Fixed perspective camera

Author: leroyvn

src/sensors/perspective.cpp

@@ -57,7 +57,7 @@ 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.
 
@@ -161,7 +161,10 @@ class PerspectiveCamera final : public ProjectiveCamera<Float, Spectrum> {
                 sample_wavelength<Float, Spectrum>(wavelength_sample);
         } else {
             std::tie(wavelengths, wav_weight) = 
-                m_srf->sample_spectrum(zero<SurfaceInteraction3f>(), wavelength_sample);
+                m_srf->sample_spectrum(
+                    zero<SurfaceInteraction3f>(), 
+                    math::sample_shifted<Wavelength>(wavelength_sample)
+                );
         }
 
         Ray3f ray;

src/sensors/tests/test_perspective.py

@@ -184,8 +184,9 @@ def check_fov(camera, sample):
 }
 
 
+@pytest.mark.parametrize("ray_differential", [False, True])
 @pytest.mark.parametrize("srf", list(srf_dict.keys()))
-def test_srf(variant_scalar_spectral, srf):
+def test_srf(variant_scalar_spectral, ray_differential, srf):
     # Test the spectral response function specification feature
     from mitsuba.core.xml import load_dict
     from mitsuba.core import sample_shifted
@@ -201,13 +202,11 @@ def test_srf(variant_scalar_spectral, srf):
     wav_sample = 0.5
     pos_sample = [0.2, 0.6]
 
-    ray, spec_weight = camera.sample_ray_differential(
-        time, wav_sample, pos_sample, 0)
+    sample_func = camera.sample_ray_differential if ray_differential else camera.sample_ray
+    ray, spec_weight = sample_func(time, wav_sample, pos_sample, 0)
 
     # Importance sample wavelength and weight
-    print(sample_shifted(wav_sample))
     wav, wav_weight = srf.sample_spectrum(SurfaceInteraction3f(), sample_shifted(wav_sample))
-    print(wav)
-
+    
     assert ek.allclose(ray.wavelengths, wav)
     assert ek.allclose(spec_weight, wav_weight)