From 9ac88031e121834885684e00886297d13ef943d1 Mon Sep 17 00:00:00 2001
From: Lactozilla <jp6781615@gmail.com>
Date: Tue, 16 Jan 2024 20:36:31 -0300
Subject: [PATCH] Add 'Invert' translation

---
 src/r_translation.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/src/r_translation.c b/src/r_translation.c
index fbd3eb4d5..a4df3cde0 100644
--- a/src/r_translation.c
+++ b/src/r_translation.c
@@ -33,6 +33,7 @@ static boolean PaletteRemap_AddColorRange(remaptable_t *tr, int start, int end,
 static boolean PaletteRemap_AddDesaturation(remaptable_t *tr, int start, int end, double r1, double g1, double b1, double r2, double g2, double b2);
 static boolean PaletteRemap_AddColourisation(remaptable_t *tr, int start, int end, int r, int g, int b);
 static boolean PaletteRemap_AddTint(remaptable_t *tr, int start, int end, int r, int g, int b, int amount);
+static boolean PaletteRemap_AddInvert(remaptable_t *tr, int start, int end);
 
 enum PaletteRemapType
 {
@@ -101,6 +102,12 @@ void PaletteRemap_Init(void)
 	memset(allBlack->remap, 31, NUM_PALETTE_ENTRIES * sizeof(UINT8));
 	R_AddCustomTranslation("AllBlack", PaletteRemap_Add(allBlack));
 
+	// Invert
+	remaptable_t *invertRemap = PaletteRemap_New();
+	PaletteRemap_SetIdentity(invertRemap);
+	PaletteRemap_AddInvert(invertRemap, 0, 255);
+	R_AddCustomTranslation("Invert", PaletteRemap_Add(invertRemap));
+
 	// Dash mode (TC_DASHMODE)
 	MakeDashModeRemap();
 }
@@ -417,6 +424,23 @@ static boolean PaletteRemap_AddTint(remaptable_t *tr, int start, int end, int r,
 	return true;
 }
 
+static boolean PaletteRemap_AddInvert(remaptable_t *tr, int start, int end)
+{
+	if (IndicesOutOfRange(start, end))
+		return false;
+
+	for (int i = start; i < end; ++i)
+	{
+		tr->remap[i] = NearestColor(
+		    255 - tr->remap[pMasterPalette[i].s.red],
+		    255 - tr->remap[pMasterPalette[i].s.green],
+		    255 - tr->remap[pMasterPalette[i].s.blue]
+		);
+	}
+
+	return true;
+}
+
 struct ParsedTranslation
 {
 	struct ParsedTranslation *next;