Now signing our exr snapshots.

src/SDL/EXRSnapshotSupport/OOSaveEXRSnapshot.cpp

@@ -1,5 +1,6 @@
 #include <cstdio>
 #include <cstdlib>
+#include <ctime>
 #include <vector>
 
 extern "C" {
@@ -44,6 +45,21 @@ int SaveEXRSnapshot(const char* outfilename, int width, int height, const float*
 	header.num_channels = 3;
 	header.compression_type = TINYEXR_COMPRESSIONTYPE_ZIP;
 	header.channels = (EXRChannelInfo *)malloc(sizeof(EXRChannelInfo) * header.num_channels); 
+
+	// sign our snapshot
+	header.num_custom_attributes = 1;
+	header.custom_attributes = static_cast<EXRAttribute *>(malloc(sizeof(EXRAttribute)));
+	strncpy(header.custom_attributes[0].name, "signature", 255);
+	strncpy(header.custom_attributes[0].type, "string", 255);
+	std::time_t timestamp;
+	std::time(&timestamp);
+	char signatureStringIntro[255] = "Generated by Oolite ";
+	char *signatureString = strcat(signatureStringIntro, std::ctime(&timestamp));
+	// ctime adds a newline at the end of the string, strip it
+	signatureString[strlen(signatureString) - 1] = '\0';
+	header.custom_attributes[0].value = reinterpret_cast<uint8_t *>(signatureString);
+	header.custom_attributes[0].size  = strlen(signatureString);
+
 	// Must be BGR(A) order, since most of EXR viewers expect this channel order.
 	strncpy(header.channels[0].name, "B", 255); header.channels[0].name[strlen("B")] = '\0';
 	strncpy(header.channels[1].name, "G", 255); header.channels[1].name[strlen("G")] = '\0';