// Bake a given set of ranges of chars
int TTFFontAsset::BakeFontBitmap(const unsigned char *data, int offset, // font location (use offset=0 for plain .ttf)
float pixel_height, // height of font in pixels
unsigned char *pixels, int pw, int ph, // bitmap to be filled in
const GlyphRanges& ranges, // characters to bake
BakedChar *chardata)
{
stbtt_fontinfo f;
stbtt_InitFont(&f, data, offset);
STBTT_memset(pixels, 0, pw*ph); // background of 0 around pixels
int x = 1, y = 1;
int bottom_y = 1;
glyphMap.clear();
float scale = stbtt_ScaleForPixelHeight(&f, pixel_height);
int bakedIdx = 0;
for (GlyphRanges::const_iterator iter = ranges.begin(); iter != ranges.end(); ++iter)
{
const Range<int>& range = *iter;
int numItemsInRange = range.high - range.low;
for (int i = 0; i <= numItemsInRange; i++, bakedIdx++)
{
int unicodeCodepoint = i + range.low;
glyphMap.insert(std::make_pair(unicodeCodepoint, bakedIdx));
int advance, lsb, x0,y0,x1,y1,gw,gh;
int g = stbtt_FindGlyphIndex(&f, unicodeCodepoint);
stbtt_GetGlyphHMetrics(&f, g, &advance, &lsb);
stbtt_GetGlyphBitmapBox(&f, g, scale,scale, &x0,&y0,&x1,&y1);
gw = x1-x0;
gh = y1-y0;
if (x + gw + 1 >= pw)
y = bottom_y, x = 1; // advance to next row
if (y + gh + 1 >= ph) // check if it fits vertically AFTER potentially moving to next row
return -i;
STBTT_assert(x+gw < pw);
STBTT_assert(y+gh < ph);
stbtt_MakeGlyphBitmap(&f, pixels+x+y*pw, gw,gh,pw, scale,scale, g);
chardata[bakedIdx].x0 = (stbtt_int16) x;
chardata[bakedIdx].y0 = (stbtt_int16) y;
chardata[bakedIdx].x1 = (stbtt_int16) (x + gw);
chardata[bakedIdx].y1 = (stbtt_int16) (y + gh);
chardata[bakedIdx].xadvance = scale * advance;
chardata[bakedIdx].xoff = (float) x0;
chardata[bakedIdx].yoff = (float) y0;
x = x + gw + 2;
if (y+gh+2 > bottom_y)
bottom_y = y+gh+2;
}
}
return bottom_y;
}
void GlFont::InitialiseFont(const unsigned char* ttf_buffer, float pixel_height, int tex_w, int tex_h)
{
font_height_px = pixel_height;
this->tex_w = tex_w;
this->tex_h = tex_h;
font_bitmap = new unsigned char[tex_w*tex_h];
const int offset = 0;
stbtt_fontinfo f;
if (!stbtt_InitFont(&f, ttf_buffer, offset)) {
throw std::runtime_error("Unable to initialise font");
}
float scale = stbtt_ScaleForPixelHeight(&f, pixel_height);
STBTT_memset(font_bitmap, 0, tex_w*tex_h);
int x = 1;
int y = 1;
int bottom_y = 1;
// Generate bitmap and char indices
for (int i=0; i < NUM_CHARS; ++i) {
int advance, lsb, x0,y0,x1,y1,gw,gh;
int g = stbtt_FindGlyphIndex(&f, FIRST_CHAR + i);
stbtt_GetGlyphHMetrics(&f, g, &advance, &lsb);
stbtt_GetGlyphBitmapBox(&f, g, scale,scale, &x0,&y0,&x1,&y1);
gw = x1-x0;
gh = y1-y0;
if (x + gw + 1 >= tex_w)
y = bottom_y, x = 1; // advance to next row
if (y + gh + 1 >= tex_h) // check if it fits vertically AFTER potentially moving to next row
throw std::runtime_error("Unable to initialise font");
STBTT_assert(x+gw < tex_w);
STBTT_assert(y+gh < tex_h);
stbtt_MakeGlyphBitmap(&f, font_bitmap+x+y*tex_w, gw,gh,tex_w, scale,scale, g);
// Adjust offset for edges of pixels
chardata[i] = GlChar(tex_w,tex_h, x, y, gw, gh, scale*advance, x0 -0.5, -y0 -0.5);
x = x + gw + 1;
if (y+gh+1 > bottom_y)
bottom_y = y+gh+1;
}
// Generate kern table
for (int i=0; i < NUM_CHARS; ++i) {
for (int j=0; j < NUM_CHARS; ++j) {
kern_table[i*NUM_CHARS+j] = scale * stbtt_GetCodepointKernAdvance(&f,i,j);
}
}
}
