e813e46327
This is an intermediate steps towards making lights actual geometry. Light is now a subclass of Geometry, which simplifies some code. The geometry is not added to the BVH yet, which would be the next step and improve light intersection performance with many lights. This makes object attributes work on lights. Co-authored-by: Lukas Stockner <lukas@lukasstockner.de> Pull Request: https://projects.blender.org/blender/blender/pulls/134846
87 lines
2.6 KiB
C
87 lines
2.6 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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#pragma once
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#include "kernel/types.h"
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#include "kernel/sample/mapping.h"
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CCL_NAMESPACE_BEGIN
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/* Light Sample Result */
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struct LightSample {
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float3 P; /* position on light, or direction for distant light */
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packed_float3 Ng; /* normal on light */
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float t; /* distance to light (FLT_MAX for distant light) */
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float3 D; /* direction from shading point to light */
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float u, v; /* parametric coordinate on primitive */
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float pdf; /* pdf for selecting light and point on light */
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float pdf_selection; /* pdf for selecting light */
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float eval_fac; /* intensity multiplier */
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int object; /* object id for triangle/curve lights */
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int prim; /* lamp id for lights, primitive id for triangle/curve lights */
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int shader; /* shader id */
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int group; /* lightgroup */
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LightType type; /* type of light */
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int emitter_id; /* index in the emitter array */
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};
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/* Utilities */
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ccl_device_inline float3 ellipse_sample(const float3 ru, const float3 rv, const float2 rand)
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{
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const float2 uv = sample_uniform_disk(rand);
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return ru * uv.x + rv * uv.y;
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}
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ccl_device_inline float3 rectangle_sample(const float3 ru, const float3 rv, const float2 rand)
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{
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return ru * (2.0f * rand.x - 1.0f) + rv * (2.0f * rand.y - 1.0f);
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}
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ccl_device float3 disk_light_sample(const float3 n, const float2 rand)
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{
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float3 ru;
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float3 rv;
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make_orthonormals(n, &ru, &rv);
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return ellipse_sample(ru, rv, rand);
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}
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ccl_device float light_pdf_area_to_solid_angle(const float3 Ng, const float3 I, const float t)
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{
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const float cos_pi = dot(Ng, I);
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if (cos_pi <= 0.0f) {
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return 0.0f;
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}
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return t * t / cos_pi;
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}
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/* Visibility flag om the light shader. */
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ccl_device_inline bool is_light_shader_visible_to_path(const int shader, const uint32_t path_flag)
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{
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if ((shader & SHADER_EXCLUDE_ANY) == 0) {
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return true;
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}
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if (((shader & SHADER_EXCLUDE_DIFFUSE) && (path_flag & PATH_RAY_DIFFUSE)) ||
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((shader & SHADER_EXCLUDE_GLOSSY) && ((path_flag & (PATH_RAY_GLOSSY | PATH_RAY_REFLECT)) ==
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(PATH_RAY_GLOSSY | PATH_RAY_REFLECT))) ||
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((shader & SHADER_EXCLUDE_TRANSMIT) && (path_flag & PATH_RAY_TRANSMIT)) ||
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((shader & SHADER_EXCLUDE_CAMERA) && (path_flag & PATH_RAY_CAMERA)) ||
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((shader & SHADER_EXCLUDE_SCATTER) && (path_flag & PATH_RAY_VOLUME_SCATTER)))
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{
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return false;
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}
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return true;
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}
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CCL_NAMESPACE_END
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