func (this *buffer) EnqueueReadRect(queue CommandQueue,
blocking_read cl.CL_bool,
buffer_origin [3]cl.CL_size_t,
host_origin [3]cl.CL_size_t,
region [3]cl.CL_size_t,
buffer_row_pitch cl.CL_size_t,
buffer_slice_pitch cl.CL_size_t,
host_row_pitch cl.CL_size_t,
host_slice_pitch cl.CL_size_t,
ptr unsafe.Pointer,
event_wait_list []Event) (Event, error) {
var errCode cl.CL_int
var event_id cl.CL_event
numEvents := cl.CL_uint(len(event_wait_list))
events := make([]cl.CL_event, numEvents)
for i := cl.CL_uint(0); i < numEvents; i++ {
events[i] = event_wait_list[i].GetID()
}
if errCode = cl.CLEnqueueReadBufferRect(queue.GetID(),
this.memory_id,
blocking_read,
buffer_origin,
host_origin,
region,
buffer_row_pitch,
buffer_slice_pitch,
host_row_pitch,
host_slice_pitch,
ptr,
numEvents,
events,
&event_id); errCode != cl.CL_SUCCESS {
return nil, fmt.Errorf("EnqueueReadRect failure with errcode_ret %d: %s", errCode, cl.ERROR_CODES_STRINGS[-errCode])
} else {
return &event{event_id}, nil
}
}
func main() {
/* OpenCL data structures */
var device []cl.CL_device_id
var context cl.CL_context
var queue cl.CL_command_queue
var program *cl.CL_program
var kernel cl.CL_kernel
var err cl.CL_int
/* Data and buffers */
var full_matrix, zero_matrix [80]float32
var sizeoffloat32 = cl.CL_size_t(unsafe.Sizeof(full_matrix[0]))
var buffer_origin = [3]cl.CL_size_t{5 * sizeoffloat32, 3, 0}
var host_origin = [3]cl.CL_size_t{1 * sizeoffloat32, 1, 0}
var region = [3]cl.CL_size_t{4 * sizeoffloat32, 4, 1}
var matrix_buffer cl.CL_mem
/* Initialize data */
for i := 0; i < 80; i++ {
full_matrix[i] = float32(i) * 1.0
zero_matrix[i] = 0.0
}
/* Create a device and context */
device = utils.Create_device()
context = cl.CLCreateContext(nil, 1, device[:], nil, nil, &err)
if err < 0 {
println("Couldn't create a context")
return
}
/* Build the program and create the kernel */
program = utils.Build_program(context, device[:], PROGRAM_FILE, nil)
if program == nil {
println("Couldn't build program")
return
}
kernel = cl.CLCreateKernel(*program, []byte(KERNEL_FUNC), &err)
if err < 0 {
println("Couldn't create a kernel")
return
}
/* Create a buffer to hold 80 floats */
matrix_buffer = cl.CLCreateBuffer(context, cl.CL_MEM_READ_WRITE|
cl.CL_MEM_COPY_HOST_PTR, cl.CL_size_t(unsafe.Sizeof(full_matrix)), unsafe.Pointer(&full_matrix[0]), &err)
if err < 0 {
println("Couldn't create a buffer object")
return
}
/* Set buffer as argument to the kernel */
err = cl.CLSetKernelArg(kernel, 0, cl.CL_size_t(unsafe.Sizeof(matrix_buffer)), unsafe.Pointer(&matrix_buffer))
if err < 0 {
println("Couldn't set the buffer as the kernel argument")
return
}
/* Create a command queue */
queue = cl.CLCreateCommandQueue(context, device[0], 0, &err)
if err < 0 {
println("Couldn't create a command queue")
return
}
/* Enqueue kernel */
err = cl.CLEnqueueTask(queue, kernel, 0, nil, nil)
if err < 0 {
println("Couldn't enqueue the kernel")
return
}
/* Enqueue command to write to buffer */
err = cl.CLEnqueueWriteBuffer(queue, matrix_buffer, cl.CL_TRUE, 0,
cl.CL_size_t(unsafe.Sizeof(full_matrix)), unsafe.Pointer(&full_matrix[0]), 0, nil, nil)
if err < 0 {
println("Couldn't write to the buffer object")
return
}
/* Enqueue command to read rectangle of data */
err = cl.CLEnqueueReadBufferRect(queue, matrix_buffer, cl.CL_TRUE,
buffer_origin, host_origin, region, 10*sizeoffloat32, 0,
10*sizeoffloat32, 0, unsafe.Pointer(&zero_matrix[0]), 0, nil, nil)
if err < 0 {
println("Couldn't read the rectangle from the buffer object")
return
}
/* Display updated buffer */
for i := 0; i < 8; i++ {
for j := 0; j < 10; j++ {
fmt.Printf("%6.1f", zero_matrix[j+i*10])
}
fmt.Printf("\n")
}
/* Deallocate resources */
cl.CLReleaseMemObject(matrix_buffer)
cl.CLReleaseKernel(kernel)
cl.CLReleaseCommandQueue(queue)
cl.CLReleaseProgram(*program)
cl.CLReleaseContext(context)
}