) / 10.0);
         update_palette();
         if ((unsigned)configuration.border_mode <= GB_BORDER_ALWAYS) {
             GB_set_border_mode(&gb, configuration.border_mode);
@@ -646,6 +648,7 @@ int main(int argc, char **argv)
         configuration.dmg_palette %= 3;
         configuration.border_mode %= GB_BORDER_ALWAYS + 1;
         configuration.rumble_mode %= GB_RUMBLE_ALL_GAMES + 1;
+        configuration.color_temperature %= 21;
     }
     
     if (configuration.model >= MODEL_MAX) {