Creating new samples using std::vector

Creating new samples using std::vector

Bronxz

Member #16,061

August 2015

Hi! I would like to create empty sounds using std::vector, but I don't know what to type in "al_create_sample" function in order to create an empty sound.

For example, when I create empty bitmaps with std::vector I do it like that:

std::vector < ALLEGRO_BITMAP* > empty_bitmap;

[...]

empty_bitmap.push_back(al_create_bitmap(0,0));

In documentation, al_create_sample function looks like that: al_create_sample(void *buf, unsigned int samples,
unsigned int freq, ALLEGRO_AUDIO_DEPTH depth,
ALLEGRO_CHANNEL_CONF chan_conf, bool free_buf)

what do I have to type in this function in order to create an empty sound? Please help.

And sorry for my english

torhu

Member #2,727

September 2002

I don't know, but why not just set the pointer to NULL instead?

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#00JMP00

Member #14,740

November 2012

I have some ideas to solve it.

1st. Create an empty sample, as you would do normal. Then you keep pushing this example into the vector. Sadly you can end up with having a vector filled with samples pointing all at the same memory :-)

2nd, somewhat more complicated solution. Find the header for the sample definition. There look at the copy constructor of sample. You will need the same information as the copy constructor, since you make a copy.

3rd solution. You create a proforma class with sample included. There you define you're on copy constructor. When doing this, surely new objects will be created.

Once I had this problems with bitmaps in vectors...

Peter Hull

Member #1,136

March 2001

torhu said:

I don't know, but why not just set the pointer to NULL instead?

This sounds most sensible to me - just make sure you don't pass a null pointer to al_play_sample

If you absolutely have to have a non-NULL, but empty, sample, I think this will work:

  void* dummy = al_malloc(0);
  ALLEGRO_SAMPLE* samp = al_create_sample(dummy,
                          0,
                          44100,
                          ALLEGRO_AUDIO_DEPTH_INT16,
                          ALLEGRO_CHANNEL_CONF_1,
                          true);

so for you, you could call it as

std::vector<ALLEGRO_SAMPLE*> samples;
[ ... ]
samples.push_back(al_create_sample(al_malloc(0), 0, 44100, ALLEGRO_AUDIO_DEPTH_INT16, ALLEGRO_CHANNEL_CONF_1, true));

Bronxz

Member #16,061

August 2015

Than you all for help

Problem solved.