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gfx: make Text ECS module use style entities (cleaner API design)

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Signed-off-by: Stephen Gutekanst <stephen@hexops.com>
This commit is contained in:
Stephen Gutekanst 2024-03-20 09:32:22 -07:00 • committed by Stephen Gutekanst
parent 0c3ae9a048
commit aa33896935
2 changed files with 83 additions and 70 deletions
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69
src/gfx/Text.zig
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@ -38,30 +38,30 @@ pub const components = struct {
/// origin (0, 0) lives at the center of the window.
pub const transform = Mat4x4;
/// Segments of text to render.
pub const text = []const Segment;
};
/// String segments of UTF-8 encoded text to render.
///
/// Expected to match the length of the style component.
pub const text = []const []const u8;
pub const Segment = struct {
/// A string of UTF-8 encoded text.
string: []const u8,
/// The style to apply to each segment of text.
///
/// Expected to match the length of the text component.
pub const style = []const mach.ecs.EntityID;
/// Which style this text should use.
style: *const Style,
};
/// Style component: desired font to render text with.
pub const font_name = []const u8; // TODO: ship a default font
pub const Style = struct {
/// The desired font to render text with.
font_name: []const u8, // TODO: ship a default font
/// Style component: font size in pixels
pub const font_size = f32; // e.g. 12 * mach.gfx.px_per_pt // 12pt
/// Font size in pixels.
font_size: f32 = 12 * mach.gfx.px_per_pt, // 12pt
/// Style component: font weight
pub const font_weight = u16; // e.g. mach.gfx.font_weight_normal
font_weight: u16 = mach.gfx.font_weight_normal,
/// Style component: italic text
pub const italic = bool; // e.g. false
italic: bool = false,
color: Vec4 = vec4(0, 0, 0, 1.0),
/// Style component: fill color
pub const color = Vec4; // e.g. vec4(0, 0, 0, 1.0),
};
const Uniforms = extern struct {
@ -371,11 +371,9 @@ pub const local = struct {
pipeline.num_glyphs = 0;
var glyphs = std.ArrayListUnmanaged(Glyph){};
var transforms_offset: usize = 0;
// var colors_offset: usize = 0;
var texture_update = false;
while (archetypes_iter.next()) |archetype| {
const transforms = archetype.slice(.mach_gfx_text, .transform);
// var colors = archetype.slice(.mach_gfx_text, .color);
// TODO: confirm the lifetime of these slices is OK for writeBuffer, how long do they need
// to live?
@ -390,37 +388,46 @@ pub const local = struct {
// TODO: this is very expensive and shouldn't be done here, should be done only on detected
// text change.
const px_density = 2.0;
// var font_names = archetype.slice(.mach_gfx_text, .font_name);
// var font_sizes = archetype.slice(.mach_gfx_text, .font_size);
const texts = archetype.slice(.mach_gfx_text, .text);
for (texts) |text| {
const segment_lists = archetype.slice(.mach_gfx_text, .text);
const style_lists = archetype.slice(.mach_gfx_text, .style);
for (segment_lists, style_lists) |segments, styles| {
var origin_x: f32 = 0.0;
var origin_y: f32 = 0.0;
for (text) |segment| {
for (segments, styles) |segment, style| {
// Load a font
// TODO: resolve font by name, not hard-code
const font_name = engine.entities.getComponent(style, .mach_gfx_text, .font_name).?;
_ = font_name; // TODO: actually use font name
const font_bytes = @import("font-assets").fira_sans_regular_ttf;
var font = try gfx.Font.initBytes(font_bytes);
defer font.deinit(engine.allocator);
const font_size = engine.entities.getComponent(style, .mach_gfx_text, .font_size).?;
const font_weight = engine.entities.getComponent(style, .mach_gfx_text, .font_weight);
const italic = engine.entities.getComponent(style, .mach_gfx_text, .italic);
const color = engine.entities.getComponent(style, .mach_gfx_text, .color);
// TODO: actually apply these
_ = font_weight;
_ = italic;
_ = color;
// Create a text shaper
var run = try gfx.TextRun.init();
run.font_size_px = segment.style.font_size;
run.font_size_px = font_size;
run.px_density = 2; // TODO
defer run.deinit();
run.addText(segment.string);
run.addText(segment);
try font.shape(&run);
while (run.next()) |glyph| {
const codepoint = segment.string[glyph.cluster];
const codepoint = segment[glyph.cluster];
// TODO: use flags(?) to detect newline, or at least something more reliable?
if (codepoint != '\n') {
const region = try pipeline.regions.getOrPut(engine.allocator, .{
.index = glyph.glyph_index,
.size = @bitCast(segment.style.font_size),
.size = @bitCast(font_size),
});
if (!region.found_existing) {
const rendered_glyph = try font.render(engine.allocator, glyph.glyph_index, .{
@ -466,7 +473,7 @@ pub const local = struct {
if (codepoint == '\n') {
origin_x = 0;
origin_y -= segment.style.font_size;
origin_y -= font_size;
} else {
origin_x += glyph.advance.x();
}