Copy texture files to output dir when appropriate. (#23)

When we've successfully located a referenced texture image on the local
filesystem and we're generating non-binary, non-embedded output, copy
the source folder wholesale into the destination directory.

This means the output folder is always a full, free-standing deployment,
one that can be dragged into e.g. https://gltf-viewer.donmccurdy.com/

src/Raw2Gltf.cpp

@@ -15,6 +15,7 @@
 #include "FBX2glTF.h"
 #include "utils/String_Utils.h"
 #include "utils/Image_Utils.h"
+#include <utils/File_Utils.h>
 #include "RawModel.h"
 #include "Raw2Gltf.h"
 
@@ -249,6 +250,7 @@ static const std::string materialHash(const RawMaterial &m) {
 
 ModelData *Raw2Gltf(
     std::ofstream &gltfOutStream,
+    const std::string &outputFolder,
     const RawModel &raw,
     const GltfOptions &options
 )
@@ -373,8 +375,18 @@ ModelData *Raw2Gltf(
                     source = new ImageData(relativeFilename, *bufferView, suffixToMimeType(suffix));
                 }
 
-            } else {
+            } else if (!relativeFilename.empty()) {
                 source = new ImageData(relativeFilename, relativeFilename);
+                std::string outputPath = outputFolder + relativeFilename;
+                if (FileUtils::CopyFile(texture.fileLocation, outputPath)) {
+                    if (verboseOutput) {
+                        fmt::printf("Copied texture '%s' to output folder: %s\n", textureName, outputPath);
+                    }
+                } else {
+                    // no point commenting further on read/write error; CopyFile() does enough of that, and we
+                    // certainly want to to add an image struct to the glTF JSON, with the correct relative path
+                    // reference, even if the copy failed.
+                }
             }
             if (!source) {
                 // fallback is tiny transparent gif

src/Raw2Gltf.h

@@ -197,6 +197,7 @@ struct ModelData
 
 ModelData *Raw2Gltf(
     std::ofstream &gltfOutStream,
+    const std::string &outputFolder,
     const RawModel &raw,
     const GltfOptions &options
 );

src/main.cpp

@@ -172,6 +172,7 @@ Copyright (c) 2016-2017 Oculus VR, LLC.
     if (gltfOptions.outputBinary) {
         // in binary mode, we write precisely where we're asked
         modelPath = outputPath + ".glb";
+
     } else {
         // in gltf mode, we create a folder and write into that
         outputFolder = outputPath + "_out/";
@@ -206,7 +207,7 @@ Copyright (c) 2016-2017 Oculus VR, LLC.
         fmt::fprintf(stderr, "ERROR:: Couldn't open file for writing: %s\n", modelPath.c_str());
         return 1;
     }
-    data_render_model = Raw2Gltf(outStream, raw, gltfOptions);
+    data_render_model = Raw2Gltf(outStream, outputFolder, raw, gltfOptions);
 
     if (gltfOptions.outputBinary) {
         fmt::printf(

src/utils/File_Utils.cpp

@@ -9,6 +9,7 @@
 
 #include <string>
 #include <vector>
+#include <fstream>
 
 #include <stdint.h>
 #include <stdio.h>
@@ -174,4 +175,29 @@ namespace FileUtils {
         }
         return true;
     }
+
+    bool CopyFile(const std::string &srcFilename, const std::string &dstFilename) {
+        std::ifstream srcFile(srcFilename, std::ios::binary);
+        if (!srcFile) {
+            fmt::printf("Warning: Couldn't open file %s for reading.\n", srcFilename);
+            return false;
+        }
+        // find source file length
+        srcFile.seekg(0, std::ios::end);
+        std::streamsize srcSize = srcFile.tellg();
+        srcFile.seekg(0, std::ios::beg);
+
+        std::ofstream dstFile(dstFilename, std::ios::binary | std::ios::trunc);
+        if (!dstFile) {
+            fmt::printf("Warning: Couldn't open file %s for writing.\n", srcFilename);
+            return false;
+        }
+        dstFile << srcFile.rdbuf();
+        std::streamsize dstSize = dstFile.tellp();
+        if (srcSize == dstSize) {
+            return true;
+        }
+        fmt::printf("Warning: Only copied %lu bytes to %s, when %s is %lu bytes long.\n", dstSize, dstFilename, srcFilename, srcSize);
+        return false;
+    }
 }

src/utils/File_Utils.h

@@ -19,6 +19,8 @@ namespace FileUtils {
     std::vector<std::string> ListFolderFiles(const char *folder, const char *matchExtensions);
 
     bool CreatePath(const char *path);
+
+    bool CopyFile(const std::string &srcFilename, const std::string &dstFilename);
 }
 
 #endif // !__FILE_UTILS_H__