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blender/intern/cycles/kernel/closure/bsdf_hair.h
Michael Jones a0f269f682 Cycles: Kernel address space changes for MSL 
This is the first of a sequence of changes to support compiling Cycles kernels as MSL (Metal Shading Language) in preparation for a Metal GPU device implementation.

MSL requires that all pointer types be declared with explicit address space attributes (device, thread, etc...). There is already precedent for this with Cycles' address space macros (ccl_global, ccl_private, etc...), therefore the first step of MSL-enablement is to apply these consistently. Line-for-line this represents the largest change required to enable MSL. Applying this change first will simplify future patches as well as offering the emergent benefit of enhanced descriptiveness.

The vast majority of deltas in this patch fall into one of two cases:

- Ensuring ccl_private is specified for thread-local pointer types
- Ensuring ccl_global is specified for device-wide pointer types

Additionally, the ccl_addr_space qualifier can be removed. Prior to Cycles X, ccl_addr_space was used as a context-dependent address space qualifier, but now it is either redundant (e.g. in struct typedefs), or can be replaced by ccl_global in the case of pointer types. Associated function variants (e.g. lcg_step_float_addrspace) are also redundant.

In cases where address space qualifiers are chained with "const", this patch places the address space qualifier first. The rationale for this is that the choice of address space is likely to have the greater impact on runtime performance and overall architecture.

The final part of this patch is the addition of a metal/compat.h header. This is partially complete and will be extended in future patches, paving the way for the full Metal implementation.

Ref T92212

Reviewed By: brecht

Maniphest Tasks: T92212

Differential Revision: https://developer.blender.org/D12864
2021-10-14 16:14:43 +01:00

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/*
* Adapted from Open Shading Language with this license:
*
* Copyright (c) 2009-2010 Sony Pictures Imageworks Inc., et al.
* All Rights Reserved.
*
* Modifications Copyright 2011, Blender Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Sony Pictures Imageworks nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
CCL_NAMESPACE_BEGIN
typedef struct HairBsdf {
SHADER_CLOSURE_BASE;
float3 T;
float roughness1;
float roughness2;
float offset;
} HairBsdf;
static_assert(sizeof(ShaderClosure) >= sizeof(HairBsdf), "HairBsdf is too large!");
ccl_device int bsdf_hair_reflection_setup(ccl_private HairBsdf *bsdf)
{
bsdf->type = CLOSURE_BSDF_HAIR_REFLECTION_ID;
bsdf->roughness1 = clamp(bsdf->roughness1, 0.001f, 1.0f);
bsdf->roughness2 = clamp(bsdf->roughness2, 0.001f, 1.0f);
return SD_BSDF | SD_BSDF_HAS_EVAL;
}
ccl_device int bsdf_hair_transmission_setup(ccl_private HairBsdf *bsdf)
{
bsdf->type = CLOSURE_BSDF_HAIR_TRANSMISSION_ID;
bsdf->roughness1 = clamp(bsdf->roughness1, 0.001f, 1.0f);
bsdf->roughness2 = clamp(bsdf->roughness2, 0.001f, 1.0f);
return SD_BSDF | SD_BSDF_HAS_EVAL;
}
ccl_device float3 bsdf_hair_reflection_eval_reflect(ccl_private const ShaderClosure *sc,
const float3 I,
const float3 omega_in,
ccl_private float *pdf)
{
ccl_private const HairBsdf *bsdf = (ccl_private const HairBsdf *)sc;
float offset = bsdf->offset;
float3 Tg = bsdf->T;
float roughness1 = bsdf->roughness1;
float roughness2 = bsdf->roughness2;
float Iz = dot(Tg, I);
float3 locy = normalize(I - Tg * Iz);
float theta_r = M_PI_2_F - fast_acosf(Iz);
float omega_in_z = dot(Tg, omega_in);
float3 omega_in_y = normalize(omega_in - Tg * omega_in_z);
float theta_i = M_PI_2_F - fast_acosf(omega_in_z);
float cosphi_i = dot(omega_in_y, locy);
if (M_PI_2_F - fabsf(theta_i) < 0.001f || cosphi_i < 0.0f) {
*pdf = 0.0f;
return make_float3(*pdf, *pdf, *pdf);
}
float roughness1_inv = 1.0f / roughness1;
float roughness2_inv = 1.0f / roughness2;
float phi_i = fast_acosf(cosphi_i) * roughness2_inv;
phi_i = fabsf(phi_i) < M_PI_F ? phi_i : M_PI_F;
float costheta_i = fast_cosf(theta_i);
float a_R = fast_atan2f(((M_PI_2_F + theta_r) * 0.5f - offset) * roughness1_inv, 1.0f);
float b_R = fast_atan2f(((-M_PI_2_F + theta_r) * 0.5f - offset) * roughness1_inv, 1.0f);
float theta_h = (theta_i + theta_r) * 0.5f;
float t = theta_h - offset;
float phi_pdf = fast_cosf(phi_i * 0.5f) * 0.25f * roughness2_inv;
float theta_pdf = roughness1 /
(2 * (t * t + roughness1 * roughness1) * (a_R - b_R) * costheta_i);
*pdf = phi_pdf * theta_pdf;
return make_float3(*pdf, *pdf, *pdf);
}
ccl_device float3 bsdf_hair_transmission_eval_reflect(ccl_private const ShaderClosure *sc,
const float3 I,
const float3 omega_in,
ccl_private float *pdf)
{
return make_float3(0.0f, 0.0f, 0.0f);
}
ccl_device float3 bsdf_hair_reflection_eval_transmit(ccl_private const ShaderClosure *sc,
const float3 I,
const float3 omega_in,
ccl_private float *pdf)
{
return make_float3(0.0f, 0.0f, 0.0f);
}
ccl_device float3 bsdf_hair_transmission_eval_transmit(ccl_private const ShaderClosure *sc,
const float3 I,
const float3 omega_in,
ccl_private float *pdf)
{
ccl_private const HairBsdf *bsdf = (ccl_private const HairBsdf *)sc;
float offset = bsdf->offset;
float3 Tg = bsdf->T;
float roughness1 = bsdf->roughness1;
float roughness2 = bsdf->roughness2;
float Iz = dot(Tg, I);
float3 locy = normalize(I - Tg * Iz);
float theta_r = M_PI_2_F - fast_acosf(Iz);
float omega_in_z = dot(Tg, omega_in);
float3 omega_in_y = normalize(omega_in - Tg * omega_in_z);
float theta_i = M_PI_2_F - fast_acosf(omega_in_z);
float phi_i = fast_acosf(dot(omega_in_y, locy));
if (M_PI_2_F - fabsf(theta_i) < 0.001f) {
*pdf = 0.0f;
return make_float3(*pdf, *pdf, *pdf);
}
float costheta_i = fast_cosf(theta_i);
float roughness1_inv = 1.0f / roughness1;
float a_TT = fast_atan2f(((M_PI_2_F + theta_r) / 2 - offset) * roughness1_inv, 1.0f);
float b_TT = fast_atan2f(((-M_PI_2_F + theta_r) / 2 - offset) * roughness1_inv, 1.0f);
float c_TT = 2 * fast_atan2f(M_PI_2_F / roughness2, 1.0f);
float theta_h = (theta_i + theta_r) / 2;
float t = theta_h - offset;
float phi = fabsf(phi_i);
float p = M_PI_F - phi;
float theta_pdf = roughness1 /
(2 * (t * t + roughness1 * roughness1) * (a_TT - b_TT) * costheta_i);
float phi_pdf = roughness2 / (c_TT * (p * p + roughness2 * roughness2));
*pdf = phi_pdf * theta_pdf;
return make_float3(*pdf, *pdf, *pdf);
}
ccl_device int bsdf_hair_reflection_sample(ccl_private const ShaderClosure *sc,
float3 Ng,
float3 I,
float3 dIdx,
float3 dIdy,
float randu,
float randv,
ccl_private float3 *eval,
ccl_private float3 *omega_in,
ccl_private float3 *domega_in_dx,
ccl_private float3 *domega_in_dy,
ccl_private float *pdf)
{
ccl_private const HairBsdf *bsdf = (ccl_private const HairBsdf *)sc;
float offset = bsdf->offset;
float3 Tg = bsdf->T;
float roughness1 = bsdf->roughness1;
float roughness2 = bsdf->roughness2;
float Iz = dot(Tg, I);
float3 locy = normalize(I - Tg * Iz);
float3 locx = cross(locy, Tg);
float theta_r = M_PI_2_F - fast_acosf(Iz);
float roughness1_inv = 1.0f / roughness1;
float a_R = fast_atan2f(((M_PI_2_F + theta_r) * 0.5f - offset) * roughness1_inv, 1.0f);
float b_R = fast_atan2f(((-M_PI_2_F + theta_r) * 0.5f - offset) * roughness1_inv, 1.0f);
float t = roughness1 * tanf(randu * (a_R - b_R) + b_R);
float theta_h = t + offset;
float theta_i = 2 * theta_h - theta_r;
float costheta_i, sintheta_i;
fast_sincosf(theta_i, &sintheta_i, &costheta_i);
float phi = 2 * safe_asinf(1 - 2 * randv) * roughness2;
float phi_pdf = fast_cosf(phi * 0.5f) * 0.25f / roughness2;
float theta_pdf = roughness1 /
(2 * (t * t + roughness1 * roughness1) * (a_R - b_R) * costheta_i);
float sinphi, cosphi;
fast_sincosf(phi, &sinphi, &cosphi);
*omega_in = (cosphi * costheta_i) * locy - (sinphi * costheta_i) * locx + (sintheta_i)*Tg;
// differentials - TODO: find a better approximation for the reflective bounce
#ifdef __RAY_DIFFERENTIALS__
*domega_in_dx = 2 * dot(locy, dIdx) * locy - dIdx;
*domega_in_dy = 2 * dot(locy, dIdy) * locy - dIdy;
#endif
*pdf = fabsf(phi_pdf * theta_pdf);
if (M_PI_2_F - fabsf(theta_i) < 0.001f)
*pdf = 0.0f;
*eval = make_float3(*pdf, *pdf, *pdf);
return LABEL_REFLECT | LABEL_GLOSSY;
}
ccl_device int bsdf_hair_transmission_sample(ccl_private const ShaderClosure *sc,
float3 Ng,
float3 I,
float3 dIdx,
float3 dIdy,
float randu,
float randv,
ccl_private float3 *eval,
ccl_private float3 *omega_in,
ccl_private float3 *domega_in_dx,
ccl_private float3 *domega_in_dy,
ccl_private float *pdf)
{
ccl_private const HairBsdf *bsdf = (ccl_private const HairBsdf *)sc;
float offset = bsdf->offset;
float3 Tg = bsdf->T;
float roughness1 = bsdf->roughness1;
float roughness2 = bsdf->roughness2;
float Iz = dot(Tg, I);
float3 locy = normalize(I - Tg * Iz);
float3 locx = cross(locy, Tg);
float theta_r = M_PI_2_F - fast_acosf(Iz);
float roughness1_inv = 1.0f / roughness1;
float a_TT = fast_atan2f(((M_PI_2_F + theta_r) / 2 - offset) * roughness1_inv, 1.0f);
float b_TT = fast_atan2f(((-M_PI_2_F + theta_r) / 2 - offset) * roughness1_inv, 1.0f);
float c_TT = 2 * fast_atan2f(M_PI_2_F / roughness2, 1.0f);
float t = roughness1 * tanf(randu * (a_TT - b_TT) + b_TT);
float theta_h = t + offset;
float theta_i = 2 * theta_h - theta_r;
float costheta_i, sintheta_i;
fast_sincosf(theta_i, &sintheta_i, &costheta_i);
float p = roughness2 * tanf(c_TT * (randv - 0.5f));
float phi = p + M_PI_F;
float theta_pdf = roughness1 /
(2 * (t * t + roughness1 * roughness1) * (a_TT - b_TT) * costheta_i);
float phi_pdf = roughness2 / (c_TT * (p * p + roughness2 * roughness2));
float sinphi, cosphi;
fast_sincosf(phi, &sinphi, &cosphi);
*omega_in = (cosphi * costheta_i) * locy - (sinphi * costheta_i) * locx + (sintheta_i)*Tg;
// differentials - TODO: find a better approximation for the transmission bounce
#ifdef __RAY_DIFFERENTIALS__
*domega_in_dx = 2 * dot(locy, dIdx) * locy - dIdx;
*domega_in_dy = 2 * dot(locy, dIdy) * locy - dIdy;
#endif
*pdf = fabsf(phi_pdf * theta_pdf);
if (M_PI_2_F - fabsf(theta_i) < 0.001f) {
*pdf = 0.0f;
}
*eval = make_float3(*pdf, *pdf, *pdf);
/* TODO(sergey): Should always be negative, but seems some precision issue
* is involved here.
*/
kernel_assert(dot(locy, *omega_in) < 1e-4f);
return LABEL_TRANSMIT | LABEL_GLOSSY;
}
CCL_NAMESPACE_END
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