forked from bartvdbraak/blender
9815f8a623
The idea is to switch from allocating separate buffers for shader data's structure of arrays to allocating one huge memory block and do some index trickery to make it accessed as SOA. This saves quite reasonable amount of lines of code in device_opencl and also makes it possible to get rid of special declaration of ShaderData structure. As a side effect it also makes it easier to experiment with SOA vs. AOS for split kernel. Works fine here on NVidia GTX580, Intel CPU amd AMD Fiji cards. Reviewers: #cycles, brecht, juicyfruit, dingto Differential Revision: https://developer.blender.org/D1593
301 lines
8.8 KiB
C
301 lines
8.8 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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#ifdef __SHADOW_RECORD_ALL__
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/* Shadow function to compute how much light is blocked, CPU variation.
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*
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* We trace a single ray. If it hits any opaque surface, or more than a given
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* number of transparent surfaces is hit, then we consider the geometry to be
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* entirely blocked. If not, all transparent surfaces will be recorded and we
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* will shade them one by one to determine how much light is blocked. This all
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* happens in one scene intersection function.
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*
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* Recording all hits works well in some cases but may be slower in others. If
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* we have many semi-transparent hairs, one intersection may be faster because
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* you'd be reinteresecting the same hairs a lot with each step otherwise. If
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* however there is mostly binary transparency then we may be recording many
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* unnecessary intersections when one of the first surfaces blocks all light.
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*
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* From tests in real scenes it seems the performance loss is either minimal,
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* or there is a performance increase anyway due to avoiding the need to send
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* two rays with transparent shadows.
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*
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* This is CPU only because of qsort, and malloc or high stack space usage to
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* record all these intersections. */
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#define STACK_MAX_HITS 64
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ccl_device_inline bool shadow_blocked(KernelGlobals *kg, PathState *state, Ray *ray, float3 *shadow)
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{
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*shadow = make_float3(1.0f, 1.0f, 1.0f);
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if(ray->t == 0.0f)
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return false;
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bool blocked;
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if(kernel_data.integrator.transparent_shadows) {
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/* check transparent bounces here, for volume scatter which can do
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* lighting before surface path termination is checked */
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if(state->transparent_bounce >= kernel_data.integrator.transparent_max_bounce)
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return true;
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/* intersect to find an opaque surface, or record all transparent surface hits */
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Intersection hits_stack[STACK_MAX_HITS];
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Intersection *hits = hits_stack;
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uint max_hits = kernel_data.integrator.transparent_max_bounce - state->transparent_bounce - 1;
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/* prefer to use stack but use dynamic allocation if too deep max hits
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* we need max_hits + 1 storage space due to the logic in
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* scene_intersect_shadow_all which will first store and then check if
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* the limit is exceeded */
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if(max_hits + 1 > STACK_MAX_HITS)
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hits = (Intersection*)malloc(sizeof(Intersection)*(max_hits + 1));
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uint num_hits;
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blocked = scene_intersect_shadow_all(kg, ray, hits, max_hits, &num_hits);
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/* if no opaque surface found but we did find transparent hits, shade them */
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if(!blocked && num_hits > 0) {
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float3 throughput = make_float3(1.0f, 1.0f, 1.0f);
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float3 Pend = ray->P + ray->D*ray->t;
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float last_t = 0.0f;
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int bounce = state->transparent_bounce;
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Intersection *isect = hits;
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#ifdef __VOLUME__
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PathState ps = *state;
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#endif
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qsort(hits, num_hits, sizeof(Intersection), intersections_compare);
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for(int hit = 0; hit < num_hits; hit++, isect++) {
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/* adjust intersection distance for moving ray forward */
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float new_t = isect->t;
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isect->t -= last_t;
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/* skip hit if we did not move forward, step by step raytracing
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* would have skipped it as well then */
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if(last_t == new_t)
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continue;
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last_t = new_t;
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#ifdef __VOLUME__
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/* attenuation between last surface and next surface */
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if(ps.volume_stack[0].shader != SHADER_NONE) {
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Ray segment_ray = *ray;
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segment_ray.t = isect->t;
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kernel_volume_shadow(kg, &ps, &segment_ray, &throughput);
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}
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#endif
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/* setup shader data at surface */
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ShaderData sd;
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shader_setup_from_ray(kg, &sd, isect, ray);
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/* attenuation from transparent surface */
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if(!(sd.flag & SD_HAS_ONLY_VOLUME)) {
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path_state_modify_bounce(state, true);
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shader_eval_surface(kg, &sd, state, 0.0f, PATH_RAY_SHADOW, SHADER_CONTEXT_SHADOW);
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path_state_modify_bounce(state, false);
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throughput *= shader_bsdf_transparency(kg, &sd);
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}
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/* stop if all light is blocked */
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if(is_zero(throughput)) {
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/* free dynamic storage */
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if(hits != hits_stack)
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free(hits);
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return true;
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}
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/* move ray forward */
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ray->P = sd.P;
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if(ray->t != FLT_MAX)
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ray->D = normalize_len(Pend - ray->P, &ray->t);
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#ifdef __VOLUME__
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/* exit/enter volume */
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kernel_volume_stack_enter_exit(kg, &sd, ps.volume_stack);
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#endif
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bounce++;
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}
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#ifdef __VOLUME__
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/* attenuation for last line segment towards light */
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if(ps.volume_stack[0].shader != SHADER_NONE)
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kernel_volume_shadow(kg, &ps, ray, &throughput);
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#endif
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*shadow = throughput;
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if(hits != hits_stack)
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free(hits);
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return is_zero(throughput);
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}
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/* free dynamic storage */
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if(hits != hits_stack)
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free(hits);
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}
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else {
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Intersection isect;
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blocked = scene_intersect(kg, ray, PATH_RAY_SHADOW_OPAQUE, &isect, NULL, 0.0f, 0.0f);
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}
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#ifdef __VOLUME__
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if(!blocked && state->volume_stack[0].shader != SHADER_NONE) {
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/* apply attenuation from current volume shader */
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kernel_volume_shadow(kg, state, ray, shadow);
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}
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#endif
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return blocked;
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}
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#undef STACK_MAX_HITS
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#else
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/* Shadow function to compute how much light is blocked, GPU variation.
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*
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* Here we raytrace from one transparent surface to the next step by step.
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* To minimize overhead in cases where we don't need transparent shadows, we
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* first trace a regular shadow ray. We check if the hit primitive was
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* potentially transparent, and only in that case start marching. this gives
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* one extra ray cast for the cases were we do want transparency. */
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ccl_device_noinline bool shadow_blocked(KernelGlobals *kg,
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ccl_addr_space PathState *state,
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ccl_addr_space Ray *ray_input,
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float3 *shadow)
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{
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*shadow = make_float3(1.0f, 1.0f, 1.0f);
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if(ray_input->t == 0.0f)
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return false;
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#ifdef __SPLIT_KERNEL__
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Ray private_ray = *ray_input;
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Ray *ray = &private_ray;
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#else
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Ray *ray = ray_input;
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#endif
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#ifdef __SPLIT_KERNEL__
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Intersection *isect = &kg->isect_shadow[SD_THREAD];
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#else
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Intersection isect_object;
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Intersection *isect = &isect_object;
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#endif
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bool blocked = scene_intersect(kg, ray, PATH_RAY_SHADOW_OPAQUE, isect, NULL, 0.0f, 0.0f);
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#ifdef __TRANSPARENT_SHADOWS__
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if(blocked && kernel_data.integrator.transparent_shadows) {
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if(shader_transparent_shadow(kg, isect)) {
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float3 throughput = make_float3(1.0f, 1.0f, 1.0f);
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float3 Pend = ray->P + ray->D*ray->t;
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int bounce = state->transparent_bounce;
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#ifdef __VOLUME__
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PathState ps = *state;
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#endif
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for(;;) {
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if(bounce >= kernel_data.integrator.transparent_max_bounce)
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return true;
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if(!scene_intersect(kg, ray, PATH_RAY_SHADOW_TRANSPARENT, isect, NULL, 0.0f, 0.0f))
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{
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#ifdef __VOLUME__
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/* attenuation for last line segment towards light */
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if(ps.volume_stack[0].shader != SHADER_NONE)
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kernel_volume_shadow(kg, &ps, ray, &throughput);
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#endif
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*shadow *= throughput;
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return false;
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}
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if(!shader_transparent_shadow(kg, isect))
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return true;
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#ifdef __VOLUME__
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/* attenuation between last surface and next surface */
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if(ps.volume_stack[0].shader != SHADER_NONE) {
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Ray segment_ray = *ray;
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segment_ray.t = isect->t;
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kernel_volume_shadow(kg, &ps, &segment_ray, &throughput);
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}
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#endif
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/* setup shader data at surface */
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#ifdef __SPLIT_KERNEL__
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ShaderData *sd = kg->sd_input;
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#else
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ShaderData sd_object;
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ShaderData *sd = &sd_object;
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#endif
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shader_setup_from_ray(kg, sd, isect, ray);
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/* attenuation from transparent surface */
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if(!(ccl_fetch(sd, flag) & SD_HAS_ONLY_VOLUME)) {
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path_state_modify_bounce(state, true);
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shader_eval_surface(kg, sd, state, 0.0f, PATH_RAY_SHADOW, SHADER_CONTEXT_SHADOW);
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path_state_modify_bounce(state, false);
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throughput *= shader_bsdf_transparency(kg, sd);
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}
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if(is_zero(throughput))
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return true;
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/* move ray forward */
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ray->P = ray_offset(ccl_fetch(sd, P), -ccl_fetch(sd, Ng));
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if(ray->t != FLT_MAX)
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ray->D = normalize_len(Pend - ray->P, &ray->t);
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#ifdef __VOLUME__
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/* exit/enter volume */
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kernel_volume_stack_enter_exit(kg, sd, ps.volume_stack);
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#endif
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bounce++;
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}
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}
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}
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#ifdef __VOLUME__
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else if(!blocked && state->volume_stack[0].shader != SHADER_NONE) {
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/* apply attenuation from current volume shader */
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kernel_volume_shadow(kg, state, ray, shadow);
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}
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#endif
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#endif
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return blocked;
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}
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#endif
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CCL_NAMESPACE_END
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