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
   7 #define NUM_CHARS 128
   8
   9
  10 typedef struct
  11 {
  12         Texture *texture;
  13         v2s32 bearing;
  14         u32 advance;
  15 } Character;
  16
  17 static struct
  18 {
  19         FT_Library library;
  20         FT_Face face;
  21         Character chars[NUM_CHARS];
  22         GLfloat height;
  23 } font;
  24
  25 typedef struct
  26 {
  27         GLfloat x, y;
  28 } __attribute__((packed)) VertexFontPosition;
  29
  30 typedef struct
  31 {
  32         GLfloat s, t;
  33 } __attribute__((packed)) VertexFontTextureCoordinates;
  34
  35 typedef struct
  36 {
  37         VertexFontPosition position;
  38         VertexFontTextureCoordinates textureCoordinates;
  39 } __attribute__((packed)) VertexFont;
  40
  41 static VertexAttribute vertex_attributes[2] = {
  42         // position
  43         {
  44                 .type = GL_FLOAT,
  45                 .length = 2,
  46                 .size = sizeof(VertexFontPosition),
  47         },
  48         // textureCoordinates
  49         {
  50                 .type = GL_FLOAT,
  51                 .length = 2,
  52                 .size = sizeof(VertexFontTextureCoordinates),
  53         },
  54 };
  55
  56 static VertexLayout vertex_layout = {
  57         .attributes = vertex_attributes,
  58         .count = 2,
  59         .size = sizeof(VertexFont),
  60 };
  61
  62 bool font_init()
  63 {
  64         if (FT_Init_FreeType(&font.library)) {
  65                 fprintf(stderr, "Failed to initialize Freetype\n");
  66                 return false;
  67         }
  68
  69         if (FT_New_Face(font.library, RESSOURCEPATH "fonts/Minecraftia.ttf", 0, &font.face)) {
  70                 fprintf(stderr, "Failed to load Minecraftia.ttf\n");
  71                 return false;
  72         }
  73
  74         glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
  75         FT_Set_Pixel_Sizes(font.face, 0, 16);
  76
  77         for (unsigned char c = 0; c < NUM_CHARS; c++) {
  78                 if (FT_Load_Char(font.face, c, FT_LOAD_RENDER)) {
  79                         fprintf(stderr, "Failed to load glyph %c\n", c);
  80
  81                         font.chars[c] = (Character) {
  82                                 .texture = NULL,
  83                                 .bearing = {0, 0},
  84                                 .advance = 0,
  85                         };
  86                 } else {
  87                         font.chars[c] = (Character) {
  88                                 .texture = texture_create(font.face->glyph->bitmap.buffer, font.face->glyph->bitmap.width, font.face->glyph->bitmap.rows, GL_RED),
  89                                 .bearing = {font.face->glyph->bitmap_left, font.face->glyph->bitmap_top},
  90                                 .advance = font.face->glyph->advance.x,
  91                         };
  92                 }
  93         }
  94
  95         font.height = font.chars['|'].texture->height;
  96
  97         FT_Done_Face(font.face);
  98         FT_Done_FreeType(font.library);
  99
 100         return true;
 101 }
 102
 103 void font_deinit()
 104 {
 105         for (unsigned char c = 0; c < NUM_CHARS; c++) {
 106                 if (font.chars[c].texture)
 107                         texture_delete(font.chars[c].texture);
 108         }
 109 }
 110
 111 Font *font_create(const char *text)
 112 {
 113         Font *fnt = malloc(sizeof(fnt));
 114
 115         size_t len = strlen(text);
 116
 117         fnt->meshes = malloc(sizeof(Mesh *) * len);
 118         fnt->meshes_count = len;
 119
 120         GLfloat offset = 0.0f;
 121
 122         for (size_t i = 0; i < len; i++) {
 123                 unsigned char c = text[i];
 124
 125                 if (c >= NUM_CHARS || ! font.chars[c].texture)
 126                         c = '?';
 127
 128                 Character *ch = &font.chars[c];
 129
 130                 GLfloat width = ch->texture->width;
 131         GLfloat height = ch->texture->height;
 132
 133                 GLfloat x = ch->bearing.x + offset;
 134         GLfloat y = font.height - ch->bearing.y;
 135
 136         VertexFont vertices[6] = {
 137             {{x,         y         }, {0.0f, 0.0f}},
 138             {{x,         y + height}, {0.0f, 1.0f}},
 139             {{x + width, y + height}, {1.0f, 1.0f}},
 140             {{x,         y         }, {0.0f, 0.0f}},
 141             {{x + width, y + height}, {1.0f, 1.0f}},
 142             {{x + width, y         }, {1.0f, 0.0f}},
 143         };
 144
 145                 Mesh *mesh = fnt->meshes[i] = mesh_create();
 146                 mesh->textures = &ch->texture->id;
 147                 mesh->textures_count = 1;
 148                 mesh->free_textures = false;
 149                 mesh->vertices = vertices;
 150                 mesh->vertices_count = 6;
 151                 mesh->free_vertices = false;
 152                 mesh->layout = &vertex_layout;
 153                 mesh_configure(mesh);
 154
 155                 offset += ch->advance >> 6;
 156         }
 157
 158         fnt->size = (v2f32) {offset, font.height};
 159
 160         return fnt;
 161 }
 162
 163 void font_delete(Font *fnt)
 164 {
 165         for (size_t i = 0; i < fnt->meshes_count; i++)
 166                 mesh_delete(fnt->meshes[i]);
 167
 168         free(fnt);
 169 }
 170
 171 void font_render(Font *fnt)
 172 {
 173         for (size_t i = 0; i < fnt->meshes_count; i++)
 174                 mesh_render(fnt->meshes[i]);
 175 }