From 014014ca0f50f44d8767e46eb82625b2120282e0 Mon Sep 17 00:00:00 2001 From: Jesse Plamondon-Willard Date: Sat, 29 Apr 2017 19:51:47 -0400 Subject: premultiply alpha when loading PNGs to avoid transparency issues (#257) --- src/StardewModdingAPI/Framework/ContentHelper.cs | 179 +++++++++++++++-------- src/StardewModdingAPI/IContentHelper.cs | 8 +- 2 files changed, 120 insertions(+), 67 deletions(-) diff --git a/src/StardewModdingAPI/Framework/ContentHelper.cs b/src/StardewModdingAPI/Framework/ContentHelper.cs index 0d063ef0..9abfc7e9 100644 --- a/src/StardewModdingAPI/Framework/ContentHelper.cs +++ b/src/StardewModdingAPI/Framework/ContentHelper.cs @@ -1,6 +1,7 @@ using System; using System.IO; using System.Linq; +using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Content; using Microsoft.Xna.Framework.Graphics; using StardewValley; @@ -41,7 +42,7 @@ namespace StardewModdingAPI.Framework this.RelativeContentFolder = this.GetRelativePath(contentManager.FullRootDirectory, modFolderPath); } - /// Fetch and cache content from the game content or mod folder (if not already cached), and return it. + /// Load content from the game folder or mod folder (if not already cached), and return it. When loading a .png file, this must be called outside the game's draw loop. /// The expected data type. The main supported types are and dictionaries; other types may be supported by the game's content pipeline. /// The asset key to fetch (if the is ), or the local path to an XNB file relative to the mod folder. /// Where to search for a matching content asset. @@ -56,78 +57,68 @@ namespace StardewModdingAPI.Framework throw new ArgumentException("The asset key or local path contains invalid characters."); // load content - switch (source) - { - case ContentSource.GameContent: - return this.LoadFromGameContent(key, key, source); - - case ContentSource.ModFolder: - // find content file - FileInfo file = new FileInfo(Path.Combine(this.ModFolderPath, key)); - if (!file.Exists && file.Extension == "") - file = new FileInfo(Path.Combine(this.ModFolderPath, key + ".xnb")); - if (!file.Exists) - throw new ContentLoadException($"There is no file at path '{file.FullName}'."); - - // get content-relative path - string contentPath = Path.Combine(this.RelativeContentFolder, key); - if (contentPath.EndsWith(".xnb")) - contentPath = contentPath.Substring(0, contentPath.Length - 4); - - // load content - switch (file.Extension.ToLower()) - { - case ".xnb": - return this.LoadFromGameContent(contentPath, key, source); - - case ".png": - // validate - if (typeof(T) != typeof(Texture2D)) - throw new ContentLoadException($"Can't read file with extension '{file.Extension}' as type '{typeof(T)}'; must be type '{typeof(Texture2D)}'."); - - // try cache - if (this.ContentManager.IsLoaded(contentPath)) - return this.LoadFromGameContent(contentPath, key, source); - - // fetch & cache - using (FileStream stream = File.OpenRead(file.FullName)) - { - Texture2D texture = Texture2D.FromStream(Game1.graphics.GraphicsDevice, stream); - this.ContentManager.Inject(contentPath, texture); - return (T)(object)texture; - } - - default: - throw new ContentLoadException($"Unknown file extension '{file.Extension}'; must be '.xnb' or '.png'."); - } - - default: - throw new NotSupportedException($"Unknown content source '{source}'."); - } - } - - - /********* - ** Private methods - *********/ - /// Load a content asset through the underlying content manager, and throw a friendly error if it fails. - /// The expected data type. - /// The content key. - /// The friendly content key to show in errors. - /// The content source for use in errors. - /// The content couldn't be loaded. - private T LoadFromGameContent(string assetKey, string friendlyKey, ContentSource source) - { try { - return this.ContentManager.Load(assetKey); + switch (source) + { + case ContentSource.GameContent: + return this.ContentManager.Load(key); + + case ContentSource.ModFolder: + // find content file + FileInfo file = new FileInfo(Path.Combine(this.ModFolderPath, key)); + if (!file.Exists && file.Extension == "") + file = new FileInfo(Path.Combine(this.ModFolderPath, key + ".xnb")); + if (!file.Exists) + throw new ContentLoadException($"There is no file at path '{file.FullName}'."); + + // get content-relative path + string contentPath = Path.Combine(this.RelativeContentFolder, key); + if (contentPath.EndsWith(".xnb")) + contentPath = contentPath.Substring(0, contentPath.Length - 4); + + // load content + switch (file.Extension.ToLower()) + { + case ".xnb": + return this.ContentManager.Load(contentPath); + + case ".png": + // validate + if (typeof(T) != typeof(Texture2D)) + throw new ContentLoadException($"Can't read file with extension '{file.Extension}' as type '{typeof(T)}'; must be type '{typeof(Texture2D)}'."); + + // try cache + if (this.ContentManager.IsLoaded(contentPath)) + return this.ContentManager.Load(contentPath); + + // fetch & cache + using (FileStream stream = File.OpenRead(file.FullName)) + { + var texture = Texture2D.FromStream(Game1.graphics.GraphicsDevice, stream); + texture = this.PremultiplyTransparency(texture); + this.ContentManager.Inject(contentPath, texture); + return (T)(object)texture; + } + + default: + throw new ContentLoadException($"Unknown file extension '{file.Extension}'; must be '.xnb' or '.png'."); + } + + default: + throw new NotSupportedException($"Unknown content source '{source}'."); + } } catch (Exception ex) { - throw new ContentLoadException($"{this.ModName} failed loading content asset '{friendlyKey}' from {source}.", ex); + throw new ContentLoadException($"{this.ModName} failed loading content asset '{key}' from {source}.", ex); } } + + /********* + ** Private methods + *********/ /// Get a directory path relative to a given root. /// The root path from which the path should be relative. /// The target file path. @@ -143,5 +134,63 @@ namespace StardewModdingAPI.Framework return Uri.UnescapeDataString(from.MakeRelativeUri(to).ToString()) .Replace(Path.DirectorySeparatorChar == '/' ? '\\' : '/', Path.DirectorySeparatorChar); // use correct separator for platform } + + /// Premultiply a texture's alpha values to avoid transparency issues in the game. This is only possible if the game isn't currently drawing. + /// The texture to premultiply. + /// Returns a premultiplied texture. + /// Based on code by Layoric. + private Texture2D PremultiplyTransparency(Texture2D texture) + { + if (Game1.graphics.GraphicsDevice.GetRenderTargets().Any()) // TODO: use a more robust check to detect if the game is drawing + throw new NotSupportedException("Can't load a PNG file while the game is drawing to the screen. Make sure you load content outside the draw loop."); + + using (RenderTarget2D renderTarget = new RenderTarget2D(Game1.graphics.GraphicsDevice, texture.Width, texture.Height)) + using (SpriteBatch spriteBatch = new SpriteBatch(Game1.graphics.GraphicsDevice)) + { + //Viewport originalViewport = Game1.graphics.GraphicsDevice.Viewport; + + // create blank slate in render target + Game1.graphics.GraphicsDevice.SetRenderTarget(renderTarget); + Game1.graphics.GraphicsDevice.Clear(Color.Black); + + // multiply each color by the source alpha, and write just the color values into the final texture + spriteBatch.Begin(SpriteSortMode.Immediate, new BlendState + { + ColorDestinationBlend = Blend.Zero, + ColorWriteChannels = ColorWriteChannels.Red | ColorWriteChannels.Green | ColorWriteChannels.Blue, + AlphaDestinationBlend = Blend.Zero, + AlphaSourceBlend = Blend.SourceAlpha, + ColorSourceBlend = Blend.SourceAlpha + }); + spriteBatch.Draw(texture, texture.Bounds, Color.White); + spriteBatch.End(); + + // copy the alpha values from the source texture into the final one without multiplying them + spriteBatch.Begin(SpriteSortMode.Immediate, new BlendState + { + ColorWriteChannels = ColorWriteChannels.Alpha, + AlphaDestinationBlend = Blend.Zero, + ColorDestinationBlend = Blend.Zero, + AlphaSourceBlend = Blend.One, + ColorSourceBlend = Blend.One + }); + spriteBatch.Draw(texture, texture.Bounds, Color.White); + spriteBatch.End(); + + // release the GPU + Game1.graphics.GraphicsDevice.SetRenderTarget(null); + //Game1.graphics.GraphicsDevice.Viewport = originalViewport; + + // store data from render target because the RenderTarget2D is volatile + var data = new Color[texture.Width * texture.Height]; + renderTarget.GetData(data); + + // unset texture from graphic device and set modified data back to it + Game1.graphics.GraphicsDevice.Textures[0] = null; + texture.SetData(data); + } + + return texture; + } } } diff --git a/src/StardewModdingAPI/IContentHelper.cs b/src/StardewModdingAPI/IContentHelper.cs index 09f58a71..b878dfe5 100644 --- a/src/StardewModdingAPI/IContentHelper.cs +++ b/src/StardewModdingAPI/IContentHelper.cs @@ -1,14 +1,18 @@ -using Microsoft.Xna.Framework.Graphics; +using System; +using Microsoft.Xna.Framework.Content; +using Microsoft.Xna.Framework.Graphics; namespace StardewModdingAPI { /// Provides an API for loading content assets. public interface IContentHelper { - /// Fetch and cache content from the game content or mod folder (if not already cached), and return it. + /// Load content from the game folder or mod folder (if not already cached), and return it. When loading a .png file, this must be called outside the game's draw loop. /// The expected data type. The main supported types are and dictionaries; other types may be supported by the game's content pipeline. /// The asset key to fetch (if the is ), or the local path to an XNB file relative to the mod folder. /// Where to search for a matching content asset. + /// The is empty or contains invalid characters. + /// The content asset couldn't be loaded (e.g. because it doesn't exist). T Load(string key, ContentSource source); } } -- cgit