Cycles render engine, initial commit. This is the engine itself, blender modifications and build instructions will follow later.

Cycles uses code from some great open source projects, many thanks them:

* BVH building and traversal code from NVidia's "Understanding the Efficiency of Ray Traversal on GPUs":
http://code.google.com/p/understanding-the-efficiency-of-ray-traversal-on-gpus/
* Open Shading Language for a large part of the shading system:
http://code.google.com/p/openshadinglanguage/
* Blender for procedural textures and a few other nodes.
* Approximate Catmull Clark subdivision from NVidia Mesh tools:
http://code.google.com/p/nvidia-mesh-tools/
* Sobol direction vectors from:
http://web.maths.unsw.edu.au/~fkuo/sobol/
* Film response functions from:
http://www.cs.columbia.edu/CAVE/software/softlib/dorf.php

1 files changed, 175 insertions, 0 deletions

diff --git a/intern/cycles/kernel/osl/bsdf_ashikhmin_velvet.cpp b/intern/cycles/kernel/osl/bsdf_ashikhmin_velvet.cpp
new file mode 100644
index 00000000000..a38c5b55cf5
--- /dev/null
+++ b/intern/cycles/kernel/osl/bsdf_ashikhmin_velvet.cpp
@@ -0,0 +1,175 @@
+/*
+ * 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.
+ */
+
+#include <OpenImageIO/fmath.h>
+
+#include <OSL/genclosure.h>
+
+#include "osl_closures.h"
+
+CCL_NAMESPACE_BEGIN
+
+using namespace OSL;
+
+class AshikhminVelvetClosure : public BSDFClosure {
+public:
+    Vec3 m_N;
+    float m_sigma;
+    float m_invsigma2;
+
+    AshikhminVelvetClosure() : BSDFClosure(Labels::DIFFUSE) { }
+
+    void setup()
+    {
+        m_sigma = std::max(m_sigma, 0.01f);
+        m_invsigma2 = 1.0f/(m_sigma * m_sigma);
+    }
+
+    bool mergeable (const ClosurePrimitive *other) const {
+        const AshikhminVelvetClosure *comp = (const AshikhminVelvetClosure *)other;
+        return m_N == comp->m_N && m_sigma == comp->m_sigma &&
+            BSDFClosure::mergeable(other);
+    }
+
+    size_t memsize () const { return sizeof(*this); }
+
+    const char *name () const { return "ashikhmin_velvet"; }
+
+    void print_on (std::ostream &out) const
+    {
+        out << name() << " (";
+        out << "(" << m_N[0] << ", " << m_N[1] << ", " << m_N[2] << "), ";
+        out << m_sigma;
+        out << ")";
+    }
+
+    float albedo (const Vec3 &omega_out) const
+    {
+		return 1.0f;
+    }
+
+    Color3 eval_reflect (const Vec3 &omega_out, const Vec3 &omega_in, float& pdf) const
+    {
+        float cosNO = m_N.dot(omega_out);
+        float cosNI = m_N.dot(omega_in);
+        if (cosNO > 0 && cosNI > 0) {
+            Vec3 H = omega_in + omega_out;
+            H.normalize();
+
+            float cosNH = m_N.dot(H);
+            float cosHO = fabsf(omega_out.dot(H));
+
+            float cosNHdivHO = cosNH / cosHO;
+            cosNHdivHO = std::max(cosNHdivHO, 0.00001f);
+
+            float fac1 = 2 * fabsf(cosNHdivHO * cosNO);
+            float fac2 = 2 * fabsf(cosNHdivHO * cosNI);
+
+            float sinNH2 = 1 - cosNH * cosNH;
+            float sinNH4 = sinNH2 * sinNH2;
+            float cotangent2 =  (cosNH * cosNH) / sinNH2; 
+
+            float D = expf(-cotangent2 * m_invsigma2) * m_invsigma2 * float(M_1_PI) / sinNH4;
+            float G = std::min(1.0f, std::min(fac1, fac2)); // TODO: derive G from D analytically
+
+            float out = 0.25f * (D * G) / cosNO;
+
+            pdf = 0.5f * (float) M_1_PI;
+            return Color3 (out, out, out);
+        }
+        return Color3 (0, 0, 0);
+    }
+
+    Color3 eval_transmit (const Vec3 &omega_out, const Vec3 &omega_in, float& pdf) const
+    {
+        return Color3 (0, 0, 0);
+    }
+
+    ustring sample (const Vec3 &Ng,
+                 const Vec3 &omega_out, const Vec3 &domega_out_dx, const Vec3 &domega_out_dy,
+                 float randu, float randv,
+                 Vec3 &omega_in, Vec3 &domega_in_dx, Vec3 &domega_in_dy,
+                 float &pdf, Color3 &eval) const
+    {
+        // we are viewing the surface from above - send a ray out with uniform
+        // distribution over the hemisphere
+        sample_uniform_hemisphere (m_N, omega_out, randu, randv, omega_in, pdf);
+        if (Ng.dot(omega_in) > 0) {
+            Vec3 H = omega_in + omega_out;
+            H.normalize();
+
+            float cosNI = m_N.dot(omega_in);
+            float cosNO = m_N.dot(omega_out);
+            float cosNH = m_N.dot(H);
+            float cosHO = fabsf(omega_out.dot(H));
+
+            float cosNHdivHO = cosNH / cosHO;
+            cosNHdivHO = std::max(cosNHdivHO, 0.00001f);
+
+            float fac1 = 2 * fabsf(cosNHdivHO * cosNO);
+            float fac2 = 2 * fabsf(cosNHdivHO * cosNI);
+
+            float sinNH2 = 1 - cosNH * cosNH;
+            float sinNH4 = sinNH2 * sinNH2;
+            float cotangent2 =  (cosNH * cosNH) / sinNH2; 
+
+            float D = expf(-cotangent2 * m_invsigma2) * m_invsigma2 * float(M_1_PI) / sinNH4;
+            float G = std::min(1.0f, std::min(fac1, fac2)); // TODO: derive G from D analytically
+
+            float power = 0.25f * (D * G) / cosNO;
+
+            eval.setValue(power, power, power);
+
+            // TODO: find a better approximation for the retroreflective bounce
+            domega_in_dx = (2 * m_N.dot(domega_out_dx)) * m_N - domega_out_dx;
+            domega_in_dy = (2 * m_N.dot(domega_out_dy)) * m_N - domega_out_dy;
+            domega_in_dx *= 125;
+            domega_in_dy *= 125;
+        } else
+            pdf = 0;
+        return Labels::REFLECT;
+    }
+
+};
+
+
+
+ClosureParam bsdf_ashikhmin_velvet_params[] = {
+    CLOSURE_VECTOR_PARAM(AshikhminVelvetClosure, m_N),
+    CLOSURE_FLOAT_PARAM (AshikhminVelvetClosure, m_sigma),
+    CLOSURE_STRING_KEYPARAM("label"),
+    CLOSURE_FINISH_PARAM(AshikhminVelvetClosure) };
+
+CLOSURE_PREPARE(bsdf_ashikhmin_velvet_prepare, AshikhminVelvetClosure)
+
+CCL_NAMESPACE_END
+