I'm binding a Shader Storage Buffer Object (SSBO) and use in the Fragment Shader. The bindings are fine, the buffer block is a multiple of vec4(4B) blocks as required by the specifications. However, the following code has an unexpected behavior. The variable 'datapoint' has the correct 'a' value, but the 'b,c,d' values are garbage.
I'm using an Nvidia Quadro K5000 with driver version 340.52.
struct data
{
int a;
float b;
float c;
float d;
};
// the same location '0' is used on the host
layout(std430, binding = 0) buffer MyBuffer
{
data mydata[];
}
data datapoint;
void main()
{
...
datapoint = mydata[some_index]; // some_index is withing range
...
}
Related
See update 1 below for my guess as to why the error is happening
I'm trying to develop an application with some C#/WPF and C++. I am having a problem on the C++ side on a part of the code that involves optimizing an object using GNU Scientific Library (GSL) optimization functions. I will avoid including any of the C#/WPF/GSL code in order to keep this question more generic and because the problem is within my C++ code.
For the minimal, complete and verifiable example below, here is what I have. I have a class Foo. And a class Optimizer. An object of class Optimizer is a member of class Foo, so that objects of Foo can optimize themselves when it is required.
The way GSL optimization functions take in external parameters is through a void pointer. I first define a struct Params to hold all the required parameters. Then I define an object of Params and convert it into a void pointer. A copy of this data is made with memcpy_s and a member void pointer optimParamsPtr of Optimizer class points to it so it can access the parameters when the optimizer is called to run later in time. When optimParamsPtr is accessed by CostFn(), I get the following error.
Managed Debugging Assistant 'FatalExecutionEngineError' : 'The runtime
has encountered a fatal error. The address of the error was at
0x6f25e01e, on thread 0x431c. The error code is 0xc0000005. This error
may be a bug in the CLR or in the unsafe or non-verifiable portions of
user code. Common sources of this bug include user marshaling errors
for COM-interop or PInvoke, which may corrupt the stack.'
Just to ensure the validity of the void pointer I made, I call CostFn() at line 81 with the void * pointer passed as an argument to InitOptimizer() and everything works. But in line 85 when the same CostFn() is called with the optimParamsPtr pointing to data copied by memcpy_s, I get the error. So I am guessing something is going wrong with the memcpy_s step. Anyone have any ideas as to what?
#include "pch.h"
#include <iostream>
using namespace System;
using namespace System::Runtime::InteropServices;
using namespace std;
// An optimizer for various kinds of objects
class Optimizer // GSL requires this to be an unmanaged class
{
public:
double InitOptimizer(int ptrID, void *optimParams, size_t optimParamsSize);
void FreeOptimizer();
void * optimParamsPtr;
private:
double cost = 0;
};
ref class Foo // A class whose objects can be optimized
{
private:
int a; // An internal variable that can be changed to optimize the object
Optimizer *fooOptimizer; // Optimizer for a Foo object
public:
Foo(int val) // Constructor
{
a = val;
fooOptimizer = new Optimizer;
}
~Foo()
{
if (fooOptimizer != NULL)
{
delete fooOptimizer;
}
}
void SetA(int val) // Mutator
{
a = val;
}
int GetA() // Accessor
{
return a;
}
double Optimize(int ptrID); // Optimize object
// ptrID is a variable just to change behavior of Optimize() and show what works and what doesn't
};
ref struct Params // Parameters required by the cost function
{
int cost_scaling;
Foo ^ FooObj;
};
double CostFn(void *params) // GSL requires cost function to be of this type and cannot be a member of a class
{
// Cast void * to Params type
GCHandle h = GCHandle::FromIntPtr(IntPtr(params));
Params ^ paramsArg = safe_cast<Params^>(h.Target);
h.Free(); // Deallocate
// Return the cost
int val = paramsArg->FooObj->GetA();
return (double)(paramsArg->cost_scaling * val);
}
double Optimizer::InitOptimizer(int ptrID, void *optimParamsArg, size_t optimParamsSizeArg)
{
optimParamsPtr = ::operator new(optimParamsSizeArg);
memcpy_s(optimParamsPtr, optimParamsSizeArg, optimParamsArg, optimParamsSizeArg);
double ret_val;
// Here is where the GSL stuff would be. But I replace that with a call to CostFn to show the error
if (ptrID == 1)
{
ret_val = CostFn(optimParamsArg); // Works
}
else
{
ret_val = CostFn(optimParamsPtr); // Doesn't work
}
return ret_val;
}
// Release memory used by unmanaged variables in Optimizer
void Optimizer::FreeOptimizer()
{
if (optimParamsPtr != NULL)
{
delete optimParamsPtr;
}
}
double Foo::Optimize(int ptrID)
{
// Create and initialize params object
Params^ paramsArg = gcnew Params;
paramsArg->cost_scaling = 11;
paramsArg->FooObj = this;
// Convert Params type object to void *
void * paramsArgVPtr = GCHandle::ToIntPtr(GCHandle::Alloc(paramsArg)).ToPointer();
size_t paramsArgSize = sizeof(paramsArg); // size of memory block in bytes pointed to by void pointer
double result = 0;
// Initialize optimizer
result = fooOptimizer->InitOptimizer(ptrID, paramsArgVPtr, paramsArgSize);
// Here is where the loop that does the optimization will be. Removed from this example for simplicity.
return result;
}
int main()
{
Foo Foo1(2);
std::cout << Foo1.Optimize(1) << endl; // Use orig void * arg in line 81 and it works
std::cout << Foo1.Optimize(2) << endl; // Use memcpy_s-ed new void * public member of Optimizer in line 85 and it doesn't work
}
Just to reiterate I need to copy the params to a member in the optimizer because the optimizer will run all through the lifetime of the Foo object. So it needs to exist as long as the Optimizer object exist and not just in the scope of Foo::Optimize()
/clr support need to be selected in project properties for the code to compile. Running on an x64 solution platform.
Update 1: While trying to debug this, I got suspicious of the way I get the size of paramsArg at line 109. Looks like I am getting the size of paramsArg as size of int cost_scaling plus size of the memory storing the address to FooObj instead of the size of memory storing FooObj itself. I realized this after stumbling across this answer to another post. I confirmed this by checking the value of paramsArg after adding some new dummy double members to Foo class. As expected the value of paramsArg doesn't change. I suppose this explains why I get the error. A solution would be to write code to correctly calculate the size of a Foo class object and set that to paramsArg instead of using sizeof. But that is turning out to be too complicated and probably another question in itself. For example, how to get size of a ref class object? Anyways hopefully someone will find this helpful.
I'm writing a plugin for unity, and I need to send a texture from ios to unity.
There is a UnitySendMessage function which takes char* as a parameter, but I didn't find a way to convert id<MTLTexture> to char*.
How can I send id<MTLTexture> from ios and receive it in unity?
My current code :
//ios side ...
id<MTLTexture> _texture = CVMetalTextureGetTexture(texture);
UnitySendMessage(CALLBACK_OBJECT, CALLBACK_TEXTURE_READY,_texture);//error
//...
//unity side
private void OnTextureReady(string texture_str)
{
IntPtr texture = new IntPtr(Int32.Parse(texture_str));
int width = 256;
int height = 256;
rawImage.texture = Texture2D.CreateExternalTexture(width, height,
TextureFormat.ARGB32, false, false, texture);
}
iOS plugin documentation says that you can only pass strings using UnitySendMessage.
The workaround would be to create a mapping from string to texture objects in Objective-C side, pass the string key via UnitySendMessage and then retrieve the texture object using a custom DllImport function.
Declare you map:
// class field
{
NSMutableDictionary<NSString *, id<MTLTexture>> _textures;
}
// in constructor
_textures = [NSMutableDictionary new];
// in function code
NSString *textureName = #"cookies";
_textures[textureName] = texture; // save MTLTexture for later
UnitySendMessage(CALLBACK_OBJECT, CALLBACK_TEXTURE_READY, textureName);
On the C# side CreateExternalTexture requires a pointer to a texture object of type IntPtr. To obtain it you can declare a DllImport function that takes a texture name and returns IntPtr:
[DllImport("__Internal")]
static extern IntPtr GetMetalTexturePointerByName(string textureName);
and implement it on the iOS side like so:
return plugin->_textures[textureName];
Not sure if it works though in terms of what CreateExternalTexture expects.
See also this post, a guy is doing something similar (but reverse):
Convert uintptr_t to id<MTLTexture>
I'm confused by the OpenCV Mat element types. This is from the docs:
There is a limited fixed set of primitive data types the library can operate on.
That is, array elements should have one of the following types:
8-bit unsigned integer (uchar)
8-bit signed integer (schar)
16-bit unsigned integer (ushort)
16-bit signed integer (short)
32-bit signed integer (int)
32-bit floating-point number (float)
64-bit floating-point number (double)
...
For these basic types, the following enumeration is applied:
enum { CV_8U=0, CV_8S=1, CV_16U=2, CV_16S=3, CV_32S=4, CV_32F=5, CV_64F=6 };
It's known that C++ standard doesn't define the size of basic types in bytes, so how do they use such assumptions? And what type should I expect from, let's say, CV_32S, is it int32_t or int?
Developing from Miki's answer,
In OpenCV 3 definition has moved to modules/core/include/opencv2/core/traits.hpp, where you can find:
/** #brief A helper class for cv::DataType
The class is specialized for each fundamental numerical data type supported by OpenCV. It provides
DataDepth<T>::value constant.
*/
template<typename _Tp> class DataDepth
{
public:
enum
{
value = DataType<_Tp>::depth,
fmt = DataType<_Tp>::fmt
};
};
template<int _depth> class TypeDepth
{
enum { depth = CV_USRTYPE1 };
typedef void value_type;
};
template<> class TypeDepth<CV_8U>
{
enum { depth = CV_8U };
typedef uchar value_type;
};
template<> class TypeDepth<CV_8S>
{
enum { depth = CV_8S };
typedef schar value_type;
};
template<> class TypeDepth<CV_16U>
{
enum { depth = CV_16U };
typedef ushort value_type;
};
template<> class TypeDepth<CV_16S>
{
enum { depth = CV_16S };
typedef short value_type;
};
template<> class TypeDepth<CV_32S>
{
enum { depth = CV_32S };
typedef int value_type;
};
template<> class TypeDepth<CV_32F>
{
enum { depth = CV_32F };
typedef float value_type;
};
template<> class TypeDepth<CV_64F>
{
enum { depth = CV_64F };
typedef double value_type;
};
In most of the cases/compilers you should be fine using C++ exact data types. You wouldn't have problems with single byte data types (CV_8U -> uint8_t and CV_8U -> int8_t) as unambiguously defined in C++. The same for float (32bit) and double (64bit). However, it is true that for other data types to be completely sure you use the correct data type (for example when using the at<> method) you should use for example:
typedef TypeDepth<CV_WHATEVER_YOU_USED_TO_CREATE_YOUR_MAT>::value_type access_type;
myMat.at<access_type>(y,x) = 0;
As a side note, I am surprised they decided to take such an ambiguous approach, instead of simply using exact data types.
Therefore, regarding your last question:
What type should I expect from, let's say, CV_32S?
I believe the most precise answer, in OpenCV 3, is:
TypeDepth<CV_32S>::value_type
In core.hpp you can find the following:
/*!
A helper class for cv::DataType
The class is specialized for each fundamental numerical data type supported by OpenCV.
It provides DataDepth<T>::value constant.
*/
template<typename _Tp> class DataDepth {};
template<> class DataDepth<bool> { public: enum { value = CV_8U, fmt=(int)'u' }; };
template<> class DataDepth<uchar> { public: enum { value = CV_8U, fmt=(int)'u' }; };
template<> class DataDepth<schar> { public: enum { value = CV_8S, fmt=(int)'c' }; };
template<> class DataDepth<char> { public: enum { value = CV_8S, fmt=(int)'c' }; };
template<> class DataDepth<ushort> { public: enum { value = CV_16U, fmt=(int)'w' }; };
template<> class DataDepth<short> { public: enum { value = CV_16S, fmt=(int)'s' }; };
template<> class DataDepth<int> { public: enum { value = CV_32S, fmt=(int)'i' }; };
// this is temporary solution to support 32-bit unsigned integers
template<> class DataDepth<unsigned> { public: enum { value = CV_32S, fmt=(int)'i' }; };
template<> class DataDepth<float> { public: enum { value = CV_32F, fmt=(int)'f' }; };
template<> class DataDepth<double> { public: enum { value = CV_64F, fmt=(int)'d' }; };
template<typename _Tp> class DataDepth<_Tp*> { public: enum { value = CV_USRTYPE1, fmt=(int)'r' }; };
You can see that CV_32S is the value for the type int, not int32_t.
While C++ doesn't define the size of an element, the question is hypothetical: for systems OpenCV is run on, the sizes are known. Given
cv::Mat m(32,32,CV_32SC1, cv:Scalar(0));
std::cout << "size of the element in bytes: " << m.depth() << std::endl;
std::cout << "or " << m.step.p[ m.dims-1 ]/m.channels() << std::endl;
So how can you be sure it is int?
An attempt to call
int pxVal = m.at<int>(0,0);
will
CV_DbgAssert( elemSize()==sizeof(int) );
Where the left hand is defined via the cv::Mat::flags -- in this example as the predefined depth of the CV_32SC1 equal to
CV_DbgAssert( m.depth() == sizeof(int) )
or
CV_DbgAssert( 4 == sizeof(int) )
So if you succeeded you are left only the endianness. And that was checked when the cvconfig.h was generated (by CMake).
TL;DR, expect the types given in the header and you'll be fine.
You can find all definitions on your questions in opencv's sources.
See https://github.com/Itseez/opencv/blob/master/modules/core/include/opencv2/core/cvdef.h file.
I have found several #define in OpenCV's code related to CV_8UC1, CV_32SC1, etc. To make the enumerations work, OpenCV put additional codes to convert the plain numbers together as a parameter (i.e, CV_8UC1, CV_16UC2...are all represented by their respective numbers), and break the depth and channels apart in the definition of CvMat(I guess Mat may have similar codes in its definition). Then, it uses create() to allocate spaces for the matrix. Since create() is inline, I can only guess that it is similar to malloc() or something.
As source codes changes a lot from 2.4.9 to 3.0.0, I need to post more evidence later. Please allow me a little time to find out more and edit my answer.
In short the table you provided is correct.
If you want to directly access a pixel, you typecast it to the specifier to the right, for example CV_32S is a signed 32-bit.
The S always means a signed integral number (signed char, signed short, signed int)
The F always means a floating point number (float, double)
The U always means an unsigned integral number.
The enumeration is used only when creating or converting a Mat. It's a way of telling the mat which is the desired type, as I understand it it's the C predecessor to when templates were not used.
I use the C functionality exclusively, and in order to create an image, it would be an error to pass the following:
cvCreateImage(mySize,char, nChannels);
Instead, I pass the following:
cvCreateImage(mySize, IPL_DEPTH_8U, nChannels);
Here, the IPL_DEPTH_8U is a flag that is used by the function. The function itself has a switch-type statement that checks the flag. The actual value of the flag is most often meaningless as it's most often controlled by conditional, not algebraic statements.
I'm newer to C++. I have written some code, but when i run it, there's always this:
raised exception class
EAccessViolation with message 'Access
violation at address'
i don't understand this. Would you like to help me solve it? It's important to me. Really, really thank you!
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <math.h>
#include <conio.h>
#define k 2
#define minoffset 0.5
using namespace std;
struct Point
{
double X;
double Y;
};
vector<Point> dataprocess();
void k_means(vector<Point> points,int N);
double getdistance(Point p1,Point p2)
{ double distance;
distance=sqrt((p1.X-p2.X)*(p1.X-p2.X)+(p1.Y-p2.Y)*(p1.Y-p2.Y));
return distance;
}
int getmindis(Point p,Point means[])
{
int i;
int c;
double dis=getdistance(p,means[0]);
for(i=1;i<k;i++)
{
double term=getdistance(p,means[i]);
if(term<dis)
{
c=i;
dis=term;
}
}
return c;
}
Point getmeans(vector<Point> points)
{
int i;
double sumX,sumY;
Point p;
int M=points.size();
for(i=0;i<M;i++)
{
sumX=points[i].X;
sumY=points[i].Y;
}
p.X=sumX/M;
p.Y=sumY/M;
return p;
}
int main()
{ int N;
vector<Point> stars;
stars=dataprocess();
N=stars.size();
cout<<"the size is:"<<N<<endl;
k_means(stars,N);
getch();
}
vector<Point> dataprocess()
{
int i;
int N;
double x,y;
vector<Point> points;
Point p;
string import_file;
cout<<"input the filename:"<<endl;
cin>>import_file;
ifstream infile(import_file.c_str());
if(!infile)
{
cout<<"read error!"<<endl;
}
else
{
while(infile>>x>>y)
{
p.X=x;
p.Y=y;
points.push_back(p);
}
}
N=points.size();
cout<<"output the file data:"<<endl;
for(i=0;i<N;i++)
{
cout<<"the point"<<i+1<<"is:X="<<points[i].X<<" Y="<<points[i].Y<<endl;
}
return points;
}
void k_means(vector<Point> points,int N)
{
int i;
int j;
int index;
vector<Point> clusters[k];
Point means[k];
Point newmeans[k];
double d,offset=0;
bool flag=1;
cout<<"there will be"<<k<<"clusters,input the original means:"<<endl;
for(i=0;i<k;i++)
{
cout<<"k"<<i+1<<":"<<endl;
cin>>means[i].X>>means[i].Y;
}
while(flag)
{
for(i=0;i<N;i++)
{
index=getmindis(points[i],means);
clusters[index].push_back(points[i]);
}
for(j=0;j<k;j++)
{
newmeans[j]=getmeans(clusters[j]);
offset=getdistance(newmeans[j],means[j]);
}
if(offset>d)
{
d=offset;
}
flag=(minoffset<d)?true:false;
for(i=0;i<k;i++)
{
means[i]=newmeans[i];
clusters[i].clear();
}
}
for(i=0;i<k;i++)
{
cout<<"N"<<i+1<<"="<<clusters[i].size()<<endl;
cout<<"the center of k"<<i+1<<"is:"<<means[i].X<<" "<<means[i].Y<< endl;
}
}
You surely have some algo errors in you code. It is difficult to deal with code without input data, that caused an error, but let's try:
First, lets look at function Point getmeans(vector<Point> points)
it is supposed to evaluate mean coordinates for cluster of points: if you pass an empty cluster to this function it will cause an error:
look here -
int M=points.size()
and here -
for(i=0;i<M;i++)
{
sumX=points[i].X;
sumY=points[i].Y;
}
if your cluster is empty than M will be zero and you loop will iterate 2^31 times (until 32 bit integer overflow) and each time you will try to read values of nonexistent vector items
So, You have to test if you vector is not empty before running main function loop and you have to decide which mean values should be assigned for zero cluster (May be you need an additional flag for empty cluster which will be checked before dealing with cluster's mean values)
Then lets examine function int getmindis(Point p,Point means[]) and, also, a place, where we call it:
index=getmindis(points[i],means); clusters[index].push_back(points[i]);
This function assings points to clusters. cluster number is ruled by c variable. If input point doesn't fit to any cluster, function will return uninitialized variable (holding any possible value) which. then is used as vector index of nonexisting element - possible access violation error
You probably have to initialize c to zero in declaration
Tell us when you will be ready with errors described above and also show us a sample input file (one which causes errors, if all datasets cause errors, show us the smallest one)
This is my program to display a .x mesh. I am able to display the mesh tiger.x but not able to display ball.x. What is the difference between the two meshes? Is there something I should handle in the code? But I am able to view both the meshes using standard mesh viewers like the one which come with DirectX SDK.
Thanks.
but not able to display ball.x.
The question is unclear. Does the mesh load? Does it contain vertices/faces? Or maybe it crashes app? Or loading fails?
What is the difference between the two meshes?
The difference is that the second mesh (ball.x) doesn't include "templates".
I.e. this part:
template Header {
<3D82AB43-62DA-11cf-AB39-0020AF71E433>
WORD major;
WORD minor;
DWORD flags;
}
template Vector {
<3D82AB5E-62DA-11cf-AB39-0020AF71E433>
FLOAT x;
FLOAT y;
FLOAT z;
}
template Coords2d {
<F6F23F44-7686-11cf-8F52-0040333594A3>
FLOAT u;
FLOAT v;
}
template Matrix4x4 {
<F6F23F45-7686-11cf-8F52-0040333594A3>
array FLOAT matrix[16];
}
template ColorRGBA {
<35FF44E0-6C7C-11cf-8F52-0040333594A3>
FLOAT red;
FLOAT green;
FLOAT blue;
FLOAT alpha;
}
template ColorRGB {
<D3E16E81-7835-11cf-8F52-0040333594A3>
FLOAT red;
FLOAT green;
FLOAT blue;
}
template IndexedColor {
<1630B820-7842-11cf-8F52-0040333594A3>
DWORD index;
ColorRGBA indexColor;
}
template Boolean {
<4885AE61-78E8-11cf-8F52-0040333594A3>
WORD truefalse;
}
template Boolean2d {
<4885AE63-78E8-11cf-8F52-0040333594A3>
Boolean u;
Boolean v;
}
template MaterialWrap {
<4885AE60-78E8-11cf-8F52-0040333594A3>
Boolean u;
Boolean v;
}
template TextureFilename {
<A42790E1-7810-11cf-8F52-0040333594A3>
STRING filename;
}
template Material {
<3D82AB4D-62DA-11cf-AB39-0020AF71E433>
ColorRGBA faceColor;
FLOAT power;
ColorRGB specularColor;
ColorRGB emissiveColor;
[...]
}
template MeshFace {
<3D82AB5F-62DA-11cf-AB39-0020AF71E433>
DWORD nFaceVertexIndices;
array DWORD faceVertexIndices[nFaceVertexIndices];
}
template MeshFaceWraps {
<4885AE62-78E8-11cf-8F52-0040333594A3>
DWORD nFaceWrapValues;
Boolean2d faceWrapValues;
}
template MeshTextureCoords {
<F6F23F40-7686-11cf-8F52-0040333594A3>
DWORD nTextureCoords;
array Coords2d textureCoords[nTextureCoords];
}
template MeshMaterialList {
<F6F23F42-7686-11cf-8F52-0040333594A3>
DWORD nMaterials;
DWORD nFaceIndexes;
array DWORD faceIndexes[nFaceIndexes];
[Material]
}
template MeshNormals {
<F6F23F43-7686-11cf-8F52-0040333594A3>
DWORD nNormals;
array Vector normals[nNormals];
DWORD nFaceNormals;
array MeshFace faceNormals[nFaceNormals];
}
template MeshVertexColors {
<1630B821-7842-11cf-8F52-0040333594A3>
DWORD nVertexColors;
array IndexedColor vertexColors[nVertexColors];
}
template Mesh {
<3D82AB44-62DA-11cf-AB39-0020AF71E433>
DWORD nVertices;
array Vector vertices[nVertices];
DWORD nFaces;
array MeshFace faces[nFaces];
[...]
}
template FrameTransformMatrix {
<F6F23F41-7686-11cf-8F52-0040333594A3>
Matrix4x4 frameMatrix;
}
I.e. templates/structure declarations.
Also, in ball.x mesh is a part of hierarchy of Frames. In tiger.x it isn't, and is stored on top level of hierarchy.
It's been a while since I last used *.x file directly, but as far as I know, you'll need to include templates for all "non standard" templates into file. i.e. if file uses an object with template that wasn't registred using RegisterTemplates method of ID3DXFile or IDirectXFile, then the file won't load if template isn't written at the beginning of file. Try adding template definitions for every suspicious structure in ball.x , until you find the culprit . I'd start with "Header".
If the problem is because of hierarchy, you'll need to try another loading method.
using standard mesh viewers like the one which come with DirectX SDK.
AFAIK, mesh viewer comes with source code. Read the source and see how it works.
The mesh does not have any issue but the view. It was too zoomed in to display the image. I projected the image using the following matrix and was able to view the mesh properly.
//Set Projection
D3DXMATRIXA16 matProj(1.0,0.0,0.0,0.0,
0.0,1.0,0.0,0.0,
0.0,0.0,1.0,0.0,
0.0,0.0,0.0,150.0);