Fix more font issues

bootstrap/bloat-buster/font.c

@@ -5,7 +5,6 @@
 
 TextureAtlas font_create_texture_atlas(Arena* arena, String font_path)
 {
-
     auto font_file = file_read(arena, font_path);
     stbtt_fontinfo font_info;
     if (!stbtt_InitFont(&font_info, font_file.pointer, stbtt_GetFontOffsetForIndex(font_file.pointer, 0)))
@@ -14,37 +13,39 @@ TextureAtlas font_create_texture_atlas(Arena* arena, String font_path)
     }
 
     TextureAtlas result = {};
+    u32 char_count = 256;
+    result.characters = arena_allocate(arena, FontCharacter, char_count);
     result.character_height = 64;
     result.character_width = result.character_height;
     result.height = 1024;
     result.width = result.height;
     auto atlas_size = result.width * result.height;
     result.pointer = arena_allocate(arena, u8, atlas_size);
-
-    float scale_x = 0.0f;
-    float scale_y = stbtt_ScaleForPixelHeight(&font_info, result.character_height);
+    result.scale = stbtt_ScaleForPixelHeight(&font_info, result.character_height);
     
     // Starting position in the atlas
     u32 x = 0;
     u32 y = 0; 
-    u32 char_count = 256;
 
     for (u32 i = 0; i < char_count; ++i)
     {
         u32 width;
         u32 height;
-        u32 x_offset;
-        u32 y_offset;
+        int x_offset;
+        int y_offset;
 
         auto ch = (u8)i;
-        u8* bitmap = stbtt_GetCodepointBitmap(&font_info, scale_x, scale_y, ch, (int*)&width, (int*)&height, (int*)&x_offset, (int*)&y_offset);
-        if (bitmap)
+        auto* character = &result.characters[i];
+        stbtt_GetCodepointHMetrics(&font_info, ch, (int*)&character->advance, (int*)&character->left_bearing);
+
+        u8* bitmap = stbtt_GetCodepointBitmap(&font_info, 0.0f, result.scale, ch, (int*)&width, (int*)&height, &x_offset, &y_offset);
+        if (width > 0 && height > 0)
         {
             for (u32 j = 0; j < height; ++j)
             {
                 for (u32 i = 0; i < width; ++i)
                 {
-                    auto atlas_index = (y + j) * result.width + (x + i);
+                    auto atlas_index = (y + j) * result.width + (x + i ) + 1;
                     auto bitmap_index = (height - j - 1) * width + i;
                     assert(atlas_index < atlas_size);
                     result.pointer[atlas_index] = bitmap[bitmap_index];

bootstrap/bloat-buster/gui.c

@@ -1241,17 +1241,16 @@ strlit("/usr/share/fonts/TTF/FiraSans-Regular.ttf")
 
     Vec4 color = {1, 1, 1, 1};
     static_assert(sizeof(color) == 4 * sizeof(float));
-    auto width_float = (f32)initial_width;
-    auto height_float = (f32)initial_height;
 
-    auto string = strlit("abc");
+    auto string = strlit("abcdefghi");
     VirtualBuffer(Vertex) vertices = {};
     VirtualBuffer(u32) indices = {};
     u32 index_offset = 0;
-    u32 x_offset = width_float / 2;
-    u32 y_offset = height_float / 2;
+    f32 x_offset = initial_width / 2.0f;
+    f32 y_offset = initial_height / 2.0f;
+    f32 font_scale = texture_atlas.scale;
 
-    for (u64 i = 0; i < string.length; i += 1, index_offset += 4, x_offset += texture_atlas.character_width)
+    for (u64 i = 0; i < string.length; i += 1, index_offset += 4)
     {
         auto ch = string.pointer[i];
         auto character_count_per_row = texture_atlas.width / texture_atlas.character_width;
@@ -1297,6 +1296,8 @@ strlit("/usr/share/fonts/TTF/FiraSans-Regular.ttf")
         *vb_add(&indices, 1) = index_offset + 1;
         *vb_add(&indices, 1) = index_offset + 3;
         *vb_add(&indices, 1) = index_offset + 2;
+
+        x_offset += texture_atlas.characters[i].advance * font_scale;
     }
 
     auto vertex_buffer_size = sizeof(*vertices.pointer) * vertices.length;

bootstrap/include/bloat-buster/font.h

@@ -3,7 +3,8 @@
 
 STRUCT(FontCharacter)
 {
-    int advance;
+    u32 advance;
+    u32 left_bearing;
 };
 
 STRUCT(TextureAtlas)
@@ -14,6 +15,7 @@ STRUCT(TextureAtlas)
     u32 height;
     u32 character_width;
     u32 character_height;
+    f32 scale;
 };
 
 EXPORT TextureAtlas font_create_texture_atlas(Arena* arena, String font_path);