3.2 Glyph Entry Format (16 bytes)
typedef struct {
uint16_t tex_x; /* Texture X offset */
uint16_t tex_y; /* Texture Y offset */
uint8_t tex_w; /* Glyph width in texture */
uint8_t tex_h; /* Glyph height in texture */
int8_t bearing_x; /* X offset from baseline */
int8_t bearing_y; /* Y offset from baseline */
uint8_t advance; /* Advance to next character */
uint8_t reserved; /* Reserved for future use */
} d3f_glyph_t;