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Added distant sensor plugin
Co-authored-by: Sebastian Schunke <[email protected]>
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‎src/librender/scene.cpp‎

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@@ -96,6 +96,10 @@ MTS_VARIANT Scene<Float, Spectrum>::Scene(const Properties &props) {
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// Create emitters' shapes (environment luminaires)
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for (Emitter *emitter: m_emitters)
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emitter->set_scene(this);
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// Create sensors' shapes (environment sensors)
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for (Sensor *sensor: m_sensors)
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sensor->set_scene(this);
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}
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MTS_VARIANT Scene<Float, Spectrum>::~Scene() {

‎src/sensors/CMakeLists.txt‎

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@@ -4,6 +4,7 @@ add_plugin(perspective perspective.cpp)
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add_plugin(radiancemeter radiancemeter.cpp)
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add_plugin(thinlens thinlens.cpp)
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add_plugin(irradiancemeter irradiancemeter.cpp)
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add_plugin(distant distant.cpp)
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# Register the test directory
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add_tests(${CMAKE_CURRENT_SOURCE_DIR}/tests)

‎src/sensors/distant.cpp‎

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#include <mitsuba/core/bbox.h>
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#include <mitsuba/core/bsphere.h>
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#include <mitsuba/core/math.h>
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#include <mitsuba/core/properties.h>
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#include <mitsuba/core/transform.h>
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#include <mitsuba/core/warp.h>
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#include <mitsuba/render/scene.h>
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#include <mitsuba/render/sensor.h>
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NAMESPACE_BEGIN(mitsuba)
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/**!
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.. _sensor-distant:
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Distant directional sensor (:monosp:`distant`)
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----------------------------------------------
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.. pluginparameters::
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* - to_world
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- |transform|
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- Sensor-to-world transformation matrix.
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* - direction
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- |vector|
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- Alternative (and exclusive) to `to_world`. Direction from which the
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sensor will be recording in world coordinates.
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* - target
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- |point|
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- *Optional.* Point (in world coordinates) to which sampled rays will be
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cast. Useful for one-dimensional scenes. If unset, rays will be cast
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uniformly over the entire scene.
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This sensor plugin implements a distant directional sensor which records
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radiation leaving the scene in a given direction. If the ``target`` parameter
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is not set, rays cast by the sensor will be distributed uniformly on the cross
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section of the scene's bounding sphere.
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*/
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MTS_VARIANT class DistantSensor final : public Sensor<Float, Spectrum> {
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public:
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MTS_IMPORT_BASE(Sensor, m_world_transform, m_needs_sample_3, m_film)
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MTS_IMPORT_TYPES(Scene)
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DistantSensor(const Properties &props) : Base(props) {
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/* Until `set_scene` is called, we have no information
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about the scene and default to the unit bounding sphere. */
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m_bsphere = ScalarBoundingSphere3f(ScalarPoint3f(0.f), 1.f);
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if (props.has_property("direction")) {
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if (props.has_property("to_world"))
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Throw("Only one of the parameters 'direction' and 'to_world' "
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"can be specified at the same time!'");
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ScalarVector3f direction(normalize(props.vector3f("direction")));
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auto [up, unused] = coordinate_system(direction);
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m_world_transform =
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new AnimatedTransform(ScalarTransform4f::look_at(
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ScalarPoint3f(0.0f), ScalarPoint3f(direction), up));
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}
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if (props.has_property("target")) {
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m_target = props.point3f("target");
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m_has_target = true;
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Log(Debug, "Targeting point %s", m_target);
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} else {
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m_has_target = false;
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}
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if (m_film->size() != ScalarPoint2i(1, 1))
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Throw("This sensor only supports films of size 1x1 Pixels!");
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if (m_film->reconstruction_filter()->radius() >
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0.5f + math::RayEpsilon<Float>)
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Log(Warn, "This sensor should be used with a reconstruction filter "
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"with a radius of 0.5 or lower (e.g. default box)");
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m_needs_sample_3 = false;
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}
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void set_scene(const Scene *scene) override {
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m_bsphere = scene->bbox().bounding_sphere();
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m_bsphere.radius =
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max(math::RayEpsilon<Float>,
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m_bsphere.radius * (1.f + math::RayEpsilon<Float>) );
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}
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std::pair<Ray3f, Spectrum> sample_ray(Float time, Float wavelength_sample,
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const Point2f &spatial_sample,
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const Point2f & /*direction_sample*/,
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Mask active) const override {
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MTS_MASKED_FUNCTION(ProfilerPhase::EndpointSampleRay, active);
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Ray3f ray;
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ray.time = time;
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// 1. Sample spectrum
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auto [wavelengths, wav_weight] =
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sample_wavelength<Float, Spectrum>(wavelength_sample);
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ray.wavelengths = wavelengths;
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// 2. Set ray direction
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auto trafo = m_world_transform->eval(time, active);
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ray.d = trafo.transform_affine(Vector3f{ 0.f, 0.f, 1.f });
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// 3. Sample ray origin
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if (!m_has_target) {
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// If no target point is defined, sample a target point on the
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// bounding sphere's cross section
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Point2f offset =
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warp::square_to_uniform_disk_concentric(spatial_sample);
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Vector3f perp_offset =
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trafo.transform_affine(Vector3f{ offset.x(), offset.y(), 0.f });
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ray.o = m_bsphere.center + (perp_offset - ray.d) * m_bsphere.radius;
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} else {
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ray.o = m_target - 2.f * ray.d * m_bsphere.radius;
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}
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ray.update();
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return std::make_pair(
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ray, m_has_target
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? wav_weight
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: wav_weight * (math::Pi<Float> * sqr(m_bsphere.radius)));
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}
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std::pair<RayDifferential3f, Spectrum> sample_ray_differential(
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Float time, Float wavelength_sample, const Point2f &spatial_sample,
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const Point2f & /*direction_sample*/, Mask active) const override {
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MTS_MASKED_FUNCTION(ProfilerPhase::EndpointSampleRay, active);
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RayDifferential3f ray;
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ray.time = time;
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// 1. Sample spectrum
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auto [wavelengths, wav_weight] =
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sample_wavelength<Float, Spectrum>(wavelength_sample);
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ray.wavelengths = wavelengths;
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// 2. Set ray direction
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auto trafo = m_world_transform->eval(time, active);
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ray.d = trafo.transform_affine(Vector3f{ 0.f, 0.f, 1.f });
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// 3. Sample ray origin
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if (!m_has_target) {
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// If no target point is defined, sample a target point on the
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// bounding sphere's cross section
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Point2f offset =
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warp::square_to_uniform_disk_concentric(spatial_sample);
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Vector3f perp_offset =
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trafo.transform_affine(Vector3f{ offset.x(), offset.y(), 0.f });
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ray.o = m_bsphere.center + (perp_offset - ray.d) * m_bsphere.radius;
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} else {
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ray.o = m_target - 2.f * ray.d * m_bsphere.radius;
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}
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// 4. Set differentials; since the film size is always 1x1, we don't
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// have differentials
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ray.has_differentials = false;
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ray.update();
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return std::make_pair(
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ray, m_has_target
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? wav_weight
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: wav_weight * (math::Pi<Float> * sqr(m_bsphere.radius)));
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}
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/// This sensor does not occupy any particular region of space, return an
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/// invalid bounding box
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ScalarBoundingBox3f bbox() const override { return ScalarBoundingBox3f(); }
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std::string to_string() const override {
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std::ostringstream oss;
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oss << "DistantSensor[" << std::endl
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<< " world_transform = " << m_world_transform << "," << std::endl
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<< " bsphere = " << m_bsphere << "," << std::endl
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<< " film = " << m_film << "," << std::endl
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<< "]";
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return oss.str();
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}
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MTS_DECLARE_CLASS()
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protected:
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ScalarBoundingSphere3f m_bsphere;
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ScalarPoint3f m_target;
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bool m_has_target;
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};
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MTS_IMPLEMENT_CLASS_VARIANT(DistantSensor, Sensor)
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MTS_EXPORT_PLUGIN(DistantSensor, "DistantSensor");
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NAMESPACE_END(mitsuba)

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