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/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
CCL_NAMESPACE_BEGIN
/* Motion Point Primitive
*
* These are stored as regular points, plus extra positions and radii at times
* other than the frame center. Computing the point at a given ray time is
* a matter of interpolation of the two steps between which the ray time lies.
*
* The extra points are stored as ATTR_STD_MOTION_VERTEX_POSITION.
*/
#ifdef __POINTCLOUD__
ccl_device_inline float4
motion_point_for_step(KernelGlobals kg, int offset, int numkeys, int numsteps, int step, int prim)
{
if (step == numsteps) {
/* center step: regular key location */
return kernel_tex_fetch(__points, prim);
}
else {
/* center step is not stored in this array */
if (step > numsteps)
step--;
offset += step * numkeys;
return kernel_tex_fetch(__attributes_float4, offset + prim);
}
}
/* return 2 point key locations */
ccl_device_inline float4 motion_point(KernelGlobals kg, int object, int prim, float time)
{
/* get motion info */
int numsteps, numkeys;
object_motion_info(kg, object, &numsteps, NULL, &numkeys);
/* figure out which steps we need to fetch and their interpolation factor */
int maxstep = numsteps * 2;
int step = min((int)(time * maxstep), maxstep - 1);
float t = time * maxstep - step;
/* find attribute */
int offset = intersection_find_attribute(kg, object, ATTR_STD_MOTION_VERTEX_POSITION);
kernel_assert(offset != ATTR_STD_NOT_FOUND);
/* fetch key coordinates */
float4 point = motion_point_for_step(kg, offset, numkeys, numsteps, step, prim);
float4 next_point = motion_point_for_step(kg, offset, numkeys, numsteps, step + 1, prim);
/* interpolate between steps */
return (1.0f - t) * point + t * next_point;
}
#endif
CCL_NAMESPACE_END
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