Updated test_perspective.py

Ported test_irradiancemeter.py

Ported test_radiancemeter.py

Ported test_thinlens.py

Partially revert "Updated test_perspective.py"

This reverts formatting changes in commit caf2198.

Autopep8 and isort pass

Updated perspective plugin and tests with SRF support

Added flexible spectral range and default value to uniform spectrum plugin

Fixes after rebase and ported tests to dict API

Fixed perspective camera

Added SRF to radiancemeter

Added SRF to irradiancemeter plugin

Updated plugin docs

Docs update and minor fixes to uniform spectrum plugin

Minor fix to uniform spectrum

Author: leroyvn

src/sensors/irradiancemeter.cpp

@@ -4,6 +4,7 @@
 #include <mitsuba/core/warp.h>
 #include <mitsuba/render/fwd.h>
 #include <mitsuba/render/sensor.h>
+#include <mitsuba/render/texture.h>
 
 NAMESPACE_BEGIN(mitsuba)
 
@@ -16,7 +17,10 @@ Irradiance meter (:monosp:`irradiancemeter`)
 
 .. pluginparameters::
 
- * - none
+ * - srf
+   - |spectrum|
+   - If set, sensor response function used to sample wavelengths from. This 
+     parameter is ignored if used with nonspectral variants.
 
 This sensor plugin implements an irradiance meter, which measures
 the incident power per unit area over a shape which it is attached to.
@@ -43,9 +47,18 @@ simply instantiate the desired sensor shape and specify an
 MTS_VARIANT class IrradianceMeter final : public Sensor<Float, Spectrum> {
 public:
     MTS_IMPORT_BASE(Sensor, m_film, m_world_transform, m_shape)
-    MTS_IMPORT_TYPES(Shape)
-
-    IrradianceMeter(const Properties &props) : Base(props) {
+    MTS_IMPORT_TYPES(Shape, Texture)
+
+    IrradianceMeter(const Properties &props) : Base(props), m_srf(nullptr) {
+        if (props.has_property("srf")) {
+            if constexpr(is_spectral_v<Spectrum>) {
+                m_srf = props.texture<Texture>("srf");
+            } else {
+                Log(Warn, "Ignoring spectral response function "
+                          "(not supported for non-spectral variants)");
+            }
+        }
+        
         if (props.has_property("to_world"))
             Throw("Found a 'to_world' transformation -- this is not allowed. "
                   "The irradiance meter inherits this transformation from its parent "
@@ -75,7 +88,19 @@ MTS_VARIANT class IrradianceMeter final : public Sensor<Float, Spectrum> {
         Vector3f local = warp::square_to_cosine_hemisphere(sample3);
 
         // 3. Sample spectrum
-        auto [wavelengths, wav_weight] = sample_wavelength<Float, Spectrum>(wavelength_sample);
+        Wavelength wavelengths;
+        Spectrum wav_weight;
+        
+        if (m_srf == nullptr) {
+            std::tie(wavelengths, wav_weight) = 
+                sample_wavelength<Float, Spectrum>(wavelength_sample);
+        } else {
+            std::tie(wavelengths, wav_weight) = 
+                m_srf->sample_spectrum(
+                    zero<SurfaceInteraction3f>(), 
+                    math::sample_shifted<Wavelength>(wavelength_sample)
+                );
+        }
 
         return std::make_pair(
             RayDifferential3f(ps.p, Frame3f(ps.n).to_world(local), time, wavelengths),
@@ -109,6 +134,8 @@ MTS_VARIANT class IrradianceMeter final : public Sensor<Float, Spectrum> {
     }
 
     MTS_DECLARE_CLASS()
+private:
+    ref<Texture> m_srf;
 };
 
 MTS_IMPLEMENT_CLASS_VARIANT(IrradianceMeter, Sensor)

src/sensors/perspective.cpp

@@ -2,6 +2,7 @@
 #include <mitsuba/core/properties.h>
 #include <mitsuba/core/transform.h>
 #include <mitsuba/core/bbox.h>
+#include <mitsuba/render/texture.h>
 
 NAMESPACE_BEGIN(mitsuba)
 
@@ -47,6 +48,10 @@ Perspective pinhole camera (:monosp:`perspective`)
    - |float|
    - Distance to the near/far clip planes. (Default: :monosp:`near_clip=1e-2` (i.e. :monosp:`0.01`)
      and :monosp:`far_clip=1e4` (i.e. :monosp:`10000`))
+ * - srf
+   - |spectrum|
+   - If set, sensor response function used to sample wavelengths from. This parameter is ignored if 
+     used with nonspectral variants.
 
 .. subfigstart::
 .. subfigure:: ../../resources/data/docs/images/render/sensor_perspective.jpg
@@ -56,7 +61,7 @@ Perspective pinhole camera (:monosp:`perspective`)
 .. subfigend::
    :label: fig-perspective
 
-This plugin implements a simple idealizied perspective camera model, which
+This plugin implements a simple idealized perspective camera model, which
 has an infinitely small aperture. This creates an infinite depth of field,
 i.e. no optical blurring occurs.
 
@@ -89,19 +94,27 @@ class PerspectiveCamera final : public ProjectiveCamera<Float, Spectrum> {
     MTS_IMPORT_BASE(ProjectiveCamera, m_world_transform, m_needs_sample_3,
                     m_film, m_sampler, m_resolution, m_shutter_open,
                     m_shutter_open_time, m_near_clip, m_far_clip)
-    MTS_IMPORT_TYPES()
+    MTS_IMPORT_TYPES(Texture)
 
     // =============================================================
     //! @{ \name Constructors
     // =============================================================
 
-    PerspectiveCamera(const Properties &props) : Base(props) {
+    PerspectiveCamera(const Properties &props) : Base(props), m_srf(nullptr) {
         ScalarVector2i size = m_film->size();
         m_x_fov = parse_fov(props, size.x() / (float) size.y());
 
         if (m_world_transform->has_scale())
             Throw("Scale factors in the camera-to-world transformation are not allowed!");
 
+        if (props.has_property("srf")) {
+            if constexpr(is_spectral_v<Spectrum>) {
+                m_srf = props.texture<Texture>("srf");
+            } else {
+                Log(Warn, "Ignoring spectral response function (not supported for non-spectral variants)");
+            }
+        }
+
         update_camera_transforms();
     }
 
@@ -143,7 +156,21 @@ class PerspectiveCamera final : public ProjectiveCamera<Float, Spectrum> {
                                           Mask active) const override {
         MTS_MASKED_FUNCTION(ProfilerPhase::EndpointSampleRay, active);
 
-        auto [wavelengths, wav_weight] = sample_wavelength<Float, Spectrum>(wavelength_sample);
+        // Sample spectrum
+        Wavelength wavelengths;
+        Spectrum wav_weight;
+        
+        if (m_srf == nullptr) {
+            std::tie(wavelengths, wav_weight) = 
+                sample_wavelength<Float, Spectrum>(wavelength_sample);
+        } else {
+            std::tie(wavelengths, wav_weight) = 
+                m_srf->sample_spectrum(
+                    zero<SurfaceInteraction3f>(), 
+                    math::sample_shifted<Wavelength>(wavelength_sample)
+                );
+        }
+
         Ray3f ray;
         ray.time = time;
         ray.wavelengths = wavelengths;
@@ -171,8 +198,22 @@ class PerspectiveCamera final : public ProjectiveCamera<Float, Spectrum> {
     sample_ray_differential(Float time, Float wavelength_sample, const Point2f &position_sample,
                             const Point2f & /*aperture_sample*/, Mask active) const override {
         MTS_MASKED_FUNCTION(ProfilerPhase::EndpointSampleRay, active);
-
-        auto [wavelengths, wav_weight] = sample_wavelength<Float, Spectrum>(wavelength_sample);
+        
+        // Sample spectrum
+        Wavelength wavelengths;
+        Spectrum wav_weight;
+        
+        if (m_srf == nullptr) {
+            std::tie(wavelengths, wav_weight) = 
+                sample_wavelength<Float, Spectrum>(wavelength_sample);
+        } else {
+            std::tie(wavelengths, wav_weight) = 
+                m_srf->sample_spectrum(
+                    zero<SurfaceInteraction3f>(), 
+                    math::sample_shifted<Wavelength>(wavelength_sample)
+                );
+        }
+                                         
         RayDifferential3f ray;
         ray.time = time;
         ray.wavelengths = wavelengths;
@@ -291,6 +332,7 @@ class PerspectiveCamera final : public ProjectiveCamera<Float, Spectrum> {
             << "  shutter_open = " << m_shutter_open << "," << std::endl
             << "  shutter_open_time = " << m_shutter_open_time << "," << std::endl
             << "  world_transform = " << indent(m_world_transform) << std::endl
+            << "  srf = " << indent(m_srf)  << std::endl
             << "]";
         return oss.str();
     }
@@ -303,6 +345,7 @@ class PerspectiveCamera final : public ProjectiveCamera<Float, Spectrum> {
     ScalarFloat m_normalization;
     ScalarFloat m_x_fov;
     ScalarVector3f m_dx, m_dy;
+    ref<Texture> m_srf;
 };
 
 MTS_IMPLEMENT_CLASS_VARIANT(PerspectiveCamera, ProjectiveCamera)

src/sensors/radiancemeter.cpp

@@ -3,6 +3,7 @@
 #include <mitsuba/core/transform.h>
 #include <mitsuba/render/fwd.h>
 #include <mitsuba/render/sensor.h>
+#include <mitsuba/render/texture.h>
 
 NAMESPACE_BEGIN(mitsuba)
 
@@ -27,6 +28,10 @@ Radiance meter (:monosp:`radiancemeter`)
    - |vector|
    - Alternative (and exclusive) to `to_world`. Direction in which the
      sensor is pointing in world coordinates. Must be used with `origin`.
+ * - srf
+   - |spectrum|
+   - If set, sensor response function used to sample wavelengths from. This 
+     parameter is ignored if used with nonspectral variants.
 
 This sensor plugin implements a simple radiance meter, which measures
 the incident power per unit area per unit solid angle along a
@@ -46,13 +51,23 @@ priority.
 
 */
 
-MTS_VARIANT class RadianceMeter final : public Sensor<Float, Spectrum> {
+template <typename Float, typename Spectrum>
+class RadianceMeter final : public Sensor<Float, Spectrum> {
 public:
     MTS_IMPORT_BASE(Sensor, m_film, m_world_transform, m_needs_sample_2,
                     m_needs_sample_3)
-    MTS_IMPORT_TYPES()
+    MTS_IMPORT_TYPES(Texture)
+
+    RadianceMeter(const Properties &props) : Base(props), m_srf(nullptr) {
+        if (props.has_property("srf")) {
+            if constexpr(is_spectral_v<Spectrum>) {
+                m_srf = props.texture<Texture>("srf");
+            } else {
+                Log(Warn, "Ignoring spectral response function "
+                          "(not supported for non-spectral variants)");
+            }
+        }
 
-    RadianceMeter(const Properties &props) : Base(props) {
         if (props.has_property("to_world")) {
             // if direction and origin are present but overridden by
             // to_world, they must still be marked as queried
@@ -93,22 +108,34 @@ MTS_VARIANT class RadianceMeter final : public Sensor<Float, Spectrum> {
                                           const Point2f & /*aperture_sample*/,
                                           Mask active) const override {
         MTS_MASKED_FUNCTION(ProfilerPhase::EndpointSampleRay, active);
+        
+        // 1. Sample spectrum
+        Wavelength wavelengths;
+        Spectrum wav_weight;
+        
+        if (m_srf == nullptr) {
+            std::tie(wavelengths, wav_weight) = 
+                sample_wavelength<Float, Spectrum>(wavelength_sample);
+        } else {
+            std::tie(wavelengths, wav_weight) = 
+                m_srf->sample_spectrum(
+                    zero<SurfaceInteraction3f>(), 
+                    math::sample_shifted<Wavelength>(wavelength_sample)
+                );
+        }
+
+        // 2. Set ray origin and direction
         Ray3f ray;
         ray.time = time;
-
-        // 1. Sample spectrum
-        auto [wavelengths, wav_weight] =
-            sample_wavelength<Float, Spectrum>(wavelength_sample);
         ray.wavelengths = wavelengths;
 
-        // 2. Set ray origin and direction
         auto trafo = m_world_transform->eval(time, active);
         ray.o      = trafo.transform_affine(Point3f{ 0.f, 0.f, 0.f });
         ray.d      = trafo.transform_affine(Vector3f{ 0.f, 0.f, 1.f });
 
         ray.update();
 
-        return std::make_pair(ray, wav_weight);
+        return { ray, wav_weight };
     }
 
     std::pair<RayDifferential3f, Spectrum>
@@ -117,15 +144,26 @@ MTS_VARIANT class RadianceMeter final : public Sensor<Float, Spectrum> {
                             const Point2f & /*aperture_sample*/,
                             Mask active) const override {
         MTS_MASKED_FUNCTION(ProfilerPhase::EndpointSampleRay, active);
+        // 1. Sample spectrum
+        Wavelength wavelengths;
+        Spectrum wav_weight;
+        
+        if (m_srf == nullptr) {
+            std::tie(wavelengths, wav_weight) = 
+                sample_wavelength<Float, Spectrum>(wavelength_sample);
+        } else {
+            std::tie(wavelengths, wav_weight) = 
+                m_srf->sample_spectrum(
+                    zero<SurfaceInteraction3f>(), 
+                    math::sample_shifted<Wavelength>(wavelength_sample)
+                );
+        }
+
+        // 2. Set ray origin and direction
         RayDifferential3f ray;
         ray.time = time;
-
-        // 1. Sample spectrum
-        auto [wavelengths, wav_weight] =
-            sample_wavelength<Float, Spectrum>(wavelength_sample);
         ray.wavelengths = wavelengths;
 
-        // 2. Set ray origin and direction
         auto trafo = m_world_transform->eval(time, active);
         ray.o      = trafo.transform_affine(Point3f{ 0.f, 0.f, 0.f });
         ray.d      = trafo.transform_affine(Vector3f{ 0.f, 0.f, 1.f });
@@ -136,7 +174,7 @@ MTS_VARIANT class RadianceMeter final : public Sensor<Float, Spectrum> {
 
         ray.update();
 
-        return std::make_pair(ray, wav_weight);
+        return { ray, wav_weight };
     }
 
     ScalarBoundingBox3f bbox() const override {
@@ -145,15 +183,20 @@ MTS_VARIANT class RadianceMeter final : public Sensor<Float, Spectrum> {
     }
 
     std::string to_string() const override {
+        using string::indent;
+        
         std::ostringstream oss;
         oss << "RadianceMeter[" << std::endl
             << "  world_transform = " << m_world_transform << "," << std::endl
             << "  film = " << m_film << "," << std::endl
+            << "  srf = " << indent(m_srf)  << std::endl
             << "]";
         return oss.str();
     }
 
     MTS_DECLARE_CLASS()
+private:
+    ref<Texture> m_srf;
 };
 
 MTS_IMPLEMENT_CLASS_VARIANT(RadianceMeter, Sensor)