![](/img/trans.png)
[英]C++ problems. I need help to a very simple and basic problems in C++
[英]Need help on a very simple Cuda and C++ program
我是Cuda編程的新手。 我正在嘗試創建一個簡單的cuda和cpp圖像處理程序,以改變圖像的亮度,飽和度,對比度等。我開始用一個非常簡單的功能,只是為了改變圖像的亮度,通過乘以所有RGB組件具有alpha值的圖像。
這是我的CPP計划:
#include <cutil_inline.h>
#include <cutil_gl_inline.h>
#include <cuda_runtime_api.h>
#include <cuda_gl_interop.h>
using namespace std;
struct ImageData {
unsigned char *data; /* Points to large array of R,G,B-order data */
int height;
int width;
};
ImageData imageData;
float *imageResult; // to store the image result from cuda after running the kernel
unsigned char *d_Input;
unsigned char *d_Output;
unsigned char *h_Output;
// These are CUDA functions to handle allocation and launching the kernels
extern "C" void initInput( unsigned char *data, unsigned char **device, unsigned int size);
extern "C" void filter(unsigned char *d_src, unsigned char *d_dest, int width, int height, int filterMode,
float alpha, float contrast, float saturation, bool use_array );
void initCuda()
{
unsigned int size = imageData.width * imageData.height * 3 * sizeof(unsigned char);
cutilSafeCall(cudaMalloc ((void**) &d_Input, size)); // allocate storage for device image input
cutilSafeCall(cudaMalloc ((void**) &d_Output, size)); // allocate storage for device image output
initInput( imageData.data, &d_Input, size);
}
int main () {
loadPPMImageData( (char *)"boxes.ppm", &imageData); //this function is defined in another file
cudaGLSetGLDevice( 0 );
initCuda();
filter( d_Input, d_Output, imageData.width, imageData.height, 1, 0.8, 1.0, 1.0, 1 );
cutilSafeCall(cudaMemcpy( h_Output, d_Output, size, cudaMemcpyDeviceToHost)); // copy output data from device to host
//print the output
for (int i = 0; i < imageData.size; i++) {
cout << d_Output
}
// do some memory cleanups
//done
return 0
}
這是我的kernel.cu文件:
#include <iostream>
#include <cstdlib>
#include <string>
#include <cmath>
#include <shrUtils.h>
#include <cutil_inline.h>
#include <cutil_math.h>
//Kernel function
__global__ void
applyAlpha(unsigned char* input, unsigned char* output, int width, int height, float alpha)
{
// calculate normalized coordinates
unsigned int x = blockIdx.x * blockDim.x + threadIdx.x;
unsigned int y = blockIdx.y * blockDim.y + threadIdx.y;
output[ ((y * width + x) * 3) + 0] = (int) ( (int)input [ ((y * width + x) * 3) + 0] * alpha); // r
output[ ((y * width + x) * 3) + 1] = (int) ( (int)input [ ((y * width + x) * 3) + 1] * alpha); // g
output[ ((y * width + x) * 3) + 2] = (int) ( (int)input [ ((y * width + x) * 3) + 2] * alpha); // b
}
extern "C"
int iDivUp( int a, int b ){
return (a % b != 0) ? (a / b + 1) : (a / b);
}
extern "C"
void initInput( unsigned char *data, unsigned char **deviceArray, unsigned int size) // /* image data, device pointer, etc */ )
{
/* TODO: Array version DONE
* Initialize device memory for array version
* and cuda arrays for texture version here
*/
cutilSafeCall(cudaMemcpy( deviceArray, data, size, cudaMemcpyHostToDevice)); // copy image data from host to device (array version)
//TODO: Texture version
}
extern "C"
void filter( unsigned char *d_src, unsigned char *d_dest, int width, int height, int filter_mode, float alpha, float contrast, float saturation, bool use_array )
{
/* TODO
* run different kernels for array and texture version
*/
dim3 dimBlock(16, 16, 1);
dim3 dimGrid( iDivUp (width, dimBlock.x), iDivUp( height, dimBlock.y), 1);
if (use_array) { // Array version
if (filter_mode == 1) { // filter mode: brightness (alpha)
applyAlpha<<< dimGrid, dimBlock >>>(d_src, d_dest, width, height, alpha);
// check if kernel execution generated an error
cutilCheckMsg("Kernel execution failed");
cutilSafeCall( cutilDeviceSynchronize() );
}
}
else { //Texture Version
//not yet implemented
}
}
//編輯我根據安德魯的回答修改了上述文件。 但是現在編譯后我遇到了以下錯誤:
ld: warning: ignoring file kernel.o, file was built for i386 which is not the architecture being linked (x86_64)
Undefined symbols for architecture x86_64:
"_initInput", referenced from:
initCuda() in CS380_prog4.o
"_filter", referenced from:
display() in CS380_prog4.o
(maybe you meant: ___GLEW_SGIS_texture_filter4, ___GLEW_EXT_texture_filter_anisotropic , ___GLEW_NV_multisample_filter_hint )
ld: symbol(s) not found for architecture x86_64
collect2: ld returned 1 exit status
make: *** [testprog] Error 1
我在這兩個函數中都使用了“extern C”命令:initInput和filter。 函數聲明(在test.cpp中)和定義(在kernel.cu中)也有相同的參數,但它仍然抱怨它無法找到該函數。 我該如何解決這個鏈接問題?
您將.cu文件直接包含在.cpp文件中,該文件有效地將內容復制到.cpp文件中。 nvcc將使用標准的C ++編譯器來編譯它(在unix平台上使用g ++),它不知道任何Cuda語法的含義。
您必須將每個文件編譯為目標文件,然后將它們與C ++編譯器鏈接,為.cu文件中的導出函數創建標題,方法與標准C相同。
在cuda-grayscale中有一個很好的例子。
它曾用於在CUDA 3.1上編譯。 那里有一個Makefile,在它上面巔峰。
CXX=g++
CUDA_INSTALL_PATH=/usr/local/cuda
CFLAGS= -I. -I$(CUDA_INSTALL_PATH)/include `pkg-config --cflags opencv`
LDFLAGS= -L$(CUDA_INSTALL_PATH)/lib -lcudart `pkg-config --libs opencv`
all:
$(CXX) $(CFLAGS) -c main.cpp -o Debug/main.o
nvcc $(CUDAFLAGS) -c kernel_gpu.cu -o Debug/kernel_gpu.o
$(CXX) $(LDFLAGS) Debug/main.o Debug/kernel_gpu.o -o Debug/grayscale
clean:
rm -f Debug/*.o Debug/grayscale
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.