blender/intern/cycles/kernel/kernel_camera.h
Brecht Van Lommel de9dffc61e Cycles: initial subsurface multiple scattering support. It's not working as
well as I would like, but it works, just add a subsurface scattering node and
you can use it like any other BSDF.

It is using fully raytraced sampling compatible with progressive rendering
and other more advanced rendering algorithms we might used in the future, and
it uses no extra memory so it's suitable for complex scenes.

Disadvantage is that it can be quite noisy and slow. Two limitations that will
be solved are that it does not work with bump mapping yet, and that the falloff
function used is a simple cubic function, it's not using the real BSSRDF
falloff function yet.

The node has a color input, along with a scattering radius for each RGB color
channel along with an overall scale factor for the radii.

There is also no GPU support yet, will test if I can get that working later.

Node Documentation:
http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/Nodes/Shaders#BSSRDF

Implementation notes:
http://wiki.blender.org/index.php/Dev:2.6/Source/Render/Cycles/Subsurface_Scattering
2013-04-01 20:26:52 +00:00

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8.2 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
/* Perspective Camera */
__device float2 camera_sample_aperture(KernelGlobals *kg, float u, float v)
{
float blades = kernel_data.cam.blades;
if(blades == 0.0f) {
/* sample disk */
return concentric_sample_disk(u, v);
}
else {
/* sample polygon */
float rotation = kernel_data.cam.bladesrotation;
return regular_polygon_sample(blades, rotation, u, v);
}
}
__device void camera_sample_perspective(KernelGlobals *kg, float raster_x, float raster_y, float lens_u, float lens_v, Ray *ray)
{
/* create ray form raster position */
Transform rastertocamera = kernel_data.cam.rastertocamera;
float3 Pcamera = transform_perspective(&rastertocamera, make_float3(raster_x, raster_y, 0.0f));
ray->P = make_float3(0.0f, 0.0f, 0.0f);
ray->D = Pcamera;
/* modify ray for depth of field */
float aperturesize = kernel_data.cam.aperturesize;
if(aperturesize > 0.0f) {
/* sample point on aperture */
float2 lensuv = camera_sample_aperture(kg, lens_u, lens_v)*aperturesize;
/* compute point on plane of focus */
float ft = kernel_data.cam.focaldistance/ray->D.z;
float3 Pfocus = ray->P + ray->D*ft;
/* update ray for effect of lens */
ray->P = make_float3(lensuv.x, lensuv.y, 0.0f);
ray->D = normalize(Pfocus - ray->P);
}
/* transform ray from camera to world */
Transform cameratoworld = kernel_data.cam.cameratoworld;
#ifdef __CAMERA_MOTION__
if(kernel_data.cam.have_motion)
transform_motion_interpolate(&cameratoworld, (const DecompMotionTransform*)&kernel_data.cam.motion, ray->time);
#endif
ray->P = transform_point(&cameratoworld, ray->P);
ray->D = transform_direction(&cameratoworld, ray->D);
ray->D = normalize(ray->D);
#ifdef __RAY_DIFFERENTIALS__
/* ray differential */
float3 Ddiff = transform_direction(&cameratoworld, Pcamera);
ray->dP.dx = make_float3(0.0f, 0.0f, 0.0f);
ray->dP.dy = make_float3(0.0f, 0.0f, 0.0f);
ray->dD.dx = normalize(Ddiff + float4_to_float3(kernel_data.cam.dx)) - normalize(Ddiff);
ray->dD.dy = normalize(Ddiff + float4_to_float3(kernel_data.cam.dy)) - normalize(Ddiff);
#endif
#ifdef __CAMERA_CLIPPING__
/* clipping */
ray->P += kernel_data.cam.nearclip*ray->D;
ray->t = kernel_data.cam.cliplength;
#else
ray->t = FLT_MAX;
#endif
}
/* Orthographic Camera */
__device void camera_sample_orthographic(KernelGlobals *kg, float raster_x, float raster_y, float lens_u, float lens_v, Ray *ray)
{
/* create ray form raster position */
Transform rastertocamera = kernel_data.cam.rastertocamera;
float3 Pcamera = transform_perspective(&rastertocamera, make_float3(raster_x, raster_y, 0.0f));
ray->P = Pcamera;
ray->D = make_float3(0.0f, 0.0f, 1.0f);
/* modify ray for depth of field */
float aperturesize = kernel_data.cam.aperturesize;
if(aperturesize > 0.0f) {
/* sample point on aperture */
float2 lensuv = camera_sample_aperture(kg, lens_u, lens_v)*aperturesize;
/* compute point on plane of focus */
float ft = kernel_data.cam.focaldistance/ray->D.z;
float3 Pfocus = ray->P + ray->D*ft;
/* update ray for effect of lens */
ray->P = make_float3(lensuv.x, lensuv.y, 0.0f);
ray->D = normalize(Pfocus - ray->P);
}
/* transform ray from camera to world */
Transform cameratoworld = kernel_data.cam.cameratoworld;
#ifdef __CAMERA_MOTION__
if(kernel_data.cam.have_motion)
transform_motion_interpolate(&cameratoworld, (const DecompMotionTransform*)&kernel_data.cam.motion, ray->time);
#endif
ray->P = transform_point(&cameratoworld, ray->P);
ray->D = transform_direction(&cameratoworld, ray->D);
ray->D = normalize(ray->D);
#ifdef __RAY_DIFFERENTIALS__
/* ray differential */
ray->dP.dx = float4_to_float3(kernel_data.cam.dx);
ray->dP.dy = float4_to_float3(kernel_data.cam.dy);
ray->dD.dx = make_float3(0.0f, 0.0f, 0.0f);
ray->dD.dy = make_float3(0.0f, 0.0f, 0.0f);
#endif
#ifdef __CAMERA_CLIPPING__
/* clipping */
ray->t = kernel_data.cam.cliplength;
#else
ray->t = FLT_MAX;
#endif
}
/* Panorama Camera */
__device void camera_sample_panorama(KernelGlobals *kg, float raster_x, float raster_y, float lens_u, float lens_v, Ray *ray)
{
Transform rastertocamera = kernel_data.cam.rastertocamera;
float3 Pcamera = transform_perspective(&rastertocamera, make_float3(raster_x, raster_y, 0.0f));
/* create ray form raster position */
ray->P = make_float3(0.0f, 0.0f, 0.0f);
#ifdef __CAMERA_CLIPPING__
/* clipping */
ray->t = kernel_data.cam.cliplength;
#else
ray->t = FLT_MAX;
#endif
ray->D = panorama_to_direction(kg, Pcamera.x, Pcamera.y);
/* modify ray for depth of field */
float aperturesize = kernel_data.cam.aperturesize;
if(aperturesize > 0.0f) {
/* sample point on aperture */
float2 lensuv = camera_sample_aperture(kg, lens_u, lens_v)*aperturesize;
/* compute point on plane of focus */
float3 D = normalize(ray->D);
float3 Pfocus = D * kernel_data.cam.focaldistance;
/* calculate orthonormal coordinates perpendicular to D */
float3 U, V;
make_orthonormals(D, &U, &V);
/* update ray for effect of lens */
ray->P = U * lensuv.x + V * lensuv.y;
ray->D = normalize(Pfocus - ray->P);
}
/* indicates ray should not receive any light, outside of the lens */
if(len_squared(ray->D) == 0.0f) {
ray->t = 0.0f;
return;
}
/* transform ray from camera to world */
Transform cameratoworld = kernel_data.cam.cameratoworld;
#ifdef __CAMERA_MOTION__
if(kernel_data.cam.have_motion)
transform_motion_interpolate(&cameratoworld, (const DecompMotionTransform*)&kernel_data.cam.motion, ray->time);
#endif
ray->P = transform_point(&cameratoworld, ray->P);
ray->D = transform_direction(&cameratoworld, ray->D);
ray->D = normalize(ray->D);
#ifdef __RAY_DIFFERENTIALS__
/* ray differential */
ray->dP.dx = make_float3(0.0f, 0.0f, 0.0f);
ray->dP.dy = make_float3(0.0f, 0.0f, 0.0f);
Pcamera = transform_perspective(&rastertocamera, make_float3(raster_x + 1.0f, raster_y, 0.0f));
ray->dD.dx = normalize(transform_direction(&cameratoworld, panorama_to_direction(kg, Pcamera.x, Pcamera.y))) - ray->D;
Pcamera = transform_perspective(&rastertocamera, make_float3(raster_x, raster_y + 1.0f, 0.0f));
ray->dD.dy = normalize(transform_direction(&cameratoworld, panorama_to_direction(kg, Pcamera.x, Pcamera.y))) - ray->D;
#endif
}
/* Common */
__device void camera_sample(KernelGlobals *kg, int x, int y, float filter_u, float filter_v,
float lens_u, float lens_v, float time, Ray *ray)
{
/* pixel filter */
int filter_table_offset = kernel_data.film.filter_table_offset;
float raster_x = x + lookup_table_read(kg, filter_u, filter_table_offset, FILTER_TABLE_SIZE);
float raster_y = y + lookup_table_read(kg, filter_v, filter_table_offset, FILTER_TABLE_SIZE);
#ifdef __CAMERA_MOTION__
/* motion blur */
if(kernel_data.cam.shuttertime == -1.0f)
ray->time = TIME_INVALID;
else
ray->time = 0.5f + 0.5f*(time - 0.5f)*kernel_data.cam.shuttertime;
#endif
/* sample */
if(kernel_data.cam.type == CAMERA_PERSPECTIVE)
camera_sample_perspective(kg, raster_x, raster_y, lens_u, lens_v, ray);
else if(kernel_data.cam.type == CAMERA_ORTHOGRAPHIC)
camera_sample_orthographic(kg, raster_x, raster_y, lens_u, lens_v, ray);
else
camera_sample_panorama(kg, raster_x, raster_y, lens_u, lens_v, ray);
}
/* Utilities */
__device_inline float camera_distance(KernelGlobals *kg, float3 P)
{
Transform cameratoworld = kernel_data.cam.cameratoworld;
float3 camP = make_float3(cameratoworld.x.w, cameratoworld.y.w, cameratoworld.z.w);
if(kernel_data.cam.type == CAMERA_ORTHOGRAPHIC) {
float3 camD = make_float3(cameratoworld.x.z, cameratoworld.y.z, cameratoworld.z.z);
return fabsf(dot((P - camP), camD));
}
else
return len(P - camP);
}
CCL_NAMESPACE_END