125 lines
4.9 KiB
Zig
125 lines
4.9 KiB
Zig
//! At the moment we use only rgba32, but maybe it could be useful to use also other types
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const std = @import("std");
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const ft = @import("freetype");
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const zigimg = @import("zigimg");
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const Atlas = @import("atlas.zig").Atlas;
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const UVData = @import("atlas.zig").UVData;
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const App = @import("main.zig").App;
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const draw = @import("draw.zig");
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pub const Label = @This();
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const Vec2 = @Vector(2, f32);
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const Vec4 = @Vector(4, f32);
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const GlyphInfo = struct {
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uv_data: UVData,
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metrics: ft.Glyph.GlyphMetrics,
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};
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face: ft.Face,
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size: i32,
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char_map: std.AutoHashMap(u8, GlyphInfo),
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allocator: std.mem.Allocator,
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const WriterContext = struct {
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label: *Label,
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app: *App,
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position: Vec2,
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text_color: Vec4,
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};
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const Writer = std.io.Writer(WriterContext, ft.Error, write);
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pub fn writer(label: *Label, app: *App, position: Vec2, text_color: Vec4) Writer {
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return Writer{
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.context = .{
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.label = label,
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.app = app,
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.position = position,
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.text_color = text_color,
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},
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};
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}
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pub fn init(lib: ft.Library, font_path: []const u8, face_index: i32, char_size: i32, allocator: std.mem.Allocator) !Label {
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return Label{
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.face = try lib.newFace(font_path, face_index),
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.size = char_size,
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.char_map = std.AutoHashMap(u8, GlyphInfo).init(allocator),
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.allocator = allocator,
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};
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}
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pub fn deinit(label: *Label) void {
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label.face.deinit();
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label.char_map.deinit();
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}
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// FIXME: union ft.error and hashmap error
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fn write(ctx: WriterContext, bytes: []const u8) ft.Error!usize {
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var offset = Vec2{ 0, 0 };
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for (bytes) |char| {
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switch (char) {
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'\n' => {
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offset[0] = 0;
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offset[1] -= @intToFloat(f32, ctx.label.face.sizeMetrics().?.height >> 6);
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},
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' ' => {
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const v = ctx.label.char_map.getOrPut(char) catch unreachable;
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if (!v.found_existing) {
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try ctx.label.face.setCharSize(ctx.label.size * 64, 0, 50, 0);
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try ctx.label.face.loadChar(char, .{ .render = true });
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const glyph = ctx.label.face.glyph;
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v.value_ptr.* = GlyphInfo{
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.uv_data = undefined,
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.metrics = glyph.metrics(),
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};
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}
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offset[0] += @intToFloat(f32, v.value_ptr.metrics.horiAdvance >> 6);
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},
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else => {
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const v = ctx.label.char_map.getOrPut(char) catch unreachable;
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if (!v.found_existing) {
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try ctx.label.face.setCharSize(ctx.label.size * 64, 0, 50, 0);
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try ctx.label.face.loadChar(char, .{ .render = true });
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const glyph = ctx.label.face.glyph;
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const glyph_bitmap = glyph.bitmap();
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const glyph_width = glyph_bitmap.width();
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const glyph_height = glyph_bitmap.rows();
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var glyph_data = ctx.label.allocator.alloc(zigimg.color.Rgba32, glyph_width * glyph_height) catch unreachable;
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defer ctx.label.allocator.free(glyph_data);
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const glyph_buffer = glyph_bitmap.buffer();
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for (glyph_data) |*data, i| {
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const x = i % glyph_width;
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const y = i / glyph_width;
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const glyph_col = glyph_buffer[y * glyph_width + x];
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data.* = zigimg.color.Rgba32.initRGB(glyph_col, glyph_col, glyph_col);
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}
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const glyph_atlas_region = ctx.app.texture_atlas_data.reserve(ctx.label.allocator, glyph_width, glyph_height) catch unreachable;
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const glyph_uv_data = glyph_atlas_region.getUVData(@intToFloat(f32, ctx.app.texture_atlas_data.size));
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ctx.app.texture_atlas_data.set(glyph_atlas_region, glyph_data);
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v.value_ptr.* = GlyphInfo{
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.uv_data = glyph_uv_data,
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.metrics = glyph.metrics(),
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};
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}
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draw.quad(
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ctx.app,
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ctx.position + offset + Vec2{ @intToFloat(f32, v.value_ptr.metrics.horiBearingX >> 6), @intToFloat(f32, (v.value_ptr.metrics.horiBearingY - v.value_ptr.metrics.height) >> 6) },
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.{ @intToFloat(f32, v.value_ptr.metrics.width >> 6), @intToFloat(f32, v.value_ptr.metrics.height >> 6) },
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.{ .blend_color = ctx.text_color },
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v.value_ptr.uv_data,
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) catch unreachable;
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offset[0] += @intToFloat(f32, v.value_ptr.metrics.horiAdvance >> 6);
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},
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}
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}
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return bytes.len;
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}
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pub fn print(label: *Label, app: *App, comptime fmt: []const u8, args: anytype, position: Vec2, text_color: Vec4) !void {
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const w = writer(label, app, position, text_color);
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try w.print(fmt, args);
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}
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