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