Initial commit.

Framework/lights/directional_light.cpp

@@ -0,0 +1,89 @@
+// Copyright 2009-2021 Intel Corporation
+// SPDX-License-Identifier: Apache-2.0
+
+#include "light.h"
+#include <sampling.hpp>
+#include <math/linearspace3.h>
+
+namespace embree {
+    struct DirectionalLight {
+        Light super; //!< inherited light fields
+
+        LinearSpace3fa frame; //!< coordinate frame, with vz == direction *towards* the light source
+        Vec3fa radiance; //!< RGB color and intensity of light
+        float cosAngle;
+        //!< Angular limit of the cone light in an easier to use form: cosine of the half angle in radians
+        float pdf; //!< Probability to sample a direction to the light
+    };
+
+    // for very small cones treat as singular light, because float precision is not good enough
+#define COS_ANGLE_MAX 0.99999988f
+
+
+    // Implementation
+    //////////////////////////////////////////////////////////////////////////////
+
+    Light_SampleRes DirectionalLight_sample(const Light* super,
+                                            const Sample& dg,
+                                            const Vec2f& s) {
+        const DirectionalLight* self = (DirectionalLight *) super;
+        Light_SampleRes res;
+
+        res.dir = self->frame.vz;
+        res.dist = inf;
+        res.pdf = self->pdf;
+
+        if (self->cosAngle < COS_ANGLE_MAX)
+            res.dir = self->frame * uniformSampleCone(self->cosAngle, s);
+
+        res.weight = self->radiance; // *pdf/pdf cancel
+
+        return res;
+    }
+
+    Light_EvalRes DirectionalLight_eval(const Light* super,
+                                        const Sample&,
+                                        const Vec3fa& dir) {
+        DirectionalLight* self = (DirectionalLight *) super;
+        Light_EvalRes res;
+        res.dist = inf;
+
+        if (self->cosAngle < COS_ANGLE_MAX && dot(self->frame.vz, dir) > self->cosAngle) {
+            res.value = self->radiance * self->pdf;
+            res.pdf = self->pdf;
+        } else {
+            res.value = Vec3fa(0.f);
+            res.pdf = 0.f;
+        }
+
+        return res;
+    }
+
+
+    // Exports (called from C++)
+    //////////////////////////////////////////////////////////////////////////////
+
+    //! Set the parameters of an ispc-side DirectionalLight object
+    extern "C" void DirectionalLight_set(void* super,
+                                         const Vec3fa& direction,
+                                         const Vec3fa& radiance,
+                                         float cosAngle) {
+        DirectionalLight* self = (DirectionalLight *) super;
+        self->frame = frame(direction);
+        self->radiance = radiance;
+        self->cosAngle = cosAngle;
+        self->pdf = cosAngle < COS_ANGLE_MAX ? uniformSampleConePDF(cosAngle) : inf;
+    }
+
+    //! Create an ispc-side DirectionalLight object
+    extern "C" void* DirectionalLight_create() {
+        DirectionalLight* self = (DirectionalLight *) alignedUSMMalloc(sizeof(DirectionalLight), 16);
+        Light_Constructor(&self->super);
+        //self->super.sample = GET_FUNCTION_POINTER(DirectionalLight_sample);
+        //self->super.eval = GET_FUNCTION_POINTER(DirectionalLight_eval);
+        self->super.type = LIGHT_DIRECTIONAL;
+
+        DirectionalLight_set(self, Vec3fa(0.f, 0.f, 1.f), Vec3fa(1.f), 1.f);
+        return self;
+    }
+} // namespace embree