[Bf-blender-cvs] [de479f5] soc-2013-dingto: Cycles Volume: implement volume absorption node.
Brecht Van Lommel
noreply at git.blender.org
Thu Dec 26 15:01:23 CET 2013
Commit: de479f51b62ebed3800a5aa7203f1bfd70c3508a
Author: Brecht Van Lommel
Date: Thu Dec 26 14:40:09 2013 +0100
https://developer.blender.org/rBde479f51b62ebed3800a5aa7203f1bfd70c3508a
Cycles Volume: implement volume absorption node.
This is the transparent volume node renamed, currently it is basically the
same as a scatter volume node with anisotropy 1, so it scatters light perfectly
forward.
This also does some tweaks to the henyey-greenstein closure code to avoid
division by zero and to make eval/sample consistent in some corner cases, and
some other code cleanup related to volume shaders.
===================================================================
M intern/cycles/blender/blender_shader.cpp
M intern/cycles/kernel/closure/bsdf.h
M intern/cycles/kernel/closure/volume.h
M intern/cycles/kernel/kernel_shader.h
M intern/cycles/kernel/kernel_types.h
M intern/cycles/kernel/osl/osl_closures.cpp
M intern/cycles/kernel/osl/osl_closures.h
M intern/cycles/kernel/shaders/CMakeLists.txt
A intern/cycles/kernel/shaders/node_absorption_volume.osl
M intern/cycles/kernel/shaders/node_scatter_volume.osl
M intern/cycles/kernel/shaders/stdosl.h
M intern/cycles/kernel/svm/svm_closure.h
M intern/cycles/kernel/svm/svm_types.h
M intern/cycles/render/nodes.cpp
M intern/cycles/render/nodes.h
M release/scripts/addons
M release/scripts/addons_contrib
M source/blender/blenkernel/BKE_node.h
M source/blender/blenkernel/intern/node.c
M source/blender/nodes/CMakeLists.txt
M source/blender/nodes/NOD_shader.h
M source/blender/nodes/NOD_static_types.h
A source/blender/nodes/shader/nodes/node_shader_volume_absorption.c
D source/blender/nodes/shader/nodes/node_shader_volume_transparent.c
===================================================================
diff --git a/intern/cycles/blender/blender_shader.cpp b/intern/cycles/blender/blender_shader.cpp
index 8c4e83b..be57b1d 100644
--- a/intern/cycles/blender/blender_shader.cpp
+++ b/intern/cycles/blender/blender_shader.cpp
@@ -425,8 +425,8 @@ static ShaderNode *add_node(Scene *scene, BL::BlendData b_data, BL::Scene b_scen
else if (b_node.is_a(&RNA_ShaderNodeVolumeScatter)) {
node = new ScatterVolumeNode();
}
- else if (b_node.is_a(&RNA_ShaderNodeVolumeTransparent)) {
- node = new TransparentVolumeNode();
+ else if (b_node.is_a(&RNA_ShaderNodeVolumeAbsorption)) {
+ node = new AbsorptionVolumeNode();
}
else if (b_node.is_a(&RNA_ShaderNodeNewGeometry)) {
node = new GeometryNode();
diff --git a/intern/cycles/kernel/closure/bsdf.h b/intern/cycles/kernel/closure/bsdf.h
index ff2afd0..2212259 100644
--- a/intern/cycles/kernel/closure/bsdf.h
+++ b/intern/cycles/kernel/closure/bsdf.h
@@ -146,9 +146,10 @@ ccl_device float3 bsdf_eval(KernelGlobals *kg, const ShaderData *sd, const Shade
#endif
#ifdef __VOLUME__
- // need this to keep logic in kernel_emission.h direct light in case of volume particle
+ /* need this to keep logic in kernel_emission.h direct light in case of volume particle */
+ /* todo: restructure code so this is handled better */
if (CLOSURE_IS_VOLUME(sc->type))
- return volume_eval_phase(kg, sc, sd->I, omega_in, pdf);
+ return volume_eval_phase(sc, sd->I, omega_in, pdf);
#endif
if(dot(sd->Ng, omega_in) >= 0.0f) {
diff --git a/intern/cycles/kernel/closure/volume.h b/intern/cycles/kernel/closure/volume.h
index 4b4cfd0..1e31c5a 100644
--- a/intern/cycles/kernel/closure/volume.h
+++ b/intern/cycles/kernel/closure/volume.h
@@ -21,111 +21,116 @@ CCL_NAMESPACE_BEGIN
/* HENYEY-GREENSTEIN CLOSURE */
-/* Given cosine between rays, return probability density that photon bounce to that direction
- * g parameter controls how far it difference from uniform sphere. g=0 uniform diffusion-like, g=1 - very close to sharp single ray. */
-
-ccl_device float single_peaked_henyey_greenstein(float cos_theta, float m_g)
+/* Given cosine between rays, return probability density that a photon bounces
+ * to that direction. The g parameter controls how different it is from the
+ * uniform sphere. g=0 uniform diffuse-like, g=1 close to sharp single ray. */
+ccl_device float single_peaked_henyey_greenstein(float cos_theta, float g)
{
- float p = (1.0f - m_g * m_g) / pow(1.0f + m_g * m_g - 2.0f * m_g * cos_theta, 1.5f) / 4.0f / M_PI_F;
-
- return p;
+ if(fabsf(g) < 1e-3f)
+ return M_1_PI_F * 0.25f;
+
+ return ((1.0f - g * g) / safe_powf(1.0f + g * g - 2.0f * g * cos_theta, 1.5f)) * (M_1_PI_F * 0.25f);
};
ccl_device int volume_henyey_greenstein_setup(ShaderClosure *sc)
{
sc->type = CLOSURE_VOLUME_HENYEY_GREENSTEIN_ID;
+
+ /* positive density */
+ sc->data0 = max(sc->data0, 0.0f);
+ /* clamp anisotropy to avoid delta function */
+ sc->data1 = signf(sc->data1) * min(fabsf(sc->data1), 1.0f - 1e-3f);
return SD_BSDF|SD_BSDF_HAS_EVAL;
}
-// just return bsdf at input vector
ccl_device float3 volume_henyey_greenstein_eval_phase(const ShaderClosure *sc, const float3 I, float3 omega_in, float *pdf)
{
- float m_g = sc->data1;
- const float magic_eps = 0.001f;
+ float g = sc->data1;
-// WARNING! I point in backward direction!
-// float cos_theta = dot(I, omega_in);
+ /* note that I points towards the viewer */
float cos_theta = dot(-I, omega_in);
- if(fabsf(m_g) < magic_eps)
- *pdf = M_1_PI_F * 0.25f; // ?? double check it
- else
- *pdf = single_peaked_henyey_greenstein(cos_theta, m_g);
+ *pdf = single_peaked_henyey_greenstein(cos_theta, g);
return make_float3(*pdf, *pdf, *pdf);
}
-ccl_device int volume_henyey_greenstein_sample(const ShaderClosure *sc, float3 Ng, float3 I, float3 dIdx, float3 dIdy, float randu, float randv,
+ccl_device int volume_henyey_greenstein_sample(const ShaderClosure *sc, float3 I, float3 dIdx, float3 dIdy, float randu, float randv,
float3 *eval, float3 *omega_in, float3 *domega_in_dx, float3 *domega_in_dy, float *pdf)
{
- float m_g = sc->data1;
- const float magic_eps = 0.001f;
+ float g = sc->data1;
+ float cos_phi, sin_phi, cos_theta;
- // WARNING! I point in backward direction!
-
- if(fabsf(m_g) < magic_eps) {
- *omega_in = sample_uniform_sphere(randu, randv);
- *pdf = M_1_PI_F * 0.25f; // ?? double check it
+ /* match pdf for small g */
+ if(fabsf(g) < 1e-3f) {
+ cos_theta = (1.0f - 2.0f * randu);
}
else {
- float cos_phi, sin_phi, cos_theta;
-
- if(fabsf(m_g) < magic_eps)
- cos_theta = (1.0f - 2.0f * randu);
- else {
- float k = (1.0f - m_g * m_g) / (1.0f - m_g + 2.0f * m_g * randu);
- cos_theta = (1.0f + m_g * m_g - k * k) / (2.0f * m_g);
- // float cos_theta = 1.0f / (2.0f * m_g) * (1.0f + m_g * m_g - k*k);
- // float cos_theta = (1.0f - 2.0f * randu);
- // float cos_theta = randu;
- }
- float sin_theta = sqrt(1 - cos_theta * cos_theta);
-
- float3 T, B;
- make_orthonormals(-I, &T, &B);
- float phi = M_2PI_F * randv;
- cos_phi = cosf(phi);
- sin_phi = sinf(phi);
- *omega_in = sin_theta * cos_phi * T + sin_theta * sin_phi * B + cos_theta * (-I);
- *pdf = single_peaked_henyey_greenstein(cos_theta, m_g);
+ float k = (1.0f - g * g) / (1.0f - g + 2.0f * g * randu);
+ cos_theta = (1.0f + g * g - k * k) / (2.0f * g);
}
- *eval = make_float3(*pdf, *pdf, *pdf); // perfect importance sampling
+ float sin_theta = safe_sqrtf(1.0f - cos_theta * cos_theta);
+
+ float phi = M_2PI_F * randv;
+ cos_phi = cosf(phi);
+ sin_phi = sinf(phi);
+
+ /* note that I points towards the viewer and so is used negated */
+ float3 T, B;
+ make_orthonormals(-I, &T, &B);
+ *omega_in = sin_theta * cos_phi * T + sin_theta * sin_phi * B + cos_theta * (-I);
+
+ *pdf = single_peaked_henyey_greenstein(cos_theta, g);
+ *eval = make_float3(*pdf, *pdf, *pdf); /* perfect importance sampling */
+
#ifdef __RAY_DIFFERENTIALS__
- // TODO: find a better approximation for the diffuse bounce
- *domega_in_dx = (2 * dot(Ng, dIdx)) * Ng - dIdx;
- *domega_in_dy = (2 * dot(Ng, dIdy)) * Ng - dIdy;
- *domega_in_dx *= 125.0f;
- *domega_in_dy *= 125.0f;
+ /* todo: implement ray differential estimation */
+ *domega_in_dx = make_float3(0.0f, 0.0f, 0.0f);
+ *domega_in_dy = make_float3(0.0f, 0.0f, 0.0f);
#endif
- return LABEL_REFLECT|LABEL_DIFFUSE;
+
+ /* todo: do we need a separate light path state for volume scatter? */
+ return LABEL_DIFFUSE;
}
-/* TRANSPARENT VOLUME CLOSURE */
+/* ABSORPTION VOLUME CLOSURE */
-ccl_device int volume_transparent_setup(ShaderClosure *sc)
+ccl_device int volume_absorption_setup(ShaderClosure *sc)
{
- sc->type = CLOSURE_VOLUME_TRANSPARENT_ID;
+ sc->type = CLOSURE_VOLUME_ABSORPTION_ID;
+
+ /* positive density */
+ sc->data0 = max(sc->data0, 0.0f);
return SD_VOLUME;
}
-ccl_device float3 volume_transparent_eval_phase(const ShaderClosure *sc, const float3 I, float3 omega_in, float *pdf)
+ccl_device float3 volume_absorption_eval_phase(const ShaderClosure *sc, const float3 I, float3 omega_in, float *pdf)
{
- return make_float3(1.0f, 1.0f, 1.0f);
+ /* eval to zero for delta functions */
+ return make_float3(0.0f, 0.0f, 0.0f);
}
-ccl_device int volume_transparent_sample(const ShaderClosure *sc, float3 Ng, float3 I, float3 dIdx, float3 dIdy, float randu, float randv,
+ccl_device int volume_absorption_sample(const ShaderClosure *sc, float3 I, float3 dIdx, float3 dIdy, float randu, float randv,
float3 *eval, float3 *omega_in, float3 *domega_in_dx, float3 *domega_in_dy, float *pdf)
{
- /* XXX Implement */
- return LABEL_REFLECT|LABEL_DIFFUSE;
+ *omega_in = -I;
+#ifdef __RAY_DIFFERENTIALS__
+ *domega_in_dx = -dIdx;
+ *domega_in_dy = -dIdy;
+#endif
+
+ *pdf = 1.0f;
+ *eval = make_float3(1.0f, 1.0f, 1.0f);
+
+ return LABEL_TRANSMIT|LABEL_TRANSPARENT;
}
/* VOLUME CLOSURE */
-ccl_device float3 volume_eval_phase(KernelGlobals *kg, const ShaderClosure *sc, const float3 I, float3 omega_in, float *pdf)
+ccl_device float3 volume_eval_phase(const ShaderClosure *sc, const float3 I, float3 omega_in, float *pdf)
{
float3 eval;
@@ -133,8 +138,8 @@ ccl_device float3 volume_eval_phase(KernelGlobals *kg, const ShaderClosure *sc,
case CLOSURE_VOLUME_HENYEY_GREENSTEIN_ID:
eval = volume_henyey_greenstein_eval_phase(sc, I, omega_in, pdf);
break;
- case CLOSURE_VOLUME_TRANSPARENT_ID:
- eval = volume_transparent_eval_phase(sc, I, omega_in, pdf);
+ case CLOSURE_VOLUME_ABSORPTION_ID:
+ eval = volume_absorption_eval_phase(sc, I, omega_in, pdf);
break;
default:
eval = make_float3(0.0f, 0.0f, 0.0f);
@@ -144,17 +149,17 @@ ccl_device float3 volume_eval_phase(KernelGlobals *kg, const ShaderClosure *sc,
return eval;
}
-ccl_device int volume_sample(KernelGlobals *kg, const ShaderData *sd, const ShaderClosure *sc, float randu,
+ccl_device int volume_sample(const ShaderData *sd, const ShaderClosure *sc, float randu,
float randv, float3 *eval, float3 *omega_in, differential3 *domega_in, float *pdf)
{
int label;
switch(sc->type) {
case CLOSURE_VOLUME_HENYEY_GREENSTEIN_ID:
- label = volume_henyey_greenstein_sample(sc, sd->Ng, sd->I, sd->dI.dx, sd->dI.dy, randu, randv, eval, omega_in, &domega_in->dx, &domega_in->dy, pdf);
+ label = volume_henyey_greenstein_sample(sc, sd->I, sd->dI.dx, sd->dI.dy, randu, randv, eval, omega_in, &domega_in->dx, &domega_in->dy, pdf);
break;
- case CLOSURE_VOLUME_TRANSPARENT_ID:
- label = volume_transparent_sample(sc, sd->Ng, sd->I, sd->dI.dx, sd->dI.dy, randu, randv, eval, omega_in, &domega_in->dx, &domega_in->dy, pdf);
+ case CLOSURE_VOLUME_ABSORPTION_ID:
+ label = volume_absorption_sample(sc, sd->I, sd->dI.dx, sd->dI.dy, randu, randv, eval, omega_in, &domega_in->dx, &domega_in->dy, pdf);
break;
default:
*eval = make_float3(0.0f, 0.0f, 0.0f);
@@ -162,8 +167,6 @@ ccl_device int volume_sample(KernelGlobals *kg, const ShaderData *sd, const Shad
break;
}
-// *eval *= sd->svm_closure_weight;
-
return label;
}
diff --git a/intern/cycles/kernel/kernel_shader.h b/intern/cycles/kernel/kernel_shader.h
index 7b73fd3..f98b626 100644
--- a/intern/cycles/kernel/kernel_shader.h
+++ b/intern/cycles/kernel/kernel_shader.h
@@ -1025,7 +1025,7 @@ ccl_device int shader_volume_bsdf_sample(Kerne
@@ Diff output truncated at 10240 characters. @@
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