stbtt_trouble.cpp

void paint_text(V2<float>&cursor, V4<float>&bounds, BakedFont&font, char*input_text) {
    glEnable(GL_TEXTURE_2D);
    glBindTexture(GL_TEXTURE_2D, font.texture);
    glBegin(GL_QUADS);
    char*text_end = strlen(input_text) + input_text;
    for(char*t = input_text; t<text_end; t++) {
        if (*t == '\n') {
            cursor.x  = bounds.l;
            cursor.y += font.size;
        } else if (*t >= 32) { 
            stbtt_aligned_quad q;
            cursor.x = (float)(u32)cursor.x;
            cursor.y = (float)(u32)cursor.y;
            //stbtt_GetBakedQuad(font.cdata, 512,512, *t-32, &cursor.x,&cursor.y,&q,1);
            stbtt_GetPackedQuad(font.cdata, 1024,1024, *t-32, &cursor.x,&cursor.y,&q,1);
            glTexCoord2f(q.s0,q.t1); glVertex2f(q.x0,q.y1);
            glTexCoord2f(q.s1,q.t1); glVertex2f(q.x1,q.y1);
            glTexCoord2f(q.s1,q.t0); glVertex2f(q.x1,q.y0);
            glTexCoord2f(q.s0,q.t0); glVertex2f(q.x0,q.y0);
        }
    }
    glEnd();
    glDisable(GL_TEXTURE_2D);
    assert(glGetError() == GL_NO_ERROR);
}
void bake_font(BakedFont&font, float size, char*path) {
    font.size = size;
    u8 ttf_buffer[1<<20];
    auto f = fopen(path, "rb");
    assert(f);
    fread(ttf_buffer, 1, 1<<20, f);
    fclose(f);
    u8 temp_bitmap[1024*1024];
    stbtt_pack_context pc;
    stbtt_PackBegin(&pc, temp_bitmap, 1024, 1024, 0, 1, NULL);   
    stbtt_PackSetOversampling(&pc, 8, 8);
    stbtt_pack_range ranges[] = {
        {size, 32,      NULL, 95,  font.cdata, 0, 0},  // ascii, from 32 to 127
        //{size, 0x2200,  NULL, 255, font.cdata+95, 0, 0},  // math glyphs
        //{size, 0x1D434, NULL, 255, font.cdata+95+255, 0, 0} // fancy alphabet
    };
    //static_assert (acount(font.cdata) >= 95+255+255);
    stbtt_PackFontRanges(&pc, ttf_buffer, 0, ranges, acount(ranges));
    glEnable(GL_TEXTURE_2D);
    glGenTextures(1, &font.texture);
    glBindTexture(GL_TEXTURE_2D, font.texture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, 1024,1024, 0, GL_ALPHA, GL_UNSIGNED_BYTE, temp_bitmap);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glDisable(GL_TEXTURE_2D);
    assert(glGetError() == GL_NO_ERROR);
}