641 lines
13 KiB
C
641 lines
13 KiB
C
/*
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======================================================================
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envelope.c
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Envelope functions for an LWO2 reader.
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Ernie Wright 16 Nov 00
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====================================================================== */
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#include "picointernal.h"
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#include "lwo2.h"
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/*
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======================================================================
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lwFreeEnvelope()
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Free the memory used by an lwEnvelope.
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====================================================================== */
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void lwFreeEnvelope( lwEnvelope *env ){
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if ( env ) {
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if ( env->name ) {
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_pico_free( env->name );
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}
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lwListFree( env->key, _pico_free );
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lwListFree(env->cfilter, (void (*)(void *)) lwFreePlugin);
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_pico_free( env );
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}
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}
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static int compare_keys( lwKey *k1, lwKey *k2 ){
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return k1->time > k2->time ? 1 : k1->time < k2->time ? -1 : 0;
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}
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/*
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======================================================================
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lwGetEnvelope()
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Read an ENVL chunk from an LWO2 file.
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====================================================================== */
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lwEnvelope *lwGetEnvelope( picoMemStream_t *fp, int cksize ){
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lwEnvelope *env;
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lwKey *key = NULL;
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lwPlugin *plug;
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unsigned int id;
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unsigned short sz;
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float f[ 4 ];
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int i, nparams, pos, rlen;
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/* allocate the Envelope structure */
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env = _pico_calloc( 1, sizeof( lwEnvelope ) );
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if ( !env ) {
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goto Fail;
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}
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/* remember where we started */
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set_flen( 0 );
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pos = _pico_memstream_tell( fp );
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/* index */
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env->index = getVX( fp );
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/* first subchunk header */
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id = getU4( fp );
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sz = getU2( fp );
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if ( 0 > get_flen() ) {
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goto Fail;
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}
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/* process subchunks as they're encountered */
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while ( 1 ) {
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sz += sz & 1;
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set_flen( 0 );
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switch ( id ) {
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case ID_TYPE:
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env->type = getU2( fp );
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break;
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case ID_NAME:
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env->name = getS0( fp );
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break;
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case ID_PRE:
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env->behavior[ 0 ] = getU2( fp );
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break;
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case ID_POST:
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env->behavior[ 1 ] = getU2( fp );
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break;
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case ID_KEY:
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key = _pico_calloc( 1, sizeof( lwKey ) );
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if ( !key ) {
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goto Fail;
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}
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key->time = getF4( fp );
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key->value = getF4( fp );
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lwListInsert((void **) &env->key, key, (int (*)(void *, void *)) compare_keys);
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env->nkeys++;
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break;
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case ID_SPAN:
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if ( !key ) {
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goto Fail;
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}
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key->shape = getU4( fp );
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nparams = ( sz - 4 ) / 4;
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if ( nparams > 4 ) {
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nparams = 4;
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}
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for ( i = 0; i < nparams; i++ )
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f[ i ] = getF4( fp );
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switch ( key->shape ) {
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case ID_TCB:
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key->tension = f[ 0 ];
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key->continuity = f[ 1 ];
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key->bias = f[ 2 ];
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break;
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case ID_BEZI:
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case ID_HERM:
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case ID_BEZ2:
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for ( i = 0; i < nparams; i++ )
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key->param[ i ] = f[ i ];
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break;
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}
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break;
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case ID_CHAN:
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plug = _pico_calloc( 1, sizeof( lwPlugin ) );
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if ( !plug ) {
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goto Fail;
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}
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plug->name = getS0( fp );
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plug->flags = getU2( fp );
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plug->data = getbytes( fp, sz - get_flen() );
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lwListAdd( (void *) &env->cfilter, plug );
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env->ncfilters++;
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break;
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default:
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break;
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}
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/* error while reading current subchunk? */
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rlen = get_flen();
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if ( rlen < 0 || rlen > sz ) {
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goto Fail;
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}
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/* skip unread parts of the current subchunk */
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if ( rlen < sz ) {
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_pico_memstream_seek( fp, sz - rlen, PICO_SEEK_CUR );
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}
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/* end of the ENVL chunk? */
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rlen = _pico_memstream_tell( fp ) - pos;
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if ( cksize < rlen ) {
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goto Fail;
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}
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if ( cksize == rlen ) {
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break;
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}
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/* get the next subchunk header */
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set_flen( 0 );
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id = getU4( fp );
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sz = getU2( fp );
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if ( 6 != get_flen() ) {
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goto Fail;
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}
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}
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return env;
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Fail:
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lwFreeEnvelope( env );
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return NULL;
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}
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/*
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======================================================================
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lwFindEnvelope()
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Returns an lwEnvelope pointer, given an envelope index.
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====================================================================== */
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lwEnvelope *lwFindEnvelope( lwEnvelope *list, int index ){
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lwEnvelope *env;
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env = list;
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while ( env ) {
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if ( env->index == index ) {
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break;
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}
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env = env->next;
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}
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return env;
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}
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/*
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======================================================================
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range()
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Given the value v of a periodic function, returns the equivalent value
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v2 in the principal interval [lo, hi]. If i isn't NULL, it receives
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the number of wavelengths between v and v2.
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v2 = v - i * (hi - lo)
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For example, range( 3 pi, 0, 2 pi, i ) returns pi, with i = 1.
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====================================================================== */
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static float range( float v, float lo, float hi, int *i ){
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float v2, r = hi - lo;
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if ( r == 0.0 ) {
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if ( i ) {
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*i = 0;
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}
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return lo;
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}
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v2 = lo + v - r * ( float ) floor( ( double ) v / r );
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if ( i ) {
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*i = -( int )( ( v2 - v ) / r + ( v2 > v ? 0.5 : -0.5 ) );
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}
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return v2;
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}
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/*
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======================================================================
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hermite()
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Calculate the Hermite coefficients.
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====================================================================== */
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static void hermite( float t, float *h1, float *h2, float *h3, float *h4 ){
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float t2, t3;
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t2 = t * t;
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t3 = t * t2;
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*h2 = 3.0f * t2 - t3 - t3;
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*h1 = 1.0f - *h2;
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*h4 = t3 - t2;
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*h3 = *h4 - t2 + t;
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}
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/*
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======================================================================
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bezier()
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Interpolate the value of a 1D Bezier curve.
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====================================================================== */
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static float bezier( float x0, float x1, float x2, float x3, float t ){
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float a, b, c, t2, t3;
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t2 = t * t;
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t3 = t2 * t;
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c = 3.0f * ( x1 - x0 );
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b = 3.0f * ( x2 - x1 ) - c;
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a = x3 - x0 - c - b;
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return a * t3 + b * t2 + c * t + x0;
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}
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/*
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======================================================================
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bez2_time()
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Find the t for which bezier() returns the input time. The handle
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endpoints of a BEZ2 curve represent the control points, and these have
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(time, value) coordinates, so time is used as both a coordinate and a
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parameter for this curve type.
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====================================================================== */
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static float bez2_time( float x0, float x1, float x2, float x3, float time,
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float *t0, float *t1 ){
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float v, t;
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t = *t0 + ( *t1 - *t0 ) * 0.5f;
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v = bezier( x0, x1, x2, x3, t );
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if ( fabs( time - v ) > .0001f ) {
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if ( v > time ) {
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*t1 = t;
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}
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else{
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*t0 = t;
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}
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return bez2_time( x0, x1, x2, x3, time, t0, t1 );
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}
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else{
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return t;
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}
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}
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/*
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======================================================================
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bez2()
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Interpolate the value of a BEZ2 curve.
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====================================================================== */
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static float bez2( lwKey *key0, lwKey *key1, float time ){
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float x, y, t, t0 = 0.0f, t1 = 1.0f;
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if ( key0->shape == ID_BEZ2 ) {
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x = key0->time + key0->param[ 2 ];
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}
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else{
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x = key0->time + ( key1->time - key0->time ) / 3.0f;
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}
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t = bez2_time( key0->time, x, key1->time + key1->param[ 0 ], key1->time,
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time, &t0, &t1 );
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if ( key0->shape == ID_BEZ2 ) {
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y = key0->value + key0->param[ 3 ];
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}
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else{
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y = key0->value + key0->param[ 1 ] / 3.0f;
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}
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return bezier( key0->value, y, key1->param[ 1 ] + key1->value, key1->value, t );
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}
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/*
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======================================================================
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outgoing()
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Return the outgoing tangent to the curve at key0. The value returned
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for the BEZ2 case is used when extrapolating a linear pre behavior and
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when interpolating a non-BEZ2 span.
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====================================================================== */
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static float outgoing( lwKey *key0, lwKey *key1 ){
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float a, b, d, t, out;
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switch ( key0->shape )
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{
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case ID_TCB:
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a = ( 1.0f - key0->tension )
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* ( 1.0f + key0->continuity )
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* ( 1.0f + key0->bias );
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b = ( 1.0f - key0->tension )
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* ( 1.0f - key0->continuity )
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* ( 1.0f - key0->bias );
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d = key1->value - key0->value;
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if ( key0->prev ) {
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t = ( key1->time - key0->time ) / ( key1->time - key0->prev->time );
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out = t * ( a * ( key0->value - key0->prev->value ) + b * d );
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}
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else{
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out = b * d;
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}
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break;
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case ID_LINE:
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d = key1->value - key0->value;
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if ( key0->prev ) {
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t = ( key1->time - key0->time ) / ( key1->time - key0->prev->time );
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out = t * ( key0->value - key0->prev->value + d );
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}
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else{
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out = d;
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}
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break;
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case ID_BEZI:
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case ID_HERM:
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out = key0->param[ 1 ];
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if ( key0->prev ) {
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out *= ( key1->time - key0->time ) / ( key1->time - key0->prev->time );
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}
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break;
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case ID_BEZ2:
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out = key0->param[ 3 ] * ( key1->time - key0->time );
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if ( fabs( key0->param[ 2 ] ) > 1e-5f ) {
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out /= key0->param[ 2 ];
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}
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else{
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out *= 1e5f;
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}
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break;
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case ID_STEP:
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default:
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out = 0.0f;
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break;
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}
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return out;
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}
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/*
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======================================================================
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incoming()
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Return the incoming tangent to the curve at key1. The value returned
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for the BEZ2 case is used when extrapolating a linear post behavior.
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====================================================================== */
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static float incoming( lwKey *key0, lwKey *key1 ){
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float a, b, d, t, in;
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switch ( key1->shape )
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{
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case ID_LINE:
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d = key1->value - key0->value;
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if ( key1->next ) {
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t = ( key1->time - key0->time ) / ( key1->next->time - key0->time );
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in = t * ( key1->next->value - key1->value + d );
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}
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else{
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in = d;
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}
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break;
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case ID_TCB:
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a = ( 1.0f - key1->tension )
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* ( 1.0f - key1->continuity )
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* ( 1.0f + key1->bias );
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b = ( 1.0f - key1->tension )
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* ( 1.0f + key1->continuity )
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* ( 1.0f - key1->bias );
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d = key1->value - key0->value;
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if ( key1->next ) {
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t = ( key1->time - key0->time ) / ( key1->next->time - key0->time );
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in = t * ( b * ( key1->next->value - key1->value ) + a * d );
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}
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else{
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in = a * d;
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}
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break;
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case ID_BEZI:
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case ID_HERM:
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in = key1->param[ 0 ];
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if ( key1->next ) {
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in *= ( key1->time - key0->time ) / ( key1->next->time - key0->time );
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}
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break;
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return in;
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case ID_BEZ2:
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in = key1->param[ 1 ] * ( key1->time - key0->time );
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if ( fabs( key1->param[ 0 ] ) > 1e-5f ) {
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in /= key1->param[ 0 ];
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}
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else{
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in *= 1e5f;
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}
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break;
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case ID_STEP:
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default:
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in = 0.0f;
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break;
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}
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return in;
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}
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/*
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======================================================================
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evalEnvelope()
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Given a list of keys and a time, returns the interpolated value of the
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envelope at that time.
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====================================================================== */
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float evalEnvelope( lwEnvelope *env, float time ){
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lwKey *key0, *key1, *skey, *ekey;
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float t, h1, h2, h3, h4, in, out, offset = 0.0f;
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int noff;
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/* if there's no key, the value is 0 */
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if ( env->nkeys == 0 ) {
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return 0.0f;
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}
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/* if there's only one key, the value is constant */
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if ( env->nkeys == 1 ) {
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return env->key->value;
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}
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/* find the first and last keys */
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skey = ekey = env->key;
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while ( ekey->next ) ekey = ekey->next;
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/* use pre-behavior if time is before first key time */
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if ( time < skey->time ) {
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switch ( env->behavior[ 0 ] )
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{
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case BEH_RESET:
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return 0.0f;
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case BEH_CONSTANT:
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return skey->value;
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case BEH_REPEAT:
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time = range( time, skey->time, ekey->time, NULL );
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break;
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case BEH_OSCILLATE:
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time = range( time, skey->time, ekey->time, &noff );
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if ( noff % 2 ) {
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time = ekey->time - skey->time - time;
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}
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break;
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case BEH_OFFSET:
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time = range( time, skey->time, ekey->time, &noff );
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offset = noff * ( ekey->value - skey->value );
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break;
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case BEH_LINEAR:
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out = outgoing( skey, skey->next )
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/ ( skey->next->time - skey->time );
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return out * ( time - skey->time ) + skey->value;
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}
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}
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/* use post-behavior if time is after last key time */
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else if ( time > ekey->time ) {
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switch ( env->behavior[ 1 ] )
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{
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case BEH_RESET:
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return 0.0f;
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case BEH_CONSTANT:
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return ekey->value;
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case BEH_REPEAT:
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time = range( time, skey->time, ekey->time, NULL );
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break;
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case BEH_OSCILLATE:
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time = range( time, skey->time, ekey->time, &noff );
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if ( noff % 2 ) {
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time = ekey->time - skey->time - time;
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}
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break;
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case BEH_OFFSET:
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time = range( time, skey->time, ekey->time, &noff );
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offset = noff * ( ekey->value - skey->value );
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break;
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case BEH_LINEAR:
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in = incoming( ekey->prev, ekey )
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/ ( ekey->time - ekey->prev->time );
|
|
return in * ( time - ekey->time ) + ekey->value;
|
|
}
|
|
}
|
|
|
|
/* get the endpoints of the interval being evaluated */
|
|
|
|
key0 = env->key;
|
|
while ( time > key0->next->time )
|
|
key0 = key0->next;
|
|
key1 = key0->next;
|
|
|
|
/* check for singularities first */
|
|
|
|
if ( time == key0->time ) {
|
|
return key0->value + offset;
|
|
}
|
|
else if ( time == key1->time ) {
|
|
return key1->value + offset;
|
|
}
|
|
|
|
/* get interval length, time in [0, 1] */
|
|
|
|
t = ( time - key0->time ) / ( key1->time - key0->time );
|
|
|
|
/* interpolate */
|
|
|
|
switch ( key1->shape )
|
|
{
|
|
case ID_TCB:
|
|
case ID_BEZI:
|
|
case ID_HERM:
|
|
out = outgoing( key0, key1 );
|
|
in = incoming( key0, key1 );
|
|
hermite( t, &h1, &h2, &h3, &h4 );
|
|
return h1 * key0->value + h2 * key1->value + h3 * out + h4 * in + offset;
|
|
|
|
case ID_BEZ2:
|
|
return bez2( key0, key1, time ) + offset;
|
|
|
|
case ID_LINE:
|
|
return key0->value + t * ( key1->value - key0->value ) + offset;
|
|
|
|
case ID_STEP:
|
|
return key0->value + offset;
|
|
|
|
default:
|
|
return offset;
|
|
}
|
|
}
|