Add optional alpha threshold option for fonts

source/core/StarFont.cpp

@@ -51,7 +51,7 @@ FontPtr Font::loadTrueTypeFont(ByteArrayConstPtr const& bytes, unsigned pixelSiz
   return font;
 }
 
-Font::Font() : m_pixelSize(0) {}
+Font::Font() : m_pixelSize(0), m_alphaThreshold(0) {}
 
 FontPtr Font::clone() const {
   return Font::loadTrueTypeFont(m_fontBuffer, m_pixelSize);
@@ -70,6 +70,10 @@ void Font::setPixelSize(unsigned pixelSize) {
   m_pixelSize = pixelSize;
 }
 
+void Font::setAlphaThreshold(uint8_t alphaThreshold) {
+  m_alphaThreshold = alphaThreshold;
+}
+
 unsigned Font::height() const {
   return m_pixelSize;
 }
@@ -112,8 +116,14 @@ std::pair<Image, Vec2I> Font::render(String::Char c) {
     uint8_t* p = slot->bitmap.buffer + y * slot->bitmap.pitch;
     for (unsigned x = 0; x != width; ++x) {
       if (x >= 0 && y >= 0 && x < width && y < height) {
-        if (uint8_t val = *(p + x)) {
-          white.setW(val);
+        uint8_t value = *(p + x);
+        if (m_alphaThreshold) {
+          if (value >= m_alphaThreshold) {
+            white[3] = 255;
+            image.set(x + 1, height - y, white);
+          }
+        } else if (value) {
+          white[3] = value;
           image.set(x + 1, height - y, white);
         }
       }

source/core/StarFont.hpp

@@ -27,6 +27,7 @@ public:
   FontPtr clone() const;
 
   void setPixelSize(unsigned pixelSize);
+  void setAlphaThreshold(uint8_t alphaThreshold = 0);
 
   unsigned height() const;
   unsigned width(String::Char c);
@@ -40,6 +41,7 @@ private:
   FontImplPtr m_fontImpl;
   ByteArrayConstPtr m_fontBuffer;
   unsigned m_pixelSize;
+  uint8_t m_alphaThreshold;
 
   HashMap<pair<String::Char, unsigned>, unsigned> m_widthCache;
 };

source/rendering/StarTextPainter.cpp

@@ -338,16 +338,18 @@ void TextPainter::reloadFonts() {
   m_fontTextureGroup.clearFonts();
   m_fontTextureGroup.cleanup(0);
   auto assets = Root::singleton().assets();
-  auto defaultFont = assets->font("/hobo.ttf");
+  String defaultName = "hobo";
+  auto defaultFont = loadFont("/hobo.ttf", defaultName);
   for (auto& fontPath : assets->scanExtension("ttf")) {
     auto font = assets->font(fontPath);
     if (font == defaultFont)
       continue;
 
-    auto fileName = AssetPath::filename(fontPath);
-    addFont(font->clone(), fileName.substr(0, fileName.findLast(".")));
+    auto name = AssetPath::filename(fontPath);
+    name = name.substr(0, name.findLast("."));
+    addFont(loadFont(fontPath, name), name);
   }
-  m_fontTextureGroup.addFont(defaultFont->clone(), "hobo", true);
+  m_fontTextureGroup.addFont(defaultFont, defaultName, true);
 }
 
 void TextPainter::cleanup(int64_t timeout) {
@@ -512,4 +514,18 @@ void TextPainter::renderGlyph(String::Char c, Vec2F const& screenPos, unsigned f
   m_renderer->immediatePrimitives().emplace_back(std::in_place_type_t<RenderQuad>(), glyphTexture.texture, Vec2F::round(screenPos + offset), scale, color, 0.0f);
 }
 
+FontPtr TextPainter::loadFont(String const& fontPath, Maybe<String> fontName) {
+  if (!fontName) {
+    auto name = AssetPath::filename(fontPath);
+    fontName.emplace(name.substr(0, name.findLast(".")));
+  }
+
+  auto assets = Root::singleton().assets();
+
+  auto font = assets->font(fontPath)->clone();
+  if (auto fontConfig = assets->json("/interface.config:font").opt(*fontName)) {
+    font->setAlphaThreshold(fontConfig->getUInt("alphaThreshold", 0));
+  }
+  return font;
+}
 }

source/rendering/StarTextPainter.hpp

@@ -87,6 +87,7 @@ private:
   RectF doRenderGlyph(String::Char c, TextPositioning const& position, bool reallyRender);
 
   void renderGlyph(String::Char c, Vec2F const& screenPos, unsigned fontSize, float scale, Vec4B const& color, Directives const* processingDirectives = nullptr);
+  static FontPtr loadFont(String const& fontPath, Maybe<String> fontName = {});
 
   RendererPtr m_renderer;
   FontTextureGroup m_fontTextureGroup;