Here you go,
Code:
#include <amxmodx>
#include <fakemeta>
#define PLUGIN "block jumping"
#define VERSION "1.0"
#define AUTHOR "tpt"
public plugin_init()
{
register_plugin(PLUGIN, VERSION, AUTHOR);
register_forward( FM_CmdStart, "fwd_cmdstart" );
}
public fwd_cmdstart( id, uc_handle, random_seed )
{
static button; button = get_uc( uc_handle, UC_Buttons );
if( button & IN_JUMP )
{
new Float:fVel[ 3 ];
pev( id, pev_velocity, fVel );
fVel[ 2 ] = float( -abs( floatround( fVel[ 2 ] ) ) )
set_pev( id, pev_velocity, fVel )
}
}