Bitmap Fonts (BMFonts) allow you to render text as a series of glyphs (pre-rendered characters) packed into a single BufferGeometry. This method is highly optimized for performance because it batches all the glyphs into one draw call, significantly reducing the rendering load. You can also use Signed Distance Fields (SDF) to create sharp edges on glyphs, even when zoomed in, providing high-quality text rendering.
- BMFonts also support advanced typography features such as kerning (adjusting space between letters), letter spacing, and word wrapping. The MSDF (Multi-channel Signed Distance Fields) version allows for smooth scaling of text and effects like outline strokes and shadows without losing quality.
- Use Case: Ideal for applications that require rendering large amounts of dynamic text efficiently, such as real-time user interfaces, virtual dashboards, chat windows in VR, or web-based games. BMFonts are well-suited for text-heavy interfaces where performance is a concern.
- Advantages:
- Extremely performant because text is rendered in a single draw call.
- Supports advanced typography features like word wrapping, kerning, and multi-channel signed distance fields for effects like shadows.
- Works well for dynamic text, especially when handling a large number of characters.
- Limitations:
- You need to prepare the font and generate the bitmap texture beforehand, which adds a bit of setup complexity.
- Customizing fonts can require additional tools like
msdf-bmfont-webormsdf-bmfont-xml.
- Example Scenarios:
- In a VR game with a heads-up display (HUD), BMFonts are used to show real-time information such as score, health, or other statistics without degrading performance.
- A chat interface in an immersive WebXR experience, where user-generated text needs to be efficiently rendered without slowing down the main thread.