From 6ae59dab5bca9d44fdf4a7f517654b1c0f8545f1 Mon Sep 17 00:00:00 2001
From: Matthew <matthew@sleepy.day>
Date: Sat, 18 Apr 2026 14:59:57 +1000
Subject: [PATCH] add slug vertex loading

---
 fonts.d | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 76 insertions(+), 4 deletions(-)

diff --git a/fonts.d b/fonts.d
index 67be754..64f6d5e 100644
--- a/fonts.d
+++ b/fonts.d
@@ -102,9 +102,9 @@ struct SlugVertex
 		{
 			Vec2    em_space_pos;
 			U16Vec2 glyph_data_coords;
-			struct max_bands
+			struct
 			{
-				u8 x, pad, y, e;
+				u8 max_bands_x, pad, max_bands_y, max_bands_e;
 			};
 		}
 	};
@@ -121,13 +121,20 @@ struct SlugVertex
 		Vec4 band;
 		struct
 		{
-			Vec4 scale;
-			Vec4 offset;
+			Vec2 band_scale;
+			Vec2 band_offset;
 		};
 	};
 	Vec4 color;
 }
 
+struct SlugBuffer
+{
+	SlugVertex[] vertices;
+	u32[]        indices;
+	u32          quad_offset;
+}
+
 struct FontAtlas
 {
 	Glyph[128]  glyphs;
@@ -818,3 +825,68 @@ SlugBuildBands(Arena* arena, u32 index, SlugFontInfo* font_info, u32 band_count)
 		}
 	}
 }
+
+void
+SlugLoadFontVertex(u8 ch, IVec2 pos, SlugFont* font, SlugBuffer* buffer)
+{
+	ch = ch > 127 ? 0 : ch;
+
+	SlugGlyph* glyph = &font.glyphs[ch];
+
+	if(ch == ' ')
+	{
+		pos.x += cast(i32)(cast(f32)(glyph.advance) * font.scale);
+	}
+	else if(glyph.curve_count > 0)
+	{
+		Vec2 glyph_pos = Vec2(pos.x, pos.y);
+
+		Vec2 p0 = glyph_pos + glyph.rect.min * font.scale;
+		Vec2 p1 = glyph_pos + glyph.rect.max * font.scale;
+
+		u32 vertex_start = buffer.quad_offset*4;
+		u32 index_start  = buffer.quad_offset*6;
+
+		SlugVertex[] vertices = buffer.vertices[vertex_start .. vertex_start+4];
+		u32[]        indices  = buffer.indices[index_start   .. index_start+6];
+
+		const f32 NORMAL = 1.0;
+
+		f32 inv_scale = 1.0f/font.scale;
+
+		foreach(i; 0 .. 4)
+		{
+			vertices[i].band_scale        = glyph.band_scale;
+			vertices[i].band_offset       = glyph.band_offset;
+			vertices[i].glyph_data_coords = glyph.coords;
+			vertices[i].max_bands_x       = glyph.max_bands.x;
+			vertices[i].max_bands_y       = glyph.max_bands.y;
+			vertices[i].jac               = Vec4(inv_scale, 0.0, 0.0, inv_scale);
+
+			vertices[i].color = 1.0;
+		}
+
+		vertices[0].vertex_coords = p0;
+		vertices[0].normal        = Vec2(-NORMAL, +NORMAL);
+		vertices[0].em_space_pos  = Vec2(glyph.rect.min.x, glyph.rect.max.y);
+
+		vertices[1].vertex_coords = Vec2(p0.x, p1.y);
+		vertices[1].normal        = -NORMAL;
+		vertices[1].em_space_pos  = glyph.rect.min;
+
+		vertices[2].vertex_coords = Vec2(p1.x, p0.y);
+		vertices[2].normal        = +NORMAL;
+		vertices[2].em_space_pos  = glyph.rect.max;
+
+		vertices[3].vertex_coords = p1;
+		vertices[3].normal        = Vec2(+NORMAL, -NORMAL);
+		vertices[3].em_space_pos  = Vec2(glyph.rect.max.x, glyph.rect.min.y);
+
+		u32 vidx = vertex_start;
+		indices[0 .. 6] = [vidx+0, vidx+2, vidx+3, vidx+3, vidx+1, vidx+0];
+
+		buffer.quad_offset += 1;
+
+		pos.x += cast(i32)(cast(f32)(glyph.advance) * font.scale);
+	}
+}