[SDL] SDL-OpenCL code working 70% of the time

zweifel

2016-11-17 00:53:26 UTC

Hi,

I programmed a code to do convolution in SDL- OpenCL, however it is working
only 70% of the time.

Code :

#include"SDL2/SDL.h"
#include"SDL2/SDL_image.h"
#include"CL_Interface.h"

void printFilter(const float* filter, int filter_size)
{
printf("filter:\n");
int i, j;
for(i=0;i<filter_size;++i)
{
for(j=0;j<filter_size;++j)
{
printf("%.2f ", filter[i*filter_size + j]);
}
printf("\n");
}

}

int main(int argc, char** argv)
{
bool quit= false;
int filter_size=4;

SDL_Event event;

SDL_Init(SDL_INIT_VIDEO);

//ATTENTION: 24bit RGB is not supported by OpenCL!
SDL_Surface* image= IMG_Load("out.png");
int image_height=image->h;
int image_width=image->w;
int bpp = (int) image->format->BytesPerPixel;
std::cout << "Bpp " << bpp << "Size "<< image->w << image->h << std::endl;

SDL_Window* window= SDL_CreateWindow("Convolution",
SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 1024, 720, 0);

SDL_Renderer* renderer= SDL_CreateRenderer(window, -1, 0);

SDL_Texture* texture= SDL_CreateTextureFromSurface(renderer, image);

printf("Initializing OpenCL...\n");
//opencl
CL_Interface* ocl= new CL_Interface();
ocl->buildProgram("1_test.cl");
Kernel* kernel= new Kernel("convolute", ocl->program);

//input image (OpenCL have few supported formats!!! No 24bit RGB!)
const cl::ImageFormat format(CL_RGBA, CL_UNSIGNED_INT8);

cl::Image2D in(ocl->context, CL_MEM_READ_WRITE |
CL_MEM_COPY_HOST_PTR, format, image_width, image_height, 0,
image->pixels);

//float* filter= (float*)malloc(sizeof(float)*filter_size*filter_size);
float filter[]=
{ -1, 0, 1,0,
-2, 0, 2,0,
-1, 0, 1,0,
0, 0, 0,0};
printFilter(filter, 4);
cl::Buffer filter_buffer= cl::Buffer(ocl->context, CL_MEM_READ_ONLY |
CL_MEM_COPY_HOST_PTR, filter_size*filter_size*sizeof(float), filter);

//cl::Image2D out(ocl->context, CL_MEM_WRITE_ONLY, format,
image_width, image_height, 0, data2);
cl::Image2D out(ocl->context, CL_MEM_WRITE_ONLY, format, image_width,
image_height, 0, NULL);
//cl::Image2D out(ocl->context, CL_MEM_WRITE_ONLY, format,
image_width, image_height, 0, image2->pixels);
kernel->kernel.setArg(0, in);
kernel->kernel.setArg(1, out);
kernel->kernel.setArg(2, filter_buffer);
kernel->kernel.setArg(3, filter_size/2);

ocl->queue.enqueueNDRangeKernel(kernel->kernel, cl::NullRange,
cl::NDRange(image_width, image_height), cl::NullRange);

ocl->queue.finish();

//start and end coordinates for reading our image
cl::size_t<3> origin;
cl::size_t<3> size;
origin[0] = 0;
origin[1] = 0;
origin[2] = 0;
size[0] = image_width;
size[1] = image_height;

size[2] = 1;

while(!quit)
{
ocl->queue.enqueueReadImage(out, CL_TRUE, origin, size, 0, 0, image->pixels);

//SDL_Texture* texture2= SDL_CreateTextureFromSurface(renderer, image);
SDL_UpdateTexture(texture, NULL, image->pixels, image->pitch);

SDL_WaitEvent(&event);

switch(event.type)
{
case SDL_QUIT:
{
quit=true;
}
break;
}

//SDL_RenderCopy(renderer, texture2, NULL, NULL);
SDL_RenderCopy(renderer, texture, NULL, NULL);
SDL_RenderPresent(renderer);
}

SDL_DestroyTexture(texture);
SDL_FreeSurface(image);
SDL_DestroyRenderer(renderer);
SDL_DestroyWindow(window);

SDL_Quit();

return 0;
}

Both creating an texture and updating a texture give the same results.
In other words, inside the code, the four lines below can be toggled
without any improvement:
//SDL_Texture* texture2= SDL_CreateTextureFromSurface(renderer, image);
SDL_UpdateTexture(texture, NULL, image->pixels, image->pitch);
//SDL_RenderCopy(renderer, texture2, NULL, NULL);
SDL_RenderCopy(renderer, texture, NULL, NULL);

Any ideas where the problem may be?

Best,