Freetype renders crap in bitmap - c++

Question

I'm trying to create monochrome glyph atlas but encountered a problem. Freetype renders 'crap' in glyph's bitmap. I blame freetype because some of the glyphs are still rendered correctly.
The resulting texture atlas:
Why could it be and how can i fix it?
However i still could be wrong and here is bitmap processing code:
static std::vector<unsigned char> generateBitmap(FT_Face &face, unsigned int glyph, size_t *width, size_t *height) {
FT_Load_Glyph(face, FT_Get_Char_Index(face, glyph), FT_LOAD_RENDER | FT_LOAD_MONOCHROME );
FT_Bitmap bitmap;
FT_Bitmap_New(&bitmap);
FT_Bitmap_Convert(ftLib, &face->glyph->bitmap, &bitmap, 1);
*width = bitmap.width;
*height = bitmap.rows;
std::vector<unsigned char> result(bitmap.width * bitmap.rows);//
for (size_t y = 0; y < bitmap.rows; ++y)
{
for (size_t x = 0; x < bitmap.width; ++x)
{
result[(bitmap.width * y) + x] = bitmap.buffer[(bitmap.width * y) + x];
}
}
FT_Bitmap_Done(ftLib, &bitmap);
return result;
}
And code for putting it on main buffer:
static void putOnBuffer(std::vector<unsigned char> &buffer, std::vector<unsigned char> &bitmap, size_t height, size_t width) {
int r = 0;
while (r < height) {
int w = 0;
while (w < width) {
//assume buffer is enough large
size_t mainBufPos = ((currentBufferPositionY + r) * imageWidth) + (currentBufferPositionX + w);
size_t bitmapBufPos = (r * width) + w;
buffer[mainBufPos] = clamp(int(bitmap[bitmapBufPos] * 0x100), 0xff);
w++;
}
r++;
}
}

Answer 1

From documentation:
Convert a bitmap object with depth 1bpp, 2bpp, 4bpp, 8bpp or 32bpp to a bitmap object with depth 8bpp, making the number of used bytes [per] line (a.k.a. the ‘pitch’) a multiple of ‘alignment’.
In your code, you pass 1 as the value of the alignment parameter in the call to FT_Bitmap_Convert. In monochrome, one byte will be eight pixels, so the horizontal render loop needs to enforce a multiple of eight for the width.
Reference: https://www.freetype.org/freetype2/docs/reference/ft2-bitmap_handling.html