Optics: cache pixel-area Moffat kernels

src/optics.h

@@ -1,20 +1,57 @@
 #ifndef OPTICS_H
 #define OPTICS_H
 
+#include <stddef.h>
+#include <stdio.h>
+
 typedef struct { double r, g, b; } LinearRgb;
 typedef struct {
   double fwhm_pixels;
   double moffat_beta;
 } PointSpreadFunction;
 
+/* One immutable process-wide kernel for the one PSF parameter pair accepted
+ * by the current renderer.  Its storage remains private to optics.c. */
+typedef struct {
+  double fwhm_pixels, moffat_beta, alpha_pixels;
+  double max_radius_pixels, build_seconds;
+  float *weights;
+  int phase_resolution, radius_pixels;
+  int ready;
+} PsfKernelCache;
+
+typedef struct {
+  size_t cached_splats;
+  size_t direct_fallbacks;
+} PsfSplatStats;
+
 /* Integrate a Planck spectrum into absolute linear-sRGB spectral radiance
  * (W m^-2 sr^-1), before catalog amplitude and display exposure. */
 LinearRgb blackbody_to_linear_rgb(double temperature_K);
+int psf_kernel_cache_init(PsfKernelCache *cache,
+                          const PointSpreadFunction *psf);
+void psf_kernel_cache_destroy(PsfKernelCache *cache);
+void psf_kernel_cache_report(const PsfKernelCache *cache,
+                             const PsfSplatStats *stats, FILE *stream);
+/* Reference implementation: pixel-area-integrated Moffat with the same tail
+ * budgets as the cache-aware renderer. */
+void splat_moffat_direct(double *hdr, int width, int height, double x, double y,
+                         LinearRgb color, double flux,
+                         const PointSpreadFunction *psf);
 void splat_moffat(double *hdr, int width, int height, double x, double y,
                   LinearRgb color, double flux,
                   const PointSpreadFunction *psf);
+/* Returns nonzero when this event used the direct reference fallback. */
+int splat_moffat_cached(double *hdr, int width, int height, double x, double y,
+                        LinearRgb color, double flux,
+                        const PointSpreadFunction *psf,
+                        const PsfKernelCache *cache);
 /* Writes PNG when built with libpng; non-libpng builds use PPM fallback. */
 int write_tonemapped_image(const char *path, const double *hdr, int width,
                            int height);
+#ifdef ENABLE_HDR_DEBUG
+/* Test-build-only: writes the pre-tone-mapping framebuffer as RGB float PFM. */
+int write_hdr_pfm(const char *path, const double *hdr, int width, int height);
+#endif
 
 #endif