1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
|
#include "text.h"
#include "shader.h"
#include "sys.h"
#include <GL/glew.h>
#include <ft2build.h>
#include FT_FREETYPE_H
struct text_renderer init_text_renderer(i32 width, i32 height)
{
struct text_renderer renderer = {0};
renderer.shader = get_shader("text");
glUseProgram(renderer.shader);
mat projection = ortho(0.0f, width, height, 0.0f, -1.0f, 1.0f);
uniform_mat(renderer.shader, "projection", projection);
uniform_i32(renderer.shader, "glyph", 0);
glUseProgram(0);
glGenVertexArrays(1, &renderer.vao);
glGenBuffers(1, &renderer.vbo);
glBindVertexArray(renderer.vao);
glBindBuffer(GL_ARRAY_BUFFER, renderer.vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(f32) * 6 * 4, 0, GL_DYNAMIC_DRAW);
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 4 * sizeof(f32), 0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(0);
return renderer;
}
void load_font(struct text_renderer *renderer, const char *dir, const char *filename, u32 size)
{
for (i32 i = 0; i < 128; i++) {
struct text_char *c = renderer->chars + i;
c->texture = 0;
c->size = (v2){0.0f, 0.0f};
c->bearing = (v2){0.0f, 0.0f};
c->advance = 0;
}
FT_Library ft;
if (FT_Init_FreeType(&ft))
die("failed to initialize freetype library");
FT_Face face;
char path[512] = {0};
snprintf(path, 512, "%s/%s", (dir ? dir : "."), filename);
if (FT_New_Face(ft, path, 0, &face))
die("failed to load \"%s\"", path);
FT_Set_Pixel_Sizes(face, 0, size);
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
for (u8 c = 0; c < 128; c++) {
if (FT_Load_Char(face, c, FT_LOAD_RENDER))
die("failed to load char \"%c\"", c);
u32 texture;
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RED,
face->glyph->bitmap.width,
face->glyph->bitmap.rows,
0, GL_RED, GL_UNSIGNED_BYTE,
face->glyph->bitmap.buffer);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
renderer->chars[c] = (struct text_char){
texture,
{face->glyph->bitmap.width, face->glyph->bitmap.rows},
{face->glyph->bitmap_left, face->glyph->bitmap_top},
face->glyph->advance.x
};
glBindTexture(GL_TEXTURE_2D, 0);
}
FT_Done_Face(face);
FT_Done_FreeType(ft);
info("font \"%s\" loaded successfully", path);
}
v2 get_text_size(struct text_renderer renderer, const char *text, f32 scale)
{
v2 size = {0};
for (const char *c = text; *c; c++) {
struct text_char ch = renderer.chars[(u8)*c];
f32 h = ch.size.y * scale;
if (h > size.y)
size.y = h;
size.x += (ch.advance >> 6) * scale;
}
return size;
}
void render_text(struct text_renderer renderer, const char *text, v2 pos, f32 scale, v3 color)
{
glUseProgram(renderer.shader);
uniform_v3(renderer.shader, "text_color", color);
glActiveTexture(GL_TEXTURE0);
glBindVertexArray(renderer.vao);
for (const char *c = text; *c; c++) {
struct text_char ch = renderer.chars[(u8)*c];
f32 x = pos.x + ch.bearing.x * scale;
f32 y = pos.y + (renderer.chars['H'].bearing.y - ch.bearing.y) * scale;
f32 w = ch.size.x * scale;
f32 h = ch.size.y * scale;
f32 vertices[] = {
x, y + h, 0.0f, 1.0f,
x + w, y, 1.0f, 0.0f,
x, y, 0.0f, 0.0f,
x, y + h, 0.0f, 1.0f,
x + w, y + h, 1.0f, 1.0f,
x + w, y, 1.0f, 0.0f,
};
glBindTexture(GL_TEXTURE_2D, ch.texture);
glBindBuffer(GL_ARRAY_BUFFER, renderer.vbo);
glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(vertices), vertices);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glDrawArrays(GL_TRIANGLES, 0, 6);
glBindTexture(GL_TEXTURE_2D, 0);
pos.x += (ch.advance >> 6) * scale;
}
glBindVertexArray(0);
glUseProgram(0);
}
void render_text_centered(struct text_renderer renderer, const char *text, v2 pos, f32 scale, v3 color)
{
v2 size = get_text_size(renderer, text, scale);
v2 top_left = sub_v2(pos, scale_v2(size, 0.5f));
render_text(renderer, text, top_left, scale, color);
}
|
