533 lines
17 KiB
Plaintext
533 lines
17 KiB
Plaintext
#import "modules/std.sx";
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#import "modules/opengl.sx";
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#import "ui/types.sx";
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// Cached glyph data with UV coordinates into the atlas texture
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CachedGlyph :: struct {
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uv_x: f32;
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uv_y: f32;
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uv_w: f32;
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uv_h: f32;
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width: f32;
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height: f32;
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offset_x: f32;
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offset_y: f32;
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advance: f32;
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}
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// Cache entry: key + glyph data
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GlyphEntry :: struct {
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key: u32;
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glyph: CachedGlyph;
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}
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// Quantize font size to half-point increments to limit cache entries.
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// e.g., 13.0 -> 26, 13.5 -> 27, 14.0 -> 28
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quantize_size :: (font_size: f32) -> u16 {
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xx (font_size * 2.0 + 0.5);
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}
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dequantize_size :: (q: u16) -> f32 {
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xx q / 2.0;
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}
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// Pack (glyph_index, size_quantized) into a single u32 for fast comparison
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make_glyph_key :: (glyph_index: u16, size_quantized: u16) -> u32 {
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(xx glyph_index << 16) | xx size_quantized;
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}
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// Shaped glyph — output of text shaping (positioned glyph with index)
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ShapedGlyph :: struct {
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glyph_index: u16;
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x: f32; // horizontal position (logical units, cumulative)
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y: f32; // vertical offset (logical units)
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advance: f32; // advance width (logical units)
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}
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is_ascii :: (text: string) -> bool {
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i : s64 = 0;
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while i < text.len {
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if text[i] >= 128 { return false; }
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i += 1;
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}
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true;
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}
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// kbts constants (C enum values)
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KBTS_DIRECTION_DONT_KNOW :u32: 0;
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KBTS_LANGUAGE_DONT_KNOW :u32: 0;
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KBTS_USER_ID_GENERATION_MODE_CODEPOINT_INDEX :u32: 0;
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// SX structs matching kbts C struct layouts (64-bit).
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// We define these in SX to access fields directly, casting from opaque C pointers.
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KbtsGlyphIterator :: struct {
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glyph_storage: *void;
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current_glyph: *void;
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last_advance_x: s32;
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x: s32;
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y: s32;
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}
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KbtsRun :: struct {
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font: *void;
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script: u32;
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paragraph_direction: u32;
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direction: u32;
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flags: u32;
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glyphs: KbtsGlyphIterator;
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}
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KbtsGlyph :: struct {
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prev: *void;
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next: *void;
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codepoint: u32;
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id: u16;
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uid: u16;
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user_id_or_codepoint_index: s32;
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offset_x: s32;
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offset_y: s32;
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advance_x: s32;
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advance_y: s32;
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}
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// kbts_font_info2 base (simplified — we only need the Size field for dispatch)
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KBTS_FONT_INFO_STRING_ID_COUNT :s32: 7;
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KbtsFontInfo2 :: struct {
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size: u32;
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strings: [7]*void; // char* array
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string_lengths: [7]u16;
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style_flags: u32;
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weight: u32;
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width: u32;
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}
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KbtsFontInfo2_1 :: struct {
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base: KbtsFontInfo2;
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units_per_em: u16;
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x_min: s16;
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y_min: s16;
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x_max: s16;
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y_max: s16;
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ascent: s16;
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descent: s16;
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line_gap: s16;
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}
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GLYPH_ATLAS_W :s32: 1024;
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GLYPH_ATLAS_H :s32: 1024;
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FONTINFO_SIZE :s64: 256;
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PackResult :: struct {
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x, y: s32;
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}
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// Dynamic glyph cache with on-demand rasterization and texture atlas packing.
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GlyphCache :: struct {
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// Font data
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font_info: *void; // heap-allocated stbtt_fontinfo (256 bytes)
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font_data: *void; // raw TTF file bytes (kept alive for stbtt)
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// Atlas texture (GPU)
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texture_id: u32;
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atlas_width: s32;
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atlas_height: s32;
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// Atlas bitmap (CPU-side for updates)
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bitmap: [*]u8;
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// Shelf packer state
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shelf_y: s32;
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shelf_height: s32;
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cursor_x: s32;
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padding: s32;
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// Glyph lookup cache (flat list, linear scan)
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entries: List(GlyphEntry);
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// Dirty tracking for texture upload
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dirty: bool;
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// Font vertical metrics (at reference size 1.0 — scale by font_size)
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ascent: f32;
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descent: f32;
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line_gap: f32;
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// HiDPI: physical pixels per logical pixel (e.g. 2.0 on Retina)
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dpi_scale: f32;
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inv_dpi: f32;
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// Text shaping (kb_text_shape)
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shape_ctx: *void;
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shape_font: *void;
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units_per_em: u16;
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font_data_size: s32;
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shaped_buf: List(ShapedGlyph);
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init :: (self: *GlyphCache, path: [:0]u8, default_size: f32) {
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// Zero out the entire struct first (parent may be uninitialized with = ---)
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memset(self, 0, size_of(GlyphCache));
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// Load font file
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file_size : s32 = 0;
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font_data := read_file_bytes(path, @file_size);
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if xx font_data == 0 {
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out("Failed to load font: ");
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out(path);
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out("\n");
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return;
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}
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self.font_data = xx font_data;
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self.font_data_size = file_size;
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// Init stbtt_fontinfo
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self.font_info = context.allocator.alloc(FONTINFO_SIZE);
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memset(self.font_info, 0, FONTINFO_SIZE);
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stbtt_InitFont(self.font_info, font_data, 0);
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// Get font vertical metrics (in unscaled font units)
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ascent_i : s32 = 0;
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descent_i : s32 = 0;
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linegap_i : s32 = 0;
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stbtt_GetFontVMetrics(self.font_info, @ascent_i, @descent_i, @linegap_i);
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// Store unscaled metrics — we'll scale per font_size in measure_text
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self.ascent = xx ascent_i;
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self.descent = xx descent_i;
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self.line_gap = xx linegap_i;
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// Init text shaping context
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self.shape_ctx = xx kbts_CreateShapeContext(xx 0, xx 0);
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if xx self.shape_ctx != 0 {
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self.shape_font = xx kbts_ShapePushFontFromMemory(xx self.shape_ctx, self.font_data, file_size, 0);
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// Get font metrics (units_per_em) from kbts
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kb_info : KbtsFontInfo2_1 = ---;
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memset(@kb_info, 0, size_of(KbtsFontInfo2_1));
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kb_info.base.size = xx size_of(KbtsFontInfo2_1);
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kbts_GetFontInfo2(xx self.shape_font, xx @kb_info);
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self.units_per_em = kb_info.units_per_em;
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}
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// Allocate atlas bitmap
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self.atlas_width = GLYPH_ATLAS_W;
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self.atlas_height = GLYPH_ATLAS_H;
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bitmap_size : s64 = xx self.atlas_width * xx self.atlas_height;
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self.bitmap = xx context.allocator.alloc(bitmap_size);
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memset(self.bitmap, 0, bitmap_size);
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// Shelf packer init
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self.shelf_y = 0;
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self.shelf_height = 0;
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self.cursor_x = 0;
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self.padding = 1;
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self.dirty = false;
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self.dpi_scale = 1.0;
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self.inv_dpi = 1.0;
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// Create OpenGL texture
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glGenTextures(1, @self.texture_id);
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glBindTexture(GL_TEXTURE_2D, self.texture_id);
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glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
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glTexImage2D(GL_TEXTURE_2D, 0, xx GL_R8, self.atlas_width, self.atlas_height, 0, GL_RED, GL_UNSIGNED_BYTE, self.bitmap);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, xx GL_LINEAR);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, xx GL_LINEAR);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, xx GL_CLAMP_TO_EDGE);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, xx GL_CLAMP_TO_EDGE);
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out("GlyphCache initialized: ");
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out(path);
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out("\n");
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}
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// Look up or rasterize a glyph, returning a pointer to its cached entry.
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// Returns null for glyphs with no outline AND zero advance (shouldn't happen for valid chars).
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get_or_rasterize :: (self: *GlyphCache, glyph_index: u16, font_size: f32) -> *CachedGlyph {
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size_q := quantize_size(font_size);
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key := make_glyph_key(glyph_index, size_q);
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// Cache lookup (linear scan)
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i : s64 = 0;
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while i < self.entries.len {
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if self.entries.items[i].key == key {
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return @self.entries.items[i].glyph;
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}
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i += 1;
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}
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// Cache miss — rasterize
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actual_size := dequantize_size(size_q);
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scale := stbtt_ScaleForPixelHeight(self.font_info, actual_size);
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// Get glyph bounding box
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x0 : s32 = 0;
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y0 : s32 = 0;
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x1 : s32 = 0;
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y1 : s32 = 0;
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stbtt_GetGlyphBitmapBox(self.font_info, xx glyph_index, scale, scale, @x0, @y0, @x1, @y1);
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glyph_w := if x1 > x0 then x1 - x0 else 0;
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glyph_h := if y1 > y0 then y1 - y0 else 0;
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// Get horizontal metrics
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advance_i : s32 = 0;
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lsb_i : s32 = 0;
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stbtt_GetGlyphHMetrics(self.font_info, xx glyph_index, @advance_i, @lsb_i);
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advance : f32 = xx advance_i * scale;
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// Zero-size glyph (e.g. space) — cache with advance only
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if glyph_w == 0 or glyph_h == 0 {
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entry := GlyphEntry.{
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key = key,
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glyph = CachedGlyph.{
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uv_x = 0.0, uv_y = 0.0, uv_w = 0.0, uv_h = 0.0,
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width = 0.0, height = 0.0,
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offset_x = xx x0, offset_y = xx y0,
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advance = advance
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}
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};
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self.entries.append(entry);
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return @self.entries.items[self.entries.len - 1].glyph;
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}
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// Pack into atlas
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pack := self.try_pack(glyph_w, glyph_h);
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if pack.x < 0 {
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// Atlas full — grow and retry
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self.grow();
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return self.get_or_rasterize(glyph_index, font_size);
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}
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// Rasterize directly into atlas bitmap
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dest_offset : s64 = xx pack.y * xx self.atlas_width + xx pack.x;
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stbtt_MakeGlyphBitmap(
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self.font_info,
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@self.bitmap[dest_offset],
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glyph_w, glyph_h,
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self.atlas_width,
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scale, scale,
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xx glyph_index
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);
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self.dirty = true;
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// Compute normalized UV coordinates
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atlas_wf : f32 = xx self.atlas_width;
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atlas_hf : f32 = xx self.atlas_height;
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entry := GlyphEntry.{
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key = key,
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glyph = CachedGlyph.{
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uv_x = xx pack.x / atlas_wf,
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uv_y = xx pack.y / atlas_hf,
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uv_w = xx glyph_w / atlas_wf,
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uv_h = xx glyph_h / atlas_hf,
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width = xx glyph_w,
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height = xx glyph_h,
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offset_x = xx x0,
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offset_y = xx y0,
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advance = advance
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}
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};
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self.entries.append(entry);
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return @self.entries.items[self.entries.len - 1].glyph;
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}
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// Upload dirty atlas to GPU
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flush :: (self: *GlyphCache) {
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if self.dirty == false { return; }
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glBindTexture(GL_TEXTURE_2D, self.texture_id);
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glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
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glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, self.atlas_width, self.atlas_height, GL_RED, GL_UNSIGNED_BYTE, self.bitmap);
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self.dirty = false;
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}
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// Shelf-based rectangle packer.
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// Returns PackResult with x >= 0 on success, x = -1 if no space.
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try_pack :: (self: *GlyphCache, w: s32, h: s32) -> PackResult {
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padded_w := w + self.padding;
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padded_h := h + self.padding;
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// Try fitting on the current shelf
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eff_h := if self.shelf_height > padded_h then self.shelf_height else padded_h;
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if self.cursor_x + padded_w <= self.atlas_width and self.shelf_y + eff_h <= self.atlas_height {
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result := PackResult.{ x = self.cursor_x, y = self.shelf_y };
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self.cursor_x += padded_w;
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if padded_h > self.shelf_height {
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self.shelf_height = padded_h;
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}
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return result;
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}
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// Start a new shelf
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new_shelf_y := self.shelf_y + self.shelf_height;
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if new_shelf_y + padded_h <= self.atlas_height and padded_w <= self.atlas_width {
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self.shelf_y = new_shelf_y;
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self.shelf_height = padded_h;
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self.cursor_x = padded_w;
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return PackResult.{ x = 0, y = new_shelf_y };
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}
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// No space
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PackResult.{ x = 0 - 1, y = 0 - 1 };
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}
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// Grow the atlas by doubling dimensions
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grow :: (self: *GlyphCache) {
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new_w := self.atlas_width * 2;
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new_h := self.atlas_height * 2;
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new_size : s64 = xx new_w * xx new_h;
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new_bitmap : [*]u8 = xx context.allocator.alloc(new_size);
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memset(new_bitmap, 0, new_size);
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// Copy old rows into new bitmap
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y : s32 = 0;
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while y < self.atlas_height {
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old_off : s64 = xx y * xx self.atlas_width;
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new_off : s64 = xx y * xx new_w;
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memcpy(@new_bitmap[new_off], @self.bitmap[old_off], xx self.atlas_width);
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y += 1;
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}
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context.allocator.dealloc(self.bitmap);
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self.bitmap = new_bitmap;
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self.atlas_width = new_w;
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self.atlas_height = new_h;
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// Recreate GL texture
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glDeleteTextures(1, @self.texture_id);
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glGenTextures(1, @self.texture_id);
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glBindTexture(GL_TEXTURE_2D, self.texture_id);
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glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
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glTexImage2D(GL_TEXTURE_2D, 0, xx GL_R8, new_w, new_h, 0, GL_RED, GL_UNSIGNED_BYTE, new_bitmap);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, xx GL_LINEAR);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, xx GL_LINEAR);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, xx GL_CLAMP_TO_EDGE);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, xx GL_CLAMP_TO_EDGE);
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// Recompute UV coordinates for all cached glyphs
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atlas_wf : f32 = xx new_w;
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atlas_hf : f32 = xx new_h;
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i : s64 = 0;
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while i < self.entries.len {
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g := @self.entries.items[i].glyph;
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if g.width > 0.0 {
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g.uv_x = g.uv_x / 2.0;
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g.uv_y = g.uv_y / 2.0;
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g.uv_w = g.width / atlas_wf;
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g.uv_h = g.height / atlas_hf;
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}
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i += 1;
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}
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self.dirty = false;
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out("GlyphCache atlas grown\n");
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}
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set_dpi_scale :: (self: *GlyphCache, scale: f32) {
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self.dpi_scale = scale;
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self.inv_dpi = 1.0 / scale;
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}
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// Get the scale factor for a logical font size
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scale_for_size :: (self: *GlyphCache, font_size: f32) -> f32 {
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stbtt_ScaleForPixelHeight(self.font_info, font_size);
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}
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// Get scaled ascent for a logical font size
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get_ascent :: (self: *GlyphCache, font_size: f32) -> f32 {
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self.ascent * self.scale_for_size(font_size);
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}
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// Get scaled line height for a logical font size
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get_line_height :: (self: *GlyphCache, font_size: f32) -> f32 {
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s := self.scale_for_size(font_size);
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(self.ascent - self.descent + self.line_gap) * s;
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}
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// Shape text into positioned glyphs.
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// Uses ASCII fast-path (stbtt byte-by-byte) for pure ASCII,
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// full kb_text_shape pipeline for Unicode/complex scripts.
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// Results stored in self.shaped_buf (reused across calls).
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shape_text :: (self: *GlyphCache, text: string, font_size: f32) {
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self.shaped_buf.len = 0;
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if text.len == 0 { return; }
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if is_ascii(text) {
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self.shape_ascii(text, font_size);
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} else {
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self.shape_with_kb(text, font_size);
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}
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}
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shape_ascii :: (self: *GlyphCache, text: string, font_size: f32) {
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scale := stbtt_ScaleForPixelHeight(self.font_info, font_size);
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total : f32 = 0.0;
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i : s64 = 0;
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while i < text.len {
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ch : s32 = xx text[i];
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glyph_index : u16 = xx stbtt_FindGlyphIndex(self.font_info, ch);
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advance_i : s32 = 0;
|
|
lsb_i : s32 = 0;
|
|
stbtt_GetGlyphHMetrics(self.font_info, xx glyph_index, @advance_i, @lsb_i);
|
|
adv : f32 = xx advance_i * scale;
|
|
|
|
self.shaped_buf.append(ShapedGlyph.{
|
|
glyph_index = glyph_index,
|
|
x = total,
|
|
y = 0.0,
|
|
advance = adv
|
|
});
|
|
total += adv;
|
|
i += 1;
|
|
}
|
|
}
|
|
|
|
shape_with_kb :: (self: *GlyphCache, text: string, font_size: f32) {
|
|
if xx self.shape_ctx == 0 {
|
|
self.shape_ascii(text, font_size);
|
|
return;
|
|
}
|
|
|
|
scale : f32 = font_size / xx self.units_per_em;
|
|
total : f32 = 0.0;
|
|
|
|
kbts_ShapeBegin(xx self.shape_ctx, KBTS_DIRECTION_DONT_KNOW, KBTS_LANGUAGE_DONT_KNOW);
|
|
kbts_ShapeUtf8(xx self.shape_ctx, xx text.ptr, xx text.len, KBTS_USER_ID_GENERATION_MODE_CODEPOINT_INDEX);
|
|
kbts_ShapeEnd(xx self.shape_ctx);
|
|
|
|
run : KbtsRun = ---;
|
|
while kbts_ShapeRun(xx self.shape_ctx, xx @run) != 0 {
|
|
glyph_ptr : *KbtsGlyph = xx 0;
|
|
while kbts_GlyphIteratorNext(xx @run.glyphs, xx @glyph_ptr) != 0 {
|
|
if xx glyph_ptr == 0 { continue; }
|
|
gx := total + xx glyph_ptr.offset_x * scale;
|
|
gy : f32 = xx glyph_ptr.offset_y * scale;
|
|
adv : f32 = xx glyph_ptr.advance_x * scale;
|
|
|
|
self.shaped_buf.append(ShapedGlyph.{
|
|
glyph_index = glyph_ptr.id,
|
|
x = gx,
|
|
y = gy,
|
|
advance = adv
|
|
});
|
|
total += adv;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Measure text at a logical font size using text shaping.
|
|
// Rasterizes at physical resolution (font_size * dpi_scale), returns logical dimensions.
|
|
measure_text :: (self: *GlyphCache, text: string, font_size: f32) -> Size {
|
|
self.shape_text(text, font_size);
|
|
width : f32 = 0.0;
|
|
i : s64 = 0;
|
|
while i < self.shaped_buf.len {
|
|
width += self.shaped_buf.items[i].advance;
|
|
i += 1;
|
|
}
|
|
Size.{ width = width, height = self.get_line_height(font_size) };
|
|
}
|
|
}
|