CUDA and C++ function problems ( Visual Studio 2013) - c++

Question

I am trying to call a cuda function that is defined in a cu file from a cpp file in Visual Studio but I keep receiving the following error.
TomColourCorrectionMain.obj : error LNK2019: unresolved external symbol "public: void __cdecl hwk::TomColourCorrection::brightness(int,int)" (?brightness#TomColourCorrection#hwk##QEAAXHH#Z) referenced in function "public: virtual void __cdecl hwk::TomColourCorrection::processCore(class std::shared_ptr)" (?processCore#TomColourCorrection#hwk##UEAAXV?$shared_ptr#VIImageProcessingContext#hwk###std###Z)
Now from reading other questions similar to this, I understand its to do with how the function is defined and that there is something wrong there but I can't see it from when I have defined in the header and cuda file.
This is the code I have (I am a novice at CUDA but I can compile CUDA fine and the code runs when I don't call this function in C++):
header file
#pragma once
#include "ImageProcessorWithProperties.h"
#include <iostream>
#include <cuda_runtime.h>
#include <cuda.h>
class TomColourCorrection : public ImageProcessorWithProperties, public PropertyConsumer<TomColourCorrection>{
public: TomColourCorrection(PropNodePtr n, std::function<void()> requestReprocess);
virtual void processCore(IImageProcessingContextPtr context);
static void DeclareSettings(hwk::PropNodePtr n);
virtual ~TomColourCorrection();
void brightness(int iw, int ih); (function I am talking about)
};
}
cpp file with function call //its just segments of the important code as the rest of it isn't necessary for the actual function itself
#include "stdafx.h"
#include "TomColourCorrection.h"
#include <opencv2/imgproc/imgproc.hpp>
#include <cv.h>
#include <highgui.h>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <iostream>
#include <cuda_runtime.h>
#include <cuda.h>
namespace hwk{
TomColourCorrection::TomColourCorrection(PropNodePtr n, std::function<void()> requestReprocess) :
ImageProcessorWithProperties("sandbox", n, requestReprocess),
PropertyConsumer<TomColourCorrection>(n)
{
}
void TomColourCorrection::processCore(IImageProcessingContextPtr context){
brightness(16, 16); (just generic numbers at the moment as I am trying to resolve this issue etc)
}
}
CUDA File and function definition
#include "TomColourCorrection.h"
#include "device_launch_parameters.h"
__global__ void brightness_kernel(int iw, int ih)
{
// Calculate our pixel's location
int x = (blockIdx.x * blockDim.x) + threadIdx.x;
int y = (blockIdx.y * blockDim.y) + threadIdx.y;
// Variables to store the sum
int count = 0;
float sum = 0.0;
// Do the blur operation by summing the surround pixels
/* for (int j = -(bh / 2); j <= (bh / 2); j++)
{
for (int i = -(bw / 2); i <= (bw / 2); i++)
{
// Verify that this offset is within the image boundaries
if ((x + i) < iw && (x + i) >= 0 && (y + j) < ih && (y + j) >= 0)
{
sum += (float)source[((y + j) * iw) + (x + i)];
count++;
}
}
}*/
// Average the sum
sum /= (float)count;
// dest[(y * iw) + x] = (unsigned char)sum;
}
void brightness(int iw, int ih) //, unsigned char *source, unsigned char *dest)
{
// allocate memory for the bitmap in GPU memory
unsigned char *dev_source, *dev_dest;
// cudaHostGetDevicePointer(&dev_source, source, 0);
// cudaHostGetDevicePointer(&dev_dest, dest, 0);
// Run the boxfilter kernel
dim3 blocks(iw / 16, ih / 16);
dim3 threads(16, 16);
// Execute the kernel
brightness_kernel << <blocks, threads >> >(iw, ih);
cudaThreadSynchronize();
}

Answer 1

Modify the TomColourCorrection.h like this:
#pragma once
#include "ImageProcessorWithProperties.h"
#include <iostream>
#include <cuda_runtime.h>
#include <cuda.h>
void brightness_wrapper(int, int);
class TomColourCorrection : public ImageProcessorWithProperties, public PropertyConsumer<TomColourCorrection>{
public:
TomColourCorrection(PropNodePtr n, std::function<void()> requestReprocess);
virtual void processCore(IImageProcessingContextPtr context);
static void DeclareSettings(hwk::PropNodePtr n);
virtual ~TomColourCorrection();
void brightness(int iw, int ih);
};
Modify your cpp file like this:
#include "stdafx.h"
#include "TomColourCorrection.h"
#include <opencv2/imgproc/imgproc.hpp>
#include <cv.h>
#include <highgui.h>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <iostream>
#include <cuda_runtime.h>
#include <cuda.h>
namespace hwk{
void TomColourCorrection::brightness(int iw, int ih){
brightness_wrapper(iw, ih);}
TomColourCorrection::TomColourCorrection(PropNodePtr n, std::function<void()> requestReprocess) : ImageProcessorWithProperties("sandbox", n, requestReprocess), PropertyConsumer<TomColourCorrection>(n)
{
}
void TomColourCorrection::processCore(IImageProcessingContextPtr context){
brightness(16, 16);
}
}
And in your cuda file change this:
void brightness(int iw, int ih) //, unsigned char *source, unsigned char *dest)
to this:
void brightness_wrapper(int iw, int ih) //, unsigned char *source, unsigned char *dest)
This is mainly just spelling out the details of Ryck's answer.

Answer 2

I think you need change
void brightness(int iw, int ih)
to
void TomColourCorrection::brightness(int iw, int ih)
and move the implementation to your header file or a .cpp file.