Add Film::ResetPixel() method

src/pbrt/base/film.h

@@ -50,6 +50,7 @@ class Film : public TaggedPointer<RGBFilm, GBufferFilm, SpectralFilm> {
                                         const SampledWavelengths &lambda) const;
 
     Image GetImage(ImageMetadata *metadata, Float splatScale = 1);
+
     PBRT_CPU_GPU
     RGB GetPixelRGB(Point2i p, Float splatScale = 1) const;
 
@@ -64,6 +65,8 @@ class Film : public TaggedPointer<RGBFilm, GBufferFilm, SpectralFilm> {
                        Filter filter, const FileLoc *loc, Allocator alloc);
 
     std::string ToString() const;
+
+    PBRT_CPU_GPU inline void ResetPixel(Point2i p);
 };
 
 }  // namespace pbrt

src/pbrt/film.h

@@ -295,6 +295,10 @@ class RGBFilm : public FilmBase {
         return outputRGBFromSensorRGB * sensorRGB;
     }
 
+    PBRT_CPU_GPU void ResetPixel(Point2i p) {
+        std::memset(&pixels[p], 0, sizeof(Pixel));
+    }
+
   private:
     // RGBFilm::Pixel Definition
     struct Pixel {
@@ -367,6 +371,10 @@ class GBufferFilm : public FilmBase {
 
     std::string ToString() const;
 
+    PBRT_CPU_GPU void ResetPixel(Point2i p) {
+        std::memset(&pixels[p], 0, sizeof(Pixel));
+    }
+
   private:
     // GBufferFilm::Pixel Definition
     struct Pixel {
@@ -482,6 +490,16 @@ class SpectralFilm : public FilmBase {
         return {};
     }
 
+    PBRT_CPU_GPU void ResetPixel(Point2i p) {
+        Pixel &pix = pixels[p];
+        pix.rgbSum[0] = pix.rgbSum[1] = pix.rgbSum[2] = 0.;
+        pix.rgbWeightSum = 0.;
+        pix.rgbSplat[0] = pix.rgbSplat[1] = pix.rgbSplat[2] = 0.;
+        std::memset(pix.bucketSums, 0, nBuckets *sizeof(double));
+        std::memset(pix.weightSums, 0, nBuckets *sizeof(double));
+        std::memset(pix.bucketSplats, 0, nBuckets * sizeof(AtomicDouble));
+    }
+
   private:
     PBRT_CPU_GPU
     int LambdaToBucket(Float lambda) const {
@@ -584,6 +602,12 @@ inline const PixelSensor *Film::GetPixelSensor() const {
     return Dispatch(filter);
 }
 
+PBRT_CPU_GPU
+inline void Film::ResetPixel(Point2i p) {
+    auto rp = [&](auto ptr) { ptr->ResetPixel(p); };
+    return Dispatch(rp);
+}
+
 }  // namespace pbrt
 
 #endif  // PBRT_FILM_H