вот так получается с drop_shadow
if ( flags & drop_shadow )
{
*vertices++ = { { x + 0 + 0.5f, y + h + 0.5f, 1.0f, 1.0f }, shadowcol, x1, y2 };
*vertices++ = { { x + 0 + 0.5f, y + 0 + 0.5f, 1.0f, 1.0f }, shadowcol, x1, y1 };
*vertices++ = { { x + w + 0.5f, y + h + 0.5f, 1.0f, 1.0f }, shadowcol, x2, y2 };
*vertices++ = { { x + w + 0.5f, y + 0 + 0.5f, 1.0f, 1.0f }, shadowcol, x2, y1 };
*vertices++ = { { x + w + 0.5f, y + h + 0.5f, 1.0f, 1.0f }, shadowcol, x2, y2 };
*vertices++ = { { x + 0 + 0.5f, y + 0 + 0.5f, 1.0f, 1.0f }, shadowcol, x1, y1 };
num_triangles += 2;
*vertices++ = { { x + 0 - 1.f, y + h + 0.5f, 1.0f, 1.0f }, shadowcol, x1, y2 };
*vertices++ = { { x + 0 - 1.f, y + 0 + 0.5f, 1.0f, 1.0f }, shadowcol, x1, y1 };
*vertices++ = { { x + w - 1.f, y + h + 0.5f, 1.0f, 1.0f }, shadowcol, x2, y2 };
*vertices++ = { { x + w - 1.f, y + 0 + 0.5f, 1.0f, 1.0f }, shadowcol, x2, y1 };
*vertices++ = { { x + w - 1.f, y + h + 0.5f, 1.0f, 1.0f }, shadowcol, x2, y2 };
*vertices++ = { { x + 0 - 1.f, y + 0 + 0.5f, 1.0f, 1.0f }, shadowcol, x1, y1 };
num_triangles += 2;
*vertices++ = { { x + 0 - 1.f, y + h - 1.f, 1.0f, 1.0f }, shadowcol, x1, y2 };
*vertices++ = { { x + 0 - 1.f, y + 0 - 1.f, 1.0f, 1.0f }, shadowcol, x1, y1 };
*vertices++ = { { x + w - 1.f, y + h - 1.f, 1.0f, 1.0f }, shadowcol, x2, y2 };
*vertices++ = { { x + w - 1.f, y + 0 - 1.f, 1.0f, 1.0f }, shadowcol, x2, y1 };
*vertices++ = { { x + w - 1.f, y + h - 1.f, 1.0f, 1.0f }, shadowcol, x2, y2 };
*vertices++ = { { x + 0 - 1.f, y + 0 - 1.f, 1.0f, 1.0f }, shadowcol, x1, y1 };
num_triangles += 2;
*vertices++ = { { x + 0 + 0.5f, y + h - 0.5f, 1.0f, 1.0f }, shadowcol, x1, y2 };
*vertices++ = { { x + 0 + 0.5f, y + 0 - 0.5f, 1.0f, 1.0f }, shadowcol, x1, y1 };
*vertices++ = { { x + w + 0.5f, y + h - 0.5f, 1.0f, 1.0f }, shadowcol, x2, y2 };
*vertices++ = { { x + w + 0.5f, y + 0 - 0.5f, 1.0f, 1.0f }, shadowcol, x2, y1 };
*vertices++ = { { x + w + 0.5f, y + h - 0.5f, 1.0f, 1.0f }, shadowcol, x2, y2 };
*vertices++ = { { x + 0 + 0.5f, y + 0 - 0.5f, 1.0f, 1.0f }, shadowcol, x1, y1 };
num_triangles += 2;
}
код дропшадоу, пришла в голову одна идея, щас попробую ёё