diff --git a/libass/ass_render.c b/libass/ass_render.c index 279a40c40a..0884f58ce4 100644 --- a/libass/ass_render.c +++ b/libass/ass_render.c @@ -1589,6 +1589,18 @@ static inline void transform_vector_3d(FT_Vector* v, double *m) { a[2] = 0.; a[3] = 1.; transform_point_3d(a, m, b); + /* Apply perspective projection with the following matrix: + 2500 0 0 0 + 0 2500 0 0 + 0 0 0 0 + 0 0 8 2500 + where 2500 is camera distance, 8 - z-axis scale. + Camera is always located in (org_x, org_y, -2500). This means + that different subtitle events can be displayed at the same time + using different cameras. */ + b[0] *= 2500; + b[1] *= 2500; + b[3] = 8 * b[2] + 2500; if (b[3] < 0.001 && b[3] > -0.001) b[3] = b[3] < 0. ? -0.001 : 0.001; v->x = double_to_d6(b[0] / b[3]);