Get data on a group of particles in your physics simulation.


physics_particle_group_get_data(group, buffer, flags)

参数 描述
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.

常量 描述 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);

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.

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