I'm trying to create VkImageView which will be binded to index 0.
Here is my VkImageView creation code
void Image::createImageView() {
VkImageViewUsageCreateInfo imageViewUsage;
imageViewUsage.sType=VK_STRUCTURE_TYPE_IMAGE_VIEW_USAGE_CREATE_INFO;
imageViewUsage.pNext=nullptr;
imageViewUsage.usage=VK_IMAGE_USAGE_STORAGE_BIT;
VkImageViewCreateInfo viewInfo{};
viewInfo.sType = VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO;
viewInfo.pNext=&imageViewUsage;
viewInfo.image = textureImage;
viewInfo.viewType = VK_IMAGE_VIEW_TYPE_2D;
viewInfo.format = VK_FORMAT_R8G8B8A8_UNORM;
viewInfo.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
viewInfo.subresourceRange.baseMipLevel = 0;
viewInfo.subresourceRange.levelCount = 1;
viewInfo.subresourceRange.baseArrayLayer = 0;
viewInfo.subresourceRange.layerCount = 1;
if (vkCreateImageView(device, &viewInfo, nullptr, &textureImageView) != VK_SUCCESS) {
throw std::runtime_error("failed to create texture image view!");
}
}
When I call vkUpdateDescriptorSets I get validation error:
vkCreateImageView: Includes a pNext pointer (pCreateInfo->pNext) to a VkStructureType (VK_STRUCTURE_TYPE_IMAGE_VIEW_USAGE_CREATE_INFO), but its parent extension VK_KHR_maintenance2 has not been enabled. The Vulkan spec states: Each pNext member of any structure (including this one) in the pNext chain must be either NULL or a pointer to a valid instance of VkImageViewASTCDecodeModeEXT, VkImageViewUsageCreateInfo, VkSamplerYcbcrConversionInfo, VkVideoProfileKHR, or VkVideoProfilesKHR
Before this I had set viewInfo.pNext=nullptr; for which I was getting validation error:
Write update to VkDescriptorSet 0xf018750000000004[] allocated with VkDescriptorSetLayout 0x683e70000000002[] binding #0 failed with error message: Attempted write update to image descriptor failed due to: ImageView (VkImageView 0xa3c6870000000008[]) with usage mask 0x6 being used for a descriptor update of type VK_DESCRIPTOR_TYPE_STORAGE_IMAGE does not have VK_IMAGE_USAGE_STORAGE_BIT set
Can someone please help me with some hint how exactly I can solve the error?
The error message tells you exactly what to do. If you use VkImageViewUsageCreateInfo, that means you have to enable maintenance2 extension or in turn Vulkan 1.1 to which it was promoted.
Since you seem surprised by the existence of extensions, it feels likely your use of them is just accidental. You might simply want to stop using the VkImageViewUsageCreateInfo extension struct and always set pNext to NULL.
I acknowledge that I have used the sample codes that #Benjamin used in different examples.
I want to have both object detection numbers and accident numbers in my model. I need a code to detect object. But object detection does not necessarily lead to an accident. When an object is detected the agent(transporter) should either stop or change its route. The following code is about this functionality. field of view is a polygonal in front of the transporter.
for (Worker thisPed: main.worker) {
//for each pedestrain in model
double pedX = thisPed.getX() -getX();
double pedY = thisPed.getY() -getY();
if (fieldOfView.contains(pedX, pedY)) {
v_pedInDanger = true;
setSpeed(0);
break;
}
}
How to tell transporter to change route instead of stop? I could not find a code in this regard.
However, I should use another code to calculate distance between transporter and the detected object and if the distance <= 1 METER then we count it as an accident. like the following:
for (Worker ped: main.worker){
double dist = 0;
dist = distanceTo(ped);
if (dist <= 1){
v_pedCollisionNumber += 1;
ped.v_isWorkerCollide = true;
send ("accident", this);
}
}
the second one does not work.
Any Advise please? Any better approach?
I have the following task chain, where I want to access the variable decoder in the last task, but created in a much earlier task.
create_task(file->OpenReadAsync()).then([](IRandomAccessStream^ inStream) {
return BitmapDecoder::CreateAsync(inStream);
}).then([localFolder](BitmapDecoder^ decoder) {
return localFolder->CreateFileAsync("map.png", CreationCollisionOption::ReplaceExisting);
}).then([](StorageFile^ outFile) {
return outFile->OpenAsync(FileAccessMode::ReadWrite);
}).then([](IRandomAccessStream^ outFileStream) {
return BitmapEncoder::CreateAsync(BitmapEncoder::PngEncoderId, outFileStream);
}).then([](BitmapEncoder^ encoder) {
BitmapPixelFormat pixelFormat = decoder->BitmapPixelFormat; // how do I make decoder available here?
// Do stuff that uses encoder & decoder
});
In the end I just assigned the variables I needed to variables local to the function that contained the task chain.
Since getting started in Dart I've been watching for a way to execute Dart (Text) Source (that the same program may well be generating dynamically) as Code. Like the infamous "eval()" function.
Recently I have caught a few hints that the communication port between Isolates support some sort of "Spawn" that seems like it could allow this "trick". In Ruby there is also the possibility to load a module dynamically as a language feature, perhaps there is some way to do this in Dart?
Any clues or a simple example will be greatly appreciated.
Thanks in advance!
Ladislav Thon provided this answer on the Dart forum:
I believe it's very safe to say that Dart will never have eval. But it will have other, more structured ways of dynamically generating code (code name mirror builders). There is nothing like that right now, though.
There are two ways of spawning an isolate: spawnFunction, which runs an existing function from the existing code in a new isolate, so nothing you are looking for, and spawnUri, which downloads code from given URI and runs it in new isolate. That is essentially dynamic code loading -- but the dynamically loaded code is isolated from the existing code. It runs in a new isolate, so the only means of communicating with it is via message passing (through ports).
You can run a string as Dart code by first constructing a data URI from it and then passing it into Isolate.spawnUri.
import 'dart:isolate';
void main() async {
final uri = Uri.dataFromString(
'''
void main() {
print("Hellooooooo from the other side!");
}
''',
mimeType: 'application/dart',
);
await Isolate.spawnUri(uri, [], null);
}
Note that you can only do this in JIT mode, which means that the only place you might benefit from it is Dart VM command line apps / package:build scripts. It will not work in Flutter release builds.
To get a result back from it, you can use ports:
import 'dart:isolate';
void main() async {
final name = 'Eval Knievel';
final uri = Uri.dataFromString(
'''
import "dart:isolate";
void main(_, SendPort port) {
port.send("Nice to meet you, $name!");
}
''',
mimeType: 'application/dart',
);
final port = ReceivePort();
await Isolate.spawnUri(uri, [], port.sendPort);
final String response = await port.first;
print(response);
}
I wrote about it on my blog.
Eval(), in Ruby at least, can execute anything from a single statement (like an assignment) to complete involved programs. There is a substantial time penalty for executing many small snippets over most any other form of execution that is possible.
Looking at the problem closer, there are at least three different functions that were at the base of the various schemes where eval might be used. Dart handles at least 2 of these in at least minimal ways.
Dart does not, nor does it look like there is any plan to support "general" script execution.
However, the NoSuchMethod method can be used to effectively implement the dynamic "injection" of variables into your local class environment. It replaces an eval() with a string that would look like this: eval( "String text = 'your first name here';" );
The second function that Dart readily supports now is the invocation of a method, that would look like this: eval( "Map map = SomeClass.some_method()" );
After messing about with this it finally dawned on me that a single simple class can be used to store the information needed to invoke a method, for a class, as a string which seems to have general utility. I can replace a big maintenance prone switch statement that might otherwise be necessary to invoke a series of methods. In Ruby this was almost trivial, however in Dart there are some fairly less than intuitive calls so I wanted to get this "trick" in one place, which fits will with doing ordering and filtering on the strings such as you may need.
Here's the code to "accumulate" as many classes (a whole library?) into a map using reflection such that the class.methodName() can be called with nothing more than a key (as a string).
Note: I used a few "helper methods" to do Map & List functions, you will probably want to replace them with straight Dart. However this code is used and tested only using the functions..
Here's the code:
//The used "Helpers" here..
MAP_add(var map, var key, var value){ if(key != null){map[key] = value;}return(map);}
Object MAP_fetch(var map, var key, [var dflt = null]) {var value = map[key];if (value==null) {value = dflt;}return( value );}
class ClassMethodMapper {
Map _helperMirrorsMap, _methodMap;
void accum_class_map(Object myClass){
InstanceMirror helperMirror = reflect(myClass);
List methodsAr = helperMirror.type.methods.values;
String classNm = myClass.toString().split("'")[1]; ///#FRAGILE
MAP_add(_helperMirrorsMap, classNm, helperMirror);
methodsAr.forEach(( method) {
String key = method.simpleName;
if (key.charCodeAt(0) != 95) { //Ignore private methods
MAP_add(_methodMap, "${classNm}.${key}()", method);
}
});
}
Map invoker( String methodNm ) {
var method = MAP_fetch(_methodMap, methodNm, null);
if (method != null) {
String classNm = methodNm.split('.')[0];
InstanceMirror helperMirror = MAP_fetch(_helperMirrorsMap, classNm);
helperMirror.invoke(method.simpleName, []);
}
}
ClassMethodMapper() {
_methodMap = {};
_helperMirrorsMap = {};
}
}//END_OF_CLASS( ClassMethodMapper );
============
main() {
ClassMethodMapper cMM = new ClassMethodMapper();
cMM.accum_class_map(MyFirstExampleClass);
cMM.accum_class_map(MySecondExampleClass);
//Now you're ready to execute any method (not private as per a special line of code above)
//by simply doing this:
cMM.invoker( MyFirstExampleClass.my_example_method() );
}
Actually there some libraries in pub.dev/packages but has some limitations because are young versions, so that I can recommend you this library expressions to dart and flutter.
A library to parse and evaluate simple expressions.
This library can handle simple expressions, but no blocks of code, control flow statements and so on. It supports a syntax that is common to most programming languages.
There I create an example of code to evaluate arithmetic operations and comparations of data.
import 'package:expressions/expressions.dart';
import 'dart:math';
#override
Widget build(BuildContext context) {
final parsing = FormulaMath();
// Expression example
String condition = "(cos(x)*cos(x)+sin(x)*sin(x)==1) && respuesta_texto == 'si'";
Expression expression = Expression.parse(condition);
var context = {
"x": pi / 5,
"cos": cos,
"sin": sin,
"respuesta_texto" : 'si'
};
// Evaluate expression
final evaluator = const ExpressionEvaluator();
var r = evaluator.eval(expression, context);
print(r);
return Scaffold(
body: Container(
margin: EdgeInsets.only(top: 50.0),
child: Column(
children: [
Text(condition),
Text(r.toString())
],
),
),
);
}
I/flutter (27188): true
Our project is (http://www.play4health.com/p4h_eng/) using Ogre 3D
over Ubuntu 11.04. Except for core services all is based in a plugin architecture taking advantage of Ogre 3d plugin facilities.
In our plugin architecture plugins can be:
Videogames
Interaction methods
Users configure their session creating tuples (videogame, interaction
method). The flow is a session is:
* User load his session.
* User click of one of the tuples for the session and play to
videogame with a specific interaction method.
* Repeat it until end all activities of the session.
Plugin are loaded/unloaded dynamically by demand.
One of this interaction methods is hand tracking using openni. What is
the problem?
* Fist time that openni plugin is loading all work perfectly.
* Next time that plugin openni has to be loaded system is able to
detect gestures but not do hand tracking. Note that all plugin are
executed in the same process. Right now only solution is to reboot
platform.
This is the code for init and release OpenNI in our plugin
bool IPKinectPlugin::onInitialise()
{
mHandPointer.mId = "KinectHandPointer";
mHandPointer.mHasAbsolute = true;
mHandPointer.mHasRelative = false;
XnStatus nRetVal = XN_STATUS_OK;
nRetVal = gContext.InitFromXmlFile(String(this->getPluginInfo()-
>getResPath() + "SamplesConfig.xml").c_str());
CHECK_RC(nRetVal, bContext, "InitFromXml");
#if SHOW_DEPTH
nRetVal = gContext.FindExistingNode(XN_NODE_TYPE_DEPTH,gDepthGenerator);
bDepthGenerator = (nRetVal != XN_STATUS_OK);
if (bDepthGenerator)
{
nRetVal = gDepthGenerator.Create(gContext);
CHECK_RC(nRetVal, bDepthGenerator, "Find Depth generator");
}
#endif
nRetVal = gContext.FindExistingNode(XN_NODE_TYPE_USER, gUserGenerator);
bUserGenerator = (nRetVal != XN_STATUS_OK);
if (/*bUserGenerator*/false)
{
nRetVal = gUserGenerator.Create(gContext);
CHECK_RC(nRetVal, bUserGenerator, "Find user generator");
}
nRetVal = gContext.FindExistingNode(XN_NODE_TYPE_GESTURE, gGestureGenerator);
bGestureGenerator = (nRetVal != XN_STATUS_OK);
if (bGestureGenerator)
{
nRetVal = gGestureGenerator.Create(gContext);
CHECK_RC(nRetVal, bGestureGenerator, "Find gesture generator");
XnCallbackHandle hGestureCallbacks;
gGestureGenerator.RegisterGestureCallbacks(gestureRecognized, gestureProcess, 0,
hGestureCallbacks);
}
nRetVal = gContext.FindExistingNode(XN_NODE_TYPE_HANDS,gHandsGenerator);
bHandsGenerator = (nRetVal != XN_STATUS_OK);
if (bHandsGenerator)
{
nRetVal = gHandsGenerator.Create(gContext);
CHECK_RC(nRetVal, bHandsGenerator, "Find hands generator");
XnCallbackHandle hHandsCallbacks;
gHandsGenerator.RegisterHandCallbacks(handsNew, handsMove,handsLost, 0, hHandsCallbacks);
}
nRetVal = gContext.FindExistingNode(XN_NODE_TYPE_DEVICE, gDevice);
bDevice = (nRetVal != XN_STATUS_OK);
gContext.RegisterToErrorStateChange(onErrorStateChanged, NULL, hDummyCallbackHandle);
//Preparo la textura para la webcam
if (bGenerateRGBTexture)
mWebcamTexture = KinectTools::createDepthTexture("KinectWebCamTexture", sPluginName);
return true;
}
//-----------------------------------------------------------------------------
bool IPKinectPlugin::onShutdown()
{
if (bContext)
{
if (bHandsGenerator)
{
gHandsGenerator.StopTrackingAll();
}
if (bGestureGenerator)
{
gGestureGenerator.RemoveGesture(GESTURE_TO_USE);
gGestureGenerator.RemoveGesture(GESTURE_TO_START);
}
gContext.StopGeneratingAll();
gContext.Shutdown();
}
return true;
}
Any idea about this issue? Any wrong with this code?
Maybe you already found a solution in the meantime...
I normally work with the Java Wrapper, but what I see as difference to my code is that I call contect.startGeneratingAll() after creating the generators (Depth, Hands and so on). I had also problems when I did this multiple times at start up. Another difference is that I use a context.release at shutdown.
My procedure is normally:
Init config (License, Nodes, settings)
Create generators
Start Generating All
Run your code ...
Stop Generating ALL
Context release
From OpenNI Documentation
XN_C_API void XN_C_DECL xnShutdown ( XnContext * pContext )
Shuts down an OpenNI context, destroying all its nodes. Do not call
any function of this context or any correlated node after calling this
method. NOTE: this function destroys the context and all the nodes it
holds and so should be used very carefully. Normally you should just
call xnContextRelease()