fix(texture_atlas): added texel offset to ensure correct interpolation on the GPU side

crates/comet_resources/src/texture_atlas.rs

@@ -1,13 +1,10 @@
+use crate::font::*;
+use comet_log::*;
+use image::{DynamicImage, GenericImage, GenericImageView};
 use std::collections::HashMap;
 use std::path::Path;
-use std::time::Instant;
-use image::{DynamicImage, GenericImage, GenericImageView, ImageFormat};
-use comet_log::*;
-use wgpu::{Device, FilterMode, TextureFormat, TextureUsages};
-use crate::font::GlyphData;
-use crate::Texture;
 
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub struct TextureRegion {
     u0: f32,
     v0: f32,
@@ -20,7 +17,16 @@ pub struct TextureRegion {
 }
 
 impl TextureRegion {
-	pub fn new(u0: f32, v0: f32, u1: f32, v1: f32, dimensions: (u32, u32), advance: f32, offset_x: f32, offset_y: f32) -> Self {
+    pub fn new(
+        u0: f32,
+        v0: f32,
+        u1: f32,
+        v1: f32,
+        dimensions: (u32, u32),
+        advance: f32,
+        offset_x: f32,
+        offset_y: f32,
+    ) -> Self {
         Self {
             u0,
             v0,
@@ -29,7 +35,7 @@ impl TextureRegion {
             advance,
             offset_x,
             offset_y,
-			dimensions
+            dimensions,
         }
     }
 
@@ -66,7 +72,7 @@ impl TextureRegion {
     }
 }
 
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub struct TextureAtlas {
     atlas: DynamicImage,
     textures: HashMap<String, TextureRegion>,
@@ -76,7 +82,7 @@ impl TextureAtlas {
     pub fn empty() -> Self {
         Self {
             atlas: DynamicImage::new(1, 1, image::ColorType::Rgb8),
-			textures: HashMap::new()
+            textures: HashMap::new(),
         }
     }
 
@@ -128,9 +134,7 @@ impl TextureAtlas {
         }
     }
 
-	pub fn from_texture_paths(
-		paths: Vec<String>,
-	) -> Self {
+    pub fn from_texture_paths(paths: Vec<String>) -> Self {
         let mut textures: Vec<DynamicImage> = Vec::new();
         let mut regions: HashMap<String, TextureRegion> = HashMap::new();
 
@@ -143,13 +147,19 @@ impl TextureAtlas {
         info!("Textures loaded!");
         info!("Sorting textures by height...");
 
-		let mut texture_path_pairs: Vec<(&DynamicImage, &String)> = textures.iter().zip(paths.iter()).collect();
+        let mut texture_path_pairs: Vec<(&DynamicImage, &String)> =
+            textures.iter().zip(paths.iter()).collect();
         texture_path_pairs.sort_by(|a, b| b.0.height().cmp(&a.0.height()));
-		let (sorted_textures, sorted_paths): (Vec<&DynamicImage>, Vec<&String>) = texture_path_pairs.into_iter().unzip();
-		let sorted_textures: Vec<DynamicImage> = sorted_textures.into_iter().map(|t| t.clone()).collect();
+        let (sorted_textures, sorted_paths): (Vec<&DynamicImage>, Vec<&String>) =
+            texture_path_pairs.into_iter().unzip();
+        let sorted_textures: Vec<DynamicImage> =
+            sorted_textures.into_iter().map(|t| t.clone()).collect();
         let sorted_paths: Vec<String> = sorted_paths.into_iter().map(|s| s.to_string()).collect();
 
-		let (height, width) = (Self::calculate_atlas_height(&sorted_textures), Self::calculate_atlas_width(&sorted_textures));
+        let (height, width) = (
+            Self::calculate_atlas_height(&sorted_textures),
+            Self::calculate_atlas_width(&sorted_textures),
+        );
         let mut base = DynamicImage::new_rgba8(width, height);
 
         let mut previous = sorted_textures.get(0).unwrap().height();
@@ -166,16 +176,18 @@ impl TextureAtlas {
             }
 
             Self::insert_texture_at(&mut base, &texture, x_offset, y_offset);
-			regions.insert(path.to_string(), TextureRegion::new(
-				x_offset as f32 / width as f32,
-				y_offset as f32 / height as f32,
-				(x_offset + texture.width()) as f32 / width as f32,
-				(y_offset + texture.height()) as f32 / height as f32,
-				texture.dimensions(),
-				0.0,
-				0.0,
-				0.0
-			));
+            let texel_w = 0.5 / width as f32;
+            let texel_h = 0.5 / height as f32;
+
+            let u0 = (x_offset as f32 + texel_w) / width as f32;
+            let v0 = (y_offset as f32 + texel_h) / height as f32;
+            let u1 = ((x_offset + texture.width()) as f32 - texel_w) / width as f32;
+            let v1 = ((y_offset + texture.height()) as f32 - texel_h) / height as f32;
+
+            regions.insert(
+                path.to_string(),
+                TextureRegion::new(u0, v0, u1, v1, texture.dimensions(), 0.0, 0.0, 0.0),
+            );
             x_offset += texture.width();
         }
 
@@ -183,25 +195,28 @@ impl TextureAtlas {
 
         TextureAtlas {
             atlas: base,
-			textures: regions
+            textures: regions,
         }
     }
 
-	pub fn from_textures(
-		names: Vec<String>,
-		textures: Vec<DynamicImage>,
-	) -> Self {
+    pub fn from_textures(names: Vec<String>, textures: Vec<DynamicImage>) -> Self {
         let mut regions: HashMap<String, TextureRegion> = HashMap::new();
 
         info!("Sorting textures by height...");
 
-		let mut texture_path_pairs: Vec<(&DynamicImage, &String)> = textures.iter().zip(names.iter()).collect();
+        let mut texture_path_pairs: Vec<(&DynamicImage, &String)> =
+            textures.iter().zip(names.iter()).collect();
         texture_path_pairs.sort_by(|a, b| b.0.height().cmp(&a.0.height()));
-		let (sorted_textures, sorted_paths): (Vec<&DynamicImage>, Vec<&String>) = texture_path_pairs.into_iter().unzip();
-		let sorted_textures: Vec<DynamicImage> = sorted_textures.into_iter().map(|t| t.clone()).collect();
+        let (sorted_textures, sorted_paths): (Vec<&DynamicImage>, Vec<&String>) =
+            texture_path_pairs.into_iter().unzip();
+        let sorted_textures: Vec<DynamicImage> =
+            sorted_textures.into_iter().map(|t| t.clone()).collect();
         let sorted_paths: Vec<String> = sorted_paths.into_iter().map(|s| s.to_string()).collect();
 
-		let (height, width) = (Self::calculate_atlas_height(&sorted_textures), Self::calculate_atlas_width(&sorted_textures));
+        let (height, width) = (
+            Self::calculate_atlas_height(&sorted_textures),
+            Self::calculate_atlas_width(&sorted_textures),
+        );
         let mut base = DynamicImage::new_rgba8(width, height);
 
         let mut previous = sorted_textures.get(0).unwrap().height();
@@ -218,7 +233,9 @@ impl TextureAtlas {
             }
 
             Self::insert_texture_at(&mut base, &texture, x_offset, y_offset);
-			regions.insert(name.to_string(), TextureRegion::new(
+            regions.insert(
+                name.to_string(),
+                TextureRegion::new(
                     x_offset as f32 / width as f32,
                     y_offset as f32 / height as f32,
                     (x_offset + texture.width()) as f32 / width as f32,
@@ -226,8 +243,9 @@ impl TextureAtlas {
                     texture.dimensions(),
                     0.0,
                     0.0,
-				0.0
-			));
+                    0.0,
+                ),
+            );
             x_offset += texture.width();
         }
 
@@ -235,7 +253,7 @@ impl TextureAtlas {
 
         TextureAtlas {
             atlas: base,
-			textures: regions
+            textures: regions,
         }
     }
 
@@ -243,10 +261,10 @@ impl TextureAtlas {
         glyphs.sort_by(|a, b| b.render.height().cmp(&a.render.height()));
 
         let height = Self::calculate_atlas_height(
-			&glyphs.iter().map(|g| g.render.clone()).collect::<Vec<_>>()
+            &glyphs.iter().map(|g| g.render.clone()).collect::<Vec<_>>(),
         );
         let width = Self::calculate_atlas_width(
-			&glyphs.iter().map(|g| g.render.clone()).collect::<Vec<_>>()
+            &glyphs.iter().map(|g| g.render.clone()).collect::<Vec<_>>(),
         );
 
         let padding = (glyphs.len() * 3) as u32;
@@ -257,7 +275,6 @@ impl TextureAtlas {
         let mut x_offset: u32 = 0;
         let mut y_offset: u32 = 0;
 
-
         for g in glyphs.iter() {
             let glyph_w = g.render.width();
             let glyph_h = g.render.height();
@@ -276,7 +293,10 @@ impl TextureAtlas {
             let v1 = (y_offset + glyph_h) as f32 / height as f32;
 
             let region = TextureRegion::new(
-				u0, v0, u1, v1,
+                u0,
+                v0,
+                u1,
+                v1,
                 (glyph_w, glyph_h),
                 g.advance,
                 g.offset_x,
@@ -294,6 +314,106 @@ impl TextureAtlas {
         }
     }
 
+    pub fn from_fonts(fonts: &Vec<Font>) -> Self {
+        if fonts.is_empty() {
+            return Self::empty();
+        }
+
+        let mut all_glyphs: Vec<(String, DynamicImage, TextureRegion)> = Vec::new();
+
+        let mut font_indices: Vec<usize> = (0..fonts.len()).collect();
+        font_indices.sort_by(|&a, &b| fonts[a].name().cmp(&fonts[b].name()));
+
+        for fi in font_indices {
+            let font = &fonts[fi];
+            let font_name = font.name();
+
+            let mut glyph_names: Vec<String> = font.glyphs().textures().keys().cloned().collect();
+            glyph_names.sort();
+
+            for glyph_name in glyph_names {
+                let region = font.glyphs().textures().get(&glyph_name).unwrap();
+
+                let (u0, v0, u1, v1) = (region.u0(), region.v0(), region.u1(), region.v1());
+                let (width, height) = region.dimensions();
+
+                let src_x = (u0 * font.glyphs().atlas().width() as f32) as u32;
+                let src_y = (v0 * font.glyphs().atlas().height() as f32) as u32;
+
+                let glyph_img = DynamicImage::ImageRgba8(
+                    font.glyphs()
+                        .atlas()
+                        .view(src_x, src_y, width, height)
+                        .to_image(),
+                );
+
+                let key = format!("{}::{}", font_name, glyph_name);
+
+                all_glyphs.push((key, glyph_img, region.clone()));
+            }
+        }
+
+        all_glyphs.sort_by(|a, b| {
+            let ha = a.1.height();
+            let hb = b.1.height();
+            match hb.cmp(&ha) {
+                std::cmp::Ordering::Equal => a.0.cmp(&b.0),
+                other => other,
+            }
+        });
+
+        let textures: Vec<DynamicImage> =
+            all_glyphs.iter().map(|(_, img, _)| img.clone()).collect();
+        let atlas_height = Self::calculate_atlas_height(&textures);
+        let atlas_width = Self::calculate_atlas_width(&textures);
+
+        let padding = (all_glyphs.len() * 3) as u32;
+        let mut base = DynamicImage::new_rgba8(atlas_width + padding, atlas_height);
+        let mut regions = HashMap::new();
+
+        let mut current_row_height = textures[0].height();
+        let mut x_offset: u32 = 0;
+        let mut y_offset: u32 = 0;
+
+        for (key, img, original_region) in all_glyphs {
+            let w = img.width();
+            let h = img.height();
+
+            if h != current_row_height {
+                y_offset += current_row_height + 3;
+                x_offset = 0;
+                current_row_height = h;
+            }
+
+            Self::insert_texture_at(&mut base, &img, x_offset, y_offset);
+
+            let u0 = x_offset as f32 / (atlas_width + padding) as f32;
+            let v0 = y_offset as f32 / atlas_height as f32;
+            let u1 = (x_offset + w) as f32 / (atlas_width + padding) as f32;
+            let v1 = (y_offset + h) as f32 / atlas_height as f32;
+
+            let region = TextureRegion::new(
+                u0,
+                v0,
+                u1,
+                v1,
+                (w, h),
+                original_region.advance(),
+                original_region.offset_x(),
+                original_region.offset_y(),
+            );
+
+            regions.insert(key, region);
+
+            x_offset += w + 3;
+        }
+
+        TextureAtlas {
+            atlas: base,
+            textures: regions,
+        }
+    }
+
     pub fn atlas(&self) -> &DynamicImage {
         &self.atlas
     }