extern "C" DLLEXPORT miBoolean MYMR_AmbientOcclusion(
miColor *result ,
miState *state,
struct MYMR_AmbientOcclusion_p *paras)
{
miUint samples = * mi_eval_integer(¶s->samples);
miVector trace_direction;
miUshort dimension = 2;
int instance = 0, found=0;
double amb_exp;
double sample[dimension];
//Try to get samples to random places monte carlo style
while (mi_sample(sample,&instance,state,dimension,&samples)){
// get the direction of the ray given the sample
mi_reflection_dir_diffuse_x(&trace_direction,state,sample);
if (mi_trace_probe(state, &trace_direction, &state->point)){
found++;
}
}
printf("%d %d\n",found,samples);
amb_exp = 1.0 - ((double)found/(double)samples);
printf("%f\n",amb_exp);
result->r = result->g = result->b = amb_exp;
return miTRUE;
}
static miBoolean miao_trace_the_ray(
miState *state,
miVector *dir,
miVector *point,
miao_trace_info *ti)
{
int label = 0, childlabel = 0;
miVector base_point = *point;
miScalar base_dist = 0;
miBoolean result = miFALSE;
play_it_again:
/* Trace the ray */
result = mi_trace_probe(state, dir, &base_point);
/* If a miss, or compatible mode - then simply return */
if (!result || ti->compatible) return result;
childlabel = miao_get_label(state->child->instance);
/* Test non-self-occlusion. A hit on this object id that
originates on the same object id is considered a total
miss, i.e. the environment */
if (ti->id_nonself > 0)
{
int label = miao_get_label(state->instance);
/* Compare parent AND child labels */
if (label == ti->id_nonself &&
childlabel == ti->id_nonself)
return miFALSE;
}
/* Test the include/exclude. However, a miss here causes
the ray to continue to be traced, in case of a hit */
/* Positive inclexcl == include */
if (ti->id_inclexcl > 0 && childlabel != ti->id_inclexcl)
result = miFALSE;
/* Negative inclexcl == exclude */
if (ti->id_inclexcl < 0 && childlabel == -ti->id_inclexcl)
result = miFALSE;
/* Was this hit rejected? */
if (!result)
{
/* Remember distance traced so far */
base_dist += state->child->dist;
/* Advance the point */
base_point.x += base_dist * dir->x;
base_point.y += base_dist * dir->y;
base_point.z += base_dist * dir->z;
/* Keep tracing ray */
goto play_it_again;
}
/* Plug originals back, if necessary */
/* state->child->dist += base_dist; */
return result;
}
