vgmstream/src/layout/layered.c

#include "layout.h"
#include "../vgmstream.h"


/* NOTE: if loop settings change the layered vgmstreams must be notified (preferably using vgmstream_force_loop) */
#define LAYER_BUF_SIZE 512
#define LAYER_MAX_CHANNELS 6 /* at least 2, but let's be generous */

/* Decodes samples for layered streams.
 * Similar to interleave layout, but decodec samples are mixed from complete vgmstreams, each
 * with custom codecs and different number of channels, creating a single super-vgmstream.
 * Usually combined with custom streamfiles to handle data interleaved in weird ways. */
void render_vgmstream_layered(sample_t * buffer, int32_t sample_count, VGMSTREAM * vgmstream) {
    int samples_written = 0;
    layered_layout_data *data = vgmstream->layout_data;
    sample_t interleave_buf[LAYER_BUF_SIZE*LAYER_MAX_CHANNELS];


    while (samples_written < sample_count) {
        int samples_to_do = LAYER_BUF_SIZE;
        int layer, ch = 0;

        if (samples_to_do > sample_count - samples_written)
            samples_to_do = sample_count - samples_written;

        for (layer = 0; layer < data->layer_count; layer++) {
            int s, layer_ch;
            int layer_channels = data->layers[layer]->channels;

            /* each layer will handle its own looping internally */

            render_vgmstream(interleave_buf, samples_to_do, data->layers[layer]);

            /* mix layer samples to main samples */
            for (layer_ch = 0; layer_ch < layer_channels; layer_ch++) {
                for (s = 0; s < samples_to_do; s++) {
                    size_t layer_sample = s*layer_channels + layer_ch;
                    size_t buffer_sample = (samples_written+s)*vgmstream->channels + ch;

                    buffer[buffer_sample] = interleave_buf[layer_sample];
                }
                ch++;
            }
        }

        samples_written += samples_to_do;
        vgmstream->current_sample = data->layers[0]->current_sample; /* just in case it's used for info */
        //vgmstream->samples_into_block = 0; /* handled in each layer */
    }
}


layered_layout_data* init_layout_layered(int layer_count) {
    layered_layout_data *data = NULL;

    if (layer_count <= 0 || layer_count > 255)
        goto fail;

    data = calloc(1, sizeof(layered_layout_data));
    if (!data) goto fail;

    data->layer_count = layer_count;

    data->layers = calloc(layer_count, sizeof(VGMSTREAM*));
    if (!data->layers) goto fail;

    return data;
fail:
    free_layout_layered(data);
    return NULL;
}

int setup_layout_layered(layered_layout_data* data) {
    int i;

    /* setup each VGMSTREAM (roughly equivalent to vgmstream.c's init_vgmstream_internal stuff) */
    for (i = 0; i < data->layer_count; i++) {
        if (!data->layers[i])
            goto fail;

        if (data->layers[i]->num_samples <= 0)
            goto fail;

        if (data->layers[i]->channels > LAYER_MAX_CHANNELS)
            goto fail;

        if (i > 0) {
            /* a bit weird, but no matter */
            if (data->layers[i]->sample_rate != data->layers[i-1]->sample_rate) {
                VGM_LOG("layered layout: layer %i has different sample rate\n", i);
            }

            /* also weird */
            if (data->layers[i]->coding_type != data->layers[i-1]->coding_type) {
                VGM_LOG("layered layout: layer %i has different coding type\n", i);
            }
        }

        /* loops and other values could be mismatched but hopefully not */

        setup_vgmstream(data->layers[i]); /* final setup in case the VGMSTREAM was created manually */
    }

    return 1;
fail:
    return 0; /* caller is expected to free */
}

void free_layout_layered(layered_layout_data *data) {
    int i;

    if (!data)
        return;

    if (data->layers) {
        for (i = 0; i < data->layer_count; i++) {
            close_vgmstream(data->layers[i]);
        }
        free(data->layers);
    }
    free(data);
}

void reset_layout_layered(layered_layout_data *data) {
    int i;

    if (!data)
        return;

    for (i = 0; i < data->layer_count; i++) {
        reset_vgmstream(data->layers[i]);
    }
}