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Optimize glyph calculation

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SamratGhale
2026-03-22 14:13:00 +05:45
parent 9294a1699f
commit 157f04060e
1 changed files with 79 additions and 87 deletions
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glyph/glyph.odin
+79 -87
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@@ -3,11 +3,11 @@ package e2glyph
/* /*
Provides text rendering using glfw, stb_truetype for the engine Provides text rendering using glfw, stb_truetype for the engine
TODO:
Optimize for only calculate when there's changes
*/ */
import "core:math" import "core:math"
import os "core:os" import os "core:os"
import "core:mem" import "core:mem"
@@ -52,16 +52,10 @@ GlyphState :: struct {
} }
glyph_init :: proc(glyph: ^GlyphState) { glyph_init :: proc(glyph: ^GlyphState, filepath : string) {
ok : bool ok : bool
glyph.program_id, ok = gl.load_shaders_source( glyph.program_id, ok = gl.load_shaders_source(#load("./shaders/font_vert.glsl"), #load("./shaders/font_frag.glsl"), )
#load("./shaders/font_vert.glsl"),
#load("./shaders/font_frag.glsl"),
)
//gl.UseProgram(glyph.program_id)
gl.CreateBuffers(1, &glyph.rect_instances_vbo) gl.CreateBuffers(1, &glyph.rect_instances_vbo)
gl.CreateVertexArrays(1, &glyph.vao) gl.CreateVertexArrays(1, &glyph.vao)
@@ -88,19 +82,7 @@ glyph_init :: proc(glyph: ^GlyphState) {
gl.CreateTextures(gl.TEXTURE_RECTANGLE, 1, &glyph.atlas_texture) gl.CreateTextures(gl.TEXTURE_RECTANGLE, 1, &glyph.atlas_texture)
gl.TextureStorage2D(glyph.atlas_texture, 1, gl.RGB8, glyph.atlas_width, glyph.atlas_height) gl.TextureStorage2D(glyph.atlas_texture, 1, gl.RGB8, glyph.atlas_width, glyph.atlas_height)
font_data, _ := os.read_entire_file_from_path(filepath, context.allocator)
/*
gl.BindVertexArray(0)
gl.BindBuffer(gl.ARRAY_BUFFER, 0)
gl.BindTexture(gl.TEXTURE_RECTANGLE, 0)
gl.BindTexture(gl.TEXTURE_2D, 0)
gl.DisableVertexArrayAttrib(glyph.vao, 0)
gl.DisableVertexArrayAttrib(glyph.vao, 1)
gl.DisableVertexArrayAttrib(glyph.vao, 2)
gl.DisableVertexArrayAttrib(glyph.vao, 3)
*/
font_data, _ := os.read_entire_file_from_path("./Ubuntu-Regular.ttf", context.allocator)
stbtt.InitFont(&glyph.font_info, &font_data[0], 0) stbtt.InitFont(&glyph.font_info, &font_data[0], 0)
@@ -160,92 +142,103 @@ glyph_draw_font :: proc(glyph_state: ^GlyphState, text: string, pos : [2]f32, co
glyph_state.curr.x += 2 * glyph_state.font_size_pt glyph_state.curr.x += 2 * glyph_state.font_size_pt
} else { } else {
horizontal_filter_padding, subpixel_positioning_left_padding: i32 = 1, 1 horizontal_filter_padding, subpixel_positioning_left_padding: i32 = 1, 1
assert(codepoint <= 127) assert(codepoint <= 127)
glyph_atlas := glyph_state.atlas_items[codepoint] glyph_atlas := glyph_state.atlas_items[codepoint]
glyph_index := stbtt.FindGlyphIndex(&glyph_state.font_info, c) if !glyph_atlas.filled
x0, y0, x1, y1: i32 = 0, 0, 0, 0
stbtt.GetGlyphBitmapBox(&glyph_state.font_info, glyph_index, font_scale, font_scale, &x0, &y0, &x1, &y1)
glyph_width_px : i32 = x1 - x0
glyph_height_px: i32 = y1 - y0
distance_from_baseline_to_top_px: i32 = -y0
if glyph_width_px > 0 && glyph_height_px > 0
{ {
padded_glyph_width_px : i32 = subpixel_positioning_left_padding + horizontal_filter_padding + glyph_width_px + horizontal_filter_padding glyph_index := stbtt.FindGlyphIndex(&glyph_state.font_info, c)
padded_glyph_height_px: i32 = glyph_height_px
atlas_item_width, atlas_item_height: i32 = 32, 32 x0, y0, x1, y1: i32 = 0, 0, 0, 0
atlas_item_x: i32 = i32( codepoint % u32(glyph_state.atlas_width / atlas_item_width), ) * atlas_item_width stbtt.GetGlyphBitmapBox(&glyph_state.font_info, glyph_index, font_scale, font_scale, &x0, &y0, &x1, &y1)
atlas_item_y: i32 = i32( codepoint / u32(glyph_state.atlas_height / atlas_item_height), ) * atlas_item_height
assert(padded_glyph_width_px <= atlas_item_width && padded_glyph_height_px <= atlas_item_height) glyph_width_px : i32 = x1 - x0
glyph_height_px: i32 = y1 - y0
horizontal_resolution: i32 = 3 distance_from_baseline_to_top_px: i32 = -y0
bitmap_stride : i32 = atlas_item_width * horizontal_resolution
bitmap_size : uint = uint(bitmap_stride * atlas_item_height)
glyph_bitmap, _ := mem.alloc_bytes(int(bitmap_size))
glyph_offset_x := (subpixel_positioning_left_padding + horizontal_filter_padding) * horizontal_resolution
stbtt.MakeGlyphBitmap(&glyph_state.font_info, &glyph_bitmap[glyph_offset_x], atlas_item_width * horizontal_resolution, atlas_item_height, bitmap_stride, font_scale * f32(horizontal_resolution), font_scale, glyph_index) if glyph_width_px > 0 && glyph_height_px > 0
atlas_item_bitmap, _ := mem.alloc_bytes(int(bitmap_size))
filter_weights: [5]u8 = {0x08, 0x4D, 0x56, 0x4D, 0x08}
for y in 0 ..< padded_glyph_height_px
{ {
padded_glyph_width_px : i32 = subpixel_positioning_left_padding + horizontal_filter_padding + glyph_width_px + horizontal_filter_padding
padded_glyph_height_px: i32 = glyph_height_px
x_end: i32 = padded_glyph_width_px * horizontal_resolution - 1 atlas_item_width, atlas_item_height: i32 = 32, 32
for x in 4 ..< x_end { atlas_item_x: i32 = i32( codepoint % u32(glyph_state.atlas_width / atlas_item_width), ) * atlas_item_width
filter_weight_index: i32 = 0 atlas_item_y: i32 = i32( codepoint / u32(glyph_state.atlas_height / atlas_item_height), ) * atlas_item_height
sum: i32
kernel_x_end: i32 = (x == x_end - 1) ? x + 1 : x + 2
for kernel_x in x - 2 ..= kernel_x_end assert(padded_glyph_width_px <= atlas_item_width && padded_glyph_height_px <= atlas_item_height)
{
assert(kernel_x >= 0 && kernel_x < x_end + 1)
assert(y >= 0 && y < padded_glyph_height_px)
offset: i32 = kernel_x + y * bitmap_stride horizontal_resolution: i32 = 3
assert(offset >= 0 && uint(offset) < bitmap_size) bitmap_stride : i32 = atlas_item_width * horizontal_resolution
bitmap_size : uint = uint(bitmap_stride * atlas_item_height)
glyph_bitmap, _ := mem.alloc_bytes(int(bitmap_size))
glyph_offset_x := (subpixel_positioning_left_padding + horizontal_filter_padding) * horizontal_resolution
sum += i32(i32(glyph_bitmap[offset]) * i32(filter_weights[filter_weight_index])) stbtt.MakeGlyphBitmap(
&glyph_state.font_info,
&glyph_bitmap[glyph_offset_x],
atlas_item_width * horizontal_resolution,
atlas_item_height, bitmap_stride,
font_scale * f32(horizontal_resolution),
font_scale, glyph_index
)
filter_weight_index += 1 atlas_item_bitmap, _ := mem.alloc_bytes(int(bitmap_size))
filter_weights: [5]u8 = {0x08, 0x4D, 0x56, 0x4D, 0x08}
for y in 0 ..< padded_glyph_height_px
{
x_end: i32 = padded_glyph_width_px * horizontal_resolution - 1
for x in 4 ..< x_end {
filter_weight_index: i32 = 0
sum: i32
kernel_x_end: i32 = (x == x_end - 1) ? x + 1 : x + 2
for kernel_x in x - 2 ..= kernel_x_end
{
assert(kernel_x >= 0 && kernel_x < x_end + 1)
assert(y >= 0 && y < padded_glyph_height_px)
offset: i32 = kernel_x + y * bitmap_stride
assert(offset >= 0 && uint(offset) < bitmap_size)
sum += i32(i32(glyph_bitmap[offset]) * i32(filter_weights[filter_weight_index]))
filter_weight_index += 1
}
sum = sum / 255
atlas_item_bitmap[x + y * bitmap_stride] = (sum > 255) ? 255 : u8(sum)
} }
sum = sum / 255
atlas_item_bitmap[x + y * bitmap_stride] = (sum > 255) ? 255 : u8(sum)
} }
mem.free_bytes(glyph_bitmap)
gl.TextureSubImage2D(glyph_state.atlas_texture, 0, atlas_item_x, atlas_item_y, atlas_item_width, atlas_item_height, gl.RGB, gl.UNSIGNED_BYTE, rawptr(&atlas_item_bitmap[0]))
mem.free_bytes(atlas_item_bitmap)
glyph_atlas.tex_coords.l = f32(atlas_item_x)
glyph_atlas.tex_coords.t = f32(atlas_item_y)
glyph_atlas.tex_coords.r = f32(atlas_item_x + padded_glyph_width_px)
glyph_atlas.tex_coords.b = f32(atlas_item_y + padded_glyph_height_px)
} else {
glyph_atlas.tex_coords.l = -1
glyph_atlas.tex_coords.t = -1
glyph_atlas.tex_coords.r = -1
glyph_atlas.tex_coords.b = -1
} }
mem.free_bytes(glyph_bitmap) glyph_atlas.index = glyph_index
gl.TextureSubImage2D(glyph_state.atlas_texture, 0, atlas_item_x, atlas_item_y, atlas_item_width, atlas_item_height, gl.RGB, gl.UNSIGNED_BYTE, rawptr(&atlas_item_bitmap[0])) glyph_atlas.distance_b2t = distance_from_baseline_to_top_px
glyph_atlas.filled = true
mem.free_bytes(atlas_item_bitmap) glyph_state.atlas_items[codepoint] = glyph_atlas
glyph_atlas.tex_coords.l = f32(atlas_item_x)
glyph_atlas.tex_coords.t = f32(atlas_item_y)
glyph_atlas.tex_coords.r = f32(atlas_item_x + padded_glyph_width_px)
glyph_atlas.tex_coords.b = f32(atlas_item_y + padded_glyph_height_px)
} else {
glyph_atlas.tex_coords.l = -1
glyph_atlas.tex_coords.t = -1
glyph_atlas.tex_coords.r = -1
glyph_atlas.tex_coords.b = -1
} }
glyph_atlas.index = glyph_index
glyph_atlas.distance_b2t = distance_from_baseline_to_top_px
glyph_atlas.filled = true
glyph_state.atlas_items[codepoint] = glyph_atlas
glyph_advance_width, glyph_left_side_bearing: i32 = 0, 0 glyph_advance_width, glyph_left_side_bearing: i32 = 0, 0
stbtt.GetGlyphHMetrics(&glyph_state.font_info, glyph_atlas.index, &glyph_advance_width, &glyph_left_side_bearing) stbtt.GetGlyphHMetrics(&glyph_state.font_info, glyph_atlas.index, &glyph_advance_width, &glyph_left_side_bearing)
@@ -274,7 +267,6 @@ glyph_draw_font :: proc(glyph_state: ^GlyphState, text: string, pos : [2]f32, co
r.color = text_color r.color = text_color
r.index = u32(i + 1) r.index = u32(i + 1)
append(&glyph_state.rect_buffer, r) append(&glyph_state.rect_buffer, r)
} }