366 lines
		
	
	
		
			9.2 KiB
		
	
	
	
		
			V
		
	
	
			
		
		
	
	
			366 lines
		
	
	
		
			9.2 KiB
		
	
	
	
		
			V
		
	
	
// Copyright (c) 2019 Alexander Medvednikov. All rights reserved.
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// Use of this source code is governed by an MIT license
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// that can be found in the LICENSE file.
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module freetype
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import (
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	os
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	gx
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	gg
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	stbi
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	glm
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	gl
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)
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#flag windows -I @VROOT/thirdparty/freetype/include
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#flag windows -L @VROOT/thirdparty/freetype/win64
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#flag darwin -I/usr/local/include/freetype2
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#flag darwin -I/opt/local/include/freetype2
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#flag -lfreetype
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//#flag -I @VROOT/thirdparty/freetype
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//#flag @VROOT/thirdparty/freetype/libfreetype.a
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#flag darwin -lpng -lbz2 -lz
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#flag linux 	-I/usr/include/freetype2
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#flag linux -I.
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#include "ft2build.h"
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#include FT_FREETYPE_H
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const (
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	DEFAULT_FONT_SIZE = 12
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)
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struct Character {
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	texture_id u32
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	size       gg.Vec2
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	bearing    gg.Vec2
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	advance    u32
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}
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[typedef]
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struct C.FT_Library {
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}
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struct Context {
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	shader    gl.Shader
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	// use_ortho bool
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	width     int
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	height    int
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	vao       u32
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	rect_vao  u32
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	rect_vbo  u32
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	line_vao  u32
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	line_vbo  u32
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	vbo       u32
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	chars     []Character
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	utf_runes []string
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	utf_chars []Character
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	face      C.FT_Face
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	scale     int // retina = 2 , normal = 1
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}
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struct C.Bitmap {
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	width int
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	rows int
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	buffer int
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}
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struct C.Advance {
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	x int
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}
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struct C.Glyph {
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	bitmap Bitmap
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	bitmap_left int
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	bitmap_top int
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	advance Advance
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}
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[typedef]
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struct C.FT_Face {
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	glyph *Glyph
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}
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fn C.FT_Load_Char(voidptr, i64, int) int
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fn ft_load_char(face C.FT_Face, code i64) Character {
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	//println('\nftload_char( code=$code)')
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	//C.printf('face=%p\n', face)
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	//C.printf('cobj=%p\n', _face.cobj)
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	ret := C.FT_Load_Char(face, code, C.FT_LOAD_RENDER)
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	//println('ret=$ret')
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	if ret != 0 {
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		println('freetype: failed to load glyph (utf32 code=$code, ' +
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			'error code=$ret)')
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		return Character{}
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	}
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	// Generate texture
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	mut texture := 0
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	C.glGenTextures(1, &texture)
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	C.glBindTexture(C.GL_TEXTURE_2D, texture)
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	fgwidth := face.glyph.bitmap.width
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	fgrows  := face.glyph.bitmap.rows
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	C.glTexImage2D(C.GL_TEXTURE_2D, 0, C.GL_RED, fgwidth,  fgrows,
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		0, C.GL_RED, C.GL_UNSIGNED_BYTE, face.glyph.bitmap.buffer)
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	// Set texture options
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	C.glTexParameteri(C.GL_TEXTURE_2D, C.GL_TEXTURE_WRAP_S, C.GL_CLAMP_TO_EDGE)
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	C.glTexParameteri(C.GL_TEXTURE_2D, C.GL_TEXTURE_WRAP_T, C.GL_CLAMP_TO_EDGE)
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	C.glTexParameteri(C.GL_TEXTURE_2D, C.GL_TEXTURE_MIN_FILTER, C.GL_LINEAR)
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	C.glTexParameteri(C.GL_TEXTURE_2D, C.GL_TEXTURE_MAG_FILTER, C.GL_LINEAR)
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	fgleft := face.glyph.bitmap_left
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	fgtop := face.glyph.bitmap_top
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	// Create the character
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	return Character {
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		texture_id: u32(texture)
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		size:    gg.vec2(int(u32(fgwidth)), int(u32(fgrows)))
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		bearing: gg.vec2(int(u32(fgleft)), int(u32(fgtop)))
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		advance: (u32(face.glyph.advance.x))
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	}
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}
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pub fn new_context(cfg gg.Cfg) *Context {
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	scale := cfg.scale
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	// Can only have text in ortho mode
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	if !cfg.use_ortho {
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		return &Context{}
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	}
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	mut width := cfg.width * scale
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	mut height := cfg.height * scale
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	font_size := cfg.font_size * scale
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	// exit('fs=$font_size')
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	// if false {
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	// retina
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	// width = width * 2// scale// 2
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	// height = height * 2// scale// 2
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	// font_size *= scale// 2
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	// }
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	/*
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	gl.viewport(0, 0, width, height)
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*/
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	// gl.enable(GL_CULL_FACE) // TODO NEED CULL?
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	gl.enable(C.GL_BLEND)
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	C.glBlendFunc(C.GL_SRC_ALPHA, C.GL_ONE_MINUS_SRC_ALPHA)
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	shader := gl.new_shader('text')
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	shader.use()
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	projection := glm.ortho(0, width, 0, height)// 0 at BOT
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	shader.set_mat4('projection', projection)
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	// FREETYPE
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	ft := FT_Library{}
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	// All functions return a value different than 0 whenever
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	// an error occurred
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	mut ret := C.FT_Init_FreeType(&ft)
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	if ret != 0 {
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		panic('freetype: Could not init FreeType Library')
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	}
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	// Load font as face
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	mut font_path := cfg.font_path
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	if font_path == '' {
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		font_path = 'RobotoMono-Regular.ttf'
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	}
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	if !os.file_exists(font_path) {
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		exe_path := os.executable()
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		exe_dir := os.basedir(exe_path)
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		font_path = '$exe_dir/$font_path'
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	}
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	if !os.file_exists(font_path) {
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		println('failed to load $font_path')
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		return 0
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	}
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	println('Trying to load font from $font_path')
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	face := C.FT_Face{}
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	ret = int(C.FT_New_Face(ft, font_path.str, 0, &face))
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	if ret != 0	{
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		println('freetype: failed to load the font (error=$ret)')
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		exit(1)
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	}
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	// Set size to load glyphs as
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	C.FT_Set_Pixel_Sizes(face, 0, font_size)
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	// Disable byte-alignment restriction
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	C.glPixelStorei(C.GL_UNPACK_ALIGNMENT, 1)
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	// Gen texture
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	// Load first 128 characters of ASCII set
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	mut chars := []Character{}
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	for c := 0; c < 128; c++ {
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		mut ch := ft_load_char(face, i64(c))
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		// s := utf32_to_str(uint(0x043f))
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		// s := 'п'
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		// ch = ft_load_char(f, s.utf32_code())
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		// # unsigned long c = FT_Get_Char_Index(face,              0x043f );
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		// # printf("!!!!!!!!! %lu\n", c);
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		// # c = FT_Get_Char_Index(face,              0xd0bf );
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		// # printf("!!!!!!!!! %lu\n", c);
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		// # ch = gg__ft_load_char(f, 0xd0bf) ;  // UTF 8
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		chars << ch
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	}
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	ch := Character{}
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	// Configure VAO
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	vao := gl.gen_vertex_array()
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	println('new gg text context vao=$vao')
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	vbo := gl.gen_buffer()
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	gl.bind_vao(vao)
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	gl.bind_buffer(C.GL_ARRAY_BUFFER, vbo)
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	// # glBufferData(GL_ARRAY_BUFFER, sizeof(GLf32) * 6 * 4, NULL, GL_DYNAMIC_DRAW);
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	gl.enable_vertex_attrib_array(0)
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	gl.vertex_attrib_pointer(0, 4, C.GL_FLOAT, false, 4, 0)
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	// # glVertexAttribPointer(0, 4, GL_FLOAT,false, 4 * sizeof(GLf32), 0);
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	// gl.bind_buffer(GL_ARRAY_BUFFER, uint(0))
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	// # glBindVertexArray(0);
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	mut ctx := &Context {
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		shader: shader
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		width: width
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		height: height
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		scale: scale
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		vao: vao
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		vbo: vbo
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		chars: chars
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		face: face
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	}
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	//ctx.init_utf8_runes()
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	return ctx
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}
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/*
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// A dirty hack to implement rendering of cyrillic letters.
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// All UTF-8 must be supported. update: no longer needed
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fn (ctx mut Context) init_utf8_runes() {
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	s := '≈≠⩽⩾йцукенгшщзхъфывапролджэячсмитьбюЙЦУКЕНГШЩЗХЪФЫВАПРОЛДЖЭЯЧСМИТЬБЮ'
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	print('init utf8 runes: ')
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	//println(s)
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	us := s.ustring()
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	for i := 0; i < us.len; i++ {
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		_rune := us.at(i)
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		ch := ft_load_char(ctx.face, _rune.utf32_code())
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		// ctx.utf_rune_map.set(rune, ch)
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		ctx.utf_runes << _rune
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		ctx.utf_chars << ch
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	}
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}
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*/
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pub fn (ctx mut Context) draw_text(_x, _y int, text string, cfg gx.TextCfg) {
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	//utext := text.ustring_tmp()
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	utext := text.ustring()
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	ctx._draw_text(_x, _y, utext, cfg)
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}
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fn (ctx mut Context) draw_text_fast(_x, _y int, text ustring, cfg gx.TextCfg) {
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	ctx._draw_text(_x, _y, text, cfg)
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}
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fn (ctx mut Context) _draw_text(_x, _y int, utext ustring, cfg gx.TextCfg) {
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	/*
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	if utext.s.contains('on_seg') {
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		println('\nat(0)')
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		println(utext.runes)
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		firstc := utext.at(0)
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		println('drawtext "$utext.s" len=$utext.s.len ulen=$utext.len x=$_x firstc=$firstc')
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		if firstc != ' ' {
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			exit(1)
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		}
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	}
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*/
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	mut x := f32(_x)
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	mut y := f32(_y)
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	// println('scale=$ctx.scale size=$cfg.size')
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	if cfg.align == gx.ALIGN_RIGHT {
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		width := utext.len * 7
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		x -= width + 10
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	}
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	x *= ctx.scale// f32(2)
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	// println('y=$_y height=$ctx.height')
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	// _y = _y * int(ctx.scale) //+ 26
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	y = y * int(ctx.scale) + ((cfg.size * ctx.scale) / 2) + 5 * ctx.scale
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	y = f32(ctx.height) - y
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	color := cfg.color
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	// Activate corresponding render state
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	ctx.shader.use()
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	ctx.shader.set_color('textColor', color)
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	C.glActiveTexture(C.GL_TEXTURE0)
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	gl.bind_vao(ctx.vao)
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	// Iterate through all characters
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	// utext := text.ustring()
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	for i := 0; i < utext.len; i++ {
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		_rune := utext.at(i)
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		// println('$i => $_rune')
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		mut ch := Character{}
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		mut found := false
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		if _rune.len == 1 {
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			idx := _rune[0]
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			if idx < 0 || idx >= ctx.chars.len {
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				println('BADE RUNE $_rune')
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				continue
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			}
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			found = true
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			ch = ctx.chars[_rune[0]]
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		}
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		else if _rune.len > 1 {
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			// TODO O(1) use map
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			for j := 0; j < ctx.utf_runes.len; j++ {
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				rune_j := ctx.utf_runes[j]
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				if rune_j==_rune {
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					ch = ctx.utf_chars[j]
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					found = true
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					break
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				}
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			}
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		}
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		// A new Unicode character. Load it and cache it.
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		if !found && _rune.len > 0 && _rune[0] > 32 {
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			c := _rune[0]
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			//println('cant draw rune "$_rune" code=$c, loading')
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			//continue
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			ch = ft_load_char(ctx.face, _rune.utf32_code())
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			//println('done loading')
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			ctx.utf_runes << _rune
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			ctx.utf_chars << ch
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			//exit(1)
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			// continue
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		}
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		xpos := x + f32(ch.bearing.x) * 1
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		ypos := y - f32(ch.size.y - ch.bearing.y) * 1
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		w := f32(ch.size.x) * 1
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		h := f32(ch.size.y) * 1
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		// Update VBO for each character
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		vertices :=	[
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		 xpos,     ypos + h,   0.0, 0.0 ,
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		 xpos,     ypos,       0.0, 1.0 ,
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		 xpos + w, ypos,       1.0, 1.0 ,
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		 xpos,     ypos + h,   0.0, 0.0 ,
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		 xpos + w, ypos,       1.0, 1.0 ,
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		 xpos + w, ypos + h,   1.0, 0.0
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		]
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		// Render glyph texture over quad
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		C.glBindTexture(C.GL_TEXTURE_2D, ch.texture_id)
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		// Update content of VBO memory
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		gl.bind_buffer(C.GL_ARRAY_BUFFER, ctx.vbo)
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		// glBufferSubData(..)
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		C.glBufferData(C.GL_ARRAY_BUFFER, 96, vertices.data, C.GL_DYNAMIC_DRAW)
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		// Render quad
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		gl.draw_arrays(C.GL_TRIANGLES, 0, 6)
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		// Now advance cursors for next glyph (note that advance is number of 1/64 pixels)
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		// Bitshift by 6 to get value in pixels (2^6 = 64 (divide amount of 1/64th pixels by 64 to get amount of pixels))
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		x += ch.advance >> u32(6)
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	}
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	gl.bind_vao(u32(0))
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	C.glBindTexture(C.GL_TEXTURE_2D, 0)
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}
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pub fn (ctx mut Context) draw_text_def(x, y int, text string) {
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	cfg := gx.TextCfg {
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		color: gx.Black,
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		size: DEFAULT_FONT_SIZE,
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		align: gx.ALIGN_LEFT,
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	}
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	ctx.draw_text(x, y, text, cfg)
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}
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