Remove use_texture_alpha compatibility code for nodeboxes & meshes (#13929)

doc/lua_api.md

@@ -8837,8 +8837,8 @@ Used by `minetest.register_node`.
     --           depending on the alpha channel being below/above 50% in value
     -- * "blend": The alpha channel specifies how transparent a given pixel
     --            of the rendered node is
-    -- The default is "opaque" for drawtypes normal, liquid and flowingliquid;
+    -- The default is "opaque" for drawtypes normal, liquid and flowingliquid,
-    -- "clip" otherwise.
+    -- mesh and nodebox or "clip" otherwise.
     -- If set to a boolean value (deprecated): true either sets it to blend
     -- or clip, false sets it to clip or opaque mode depending on the drawtype.
 

src/nodedef.cpp

@@ -420,8 +420,6 @@ void ContentFeatures::reset()
 
 void ContentFeatures::setAlphaFromLegacy(u8 legacy_alpha)
 {
-	// No special handling for nodebox/mesh here as it doesn't make sense to
-	// throw warnings when the server is too old to support the "correct" way
 	switch (drawtype) {
 	case NDT_NORMAL:
 		alpha = legacy_alpha == 255 ? ALPHAMODE_OPAQUE : ALPHAMODE_CLIP;
@@ -648,6 +646,8 @@ void ContentFeatures::deSerialize(std::istream &is, u16 protocol_version)
 		if (is.eof())
 			throw SerializationError("");
 		alpha = static_cast<enum AlphaMode>(tmp);
+		if (alpha == ALPHAMODE_LEGACY_COMPAT)
+			alpha = ALPHAMODE_OPAQUE;
 
 		tmp = readU8(is);
 		if (is.eof())
@@ -749,55 +749,6 @@ static void fillTileAttribs(ITextureSource *tsrc, TileLayer *layer,
 	}
 }
 
-bool ContentFeatures::textureAlphaCheck(ITextureSource *tsrc, const TileDef *tiles, int length)
-{
-	video::IVideoDriver *driver = RenderingEngine::get_video_driver();
-	static thread_local bool long_warning_printed = false;
-	std::set<std::string> seen;
-
-	for (int i = 0; i < length; i++) {
-		if (seen.find(tiles[i].name) != seen.end())
-			continue;
-		seen.insert(tiles[i].name);
-
-		// Load the texture and see if there's any transparent pixels
-		video::ITexture *texture = tsrc->getTexture(tiles[i].name);
-		video::IImage *image = driver->createImage(texture,
-			core::position2d<s32>(0, 0), texture->getOriginalSize());
-		if (!image)
-			continue;
-		core::dimension2d<u32> dim = image->getDimension();
-		bool ok = true;
-		for (u16 x = 0; x < dim.Width; x++) {
-			for (u16 y = 0; y < dim.Height; y++) {
-				if (image->getPixel(x, y).getAlpha() < 255) {
-					ok = false;
-					goto break_loop;
-				}
-			}
-		}
-
-break_loop:
-		image->drop();
-		if (ok)
-			continue;
-		warningstream << "Texture \"" << tiles[i].name << "\" of "
-			<< name << " has transparency, assuming "
-			"use_texture_alpha = \"clip\"." << std::endl;
-		if (!long_warning_printed) {
-			warningstream << "  This warning can be a false-positive if "
-				"unused pixels in the texture are transparent. However if "
-				"it is meant to be transparent, you *MUST* update the "
-				"nodedef and set use_texture_alpha = \"clip\"! This "
-				"compatibility code will be removed in a few releases."
-				<< std::endl;
-			long_warning_printed = true;
-		}
-		return true;
-	}
-	return false;
-}
-
 bool isWorldAligned(AlignStyle style, WorldAlignMode mode, NodeDrawType drawtype)
 {
 	if (style == ALIGN_STYLE_WORLD)
@@ -841,11 +792,6 @@ void ContentFeatures::updateTextures(ITextureSource *tsrc, IShaderSource *shdsrc
 
 	bool is_liquid = false;
 
-	if (alpha == ALPHAMODE_LEGACY_COMPAT) {
-		// Before working with the alpha mode, resolve any legacy kludges
-		alpha = textureAlphaCheck(tsrc, tdef, 6) ? ALPHAMODE_CLIP : ALPHAMODE_OPAQUE;
-	}
-
 	MaterialType material_type = alpha == ALPHAMODE_OPAQUE ?
 		TILE_MATERIAL_OPAQUE : (alpha == ALPHAMODE_CLIP ? TILE_MATERIAL_BASIC :
 		TILE_MATERIAL_ALPHA);

src/nodedef.h

@@ -258,7 +258,7 @@ enum AlphaMode : u8 {
 	ALPHAMODE_BLEND,
 	ALPHAMODE_CLIP,
 	ALPHAMODE_OPAQUE,
-	ALPHAMODE_LEGACY_COMPAT, /* means either opaque or clip */
+	ALPHAMODE_LEGACY_COMPAT, /* only sent by old servers, equals OPAQUE */
 };
 
 
@@ -466,11 +466,9 @@ struct ContentFeatures
 		case NDT_NORMAL:
 		case NDT_LIQUID:
 		case NDT_FLOWINGLIQUID:
-			alpha = ALPHAMODE_OPAQUE;
-			break;
 		case NDT_NODEBOX:
 		case NDT_MESH:
-			alpha = ALPHAMODE_LEGACY_COMPAT; // this should eventually be OPAQUE
+			alpha = ALPHAMODE_OPAQUE;
 			break;
 		default:
 			alpha = ALPHAMODE_CLIP;
@@ -529,16 +527,6 @@ struct ContentFeatures
 #endif
 
 private:
-#ifndef SERVER
-	/*
-	 * Checks if any tile texture has any transparent pixels.
-	 * Prints a warning and returns true if that is the case, false otherwise.
-	 * This is supposed to be used for use_texture_alpha backwards compatibility.
-	 */
-	bool textureAlphaCheck(ITextureSource *tsrc, const TileDef *tiles,
-		int length);
-#endif
-
 	void setAlphaFromLegacy(u8 legacy_alpha);
 
 	u8 getAlphaForLegacy() const;