Cycles OSL: phong_ramp(N, exponent, colors[8]) closure added, which works like

a specular ramp shader. Note this is OSL only still, for experimenting.

Patch by Thomas.

1 files changed, 140 insertions, 0 deletions

diff --git a/intern/cycles/kernel/closure/bsdf_phong_ramp.h b/intern/cycles/kernel/closure/bsdf_phong_ramp.h
new file mode 100644
index 00000000000..a2df77c2d2b
--- /dev/null
+++ b/intern/cycles/kernel/closure/bsdf_phong_ramp.h
@@ -0,0 +1,140 @@
+/*
+ * Adapted from Open Shading Language with this license:
+ *
+ * Copyright (c) 2009-2010 Sony Pictures Imageworks Inc., et al.
+ * All Rights Reserved.
+ *
+ * Modifications Copyright 2012, 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.
+ */
+
+#ifndef __BSDF_PHONG_RAMP_H__
+#define __BSDF_PHONG_RAMP_H__
+
+CCL_NAMESPACE_BEGIN
+
+__device float3 bsdf_phong_ramp_get_color(const ShaderClosure *sc, const float3 colors[8], float pos)
+{
+	int MAXCOLORS = 8;
+	
+	float npos = pos * (float)(MAXCOLORS - 1);
+	int ipos = (int)npos;
+	if (ipos >= (MAXCOLORS - 1))
+		return colors[MAXCOLORS - 1];
+	float offset = npos - (float)ipos;
+	return colors[ipos] * (1.0f - offset) + colors[ipos+1] * offset;
+}
+
+__device int bsdf_phong_ramp_setup(ShaderClosure *sc)
+{
+	sc->type = CLOSURE_BSDF_PHONG_RAMP_ID;
+	return SD_BSDF | SD_BSDF_HAS_EVAL | SD_BSDF_GLOSSY;
+}
+
+__device void bsdf_phong_ramp_blur(ShaderClosure *sc, float roughness)
+{
+}
+
+__device float3 bsdf_phong_ramp_eval_reflect(const ShaderClosure *sc, const float3 colors[8], const float3 I, const float3 omega_in, float *pdf)
+{
+	float m_exponent = sc->data0;
+	float cosNI = dot(sc->N, omega_in);
+	float cosNO = dot(sc->N, I);
+	
+	if (cosNI > 0 && cosNO > 0) {
+		// reflect the view vector
+		float3 R = (2 * cosNO) * sc->N - I;
+		float cosRI = dot(R, omega_in);
+		if (cosRI > 0) {
+			float cosp = powf(cosRI, m_exponent);
+			float common = 0.5f * (float) M_1_PI_F * cosp;
+			float out = cosNI * (m_exponent + 2) * common;
+			*pdf = (m_exponent + 1) * common;
+			return bsdf_phong_ramp_get_color(sc, colors, cosp) * out;
+		}
+	}
+	
+	return make_float3(0.0f, 0.0f, 0.0f);
+}
+
+__device float3 bsdf_phong_ramp_eval_transmit(const ShaderClosure *sc, const float3 colors[8], const float3 I, const float3 omega_in, float *pdf)
+{
+	return make_float3(0.0f, 0.0f, 0.0f);
+}
+
+__device int bsdf_phong_ramp_sample(const ShaderClosure *sc, const float3 colors[8], float3 Ng, 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 cosNO = dot(sc->N, I);
+	float m_exponent = sc->data0;
+	
+	if (cosNO > 0) {
+		// reflect the view vector
+		float3 R = (2 * cosNO) * sc->N - I;
+
+#ifdef __RAY_DIFFERENTIALS__
+		*domega_in_dx = (2 * dot(sc->N, dIdx)) * sc->N - dIdx;
+		*domega_in_dy = (2 * dot(sc->N, dIdy)) * sc->N - dIdy;
+#endif
+		
+		float3 T, B;
+		make_orthonormals (R, &T, &B);
+		float phi = 2 * M_PI_F * randu;
+		float cosTheta = powf(randv, 1 / (m_exponent + 1));
+		float sinTheta2 = 1 - cosTheta * cosTheta;
+		float sinTheta = sinTheta2 > 0 ? sqrtf(sinTheta2) : 0;
+		*omega_in = (cosf(phi) * sinTheta) * T +
+				   (sinf(phi) * sinTheta) * B +
+				   (            cosTheta) * R;
+		if (dot(Ng, *omega_in) > 0.0f)
+		{
+			// common terms for pdf and eval
+			float cosNI = dot(sc->N, *omega_in);
+			// make sure the direction we chose is still in the right hemisphere
+			if (cosNI > 0)
+			{
+				float cosp = powf(cosTheta, m_exponent);
+				float common = 0.5f * M_1_PI_F * cosp;
+				*pdf = (m_exponent + 1) * common;
+				float out = cosNI * (m_exponent + 2) * common;
+				*eval = bsdf_phong_ramp_get_color(sc, colors, cosp) * out;
+				
+#ifdef __RAY_DIFFERENTIALS__
+				// Since there is some blur to this reflection, make the
+				// derivatives a bit bigger. In theory this varies with the
+				// exponent but the exact relationship is complex and
+				// requires more ops than are practical.
+				*domega_in_dx *= 10;
+				*domega_in_dy *= 10;
+#endif
+			}
+		}
+	}
+	return LABEL_REFLECT;
+}
+
+
+CCL_NAMESPACE_END
+
+#endif /* __BSDF_PHONG_RAMP_H__ */