Implement MSDF font rendering and change default font

We now use Noto Sans, since it has the broadest Unicode support of the open source fonts. I added a README.md in the font folder, so that people can change the font if the need should arise to do so.

With this change, we unified our text rendering to use MSDF rendering. For this we have to generate the whole font map offline in advance.

Cargo.toml

@@ -8,11 +8,12 @@ bumpalo = "3.16"
 bytemuck = "1.20"
 cgmath = "0.18"
 chrono = "0.4"
-cosmic-text = "0.12"
+cosmic-text = { version = "0.12", default-features = false }
 cpal = "0.15"
 derive-new = "0.7"
 etherparse = "0.16"
 fast-srgb8 = "1"
+flate2 = "1"
 glidesort = "0.1"
 hashbrown = "0.15"
 image = { version = "0.25", default-features = false }

korangar/Cargo.toml

@@ -8,8 +8,9 @@ bumpalo = { workspace = true, features = ["allocator_api"] }
 bytemuck = { workspace = true, features = ["derive", "extern_crate_std", "min_const_generics"] }
 cgmath = { workspace = true, features = ["mint", "serde"] }
 chrono = { workspace = true }
-cosmic-text = { workspace = true }
+cosmic-text = { workspace = true, features = ["std", "fontconfig"] }
 derive-new = { workspace = true }
+flate2 = { workspace = true }
 hashbrown = { workspace = true }
 glidesort = { workspace = true }
 image = { workspace = true, features = ["bmp", "jpeg", "png", "tga", "rayon"] }

korangar/archive/data/font/OFL.txt

@@ -0,0 +1,93 @@
+Copyright 2022 The Noto Project Authors (https://github.com/notofonts/latin-greek-cyrillic)
+
+This Font Software is licensed under the SIL Open Font License, Version 1.1.
+This license is copied below, and is also available with a FAQ at:
+https://openfontlicense.org
+
+
+-----------------------------------------------------------
+SIL OPEN FONT LICENSE Version 1.1 - 26 February 2007
+-----------------------------------------------------------
+
+PREAMBLE
+The goals of the Open Font License (OFL) are to stimulate worldwide
+development of collaborative font projects, to support the font creation
+efforts of academic and linguistic communities, and to provide a free and
+open framework in which fonts may be shared and improved in partnership
+with others.
+
+The OFL allows the licensed fonts to be used, studied, modified and
+redistributed freely as long as they are not sold by themselves. The
+fonts, including any derivative works, can be bundled, embedded, 
+redistributed and/or sold with any software provided that any reserved
+names are not used by derivative works. The fonts and derivatives,
+however, cannot be released under any other type of license. The
+requirement for fonts to remain under this license does not apply
+to any document created using the fonts or their derivatives.
+
+DEFINITIONS
+"Font Software" refers to the set of files released by the Copyright
+Holder(s) under this license and clearly marked as such. This may
+include source files, build scripts and documentation.
+
+"Reserved Font Name" refers to any names specified as such after the
+copyright statement(s).
+
+"Original Version" refers to the collection of Font Software components as
+distributed by the Copyright Holder(s).
+
+"Modified Version" refers to any derivative made by adding to, deleting,
+or substituting -- in part or in whole -- any of the components of the
+Original Version, by changing formats or by porting the Font Software to a
+new environment.
+
+"Author" refers to any designer, engineer, programmer, technical
+writer or other person who contributed to the Font Software.
+
+PERMISSION & CONDITIONS
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of the Font Software, to use, study, copy, merge, embed, modify,
+redistribute, and sell modified and unmodified copies of the Font
+Software, subject to the following conditions:
+
+1) Neither the Font Software nor any of its individual components,
+in Original or Modified Versions, may be sold by itself.
+
+2) Original or Modified Versions of the Font Software may be bundled,
+redistributed and/or sold with any software, provided that each copy
+contains the above copyright notice and this license. These can be
+included either as stand-alone text files, human-readable headers or
+in the appropriate machine-readable metadata fields within text or
+binary files as long as those fields can be easily viewed by the user.
+
+3) No Modified Version of the Font Software may use the Reserved Font
+Name(s) unless explicit written permission is granted by the corresponding
+Copyright Holder. This restriction only applies to the primary font name as
+presented to the users.
+
+4) The name(s) of the Copyright Holder(s) or the Author(s) of the Font
+Software shall not be used to promote, endorse or advertise any
+Modified Version, except to acknowledge the contribution(s) of the
+Copyright Holder(s) and the Author(s) or with their explicit written
+permission.
+
+5) The Font Software, modified or unmodified, in part or in whole,
+must be distributed entirely under this license, and must not be
+distributed under any other license. The requirement for fonts to
+remain under this license does not apply to any document created
+using the Font Software.
+
+TERMINATION
+This license becomes null and void if any of the above conditions are
+not met.
+
+DISCLAIMER
+THE FONT SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
+OF COPYRIGHT, PATENT, TRADEMARK, OR OTHER RIGHT. IN NO EVENT SHALL THE
+COPYRIGHT HOLDER BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+INCLUDING ANY GENERAL, SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL
+DAMAGES, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF THE USE OR INABILITY TO USE THE FONT SOFTWARE OR FROM
+OTHER DEALINGS IN THE FONT SOFTWARE.

korangar/archive/data/font/README.md

@@ -0,0 +1,21 @@
+# How to use a different font
+
+It is possible to use a different font in Korangar. This may be needed, if you want to support languages that are not
+included in the distributed font file. Currently, we use "Noto Sans", which includes all glyphs for the Latin, Cyrillic,
+and Greek alphabets. If you need to support a different alphabet, then you need to use a different font (for example
+"Noto Sans Japanese"). Since Korangar uses a pre-assembled font map, that includes all glyphs of a font file in
+a multichannel signed distance field (MSDF) representation, you need to create a such a font map and also a font map
+description file in the CSV format:
+
+1. Use [msdfgen](https://github.com/Chlumsky/msdfgen) to create the font map image and the description file in the
+   CSV format.
+   ```sh
+   msdf-atlas-gen -allglyphs -pxrange 6 -size 32 -yorigin top -type mtsdf -format png -font NotoSans.ttf -csv NotoSans.csv -imageout NotoSans.png
+   ```
+2. Copy the original font file and also the generated PNG and CSV file into the `archive/data/font` folder.
+3. Optionally compress the CSV file with gzip:
+   ```sh
+   gzip NotoSans.csv
+   ```
+4. Update the `FONT_FILE_PATH`, `FONT_MAP_DESCRIPTION_FILE_PATH`, `FONT_MAP_FILE_PATH` and `FONT_FAMILY_NAME` in the
+   `korangar/src/loaders/font/mod.rs` file.

korangar/src/graphics/instruction.rs

@@ -41,7 +41,7 @@ pub struct RenderInstruction<'a> {
     pub effects: &'a [EffectInstruction],
     pub water: Option<WaterInstruction<'a>>,
     pub map_picker_tile_vertex_buffer: &'a Buffer<TileVertex>,
-    pub font_atlas_texture: &'a Texture,
+    pub font_map_texture: &'a Texture,
     #[cfg(feature = "debug")]
     pub render_settings: RenderSettings,
     #[cfg(feature = "debug")]
@@ -121,6 +121,15 @@ pub enum RectangleInstruction {
         screen_size: ScreenSize,
         color: Color,
     },
+    Sprite {
+        screen_position: ScreenPosition,
+        screen_size: ScreenSize,
+        color: Color,
+        texture_position: Vector2<f32>,
+        texture_size: Vector2<f32>,
+        linear_filtering: bool,
+        texture: Arc<Texture>,
+    },
     Sdf {
         screen_position: ScreenPosition,
         screen_size: ScreenSize,
@@ -129,15 +138,21 @@ pub enum RectangleInstruction {
         texture_size: Vector2<f32>,
         texture: Arc<Texture>,
     },
-    Sprite {
+    Msdf {
         screen_position: ScreenPosition,
         screen_size: ScreenSize,
         color: Color,
         texture_position: Vector2<f32>,
         texture_size: Vector2<f32>,
-        linear_filtering: bool,
         texture: Arc<Texture>,
     },
+    Text {
+        screen_position: ScreenPosition,
+        screen_size: ScreenSize,
+        color: Color,
+        texture_position: Vector2<f32>,
+        texture_size: Vector2<f32>,
+    },
 }
 
 #[derive(Clone, Debug)]
@@ -149,6 +164,15 @@ pub enum InterfaceRectangleInstruction {
         color: Color,
         corner_radius: CornerRadius,
     },
+    Sprite {
+        screen_position: ScreenPosition,
+        screen_size: ScreenSize,
+        screen_clip: ScreenClip,
+        color: Color,
+        corner_radius: CornerRadius,
+        texture: Arc<Texture>,
+        smooth: bool,
+    },
     Sdf {
         screen_position: ScreenPosition,
         screen_size: ScreenSize,
@@ -157,14 +181,13 @@ pub enum InterfaceRectangleInstruction {
         corner_radius: CornerRadius,
         texture: Arc<Texture>,
     },
-    Sprite {
+    Msdf {
         screen_position: ScreenPosition,
         screen_size: ScreenSize,
         screen_clip: ScreenClip,
         color: Color,
         corner_radius: CornerRadius,
         texture: Arc<Texture>,
-        smooth: bool,
     },
     Text {
         screen_position: ScreenPosition,

korangar/src/graphics/mod.rs

@@ -115,7 +115,7 @@ pub(crate) struct DebugUniforms {
     show_directional_shadow_map: u32,
     show_point_shadow_map: u32,
     show_light_culling_count_buffer: u32,
-    show_font_atlas: u32,
+    show_font_map: u32,
 }
 
 #[derive(Copy, Clone, Pod, Zeroable)]
@@ -272,7 +272,7 @@ impl Prepare for GlobalContext {
                     .map(|value| value.get())
                     .unwrap_or(0),
                 show_light_culling_count_buffer: instructions.render_settings.show_light_culling_count_buffer as u32,
-                show_font_atlas: instructions.render_settings.show_font_atlas as u32,
+                show_font_map: instructions.render_settings.show_font_map as u32,
             };
         }
     }