Question

我正在尝试从OpenCL内核填充OpenCL-OpenGL共享缓冲区。我写了一个简单的程序来绘制3点。 3个顶点的（x，y，z）值填充在内核中。但这些点并未按预期绘制。我知道我没有正确访问共享缓冲区。代码如下：

cl_GLuint vbo;
struct vertex
{
  float x, y, z, w; // position

}pos[3];


void CreateVBO(){

   glGenBuffers(1,&vbo);
   glBindBuffer(GL_ARRAY_BUFFER,vbo);
   glBufferData(GL_ARRAY_BUFFER,3*sizeof(vertex),pos,GL_DYNAMIC_DRAW);

}

void Display(void)
{

    glLoadIdentity();
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glPointSize(10.0);
    CreateVBO();
    glBindBuffer(GL_ARRAY_BUFFER,vbo);
    glEnableClientState(GL_VERTEX_ARRAY);
    glVertexPointer(4, GL_FLOAT, 0, 0);
    glDrawArrays(GL_POINTS,0,3);
    glDisableClientState(GL_VERTEX_ARRAY);
    glBindBuffer(GL_ARRAY_BUFFER,0);  
    glutSwapBuffers();
}

void InitGL(int argc , char * argv[])
{
    glutInit(&argc , argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
    glutCreateWindow("Draw Points");
    glewInit();   
    glutDisplayFunc(Display);
    glClearColor(0,0,0,1);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glMatrixMode(GL_MODELVIEW);
    glEnable( GL_POINT_SMOOTH | GL_DEPTH_TEST );
}

//MAIN program  

global_item_size = local_item_size = 1
InitGL(argc,argv);

//set properties
cl_context_properties properties[] =
{
    CL_GL_CONTEXT_KHR,   (cl_context_properties)wglGetCurrentContext(),
    CL_WGL_HDC_KHR,      (cl_context_properties)wglGetCurrentDC(),
    CL_CONTEXT_PLATFORM, (cl_context_properties)platforms[i], 
    0
};

/* Create OpenCL context */
context = clCreateContext(properties, 1, device_id, NULL, NULL, &ret);

/* Create Command Queue */
cmd_queue = clCreateCommandQueue(context, device_id[0], 0, &ret);

/* Create Kernel Program from the source */
program = clCreateProgramWithSource(context, 1, (const char **)&source_str, (const size_t *)&source_size, &ret);

/* Build Kernel Program */
ret = clBuildProgram(program, 1, device_id, NULL, NULL, NULL);

/* Create OpenCL Kernel */ 
kernel = clCreateKernel(program, "drawPoints", &ret);

/* create opencl buffer*/
vbo_cl = clCreateFromGLBuffer(context,CL_MEM_READ_WRITE,vbo,NULL);

/* Set OpenCL Kernel Parameters */
ret = clSetKernelArg(kernel, 0,sizeof(cl_mem), (void *)&vbo_cl); //,

glFlush(); 
ret = clEnqueueAcquireGLObjects(cmd_queue, 1, &vbo_cl, 0,0,0);

/* Execute OpenCL Kernel */
ret = clEnqueueNDRangeKernel(cmd_queue, kernel, 1, NULL,&global_item_size, &local_item_size, 0, NULL, &event);

ret = clEnqueueReleaseGLObjects(cmd_queue, 1, &vbo_cl, 0,0,0);
clFinish(cmd_queue);

Display();
glutMainLoop();




//KERNEL CODE (Nvidia 820M Geforce GPU )
__kernel void drawPoints(__global float4* buffer) 
{
buffer[0] = (float4)(0, 1, -1, 1.0f);
buffer[1] = (float4)(-1, -1, -1, 1.0f);
buffer[2] = (float4)(1, -1, -1, 1.0f);
}

我使用的是NVIDIA Geforce 820M GPU。目前内核只填充缓冲区。我尝试初始化pos[3]函数中的CreateVBO()值，然后尝试在内核中更新它。在这两种情况下，程序都会执行而没有任何错误。在坐标（0,0,0）处绘制点，这不是预期结果。请告诉我从OpenCL内核修改/更新OpenGL缓冲区数据的正确方法。

Answer 1

确定。我发现了这个问题。我在CreateVBO();内呼叫DisplayGL()。 CreateVBO()初始化缓冲区，因此设置为（0,0,0）。

如何在OpenCL内核中更新OpenCL-OpenGL共享缓冲区数据？

1 个答案: