Use palette textures for translucent/sprites and apply the translation remap when requesting an indexed texture

src/common/textures/texture.cpp

@@ -346,6 +346,18 @@ FTextureBuffer FTexture::CreateTexBuffer(int translation, int flags)
 		result.mHeight = h;
 		result.mContentId = 0;
 		ImageHelpers::FlipNonSquareBlock(result.mBuffer, p, h, w, h);
+
+		auto remap = translation <= 0 || IsLuminosityTranslation(translation) ? nullptr : GPalette.TranslationToTable(translation);
+		if (remap && remap->Inactive) remap = nullptr;
+		if (remap) translation = remap->Index;
+
+		if (remap)
+		{
+			for (int i = 0, count = w * h; i < count; i++)
+			{
+				result.mBuffer[i] = remap->Remap[result.mBuffer[i]];
+			}
+		}
 	}
 	else
 	{

src/rendering/hwrenderer/scene/hw_drawinfo.cpp

@@ -900,7 +900,7 @@ void HWDrawInfo::RenderScene(FRenderState &state)
 
 	drawlists[GLDL_MODELS].Draw(this, state, false);
 
-	state.SetPaletteMode(false); // Translucent stuff uses other rules in the software renderer. We don't support that right now.
+	state.SetPaletteMode(false); // Decals run with some renderstyle that is still not correctly handled
 
 	state.SetRenderStyle(STYLE_Translucent);
 
@@ -1007,6 +1007,15 @@ void HWDrawInfo::RenderTranslucent(FRenderState &state)
 {
 	RenderAll.Clock();
 
+	if (!V_IsTrueColor())
+	{
+		state.SetPaletteMode(!V_IsTrueColor());
+
+		FColormap cm;
+		cm.Clear();
+		state.SetSWColormap(GetColorTable(cm));
+	}
+
 	// final pass: translucent stuff
 	state.AlphaFunc(Alpha_GEqual, gl_mask_sprite_threshold);
 	state.SetRenderStyle(STYLE_Translucent);
@@ -1031,6 +1040,7 @@ void HWDrawInfo::RenderTranslucent(FRenderState &state)
 	drawlists[GLDL_TRANSLUCENT].DrawSorted(this, state);
 	state.EnableBrightmap(false);
 
+	state.SetPaletteMode(false);
 
 	state.AlphaFunc(Alpha_GEqual, 0.5f);
 	state.SetDepthMask(true);

src/rendering/hwrenderer/scene/hw_sprites.cpp

@@ -43,6 +43,7 @@
 #include "vectors.h"
 #include "texturemanager.h"
 #include "basics.h"
+#include "d_main.h"
 
 #include "hw_models.h"
 #include "hwrenderer/scene/hw_drawstructs.h"
@@ -109,6 +110,13 @@ CVARD(Bool, r_showhitbox, false, CVAR_GLOBALCONFIG | CVAR_CHEAT, "show actor hit
 
 void HWSprite::DrawSprite(HWDrawInfo *di, FRenderState &state, bool translucent)
 {
+	bool paletteModeDisabled = false;
+	if ((OverrideShader != -1 || RenderStyle.BlendOp >= STYLEOP_Fuzz) && !V_IsTrueColor()) // We can't do these in palette mode with current shaders
+	{
+		paletteModeDisabled = true;
+		state.SetPaletteMode(false);
+	}
+
 	int gl_spritelight = get_gl_spritelight();
 
 	if(!actor && gl_spritelight > 1) gl_spritelight = 1;
@@ -432,6 +440,9 @@ void HWSprite::DrawSprite(HWDrawInfo *di, FRenderState &state, bool translucent)
 	state.EnableTexture(true);
 	state.SetDynLight(0, 0, 0);
 	state.SetShadeVertex(false);
+
+	if (paletteModeDisabled)
+		state.SetPaletteMode(true);
 }
 
 //==========================================================================

wadsrc/static/shaders/scene/lightmode.glsl

@@ -48,7 +48,7 @@ vec4 getLightColor(Material material)
 		int light = clamp(int((shade - vis) * 32), 0, 31);
 
 		vec3 matColor = texelFetch(textures[uColormapIndex], ivec2(color, 32), 0).rgb;
-		vec4 frag = vec4(texelFetch(textures[uColormapIndex], ivec2(color, light), 0).rgb, 1.0);
+		vec4 frag = vec4(texelFetch(textures[uColormapIndex], ivec2(color, light), 0).rgb, material.Base.a * vColor.a);
 
 		vec4 dynlight = uDynLightColor;