The distance sampling is mostly based on weighted delta tracking from [Monte Carlo Methods for Volumetric Light Transport Simulation] (http://iliyan.com/publications/VolumeSTAR/VolumeSTAR_EG2018.pdf). The recursive Monte Carlo estimation of the Radiative Transfer Equation is \[\langle L \rangle=\frac{\bar T(x\rightarrow y)}{\bar p(x\rightarrow y)}(L_e+\sigma_s L_s + \sigma_n L).\] where \(\bar T(x\rightarrow y) = e^{-\bar\sigma\Vert x-y\Vert}\) is the majorant transmittance between points \(x\) and \(y\), \(p(x\rightarrow y) = \bar\sigma e^{-\bar\sigma\Vert x-y\Vert}\) is the probability of sampling point \(y\) from point \(x\) following exponential distribution. At each recursive step, we randomly pick one of the two events proportional to their weights: * If \(\xi < \frac{\sigma_s}{\sigma_s+\vert\sigma_n\vert}\), we sample scatter event and evaluate \(L_s\). * Otherwise, no real collision happens and we continue the recursive process. The emission \(L_e\) is evaluated at each step. This also removes some unused volume settings from the UI: * "Max Steps" is removed, because the step size is automatically specified by the volume octree. There is a hard-coded threshold `VOLUME_MAX_STEPS` to prevent numerical issues. * "Homogeneous" is automatically detected during density evaluation An option "Unbiased" is added to the UI. When enabled, densities above the majorant are clamped.
508 lines
15 KiB
C++
508 lines
15 KiB
C++
/* SPDX-FileCopyrightText: 2011-2022 Blender Foundation
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*
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* SPDX-License-Identifier: Apache-2.0 */
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/* Object Primitive
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*
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* All mesh and curve primitives are part of an object. The same mesh and curves
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* may be instanced multiple times by different objects.
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*
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* If the mesh is not instanced multiple times, the object will not be explicitly
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* stored as a primitive in the BVH, rather the bare triangles are curved are
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* directly primitives in the BVH with world space locations applied, and the object
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* ID is looked up afterwards. */
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#pragma once
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#include "kernel/globals.h"
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#include "kernel/types.h"
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CCL_NAMESPACE_BEGIN
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/* Object attributes, for now a fixed size and contents */
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enum ObjectTransform {
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OBJECT_TRANSFORM = 0,
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OBJECT_INVERSE_TRANSFORM = 1,
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};
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enum ObjectVectorTransform { OBJECT_PASS_MOTION_PRE = 0, OBJECT_PASS_MOTION_POST = 1 };
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/* Object to world space transformation */
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ccl_device_inline Transform object_fetch_transform(KernelGlobals kg,
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const int object,
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enum ObjectTransform type)
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{
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if (type == OBJECT_INVERSE_TRANSFORM) {
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return kernel_data_fetch(objects, object).itfm;
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}
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return kernel_data_fetch(objects, object).tfm;
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}
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/* Object to world space transformation for motion vectors */
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ccl_device_inline Transform object_fetch_motion_pass_transform(KernelGlobals kg,
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const int object,
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enum ObjectVectorTransform type)
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{
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const int offset = object * OBJECT_MOTION_PASS_SIZE + (int)type;
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return kernel_data_fetch(object_motion_pass, offset);
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}
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/* Motion blurred object transformations */
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#ifdef __OBJECT_MOTION__
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ccl_device_inline Transform object_fetch_transform_motion(KernelGlobals kg,
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const int object,
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const float time)
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{
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const uint motion_offset = kernel_data_fetch(objects, object).motion_offset;
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const ccl_global DecomposedTransform *motion = &kernel_data_fetch(object_motion, motion_offset);
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const uint num_steps = kernel_data_fetch(objects, object).num_tfm_steps;
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Transform tfm;
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transform_motion_array_interpolate(&tfm, motion, num_steps, time);
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return tfm;
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}
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#endif /* __OBJECT_MOTION__ */
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ccl_device_inline Transform object_fetch_transform_motion_test(KernelGlobals kg,
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const int object,
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const float time,
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ccl_private Transform *itfm)
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{
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#ifdef __OBJECT_MOTION__
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const int object_flag = kernel_data_fetch(object_flag, object);
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if (object_flag & SD_OBJECT_MOTION) {
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/* if we do motion blur */
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Transform tfm = object_fetch_transform_motion(kg, object, time);
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if (itfm) {
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*itfm = transform_inverse(tfm);
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}
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return tfm;
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}
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#endif /* __OBJECT_MOTION__ */
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Transform tfm = object_fetch_transform(kg, object, OBJECT_TRANSFORM);
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if (itfm) {
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*itfm = object_fetch_transform(kg, object, OBJECT_INVERSE_TRANSFORM);
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}
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return tfm;
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}
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/* Get transform matrix for shading point. */
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ccl_device_inline Transform object_get_transform(KernelGlobals kg,
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const ccl_private ShaderData *sd)
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{
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#ifdef __OBJECT_MOTION__
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return (sd->object_flag & SD_OBJECT_MOTION) ?
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sd->ob_tfm_motion :
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object_fetch_transform(kg, sd->object, OBJECT_TRANSFORM);
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#else
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return object_fetch_transform(kg, sd->object, OBJECT_TRANSFORM);
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#endif
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}
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ccl_device_inline Transform object_get_inverse_transform(KernelGlobals kg,
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const ccl_private ShaderData *sd)
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{
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#ifdef __OBJECT_MOTION__
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return (sd->object_flag & SD_OBJECT_MOTION) ?
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sd->ob_itfm_motion :
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object_fetch_transform(kg, sd->object, OBJECT_INVERSE_TRANSFORM);
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#else
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return object_fetch_transform(kg, sd->object, OBJECT_INVERSE_TRANSFORM);
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#endif
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}
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ccl_device_inline Transform lamp_get_inverse_transform(KernelGlobals kg,
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const ccl_global KernelLight *klight)
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{
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return object_fetch_transform(kg, klight->object_id, OBJECT_INVERSE_TRANSFORM);
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}
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/* Transform position from object to world space */
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template<class T>
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ccl_device_inline void object_position_transform(KernelGlobals kg,
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const ccl_private ShaderData *sd,
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ccl_private T *P)
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{
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#ifdef __OBJECT_MOTION__
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if (sd->object_flag & SD_OBJECT_MOTION) {
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*P = transform_point_auto(&sd->ob_tfm_motion, *P);
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return;
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}
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#endif
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const Transform tfm = object_fetch_transform(kg, sd->object, OBJECT_TRANSFORM);
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*P = transform_point(&tfm, *P);
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}
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/* Transform position from world to object space */
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ccl_device_inline void object_inverse_position_transform(KernelGlobals kg,
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const ccl_private ShaderData *sd,
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ccl_private float3 *P)
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{
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#ifdef __OBJECT_MOTION__
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if (sd->object_flag & SD_OBJECT_MOTION) {
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*P = transform_point_auto(&sd->ob_itfm_motion, *P);
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return;
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}
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#endif
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const Transform tfm = object_fetch_transform(kg, sd->object, OBJECT_INVERSE_TRANSFORM);
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*P = transform_point(&tfm, *P);
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}
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/* Transform normal from world to object space */
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ccl_device_inline void object_inverse_normal_transform(KernelGlobals kg,
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const ccl_private ShaderData *sd,
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ccl_private float3 *N)
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{
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#ifdef __OBJECT_MOTION__
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if (sd->object_flag & SD_OBJECT_MOTION) {
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if (sd->object != OBJECT_NONE) {
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*N = safe_normalize(transform_direction_transposed_auto(&sd->ob_tfm_motion, *N));
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}
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return;
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}
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#endif
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if (sd->object != OBJECT_NONE) {
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const Transform tfm = object_fetch_transform(kg, sd->object, OBJECT_TRANSFORM);
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*N = safe_normalize(transform_direction_transposed(&tfm, *N));
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}
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}
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/* Transform normal from object to world space */
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ccl_device_inline void object_normal_transform(KernelGlobals kg,
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const ccl_private ShaderData *sd,
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ccl_private float3 *N)
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{
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#ifdef __OBJECT_MOTION__
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if (sd->object_flag & SD_OBJECT_MOTION) {
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*N = normalize(transform_direction_transposed_auto(&sd->ob_itfm_motion, *N));
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return;
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}
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#endif
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if (sd->object != OBJECT_NONE) {
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const Transform tfm = object_fetch_transform(kg, sd->object, OBJECT_INVERSE_TRANSFORM);
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*N = normalize(transform_direction_transposed(&tfm, *N));
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}
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}
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ccl_device_inline bool object_negative_scale_applied(const int object_flag)
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{
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return ((object_flag & SD_OBJECT_NEGATIVE_SCALE) && (object_flag & SD_OBJECT_TRANSFORM_APPLIED));
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}
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/* Transform direction vector from object to world space */
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ccl_device_inline void object_dir_transform(KernelGlobals kg,
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const ccl_private ShaderData *sd,
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ccl_private float3 *D)
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{
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#ifdef __OBJECT_MOTION__
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if (sd->object_flag & SD_OBJECT_MOTION) {
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*D = transform_direction_auto(&sd->ob_tfm_motion, *D);
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return;
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}
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#endif
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const Transform tfm = object_fetch_transform(kg, sd->object, OBJECT_TRANSFORM);
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*D = transform_direction(&tfm, *D);
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}
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/* Transform direction vector from world to object space */
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ccl_device_inline void object_inverse_dir_transform(KernelGlobals kg,
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const ccl_private ShaderData *sd,
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ccl_private float3 *D)
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{
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#ifdef __OBJECT_MOTION__
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if (sd->object_flag & SD_OBJECT_MOTION) {
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*D = transform_direction_auto(&sd->ob_itfm_motion, *D);
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return;
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}
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#endif
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const Transform tfm = object_fetch_transform(kg, sd->object, OBJECT_INVERSE_TRANSFORM);
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*D = transform_direction(&tfm, *D);
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}
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/* Object center position */
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ccl_device_inline float3 object_location(KernelGlobals kg, const ccl_private ShaderData *sd)
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{
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if (sd->object == OBJECT_NONE) {
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return make_float3(0.0f, 0.0f, 0.0f);
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}
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#ifdef __OBJECT_MOTION__
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if (sd->object_flag & SD_OBJECT_MOTION) {
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return make_float3(sd->ob_tfm_motion.x.w, sd->ob_tfm_motion.y.w, sd->ob_tfm_motion.z.w);
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}
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#endif
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const Transform tfm = object_fetch_transform(kg, sd->object, OBJECT_TRANSFORM);
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return make_float3(tfm.x.w, tfm.y.w, tfm.z.w);
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}
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/* Color of the object */
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ccl_device_inline float3 object_color(KernelGlobals kg, const int object)
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{
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if (object == OBJECT_NONE) {
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return make_float3(0.0f, 0.0f, 0.0f);
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}
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const ccl_global KernelObject *kobject = &kernel_data_fetch(objects, object);
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return make_float3(kobject->color[0], kobject->color[1], kobject->color[2]);
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}
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/* Alpha of the object */
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ccl_device_inline float object_alpha(KernelGlobals kg, const int object)
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{
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if (object == OBJECT_NONE) {
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return 0.0f;
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}
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return kernel_data_fetch(objects, object).alpha;
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}
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/* Pass ID number of object */
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ccl_device_inline float object_pass_id(KernelGlobals kg, const int object)
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{
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if (object == OBJECT_NONE) {
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return 0.0f;
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}
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return kernel_data_fetch(objects, object).pass_id;
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}
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/* Light-group of object. */
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ccl_device_inline int object_lightgroup(KernelGlobals kg, const int object)
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{
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if (object == OBJECT_NONE) {
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return LIGHTGROUP_NONE;
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}
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return kernel_data_fetch(objects, object).lightgroup;
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}
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/* Per object random number for shader variation */
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ccl_device_inline float object_random_number(KernelGlobals kg, const int object)
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{
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if (object == OBJECT_NONE) {
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return 0.0f;
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}
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return kernel_data_fetch(objects, object).random_number;
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}
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/* Particle ID from which this object was generated */
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ccl_device_inline int object_particle_id(KernelGlobals kg, const int object)
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{
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if (object == OBJECT_NONE) {
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return 0;
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}
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return kernel_data_fetch(objects, object).particle_index;
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}
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/* Generated texture coordinate on surface from where object was instanced */
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ccl_device_inline float3 object_dupli_generated(KernelGlobals kg, const int object)
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{
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if (object == OBJECT_NONE) {
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return make_float3(0.0f, 0.0f, 0.0f);
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}
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const ccl_global KernelObject *kobject = &kernel_data_fetch(objects, object);
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return make_float3(
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kobject->dupli_generated[0], kobject->dupli_generated[1], kobject->dupli_generated[2]);
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}
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/* UV texture coordinate on surface from where object was instanced */
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ccl_device_inline float3 object_dupli_uv(KernelGlobals kg, const int object)
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{
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if (object == OBJECT_NONE) {
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return make_float3(0.0f, 0.0f, 0.0f);
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}
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const ccl_global KernelObject *kobject = &kernel_data_fetch(objects, object);
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return make_float3(kobject->dupli_uv[0], kobject->dupli_uv[1], 0.0f);
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}
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/* Volume density */
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ccl_device_inline float object_volume_density(KernelGlobals kg, const int object)
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{
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if (object == OBJECT_NONE) {
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return 1.0f;
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}
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return kernel_data_fetch(objects, object).volume_density;
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}
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/* Pass ID for shader */
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ccl_device int shader_pass_id(KernelGlobals kg, const ccl_private ShaderData *sd)
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{
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return kernel_data_fetch(shaders, (sd->shader & SHADER_MASK)).pass_id;
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}
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/* Cryptomatte ID */
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ccl_device_inline float object_cryptomatte_id(KernelGlobals kg, const int object)
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{
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if (object == OBJECT_NONE) {
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return 0.0f;
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}
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return kernel_data_fetch(objects, object).cryptomatte_object;
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}
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ccl_device_inline float object_cryptomatte_asset_id(KernelGlobals kg, const int object)
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{
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if (object == OBJECT_NONE) {
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return 0;
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}
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return kernel_data_fetch(objects, object).cryptomatte_asset;
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}
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/* Particle data from which object was instanced */
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ccl_device_inline uint particle_index(KernelGlobals kg, const int particle)
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{
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return kernel_data_fetch(particles, particle).index;
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}
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ccl_device float particle_age(KernelGlobals kg, const int particle)
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{
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return kernel_data_fetch(particles, particle).age;
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}
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ccl_device float particle_lifetime(KernelGlobals kg, const int particle)
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{
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return kernel_data_fetch(particles, particle).lifetime;
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}
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ccl_device float particle_size(KernelGlobals kg, const int particle)
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{
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return kernel_data_fetch(particles, particle).size;
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}
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ccl_device float4 particle_rotation(KernelGlobals kg, const int particle)
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{
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return kernel_data_fetch(particles, particle).rotation;
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}
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ccl_device float3 particle_location(KernelGlobals kg, const int particle)
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{
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return make_float3(kernel_data_fetch(particles, particle).location);
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}
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ccl_device float3 particle_velocity(KernelGlobals kg, const int particle)
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{
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return make_float3(kernel_data_fetch(particles, particle).velocity);
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}
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ccl_device float3 particle_angular_velocity(KernelGlobals kg, const int particle)
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{
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return make_float3(kernel_data_fetch(particles, particle).angular_velocity);
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}
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/* Object intersection in BVH */
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ccl_device_inline float3 bvh_clamp_direction(const float3 dir)
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{
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const float ooeps = 8.271806E-25f;
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return make_float3((fabsf(dir.x) > ooeps) ? dir.x : copysignf(ooeps, dir.x),
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(fabsf(dir.y) > ooeps) ? dir.y : copysignf(ooeps, dir.y),
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(fabsf(dir.z) > ooeps) ? dir.z : copysignf(ooeps, dir.z));
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}
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ccl_device_inline float3 bvh_inverse_direction(const float3 dir)
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{
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return reciprocal(dir);
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}
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/* Transform ray into object space to enter static object in BVH */
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ccl_device_inline void bvh_instance_push(KernelGlobals kg,
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const int object,
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const ccl_private Ray *ray,
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ccl_private float3 *P,
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ccl_private float3 *dir,
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ccl_private float3 *idir)
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{
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const Transform tfm = object_fetch_transform(kg, object, OBJECT_INVERSE_TRANSFORM);
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*P = transform_point(&tfm, ray->P);
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*dir = bvh_clamp_direction(transform_direction(&tfm, ray->D));
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*idir = bvh_inverse_direction(*dir);
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}
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#ifdef __OBJECT_MOTION__
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/* Transform ray into object space to enter motion blurred object in BVH */
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ccl_device_inline void bvh_instance_motion_push(KernelGlobals kg,
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const int object,
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const ccl_private Ray *ray,
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ccl_private float3 *P,
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ccl_private float3 *dir,
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ccl_private float3 *idir)
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{
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Transform tfm;
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object_fetch_transform_motion_test(kg, object, ray->time, &tfm);
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*P = transform_point(&tfm, ray->P);
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*dir = bvh_clamp_direction(transform_direction(&tfm, ray->D));
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*idir = bvh_inverse_direction(*dir);
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}
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#endif
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/* Transform ray to exit static object in BVH. */
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ccl_device_inline void bvh_instance_pop(const ccl_private Ray *ray,
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ccl_private float3 *P,
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ccl_private float3 *dir,
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ccl_private float3 *idir)
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{
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*P = ray->P;
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*dir = bvh_clamp_direction(ray->D);
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|
*idir = bvh_inverse_direction(*dir);
|
|
}
|
|
|
|
/* TODO: This can be removed when we know if no devices will require explicit
|
|
* address space qualifiers for this case. */
|
|
|
|
#define object_position_transform_auto object_position_transform
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|
#define object_dir_transform_auto object_dir_transform
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|
#define object_normal_transform_auto object_normal_transform
|
|
|
|
CCL_NAMESPACE_END
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