Spectral mode: fix accidental conversion to double

The multiplication with a double-typed constant lead to a float -> double -> float round-trip, which breaks the AD graph. It was only triggered in spectral modes.
mitsuba-renderer · Dec 7, 2022 · f3ac81b · f3ac81b
1 parent 9bd47c7
commit f3ac81b
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/include/mitsuba/core/spectrum.h b/include/mitsuba/core/spectrum.h
@@ -373,7 +373,7 @@ Color<Float, 3> spectrum_to_xyz(const Spectrum<Float, Size> &value,
     Color<Float, 3> res = { dr::mean(XYZ.x() * value),
                             dr::mean(XYZ.y() * value),
                             dr::mean(XYZ.z() * value) };
-    return res * MI_CIE_Y_NORMALIZATION;
+    return res * (dr::scalar_t<Float>) MI_CIE_Y_NORMALIZATION;
 }
 
 /**
@@ -388,7 +388,7 @@ Color<Float, 3> spectrum_to_srgb(const Spectrum<Float, Size> &value,
     Color<Float, 3> res = { dr::mean(rgb.x() * value),
                             dr::mean(rgb.y() * value),
                             dr::mean(rgb.z() * value) };
-    return res * MI_CIE_Y_NORMALIZATION;
+    return res * (dr::scalar_t<Float>) MI_CIE_Y_NORMALIZATION;
 }
 
 /// Convert ITU-R Rec. BT.709 linear RGB to XYZ tristimulus values