a7aee250b8
Random numbers for step offset were correlated, now use stratified samples which reduces noise as well for some types of volumes, mainly procedural ones where the step size is bigger than the volume features.
271 lines
7.9 KiB
C
271 lines
7.9 KiB
C
/*
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* Copyright 2011-2013 Blender Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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CCL_NAMESPACE_BEGIN
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ccl_device_inline void path_state_init(KernelGlobals *kg,
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ShaderData *stack_sd,
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ccl_addr_space PathState *state,
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uint rng_hash,
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int sample,
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ccl_addr_space Ray *ray)
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{
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state->flag = PATH_RAY_CAMERA|PATH_RAY_MIS_SKIP|PATH_RAY_TRANSPARENT_BACKGROUND;
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state->rng_hash = rng_hash;
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state->rng_offset = PRNG_BASE_NUM;
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state->sample = sample;
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state->num_samples = kernel_data.integrator.aa_samples;
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state->branch_factor = 1.0f;
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state->bounce = 0;
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state->diffuse_bounce = 0;
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state->glossy_bounce = 0;
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state->transmission_bounce = 0;
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state->transparent_bounce = 0;
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#ifdef __DENOISING_FEATURES__
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if(kernel_data.film.pass_denoising_data) {
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state->flag |= PATH_RAY_STORE_SHADOW_INFO;
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state->denoising_feature_weight = 1.0f;
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}
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else {
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state->denoising_feature_weight = 0.0f;
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}
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#endif /* __DENOISING_FEATURES__ */
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state->min_ray_pdf = FLT_MAX;
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state->ray_pdf = 0.0f;
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#ifdef __LAMP_MIS__
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state->ray_t = 0.0f;
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#endif
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#ifdef __VOLUME__
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state->volume_bounce = 0;
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state->volume_bounds_bounce = 0;
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if(kernel_data.integrator.use_volumes) {
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/* Initialize volume stack with volume we are inside of. */
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kernel_volume_stack_init(kg, stack_sd, state, ray, state->volume_stack);
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}
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else {
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state->volume_stack[0].shader = SHADER_NONE;
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}
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#endif
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}
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ccl_device_inline void path_state_next(KernelGlobals *kg, ccl_addr_space PathState *state, int label)
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{
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/* ray through transparent keeps same flags from previous ray and is
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* not counted as a regular bounce, transparent has separate max */
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if(label & LABEL_TRANSPARENT) {
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state->flag |= PATH_RAY_TRANSPARENT;
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state->transparent_bounce++;
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if(state->transparent_bounce >= kernel_data.integrator.transparent_max_bounce) {
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state->flag |= PATH_RAY_TERMINATE_IMMEDIATE;
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}
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if(!kernel_data.integrator.transparent_shadows)
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state->flag |= PATH_RAY_MIS_SKIP;
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/* random number generator next bounce */
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state->rng_offset += PRNG_BOUNCE_NUM;
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return;
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}
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state->bounce++;
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if(state->bounce >= kernel_data.integrator.max_bounce) {
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state->flag |= PATH_RAY_TERMINATE_AFTER_TRANSPARENT;
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}
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state->flag &= ~(PATH_RAY_ALL_VISIBILITY|PATH_RAY_MIS_SKIP);
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#ifdef __VOLUME__
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if(label & LABEL_VOLUME_SCATTER) {
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/* volume scatter */
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state->flag |= PATH_RAY_VOLUME_SCATTER;
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state->flag &= ~PATH_RAY_TRANSPARENT_BACKGROUND;
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state->volume_bounce++;
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if(state->volume_bounce >= kernel_data.integrator.max_volume_bounce) {
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state->flag |= PATH_RAY_TERMINATE_AFTER_TRANSPARENT;
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}
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}
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else
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#endif
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{
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/* surface reflection/transmission */
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if(label & LABEL_REFLECT) {
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state->flag |= PATH_RAY_REFLECT;
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state->flag &= ~PATH_RAY_TRANSPARENT_BACKGROUND;
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if(label & LABEL_DIFFUSE) {
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state->diffuse_bounce++;
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if(state->diffuse_bounce >= kernel_data.integrator.max_diffuse_bounce) {
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state->flag |= PATH_RAY_TERMINATE_AFTER_TRANSPARENT;
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}
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}
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else {
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state->glossy_bounce++;
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if(state->glossy_bounce >= kernel_data.integrator.max_glossy_bounce) {
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state->flag |= PATH_RAY_TERMINATE_AFTER_TRANSPARENT;
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}
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}
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}
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else {
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kernel_assert(label & LABEL_TRANSMIT);
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state->flag |= PATH_RAY_TRANSMIT;
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if(!(label & LABEL_TRANSMIT_TRANSPARENT)) {
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state->flag &= ~PATH_RAY_TRANSPARENT_BACKGROUND;
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}
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state->transmission_bounce++;
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if(state->transmission_bounce >= kernel_data.integrator.max_transmission_bounce) {
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state->flag |= PATH_RAY_TERMINATE_AFTER_TRANSPARENT;
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}
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}
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/* diffuse/glossy/singular */
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if(label & LABEL_DIFFUSE) {
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state->flag |= PATH_RAY_DIFFUSE|PATH_RAY_DIFFUSE_ANCESTOR;
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}
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else if(label & LABEL_GLOSSY) {
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state->flag |= PATH_RAY_GLOSSY;
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}
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else {
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kernel_assert(label & LABEL_SINGULAR);
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state->flag |= PATH_RAY_GLOSSY|PATH_RAY_SINGULAR|PATH_RAY_MIS_SKIP;
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}
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}
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/* random number generator next bounce */
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state->rng_offset += PRNG_BOUNCE_NUM;
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#ifdef __DENOISING_FEATURES__
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if((state->denoising_feature_weight == 0.0f) && !(state->flag & PATH_RAY_SHADOW_CATCHER)) {
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state->flag &= ~PATH_RAY_STORE_SHADOW_INFO;
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}
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#endif
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}
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ccl_device_inline bool path_state_volume_next(KernelGlobals *kg, ccl_addr_space PathState *state)
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{
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/* For volume bounding meshes we pass through without counting transparent
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* bounces, only sanity check in case self intersection gets us stuck. */
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state->volume_bounds_bounce++;
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if (state->volume_bounds_bounce > VOLUME_BOUNDS_MAX) {
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return false;
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}
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/* Random number generator next bounce. */
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if(state->volume_bounds_bounce > 1) {
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state->rng_offset += PRNG_BOUNCE_NUM;
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}
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return true;
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}
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ccl_device_inline uint path_state_ray_visibility(KernelGlobals *kg, ccl_addr_space PathState *state)
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{
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uint flag = state->flag & PATH_RAY_ALL_VISIBILITY;
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/* for visibility, diffuse/glossy are for reflection only */
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if(flag & PATH_RAY_TRANSMIT)
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flag &= ~(PATH_RAY_DIFFUSE|PATH_RAY_GLOSSY);
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/* todo: this is not supported as its own ray visibility yet */
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if(state->flag & PATH_RAY_VOLUME_SCATTER)
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flag |= PATH_RAY_DIFFUSE;
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return flag;
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}
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ccl_device_inline float path_state_continuation_probability(KernelGlobals *kg,
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ccl_addr_space PathState *state,
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const float3 throughput)
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{
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if(state->flag & PATH_RAY_TERMINATE_IMMEDIATE) {
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/* Ray is to be terminated immediately. */
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return 0.0f;
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}
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else if(state->flag & PATH_RAY_TRANSPARENT) {
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/* Do at least one bounce without RR. */
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if(state->transparent_bounce <= 1) {
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return 1.0f;
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}
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#ifdef __SHADOW_TRICKS__
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/* Exception for shadow catcher not working correctly with RR. */
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else if((state->flag & PATH_RAY_SHADOW_CATCHER) && (state->transparent_bounce <= 8)) {
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return 1.0f;
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}
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#endif
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}
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else {
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/* Do at least one bounce without RR. */
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if(state->bounce <= 1) {
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return 1.0f;
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}
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#ifdef __SHADOW_TRICKS__
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/* Exception for shadow catcher not working correctly with RR. */
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else if((state->flag & PATH_RAY_SHADOW_CATCHER) && (state->bounce <= 3)) {
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return 1.0f;
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}
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#endif
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}
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/* Probabilistic termination: use sqrt() to roughly match typical view
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* transform and do path termination a bit later on average. */
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return min(sqrtf(max3(fabs(throughput)) * state->branch_factor), 1.0f);
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}
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/* TODO(DingTo): Find more meaningful name for this */
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ccl_device_inline void path_state_modify_bounce(ccl_addr_space PathState *state, bool increase)
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{
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/* Modify bounce temporarily for shader eval */
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if(increase)
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state->bounce += 1;
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else
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state->bounce -= 1;
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}
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ccl_device_inline bool path_state_ao_bounce(KernelGlobals *kg, ccl_addr_space PathState *state)
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{
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if(state->bounce <= kernel_data.integrator.ao_bounces) {
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return false;
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}
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int bounce = state->bounce - state->transmission_bounce - (state->glossy_bounce > 0);
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return (bounce > kernel_data.integrator.ao_bounces);
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}
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ccl_device_inline void path_state_branch(ccl_addr_space PathState *state,
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int branch,
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int num_branches)
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{
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if(num_branches > 1) {
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/* Path is splitting into a branch, adjust so that each branch
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* still gets a unique sample from the same sequence. */
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state->sample = state->sample*num_branches + branch;
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state->num_samples = state->num_samples*num_branches;
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state->branch_factor *= num_branches;
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}
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}
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CCL_NAMESPACE_END
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