blender/intern/cycles/kernel/kernel_light.h
Brecht Van Lommel 9307565269 Attempted fix for issue with latest CUDA kernel for 32 bit windows/linux/mac,
there seems to be some sort of compiler bug in CUDA toolkit 4.2, uninlining a
few functions seems to avoid it.
2013-02-11 22:41:11 +00:00

612 lines
16 KiB
C++

/*
* Copyright 2011, Blender Foundation.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
CCL_NAMESPACE_BEGIN
/* Light Sample result */
typedef struct LightSample {
float3 P; /* position on light, or direction for distant light */
float3 Ng; /* normal on light */
float3 D; /* direction from shading point to light */
float t; /* distance to light (FLT_MAX for distant light) */
float pdf; /* light sampling probability density function */
float eval_fac; /* intensity multiplier */
int object; /* object id for triangle/curve lights */
int prim; /* primitive id for triangle/curve ligths */
int shader; /* shader id */
int lamp; /* lamp id */
LightType type; /* type of light */
} LightSample;
/* Background Light */
#ifdef __BACKGROUND_MIS__
__device float3 background_light_sample(KernelGlobals *kg, float randu, float randv, float *pdf)
{
/* for the following, the CDF values are actually a pair of floats, with the
* function value as X and the actual CDF as Y. The last entry's function
* value is the CDF total. */
int res = kernel_data.integrator.pdf_background_res;
int cdf_count = res + 1;
/* this is basically std::lower_bound as used by pbrt */
int first = 0;
int count = res;
while(count > 0) {
int step = count >> 1;
int middle = first + step;
if(kernel_tex_fetch(__light_background_marginal_cdf, middle).y < randv) {
first = middle + 1;
count -= step + 1;
}
else
count = step;
}
int index_v = max(0, first - 1);
kernel_assert(index_v >= 0 && index_v < res);
float2 cdf_v = kernel_tex_fetch(__light_background_marginal_cdf, index_v);
float2 cdf_next_v = kernel_tex_fetch(__light_background_marginal_cdf, index_v + 1);
float2 cdf_last_v = kernel_tex_fetch(__light_background_marginal_cdf, res);
/* importance-sampled V direction */
float dv = (randv - cdf_v.y) / (cdf_next_v.y - cdf_v.y);
float v = (index_v + dv) / res;
/* this is basically std::lower_bound as used by pbrt */
first = 0;
count = res;
while(count > 0) {
int step = count >> 1;
int middle = first + step;
if(kernel_tex_fetch(__light_background_conditional_cdf, index_v * cdf_count + middle).y < randu) {
first = middle + 1;
count -= step + 1;
}
else
count = step;
}
int index_u = max(0, first - 1);
kernel_assert(index_u >= 0 && index_u < res);
float2 cdf_u = kernel_tex_fetch(__light_background_conditional_cdf, index_v * cdf_count + index_u);
float2 cdf_next_u = kernel_tex_fetch(__light_background_conditional_cdf, index_v * cdf_count + index_u + 1);
float2 cdf_last_u = kernel_tex_fetch(__light_background_conditional_cdf, index_v * cdf_count + res);
/* importance-sampled U direction */
float du = (randu - cdf_u.y) / (cdf_next_u.y - cdf_u.y);
float u = (index_u + du) / res;
/* compute pdf */
float denom = cdf_last_u.x * cdf_last_v.x;
float sin_theta = sinf(M_PI_F * v);
if(sin_theta == 0.0f || denom == 0.0f)
*pdf = 0.0f;
else
*pdf = (cdf_u.x * cdf_v.x)/(2.0f * M_PI_F * M_PI_F * sin_theta * denom);
*pdf *= kernel_data.integrator.pdf_lights;
/* compute direction */
return -equirectangular_to_direction(u, v);
}
__device float background_light_pdf(KernelGlobals *kg, float3 direction)
{
float2 uv = direction_to_equirectangular(direction);
int res = kernel_data.integrator.pdf_background_res;
float sin_theta = sinf(uv.y * M_PI_F);
if(sin_theta == 0.0f)
return 0.0f;
int index_u = clamp((int)(uv.x * res), 0, res - 1);
int index_v = clamp((int)(uv.y * res), 0, res - 1);
/* pdfs in V direction */
float2 cdf_last_u = kernel_tex_fetch(__light_background_conditional_cdf, index_v * (res + 1) + res);
float2 cdf_last_v = kernel_tex_fetch(__light_background_marginal_cdf, res);
float denom = cdf_last_u.x * cdf_last_v.x;
if(denom == 0.0f)
return 0.0f;
/* pdfs in U direction */
float2 cdf_u = kernel_tex_fetch(__light_background_conditional_cdf, index_v * (res + 1) + index_u);
float2 cdf_v = kernel_tex_fetch(__light_background_marginal_cdf, index_v);
float pdf = (cdf_u.x * cdf_v.x)/(2.0f * M_PI_F * M_PI_F * sin_theta * denom);
return pdf * kernel_data.integrator.pdf_lights;
}
#endif
/* Regular Light */
__device float3 disk_light_sample(float3 v, float randu, float randv)
{
float3 ru, rv;
make_orthonormals(v, &ru, &rv);
to_unit_disk(&randu, &randv);
return ru*randu + rv*randv;
}
__device float3 distant_light_sample(float3 D, float radius, float randu, float randv)
{
return normalize(D + disk_light_sample(D, randu, randv)*radius);
}
__device float3 sphere_light_sample(float3 P, float3 center, float radius, float randu, float randv)
{
return disk_light_sample(normalize(P - center), randu, randv)*radius;
}
__device float3 area_light_sample(float3 axisu, float3 axisv, float randu, float randv)
{
randu = randu - 0.5f;
randv = randv - 0.5f;
return axisu*randu + axisv*randv;
}
__device float spot_light_attenuation(float4 data1, float4 data2, LightSample *ls)
{
float3 dir = make_float3(data2.y, data2.z, data2.w);
float3 I = ls->Ng;
float spot_angle = data1.w;
float spot_smooth = data2.x;
float attenuation = dot(dir, I);
if(attenuation <= spot_angle) {
attenuation = 0.0f;
}
else {
float t = attenuation - spot_angle;
if(t < spot_smooth && spot_smooth != 0.0f)
attenuation *= smoothstepf(t/spot_smooth);
}
return attenuation;
}
__device float lamp_light_pdf(KernelGlobals *kg, const float3 Ng, const float3 I, float t)
{
float cos_pi = dot(Ng, I);
if(cos_pi <= 0.0f)
return 0.0f;
return t*t/cos_pi;
}
__device void lamp_light_sample(KernelGlobals *kg, int lamp,
float randu, float randv, float3 P, LightSample *ls)
{
float4 data0 = kernel_tex_fetch(__light_data, lamp*LIGHT_SIZE + 0);
float4 data1 = kernel_tex_fetch(__light_data, lamp*LIGHT_SIZE + 1);
LightType type = (LightType)__float_as_int(data0.x);
ls->type = type;
ls->shader = __float_as_int(data1.x);
ls->object = ~0;
ls->prim = ~0;
ls->lamp = lamp;
if(type == LIGHT_DISTANT) {
/* distant light */
float3 lightD = make_float3(data0.y, data0.z, data0.w);
float3 D = lightD;
float radius = data1.y;
float invarea = data1.w;
if(radius > 0.0f)
D = distant_light_sample(D, radius, randu, randv);
ls->P = D;
ls->Ng = D;
ls->D = -D;
ls->t = FLT_MAX;
float costheta = dot(lightD, D);
ls->pdf = invarea/(costheta*costheta*costheta);
ls->eval_fac = ls->pdf*kernel_data.integrator.inv_pdf_lights;
}
#ifdef __BACKGROUND_MIS__
else if(type == LIGHT_BACKGROUND) {
/* infinite area light (e.g. light dome or env light) */
float3 D = background_light_sample(kg, randu, randv, &ls->pdf);
ls->P = D;
ls->Ng = D;
ls->D = -D;
ls->t = FLT_MAX;
ls->eval_fac = 1.0f;
}
#endif
else {
ls->P = make_float3(data0.y, data0.z, data0.w);
if(type == LIGHT_POINT || type == LIGHT_SPOT) {
float radius = data1.y;
if(radius > 0.0f)
/* sphere light */
ls->P += sphere_light_sample(P, ls->P, radius, randu, randv);
ls->D = normalize_len(ls->P - P, &ls->t);
ls->Ng = -ls->D;
float invarea = data1.z;
ls->eval_fac = (0.25f*M_1_PI_F)*invarea;
ls->pdf = invarea;
if(type == LIGHT_SPOT) {
/* spot light attentuation */
float4 data2 = kernel_tex_fetch(__light_data, lamp*LIGHT_SIZE + 2);
ls->eval_fac *= spot_light_attenuation(data1, data2, ls);
}
}
else {
/* area light */
float4 data2 = kernel_tex_fetch(__light_data, lamp*LIGHT_SIZE + 2);
float4 data3 = kernel_tex_fetch(__light_data, lamp*LIGHT_SIZE + 3);
float3 axisu = make_float3(data1.y, data1.z, data1.w);
float3 axisv = make_float3(data2.y, data2.z, data2.w);
float3 D = make_float3(data3.y, data3.z, data3.w);
ls->P += area_light_sample(axisu, axisv, randu, randv);
ls->Ng = D;
ls->D = normalize_len(ls->P - P, &ls->t);
float invarea = data2.x;
ls->eval_fac = 0.25f*invarea;
ls->pdf = invarea;
}
ls->eval_fac *= kernel_data.integrator.inv_pdf_lights;
ls->pdf *= lamp_light_pdf(kg, ls->Ng, -ls->D, ls->t);
}
}
__device bool lamp_light_eval(KernelGlobals *kg, int lamp, float3 P, float3 D, float t, LightSample *ls)
{
float4 data0 = kernel_tex_fetch(__light_data, lamp*LIGHT_SIZE + 0);
float4 data1 = kernel_tex_fetch(__light_data, lamp*LIGHT_SIZE + 1);
LightType type = (LightType)__float_as_int(data0.x);
ls->type = type;
ls->shader = __float_as_int(data1.x);
ls->object = ~0;
ls->prim = ~0;
ls->lamp = lamp;
if(!(ls->shader & SHADER_USE_MIS))
return false;
if(type == LIGHT_DISTANT) {
/* distant light */
float radius = data1.y;
if(radius == 0.0f)
return false;
if(t != FLT_MAX)
return false;
/* a distant light is infinitely far away, but equivalent to a disk
* shaped light exactly 1 unit away from the current shading point.
*
* radius t^2/cos(theta)
* <----------> t = sqrt(1^2 + tan(theta)^2)
* tan(th) area = radius*radius*pi
* <----->
* \ | (1 + tan(theta)^2)/cos(theta)
* \ | (1 + tan(acos(cos(theta)))^2)/cos(theta)
* t \th| 1 simplifies to
* \-| 1/(cos(theta)^3)
* \| magic!
* P
*/
float3 lightD = make_float3(data0.y, data0.z, data0.w);
float costheta = dot(-lightD, D);
float cosangle = data1.z;
if(costheta < cosangle)
return false;
ls->P = -D;
ls->Ng = -D;
ls->D = D;
ls->t = FLT_MAX;
float invarea = data1.w;
ls->pdf = invarea/(costheta*costheta*costheta);
ls->eval_fac = ls->pdf;
}
else if(type == LIGHT_POINT || type == LIGHT_SPOT) {
float3 lightP = make_float3(data0.y, data0.z, data0.w);
float radius = data1.y;
/* sphere light */
if(radius == 0.0f)
return false;
if(!ray_aligned_disk_intersect(P, D, t,
lightP, radius, &ls->P, &ls->t))
return false;
ls->Ng = -D;
ls->D = D;
float invarea = data1.z;
ls->eval_fac = (0.25f*M_1_PI_F)*invarea;
ls->pdf = invarea;
if(type == LIGHT_SPOT) {
/* spot light attentuation */
float4 data2 = kernel_tex_fetch(__light_data, lamp*LIGHT_SIZE + 2);
ls->eval_fac *= spot_light_attenuation(data1, data2, ls);
if(ls->eval_fac == 0.0f)
return false;
}
}
else if(type == LIGHT_AREA) {
/* area light */
float4 data2 = kernel_tex_fetch(__light_data, lamp*LIGHT_SIZE + 2);
float4 data3 = kernel_tex_fetch(__light_data, lamp*LIGHT_SIZE + 3);
float invarea = data2.x;
if(invarea == 0.0f)
return false;
float3 axisu = make_float3(data1.y, data1.z, data1.w);
float3 axisv = make_float3(data2.y, data2.z, data2.w);
float3 Ng = make_float3(data3.y, data3.z, data3.w);
/* one sided */
if(dot(D, Ng) >= 0.0f)
return false;
ls->P = make_float3(data0.y, data0.z, data0.w);
if(!ray_quad_intersect(P, D, t,
ls->P, axisu, axisv, &ls->P, &ls->t))
return false;
ls->D = D;
ls->Ng = Ng;
ls->pdf = invarea;
ls->eval_fac = 0.25f*ls->pdf;
}
else
return false;
/* compute pdf */
if(ls->t != FLT_MAX)
ls->pdf *= lamp_light_pdf(kg, ls->Ng, -ls->D, ls->t);
ls->eval_fac *= kernel_data.integrator.inv_pdf_lights;
return true;
}
/* Triangle Light */
__device void object_transform_light_sample(KernelGlobals *kg, LightSample *ls, int object, float time)
{
#ifdef __INSTANCING__
/* instance transform */
if(object >= 0) {
#ifdef __OBJECT_MOTION__
Transform itfm;
Transform tfm = object_fetch_transform_motion_test(kg, object, time, &itfm);
#else
Transform tfm = object_fetch_transform(kg, object, OBJECT_TRANSFORM);
Transform itfm = object_fetch_transform(kg, object, OBJECT_INVERSE_TRANSFORM);
#endif
ls->P = transform_point(&tfm, ls->P);
ls->Ng = normalize(transform_direction(&tfm, ls->Ng));
}
#endif
}
__device void triangle_light_sample(KernelGlobals *kg, int prim, int object,
float randu, float randv, float time, LightSample *ls)
{
/* triangle, so get position, normal, shader */
ls->P = triangle_sample_MT(kg, prim, randu, randv);
ls->Ng = triangle_normal_MT(kg, prim, &ls->shader);
ls->object = object;
ls->prim = prim;
ls->lamp = ~0;
ls->shader |= SHADER_USE_MIS;
ls->t = 0.0f;
ls->type = LIGHT_TRIANGLE;
ls->eval_fac = 1.0f;
object_transform_light_sample(kg, ls, object, time);
}
__device float triangle_light_pdf(KernelGlobals *kg,
const float3 Ng, const float3 I, float t)
{
float pdf = kernel_data.integrator.pdf_triangles;
float cos_pi = fabsf(dot(Ng, I));
if(cos_pi == 0.0f)
return 0.0f;
return t*t*pdf/cos_pi;
}
/* Curve Light */
#ifdef __HAIR__
__device void curve_segment_light_sample(KernelGlobals *kg, int prim, int object,
int segment, float randu, float randv, float time, LightSample *ls)
{
/* this strand code needs completion */
float4 v00 = kernel_tex_fetch(__curves, prim);
int k0 = __float_as_int(v00.x) + segment;
int k1 = k0 + 1;
float4 P1 = kernel_tex_fetch(__curve_keys, k0);
float4 P2 = kernel_tex_fetch(__curve_keys, k1);
float l = len(P2 - P1);
float r1 = P1.w;
float r2 = P2.w;
float3 tg = float4_to_float3(P2 - P1) / l;
float3 xc = make_float3(tg.x * tg.z, tg.y * tg.z, -(tg.x * tg.x + tg.y * tg.y));
if (dot(xc, xc) == 0.0f)
xc = make_float3(tg.x * tg.y, -(tg.x * tg.x + tg.z * tg.z), tg.z * tg.y);
xc = normalize(xc);
float3 yc = cross(tg, xc);
float gd = ((r2 - r1)/l);
/* normal currently ignores gradient */
ls->Ng = sinf(2 * M_PI_F * randv) * xc + cosf(2 * M_PI_F * randv) * yc;
ls->P = randu * l * tg + (gd * l + r1) * ls->Ng;
ls->object = object;
ls->prim = prim;
ls->lamp = ~0;
ls->t = 0.0f;
ls->type = LIGHT_STRAND;
ls->eval_fac = 1.0f;
ls->shader = __float_as_int(v00.z) | SHADER_USE_MIS;
object_transform_light_sample(kg, ls, object, time);
}
#endif
/* Light Distribution */
__device int light_distribution_sample(KernelGlobals *kg, float randt)
{
/* this is basically std::upper_bound as used by pbrt, to find a point light or
* triangle to emit from, proportional to area. a good improvement would be to
* also sample proportional to power, though it's not so well defined with
* OSL shaders. */
int first = 0;
int len = kernel_data.integrator.num_distribution + 1;
while(len > 0) {
int half_len = len >> 1;
int middle = first + half_len;
if(randt < kernel_tex_fetch(__light_distribution, middle).x) {
len = half_len;
}
else {
first = middle + 1;
len = len - half_len - 1;
}
}
/* clamping should not be needed but float rounding errors seem to
* make this fail on rare occasions */
return clamp(first-1, 0, kernel_data.integrator.num_distribution-1);
}
/* Generic Light */
__device void light_sample(KernelGlobals *kg, float randt, float randu, float randv, float time, float3 P, LightSample *ls)
{
/* sample index */
int index = light_distribution_sample(kg, randt);
/* fetch light data */
float4 l = kernel_tex_fetch(__light_distribution, index);
int prim = __float_as_int(l.y);
if(prim >= 0) {
int object = __float_as_int(l.w);
#ifdef __HAIR__
int segment = __float_as_int(l.z);
#endif
#ifdef __HAIR__
if (segment != ~0)
curve_segment_light_sample(kg, prim, object, segment, randu, randv, time, ls);
else
#endif
triangle_light_sample(kg, prim, object, randu, randv, time, ls);
/* compute incoming direction, distance and pdf */
ls->D = normalize_len(ls->P - P, &ls->t);
ls->pdf = triangle_light_pdf(kg, ls->Ng, -ls->D, ls->t);
}
else {
int lamp = -prim-1;
lamp_light_sample(kg, lamp, randu, randv, P, ls);
}
}
__device int light_select_num_samples(KernelGlobals *kg, int index)
{
float4 data3 = kernel_tex_fetch(__light_data, index*LIGHT_SIZE + 3);
return __float_as_int(data3.x);
}
__device void light_select(KernelGlobals *kg, int index, float randu, float randv, float3 P, LightSample *ls)
{
lamp_light_sample(kg, index, randu, randv, P, ls);
}
__device int lamp_light_eval_sample(KernelGlobals *kg, float randt)
{
/* sample index */
int index = light_distribution_sample(kg, randt);
/* fetch light data */
float4 l = kernel_tex_fetch(__light_distribution, index);
int prim = __float_as_int(l.y);
if(prim < 0) {
int lamp = -prim-1;
return lamp;
}
else
return ~0;
}
CCL_NAMESPACE_END