add a palette fade to black.

Makefile

@@ -153,7 +153,13 @@ process-images: $(GRAPHICSFILES)
 # Rule for 8-bit images
 %_8.bin %_8.h: %.png
 	@echo "Processing 8-bit image $<"
-	@magick $< -channel-fx "red=>blue,blue=>red" $(GENERATED)/$*_8.temp.png
+	@if [ "$$(magick identify -format '%k' $<)" -ne 256 ]; then \
+		echo "  Quantizing to 256 colors..."; \
+		magick $< -colors 256 -depth 8 -type Palette $(GENERATED)/$*_8.temp.png; \
+	else \
+		echo "  Already quantized, using as-is..."; \
+		cp $< $(GENERATED)/$*_8.temp.png; \
+	fi
 	@grit $(GENERATED)/$*_8.temp.png -gb -gB8 -p -ftb -o $(GENERATED)/$*_8
 	@rm $(GENERATED)/$*_8.temp.png
 

source/main.c

@@ -9,8 +9,8 @@
 #include <maxmod.h>
 #include <mm_types.h>
 
-#include "splash_8_img_bin.h"
-#include "splash_8_pal_bin.h"
+#include "together_8_img_bin.h"
+#include "together_8_pal_bin.h"
 
 // Define any soundbank includes here
 #include "soundbank.h"
@@ -19,9 +19,20 @@
 // Global mixing buffer for maxmod
 u8 mixing_buffer[MM_MIXLEN_16KHZ] __attribute__((aligned(4)));
 
+// Set the two variables below to start the palette fade
+
+// The number of steps to fade the palette to black
+const u8 palette_fade_steps = 12;
+// The current step of the palette fade, set this to above to start the fade, the fade will decrement this value until it reaches 0
+u8 palette_fade_step = 0;
+
+const u8 fade_pause_frames = 120;
+u8 fade_pause_frame_count = 0;
+
 // Function Prototypes
 void initializeSystem(void);
 void loadIntroScreen(void);
+void fadePaletteStep(void);
 
 int main(void) {
     // Initialize GBA system and maxmod
@@ -32,7 +43,7 @@ int main(void) {
 
     // Wait for VBlank before starting music
     VBlankIntrWait();
-    mmStart(MOD_EYETIGER, MM_PLAY_LOOP);
+    mmStart(MOD_MOZARTSONATA, MM_PLAY_LOOP);
     
     // Main game loop
     while(1) {
@@ -42,12 +53,24 @@ int main(void) {
         mmFrame();
         
         // Game logic goes here
-        
-        // Wait for vertical blank
         scanKeys();
-        if (keysDown() & KEY_A) {
+        u16 keys = keysDown();
+        
+        // Check for key presses
+        if (keys & KEY_A) {
             mmEffect(SFX_WEAPON);
         }
+        
+        if ((keys & KEY_START) && palette_fade_step == 0) {
+            // Start the palette fade
+            palette_fade_step = palette_fade_steps;
+        }
+        else if (keys & KEY_SELECT) {
+            // Reset the palette to the original
+            DMA3COPY(together_8_pal_bin, BG_PALETTE, together_8_pal_bin_size >> 1);
+        }
+        
+        fadePaletteStep();
     }
     
     return 0;
@@ -71,9 +94,47 @@ void loadIntroScreen(void) {
 
     // Load the palette
     // Palette size needs to be in 16-bit units (divide by 2)
-    DMA3COPY(splash_8_pal_bin, BG_PALETTE, splash_8_pal_bin_size >> 1);
+    DMA3COPY(together_8_pal_bin, BG_PALETTE, together_8_pal_bin_size >> 1);
     
     // Copy image data to first frame buffer
     // Image size needs to be in 16-bit units (divide by 2)
-    DMA3COPY(splash_8_img_bin, (void*)VRAM, splash_8_img_bin_size >> 1);
+    DMA3COPY(together_8_img_bin, (void*)VRAM, together_8_img_bin_size >> 1);
+}
+
+// increment the palette fade step by 1
+void fadePaletteStep(void) {
+    if (fade_pause_frame_count > fade_pause_frames) {
+        ++fade_pause_frame_count;
+        return;
+    }
+    fade_pause_frame_count = 0;
+
+    if (palette_fade_steps && palette_fade_step) {
+        // Calculate how much to keep of each color component in this step
+        // As palette_fade_step goes from palette_fade_steps down to 1, 
+        // this ratio goes from 1.0 down to nearly 0.0
+        u16 keep_ratio = ((u16)palette_fade_step << 7) / (u16)palette_fade_steps;
+        
+        // fade the palette to black, by iterating over the palette memory one position at a time
+        for (u16 i = 0; i < 256; ++i) {
+            u16 color = ((u16*)together_8_pal_bin)[i];
+            
+            // Extract RGB components (GBA uses 5 bits per component)
+            u16 r = (color & 0x1F);
+            u16 g = (color >> 5) & 0x1F;
+            u16 b = (color >> 10) & 0x1F;
+            
+            // Reduce each component based on current step
+            r = (r * keep_ratio) >> 7;
+            g = (g * keep_ratio) >> 7;
+            b = (b * keep_ratio) >> 7;
+            
+            // Recombine the components
+            u16 new_color = (b << 10) | (g << 5) | r;
+            
+            BG_PALETTE[i] = new_color;
+        }
+        
+        --palette_fade_step;
+    }
 }