physics_particle_group_get_data(group, buffer, flags)
| Argument | Description |
|---|---|
| group | The group index (ID) of the particle group to get the data from. |
| buffer | The (previously created) buffer to use to store the data. |
| flags | The flags to use to extract data about specific particle types. |
Returns: Buffer data
This function returns various pieces of information about a
group of particles in the physics simulation using the given flags
checked. The group index (its ID) is that which was returned by the
function physics_particle_group_end(),
and the buffer used must have been created previously using the
function buffer_create(). It
should be of the "grow" type, with the size being approximately
that of the expected return data. The flags themselves are set
using the constants given below, and you would use the bitwise
or "|" to create a single flag value to get the desired
information.
| Constant | Description | Data Type |
|---|---|---|
| phy_particle_data_flag_typeflags | The flags value for the particle. | buffer_u32 |
| phy_particle_data_flag_position | The x and y position of the particle. | 2 x buffer_f32 |
| phy_particle_data_flag_velocity | The horizontal and vertical speed. | 2 x buffer_f32 |
| phy_particle_data_flag_colour | The colour and alpha value (hexadecimal). | buffer_f32 |
| phy_particle_data_flag_category | The particle category (as defined when you created the group to which it belongs). | buffer_f32 |
var count = physics_particle_group_count(gp);
var flags = phy_particle_data_flag_position |
phy_particle_data_flag_colour;
if (count > 0)
{
var buffer = buffer_create(count * 12,
buffer_grow, 4);
physics_particle_group_get_data(gp, buffer,
flags);
for (var n = 0; n < count; n++;)
{
var xx = buffer_read(buffer,
buffer_f32);
var yy = buffer_read(buffer,
buffer_f32);
var argb = buffer_read(buffer,
buffer_u32);
var alpha = (argb >> 24)
& 255;
draw_sprite_ext(sprBlob, 0, xx,
yy, 1, 1, 0, c_green, alpha);
}
buffer_delete(buffer);
}
The above code gets the position and velocity of the every particle in the group indexed by the variable "gp", stores the buffer data in a number of variables, and then uses that to draw a sprite at the position of each particle in the group.