From 6a90d6306de83daf59cd98504c7cf5b94ba5eab9 Mon Sep 17 00:00:00 2001
From: IonutParau <ionut.alex.parau@gmail.com>
Date: Sat, 26 Jul 2025 16:45:08 +0200
Subject: [PATCH] color mapping changes

---
 src/components/screen.c | 48 ++++++++++++++++++++++++++++++++++-------
 src/emulator.c          | 26 ++++++++++++++++++++--
 src/neonucleus.h        |  6 +++++-
 src/utils.c             |  2 +-
 4 files changed, 70 insertions(+), 12 deletions(-)

diff --git a/src/components/screen.c b/src/components/screen.c
index fc03536..1621bbc 100644
--- a/src/components/screen.c
+++ b/src/components/screen.c
@@ -360,6 +360,27 @@ void nn_getStd4BitPalette(int color[16]) {
     color[15] = nni_mcBlack; // black
 }
 
+void nn_getLegacy4BitPalette(int color[16]) {
+	// taken from https://github.com/MightyPirates/OpenComputers/blob/master-MC1.12/src/main/scala/li/cil/oc/util/PackedColor.scala
+	
+	color[0] = 0xFFFFFF;
+	color[1] = 0xFFCC33;
+	color[2] = 0xCC66CC;
+	color[3] = 0x6699FF;
+	color[4] = 0xFFFF33;
+	color[5] = 0x33CC33;
+	color[6] = 0xFF6699;
+	color[7] = 0x333333;
+	color[8] = 0xCCCCCC;
+	color[9] = 0x336699;
+	color[10] = 0x9933CC;
+	color[11] = 0x333399;
+	color[12] = 0x663300;
+	color[13] = 0x336600;
+	color[14] = 0xFF3333;
+	color[15] = 0x000000;
+}
+
 void nn_getStd8BitPalette(int color[256]) {
     // source: https://ocdoc.cil.li/component:gpu
     int reds[6] = {0x00, 0x33, 0x66, 0x99, 0xCC, 0xFF};
@@ -399,17 +420,28 @@ static nn_bool_t nni_4bit_did = false;
 static int nni_8bit_colors[256];
 static nn_bool_t nni_8bit_did = false;
 
-int nn_mapDepth(int color, int depth) {
+static int nni_4bitl_colors[16];
+static nn_bool_t nni_4bitl_did = false;
+
+int nn_mapDepth(int color, int depth, nn_bool_t legacy) {
     if(depth == 1) {
-        if(color == 0) return nni_mcBlack;
-        return nni_mcWhite;
+		if(color == 0) return nni_mcBlack;
+		return nni_mcWhite;
     }
     if(depth == 4) {
-        if(!nni_4bit_did) {
-            nni_4bit_did = true;
-            nn_getStd4BitPalette(nni_4bit_colors);
-        }
-        return nn_mapColor(color, nni_4bit_colors, 16);
+		if(legacy) {
+			if(!nni_4bitl_did) {
+				nni_4bitl_did = true;
+				nn_getLegacy4BitPalette(nni_4bitl_colors);
+			}
+			return nn_mapColor(color, nni_4bitl_colors, 16);
+		} else {
+			if(!nni_4bit_did) {
+				nni_4bit_did = true;
+				nn_getStd4BitPalette(nni_4bit_colors);
+			}
+			return nn_mapColor(color, nni_4bit_colors, 16);
+		}
     }
     if(depth == 8) {
         if(!nni_8bit_did) {
diff --git a/src/emulator.c b/src/emulator.c
index 8a9413d..720d53f 100644
--- a/src/emulator.c
+++ b/src/emulator.c
@@ -557,8 +557,11 @@ typedef struct ne_premappedPixel {
     int mappedFgRes;
     int mappedBgFor;
     int mappedBgRes;
+	nn_bool_t legacyColors;
 } ne_premappedPixel;
 
+bool ne_legacyColors = false;
+
 ne_premappedPixel ne_getPremap(ne_premappedPixel *pixels, nn_screen *screen, int x, int y) {
     int maxW, maxH;
     nn_maxResolution(screen, &maxW, &maxH);
@@ -570,6 +573,11 @@ ne_premappedPixel ne_getPremap(ne_premappedPixel *pixels, nn_screen *screen, int
     nn_scrchr_t pixel = nn_getPixel(screen, x, y);
     int fg = pixel.fg;
     int bg = pixel.bg;
+	
+	if(premapped.legacyColors != ne_legacyColors) {
+		premapped.legacyColors = ne_legacyColors;
+		premapped.mappedDepth = -1;
+	}
 
     if(premapped.mappedDepth != depth) {
         premapped.mappedDepth = depth;
@@ -578,14 +586,15 @@ ne_premappedPixel ne_getPremap(ne_premappedPixel *pixels, nn_screen *screen, int
     }
 
     bool miss = false;
+
     if(premapped.mappedFgFor != fg) {
         premapped.mappedFgFor = fg;
-        premapped.mappedFgRes = nn_mapDepth(fg, depth);
+        premapped.mappedFgRes = nn_mapDepth(fg, depth, ne_legacyColors);
         miss = true;
     }
     if(premapped.mappedBgFor != bg) {
         premapped.mappedBgFor = bg;
-        premapped.mappedBgRes = nn_mapDepth(bg, depth);
+        premapped.mappedBgRes = nn_mapDepth(bg, depth, ne_legacyColors);
         miss = true;
     }
     premapped.codepoint = pixel.codepoint;
@@ -914,6 +923,19 @@ int main(int argc, char **argv) {
         }
 
 render:
+		if(IsKeyPressed(KEY_F1)) {
+			nn_setDepth(s, 1);
+		}
+		if(IsKeyPressed(KEY_F2)) {
+			nn_setDepth(s, 4);
+		}
+		if(IsKeyPressed(KEY_F3)) {
+			nn_setDepth(s, 8);
+		}
+		if(IsKeyPressed(KEY_F4)) {
+			ne_legacyColors = !ne_legacyColors;
+		}
+
         BeginDrawing();
 
         ClearBackground(BLACK);
diff --git a/src/neonucleus.h b/src/neonucleus.h
index 351ee3f..1e8493a 100644
--- a/src/neonucleus.h
+++ b/src/neonucleus.h
@@ -894,10 +894,14 @@ const char *nn_depthName(int depth);
 double nn_colorDistance(int colorA, int colorB);
 int nn_mapColor(int color, int *palette, int paletteSize);
 
-int nn_mapDepth(int color, int depth);
+int nn_mapDepth(int color, int depth, nn_bool_t legacy);
 void nn_getStd4BitPalette(int color[16]);
 void nn_getStd8BitPalette(int color[256]);
 
+// Std4bit uses actual MC dye colors, except for white and black
+// Legacy uses OC's versions that were brightened
+void nn_getLegacy4BitPalette(int color[16]);
+
 void nn_setPixel(nn_screen *screen, int x, int y, nn_scrchr_t pixel);
 nn_scrchr_t nn_getPixel(nn_screen *screen, int x, int y);
 
diff --git a/src/utils.c b/src/utils.c
index 1646b6a..97e1f7d 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -218,7 +218,7 @@ double nn_colorDistance(int colorA, int colorB) {
     delta.g = a.g - b.g;
     delta.b = a.b - b.b;
 
-    return delta.r*delta.r + delta.g*delta.g + delta.b*delta.b;
+    return 0.2126 * delta.r*delta.r + 0.7152 * delta.g*delta.g + 0.0722 * delta.b*delta.b;
 }
 
 int nn_mapColor(int color, int *palette, int paletteSize) {