feat: Add better error messages for conversion fail and file-not-found

src/cli/action_convert.cpp

@@ -344,7 +344,11 @@ bool ActionConvert::process_file(
 	}
 	// Add standard image data
 	else if (!add_image_data(srcFile, vtfFile.get(), procFormat, true)) {
-		std::cerr << "Could not add image data from file " << srcFile << "\n";
+		if (!std::filesystem::exists(srcFile)) {
+			std::cerr << "Could not open " << srcFile << ", file does not exist\n";
+		} else {
+			std::cerr << "Could not add image data from file " << srcFile << "\n";
+		}
 		return false;
 	}
 
@@ -583,7 +587,8 @@ bool ActionConvert::add_image_data_raw(
 	// This is done here because we don't actually know w/h until now
 	if (create) {
 		if (!file->Init(w, h, 1, 1, 1, format, vlTrue, m_mips)) {
-			std::cerr << "Could not create VTF.\n";
+			// +7 so we do not print `Error:\n`, which destroys the formatting
+			std::cerr << "Could not create VTF: " << LastError.Get() + 7 << "\n";
 			free(dest);
 			return false;
 		}