src/client/font.c

   1 #include <string.h>
   2 #include <ft2build.h>
   3 #include FT_FREETYPE_H
   4 #include "client/client.h"
   5 #include "client/font.h"
   6 #include "client/texture.h"
   7
   8 #define NUM_CHARS 128
   9
  10 typedef struct {
  11         Texture texture;
  12         v2s32 bearing;
  13         u32 advance;
  14 } Character;
  15
  16 static FT_Library font_library;
  17 static FT_Face font_face;
  18 static Character font_chars[NUM_CHARS];
  19 static GLfloat font_height;
  20
  21 typedef struct {
  22         v2f32 position;
  23         v2f32 textureCoordinates;
  24 } __attribute__((packed)) FontVertex;
  25 static VertexLayout font_vertex_layout = {
  26         .attributes = (VertexAttribute[]) {
  27                 {GL_FLOAT, 2, sizeof(v2f32)}, // position
  28                 {GL_FLOAT, 2, sizeof(v2f32)}, // textureCoordinates
  29         },
  30         .count = 2,
  31         .size = sizeof(FontVertex),
  32 };
  33
  34 bool font_init()
  35 {
  36         if (FT_Init_FreeType(&font_library)) {
  37                 fprintf(stderr, "[error] failed to initialize Freetype\n");
  38                 return false;
  39         }
  40
  41         if (FT_New_Face(font_library, RESSOURCE_PATH "fonts/Minecraftia.ttf", 0, &font_face)) {
  42                 fprintf(stderr, "[error] failed to load Minecraftia.ttf\n");
  43                 return false;
  44         }
  45
  46         glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
  47         FT_Set_Pixel_Sizes(font_face, 0, 16);
  48
  49         for (unsigned char c = 0; c < NUM_CHARS; c++) {
  50                 if (FT_Load_Char(font_face, c, FT_LOAD_RENDER)) {
  51                         fprintf(stderr, "[warning] failed to load glyph %c\n", c);
  52                         font_chars[c].texture.txo = 0;
  53                         continue;
  54                 }
  55
  56                 font_chars[c].texture.width = font_face->glyph->bitmap.width;
  57                 font_chars[c].texture.height = font_face->glyph->bitmap.rows;
  58                 texture_upload(&font_chars[c].texture, font_face->glyph->bitmap.buffer, GL_RED, false);
  59
  60                 font_chars[c].bearing = (v2s32) {font_face->glyph->bitmap_left, font_face->glyph->bitmap_top};
  61                 font_chars[c].advance = font_face->glyph->advance.x;
  62         }
  63
  64         font_height = font_chars['|'].texture.height;
  65
  66         FT_Done_Face(font_face);
  67         FT_Done_FreeType(font_library);
  68
  69         return true;
  70 }
  71
  72 void font_deinit()
  73 {
  74         for (unsigned char c = 0; c < NUM_CHARS; c++)
  75                 texture_destroy(&font_chars[c].texture);
  76 }
  77
  78 Font *font_create(const char *text)
  79 {
  80         Font *font = malloc(sizeof *font);
  81
  82         font->count = strlen(text);
  83         font->meshes = malloc(font->count * sizeof *font->meshes);
  84         font->textures = malloc(font->count * sizeof *font->textures);
  85
  86         GLfloat offset = 0.0f;
  87
  88         for (size_t i = 0; i < font->count; i++) {
  89                 unsigned char c = text[i];
  90
  91                 if (c >= NUM_CHARS || !font_chars[c].texture.txo)
  92                         c = '?';
  93
  94                 Character *ch = &font_chars[c];
  95
  96                 GLfloat width = ch->texture.width;
  97                 GLfloat height = ch->texture.height;
  98
  99                 GLfloat x = ch->bearing.x + offset;
 100                 GLfloat y = font_height - ch->bearing.y;
 101
 102                 // this is art
 103                 // selling this as NFT starting price is 10 BTC
 104                 font->meshes[i].data = (FontVertex[]) {
 105                         {{x,         y         }, {0.0f, 0.0f}},
 106                         {{x,         y + height}, {0.0f, 1.0f}},
 107                         {{x + width, y + height}, {1.0f, 1.0f}},
 108                         {{x,         y         }, {0.0f, 0.0f}},
 109                         {{x + width, y + height}, {1.0f, 1.0f}},
 110                         {{x + width, y         }, {1.0f, 0.0f}},
 111                 };
 112                 font->meshes[i].count = 6;
 113                 font->meshes[i].layout = &font_vertex_layout;
 114                 font->meshes[i].vao = font->meshes[i].vbo = 0;
 115                 font->meshes[i].free_data = false;
 116                 mesh_upload(&font->meshes[i]);
 117
 118                 font->textures[i] = ch->texture.txo;
 119
 120                 offset += ch->advance >> 6;
 121         }
 122
 123         font->size = (v2f32) {offset, font_height};
 124
 125         return font;
 126 }
 127
 128 void font_delete(Font *font)
 129 {
 130         for (size_t i = 0; i < font->count; i++)
 131                 mesh_destroy(&font->meshes[i]);
 132
 133         free(font->meshes);
 134         free(font->textures);
 135         free(font);
 136 }
 137
 138 void font_render(Font *font)
 139 {
 140         for (size_t i = 0; i < font->count; i++) {
 141                 glBindTextureUnit(0, font->textures[i]);
 142                 mesh_render(&font->meshes[i]);
 143         }
 144 }