Add support for png and ktx image files for custom skybox (fixes #877)

app/src/main/cpp/BrowserWorld.cpp

@@ -510,7 +510,13 @@ BrowserWorld::InitializeJava(JNIEnv* aEnv, jobject& aActivity, jobject& aAssetMa
       std::string storagePath = VRBrowser::GetStorageAbsolutePath(INJECT_SKYBOX_PATH);
       if (std::ifstream(storagePath)) {
         skyboxPath = storagePath;
-        extension = ".jpg";
+        extension = Skybox::ValidateCustomSkyboxAndFindFileExtension(storagePath);
+        if (!extension.empty()) {
+          skyboxPath = storagePath;
+          VRB_DEBUG("Found custom skybox file extension: %s", extension.c_str());
+        } else {
+          VRB_ERROR("Failed to find custom skybox files.");
+        }
       }
     }
 #if !defined(SNAPDRAGONVR)

app/src/main/cpp/Skybox.cpp

@@ -20,11 +20,26 @@
 #include "vrb/VertexArray.h"
 
 #include <array>
+#include <list>
+#include <sys/stat.h>
 
 using namespace vrb;
 
 namespace crow {
 
+static const std::string sPosx = "posx";
+static const std::string sNegx = "negx";
+static const std::string sPosy = "posy";
+static const std::string sNegy = "negy";
+static const std::string sPosz = "posz";
+static const std::string sNegz = "negz";
+static const std::list<std::string> sBaseNameList = std::list<std::string>({
+    sPosx, sNegx, sPosy, sNegy, sPosz, sNegz
+});
+static const std::list<std::string> sFileExt = std::list<std::string>({
+    ".ktx", ".jpg", ".png"
+});
+
 static TextureCubeMapPtr LoadTextureCube(vrb::CreationContextPtr& aContext, const std::string& aBasePath,
                                          const std::string& aExtension, GLuint targetTexture = 0) {
   TextureCubeMapPtr cubemap = vrb::TextureCubeMap::Create(aContext, targetTexture);
@@ -35,8 +50,8 @@ static TextureCubeMapPtr LoadTextureCube(vrb::CreationContextPtr& aContext, cons
   cubemap->SetTextureParameter(GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
 
   auto path = [&](const std::string &name) { return aBasePath + "/" + name + aExtension; };
-  vrb::TextureCubeMap::Load(aContext, cubemap, path("posx"), path("negx"), path("posy"),
-                            path("negy"), path("posz"), path("negz"));
+  vrb::TextureCubeMap::Load(aContext, cubemap, path(sPosx), path(sNegx), path(sPosy),
+                            path(sNegy), path(sPosz), path(sNegz));
   return cubemap;
 }
 
@@ -185,6 +200,33 @@ Skybox::GetRoot() const {
   return m.root;
 }
 
+static bool
+FileDoesNotExist (const std::string& aName) {
+  struct stat buffer;
+  return (stat(aName.c_str(), &buffer) != 0);
+}
+
+std::string
+Skybox::ValidateCustomSkyboxAndFindFileExtension(const std::string& aBasePath) {
+  for (const std::string& ext: sFileExt) {
+     int32_t fileCount = 0;
+     for (const std::string& baseName: sBaseNameList) {
+       const std::string file = aBasePath + "/" + baseName + ext;
+       if (FileDoesNotExist(file)) {
+         if (fileCount > 0) {
+           VRB_ERROR("Custom skybox file missing: %s", file.c_str());
+         }
+         break;
+       }
+       fileCount++;
+     }
+     if (fileCount == sBaseNameList.size()) {
+       return ext;
+     }
+  }
+
+  return std::string();
+}
 
 SkyboxPtr
 Skybox::Create(vrb::CreationContextPtr aContext, const VRLayerCubePtr& aLayer) {

app/src/main/cpp/Skybox.h

@@ -19,6 +19,7 @@ typedef std::shared_ptr<VRLayerCube> VRLayerCubePtr;
 
 class Skybox {
 public:
+  static std::string ValidateCustomSkyboxAndFindFileExtension(const std::string& aBasePath);
   static SkyboxPtr Create(vrb::CreationContextPtr aContext, const VRLayerCubePtr& aLayer = nullptr);
   void Load(const vrb::ModelLoaderAndroidPtr& aLoader, const std::string& aBasePath, const std::string& aExtension);
   void SetVisible(bool aVisible);