1 files changed, 139 insertions, 0 deletions
diff --git a/intern/cycles/kernel/kernel_emission.h b/intern/cycles/kernel/kernel_emission.h
new file mode 100644
index 00000000000..b81db721eb3
--- /dev/null
+++ b/intern/cycles/kernel/kernel_emission.h
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+/*
+ * 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
+
+/* Direction Emission */
+
+__device float3 direct_emissive_eval(KernelGlobals *kg, float rando,
+	LightSample *ls, float u, float v, float3 I)
+{
+	/* setup shading at emitter */
+	ShaderData sd;
+
+	shader_setup_from_sample(kg, &sd, ls->P, ls->Ng, I, ls->shader, ls->object, ls->prim, u, v);
+	ls->Ng = sd.Ng;
+
+	/* no path flag, we're evaluating this for all closures. that's weak but
+	   we'd have to do multiple evaluations otherwise */
+	shader_eval_surface(kg, &sd, rando, 0);
+	
+	float3 eval;
+
+	/* evaluate emissive closure */
+	if(sd.flag & SD_EMISSION)
+		eval = shader_emissive_eval(kg, &sd);
+	else
+		eval = make_float3(0.0f, 0.0f, 0.0f);
+
+	shader_release(kg, &sd);
+
+	return eval;
+}
+
+__device bool direct_emission(KernelGlobals *kg, ShaderData *sd, int lindex,
+	float randt, float rando, float randu, float randv, Ray *ray, float3 *eval)
+{
+	LightSample ls;
+
+#ifdef __MULTI_LIGHT__
+	if(lindex != -1) {
+		/* sample position on a specified light */
+		light_select(kg, lindex, randu, randv, sd->P, &ls);
+	}
+	else
+#endif
+	{
+		/* sample a light and position on int */
+		light_sample(kg, randt, randu, randv, sd->P, &ls);
+	}
+
+	/* compute pdf */
+	float pdf = light_sample_pdf(kg, &ls, -ls.D, ls.t);
+
+	/* evaluate closure */
+	*eval = direct_emissive_eval(kg, rando, &ls, randu, randv, -ls.D);
+
+	if(is_zero(*eval) || pdf == 0.0f)
+		return false;
+
+	/* todo: use visbility flag to skip lights */
+
+	/* evaluate BSDF at shading point */
+	float bsdf_pdf;
+	float3 bsdf_eval = shader_bsdf_eval(kg, sd, ls.D, &bsdf_pdf);
+
+	*eval *= bsdf_eval/pdf;
+
+	if(is_zero(*eval))
+		return false;
+
+	if(ls.prim != ~0) {
+		/* multiple importance sampling */
+		float mis_weight = power_heuristic(pdf, bsdf_pdf);
+		*eval *= mis_weight;
+	}
+	/* todo: clean up these weights */
+	else if(ls.shader & SHADER_AREA_LIGHT)
+		*eval *= 0.25f; /* area lamp */
+	else if(ls.t != FLT_MAX)
+		*eval *= 0.25f*M_1_PI_F; /* point lamp */
+
+	if(ls.shader & SHADER_CAST_SHADOW) {
+		/* setup ray */
+		ray->P = ray_offset(sd->P, sd->Ng);
+
+		if(ls.t == FLT_MAX) {
+			/* distant light */
+			ray->D = ls.D;
+			ray->t = ls.t;
+		}
+		else {
+			/* other lights, avoid self-intersection */
+			ray->D = ray_offset(ls.P, ls.Ng) - ray->P;
+			ray->D = normalize_len(ray->D, &ray->t);
+		}
+	}
+	else {
+		/* signal to not cast shadow ray */
+		ray->t = 0.0f;
+	}
+
+	return true;
+}
+
+/* Indirect Emission */
+
+__device float3 indirect_emission(KernelGlobals *kg, ShaderData *sd, float t, int path_flag, float bsdf_pdf)
+{
+	/* evaluate emissive closure */
+	float3 L = shader_emissive_eval(kg, sd);
+
+	if(!(path_flag & PATH_RAY_MIS_SKIP) && (sd->flag & SD_SAMPLE_AS_LIGHT)) {
+		/* multiple importance sampling */
+		float pdf = triangle_light_pdf(kg, sd->Ng, sd->I, t);
+		float mis_weight = power_heuristic(bsdf_pdf, pdf);
+
+		return L*mis_weight;
+	}
+
+	return L;
+}
+
+CCL_NAMESPACE_END
+