Windows: use SetUnhandledExceptionFilter to catch exceptions

This way things like seg faults will no longer cause pbrt to just
silently terminate, which has been fairly confusing behavior...

src/pbrt/pbrt.cpp

@@ -25,8 +25,35 @@
 
 #include <stdlib.h>
 
+#ifdef PBRT_IS_WINDOWS
+#include <Windows.h>
+#endif // PBRT_IS_WINDOWS
+
 namespace pbrt {
 
+#ifdef PBRT_IS_WINDOWS
+static LONG WINAPI handleExceptions(PEXCEPTION_POINTERS info) {
+    switch (info->ExceptionRecord->ExceptionCode) { 
+    case EXCEPTION_ACCESS_VIOLATION:
+        LOG_ERROR("Access violation--terminating execution");
+        break;
+    case EXCEPTION_ARRAY_BOUNDS_EXCEEDED:
+        LOG_ERROR("Array bounds violation--terminating execution");
+        break;
+    case EXCEPTION_DATATYPE_MISALIGNMENT:
+        LOG_ERROR("Accessed misaligned data--terminating execution");
+        break;
+    case EXCEPTION_STACK_OVERFLOW:
+        LOG_ERROR("Stack overflow--terminating execution");
+        break;
+    default:
+        LOG_ERROR("Program generated exception %d--terminating execution",
+                  int(info->ExceptionRecord->ExceptionCode));
+    }
+    return EXCEPTION_EXECUTE_HANDLER;
+}
+#endif // PBRT_IS_WINDOWS
+
 // API Function Definitions
 void InitPBRT(const PBRTOptions &opt) {
     Options = new PBRTOptions(opt);
@@ -34,7 +61,9 @@ void InitPBRT(const PBRTOptions &opt) {
 
     Imf::setGlobalThreadCount(opt.nThreads ? opt.nThreads : AvailableCores());
 
-#if defined(PBRT_IS_WINDOWS) && defined(PBRT_BUILD_GPU_RENDERER)
+#if defined(PBRT_IS_WINDOWS)
+    SetUnhandledExceptionFilter(handleExceptions);
+#if defined(PBRT_BUILD_GPU_RENDERER)
     if (Options->useGPU && Options->gpuDevice && !getenv("CUDA_VISIBLE_DEVICES")) {
         // Limit CUDA to considering only a single GPU on Windows.  pbrt
         // only uses a single GPU anyway, and if there are multiple GPUs
@@ -47,7 +76,8 @@ void InitPBRT(const PBRTOptions &opt) {
         // is the one to use.
         *Options->gpuDevice = 0;
     }
-#endif  // PBRT_IS_WINDOWS && PBRT_BUILD_GPU_RENDERER
+#endif  // PBRT_BUILD_GPU_RENDERER
+#endif  // PBRT_IS_WINDOWS
 
     if (Options->quiet)
         SuppressErrorMessages();