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我有問題freetype和OpenGL。我只需要在單個紋理上繪製所有加載的符號。這裏是:使用Freetype和OpenGL渲染字體
FT_Init_FreeType(&lib);
FT_New_Face(lib, "C:\\verdana.ttf", 0, &face);
FT_Set_Pixel_Sizes(face, 0, size);
auto ww = 256 * size;
auto hh = size;
std::vector<unsigned char> buffer(ww * hh, 0);
int off = 0;
for (int c = 0; c < 256; c++)
{
FT_UInt GlyphIndex;
GlyphIndex = FT_Get_Char_Index(face, c);
FT_Load_Char(face, GlyphIndex, FT_LOAD_RENDER);
FT_Bitmap bmp = face->glyph->bitmap;
int advance = (face->glyph->advance.x >> 6);
int bW = bmp.width;
int bH = bmp.rows;
for (int h = 0; h < bH; ++h) {
for (int w = 0; w < bW; ++w) {
buffer[h * bW + off + w] = bmp.buffer[w + bW * h];
}
}
off += advance;
}
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, ww, hh, 0, GL_ALPHA, GL_UNSIGNED_BYTE, &buffer[0]);
我嘗試了很多方法來做到這一點。但我得到的是絕對黑色的紋理... 我的代碼有什麼問題?
您是否檢查從FT_Init_FreeType,FT_New_Face等返回的錯誤代碼?另外可能需要調用FT_Set_Char_Size。 – BDL 2014-12-03 11:52:02
我在代碼的任何部分都沒有發現錯誤。我用FT_Set_Pixel_Sizes設置字符大小。 – user3808059 2014-12-03 12:00:17
但是你也不檢查錯誤。每個freetype函數都返回一個值,表示它是成功/失敗的。例如:'error = FT_Init_FreeType(&library); if(error){failed; }' – BDL 2014-12-03 12:33:16