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/*
* Copyright 2011-2013 Blender Foundation
*
* 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.
*/
CCL_NAMESPACE_BEGIN
ccl_device_inline void path_state_init(KernelGlobals *kg,
ShaderData *stack_sd,
ccl_addr_space PathState *state,
ccl_addr_space RNG *rng,
int sample,
ccl_addr_space Ray *ray)
{
state->flag = PATH_RAY_CAMERA|PATH_RAY_MIS_SKIP;
state->rng_offset = PRNG_BASE_NUM;
state->sample = sample;
state->num_samples = kernel_data.integrator.aa_samples;
state->bounce = 0;
state->diffuse_bounce = 0;
state->glossy_bounce = 0;
state->transmission_bounce = 0;
state->transparent_bounce = 0;
state->min_ray_pdf = FLT_MAX;
state->ray_pdf = 0.0f;
#ifdef __LAMP_MIS__
state->ray_t = 0.0f;
#endif
#ifdef __VOLUME__
state->volume_bounce = 0;
if(kernel_data.integrator.use_volumes) {
/* Initialize volume stack with volume we are inside of. */
kernel_volume_stack_init(kg, stack_sd, state, ray, state->volume_stack);
/* Seed RNG for cases where we can't use stratified samples .*/
state->rng_congruential = lcg_init(*rng + sample*0x51633e2d);
}
else {
state->volume_stack[0].shader = SHADER_NONE;
}
#endif
}
ccl_device_inline void path_state_next(KernelGlobals *kg, ccl_addr_space PathState *state, int label)
{
/* ray through transparent keeps same flags from previous ray and is
* not counted as a regular bounce, transparent has separate max */
if(label & LABEL_TRANSPARENT) {
state->flag |= PATH_RAY_TRANSPARENT;
state->transparent_bounce++;
/* don't increase random number generator offset here, to avoid some
* unwanted patterns, see path_state_rng_1D_for_decision */
if(!kernel_data.integrator.transparent_shadows)
state->flag |= PATH_RAY_MIS_SKIP;
return;
}
state->bounce++;
#ifdef __VOLUME__
if(label & LABEL_VOLUME_SCATTER) {
/* volume scatter */
state->flag |= PATH_RAY_VOLUME_SCATTER;
state->flag &= ~(PATH_RAY_REFLECT|PATH_RAY_TRANSMIT|PATH_RAY_CAMERA|PATH_RAY_TRANSPARENT|PATH_RAY_DIFFUSE|PATH_RAY_GLOSSY|PATH_RAY_SINGULAR|PATH_RAY_MIS_SKIP);
state->volume_bounce++;
}
else
#endif
{
/* surface reflection/transmission */
if(label & LABEL_REFLECT) {
state->flag |= PATH_RAY_REFLECT;
state->flag &= ~(PATH_RAY_TRANSMIT|PATH_RAY_VOLUME_SCATTER|PATH_RAY_CAMERA|PATH_RAY_TRANSPARENT);
if(label & LABEL_DIFFUSE)
state->diffuse_bounce++;
else
state->glossy_bounce++;
}
else {
kernel_assert(label & LABEL_TRANSMIT);
state->flag |= PATH_RAY_TRANSMIT;
state->flag &= ~(PATH_RAY_REFLECT|PATH_RAY_VOLUME_SCATTER|PATH_RAY_CAMERA|PATH_RAY_TRANSPARENT);
state->transmission_bounce++;
}
/* diffuse/glossy/singular */
if(label & LABEL_DIFFUSE) {
state->flag |= PATH_RAY_DIFFUSE|PATH_RAY_DIFFUSE_ANCESTOR;
state->flag &= ~(PATH_RAY_GLOSSY|PATH_RAY_SINGULAR|PATH_RAY_MIS_SKIP);
}
else if(label & LABEL_GLOSSY) {
state->flag |= PATH_RAY_GLOSSY;
state->flag &= ~(PATH_RAY_DIFFUSE|PATH_RAY_SINGULAR|PATH_RAY_MIS_SKIP);
}
else {
kernel_assert(label & LABEL_SINGULAR);
state->flag |= PATH_RAY_GLOSSY|PATH_RAY_SINGULAR|PATH_RAY_MIS_SKIP;
state->flag &= ~PATH_RAY_DIFFUSE;
}
}
/* random number generator next bounce */
state->rng_offset += PRNG_BOUNCE_NUM;
}
ccl_device_inline uint path_state_ray_visibility(KernelGlobals *kg, PathState *state)
{
uint flag = state->flag & PATH_RAY_ALL_VISIBILITY;
/* for visibility, diffuse/glossy are for reflection only */
if(flag & PATH_RAY_TRANSMIT)
flag &= ~(PATH_RAY_DIFFUSE|PATH_RAY_GLOSSY);
/* todo: this is not supported as its own ray visibility yet */
if(state->flag & PATH_RAY_VOLUME_SCATTER)
flag |= PATH_RAY_DIFFUSE;
return flag;
}
ccl_device_inline float path_state_terminate_probability(KernelGlobals *kg, ccl_addr_space PathState *state, const float3 throughput)
{
if(state->flag & PATH_RAY_TRANSPARENT) {
/* transparent rays treated separately */
if(state->transparent_bounce >= kernel_data.integrator.transparent_max_bounce)
return 0.0f;
else if(state->transparent_bounce <= kernel_data.integrator.transparent_min_bounce)
return 1.0f;
}
else {
/* other rays */
if((state->bounce >= kernel_data.integrator.max_bounce) ||
(state->diffuse_bounce >= kernel_data.integrator.max_diffuse_bounce) ||
(state->glossy_bounce >= kernel_data.integrator.max_glossy_bounce) ||
#ifdef __VOLUME__
(state->volume_bounce >= kernel_data.integrator.max_volume_bounce) ||
#endif
(state->transmission_bounce >= kernel_data.integrator.max_transmission_bounce))
{
return 0.0f;
}
else if(state->bounce <= kernel_data.integrator.min_bounce) {
return 1.0f;
}
}
/* probalistic termination */
return average(throughput); /* todo: try using max here */
}
/* TODO(DingTo): Find more meaningful name for this */
ccl_device_inline void path_state_modify_bounce(ccl_addr_space PathState *state, bool increase)
{
/* Modify bounce temporarily for shader eval */
if(increase)
state->bounce += 1;
else
state->bounce -= 1;
}
CCL_NAMESPACE_END
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