visioncpp/examples/hello_world.cpp at master · codeplaysoftware/visioncpp · GitHub

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// This file is part of VisionCpp, a lightweight C++ template library

// for computer vision and image processing.

// Contact: visioncpp@codeplay.com

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

// http://www.apache.org/licenses/LICENSE-2.0

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

/// \file hello_world.cc

///

/// -------Example--------

/// Hello World

///

/// \brief this example converts RGB pixel to Grey

///

// include VisionCpp library

#include <visioncpp.hpp>

/// \brief This functor performs conversion from [0, 255] to [0.0f, 1.0f]

struct MyNormaliseFunctor {

/// \param in - three channel unsigned char

/// \return F32C3 - three channel float

visioncpp::pixel::F32C3 operator()(visioncpp::pixel::U8C3 in) {

const float FLOAT_TO_BYTE = 255.0f;

const float BYTE_TO_FLOAT = 1.0f / FLOAT_TO_BYTE;

return visioncpp::pixel::F32C3(static_cast<float>(in[0] * BYTE_TO_FLOAT),

static_cast<float>(in[1] * BYTE_TO_FLOAT),

static_cast<float>(in[2] * BYTE_TO_FLOAT));

}

};

/// \brief This functor performs RGB to grey convertion following rule:

/// GREY <- 0.299f * R + 0,587f * G + 0.114 * B

struct MyGreyFunctor {

/// \param in - RGB pixel.

/// \returns float - greyscale value.

float operator()(visioncpp::pixel::F32C3 in) {

return 0.299f * in[0] + 0.587f * in[1] + 0.114f * in[2];

}

};

int main(int argc, char **argv) {

if (argc < 4) {

std::cout << "You need to provide 3 uchar values" << std::endl;

std::cout << "example>: ./example_hello_world 100 13 145" << std::endl;

return -1;

}

// where VisionCpp will run.

auto dev = visioncpp::make_device<visioncpp::backend::sycl,

visioncpp::device::cpu>();

// an image pixel to be converted to grey

std::shared_ptr<unsigned char> in_rgb(new unsigned char[3]);

in_rgb.get()[0] = atoi(argv[1]);

in_rgb.get()[1] = atoi(argv[2]);

in_rgb.get()[2] = atoi(argv[3]);

// create a host container for output data

std::shared_ptr<float> out_grey(new float[1]);

// definition of the VisionCpp pipe:

{

// put expression tree in a curly braces in order to define the scope for

// the expression

// create terminal nodes - a leaf node in the expression tree.

// terminal struct takes 4 arguments

// 1st template parameter specifies the data U8 (unsigned char) C3 (three

// channels)

// 2nd number of columns in the storage

// 3rd number of rows in the storage

// 4th underlying storage type - currently only Buffer2D supported

auto data =

visioncpp::terminal<visioncpp::pixel::U8C3, 1, 1,

visioncpp::memory_type::Buffer2D>(in_rgb.get());

auto data_out =

visioncpp::terminal<visioncpp::pixel::F32C1, 1, 1,

visioncpp::memory_type::Buffer2D>(out_grey.get());

// converting unsigned char value to normalised float value

auto node = visioncpp::point_operation<MyNormaliseFunctor>(data);

// float RGB to float Grey conversion

auto node2 = visioncpp::point_operation<MyGreyFunctor>(node);

// converting float value for the grey to the unsigned char

// assign operation that writes output of the pipe to output terminal node

auto pipe = visioncpp::assign(data_out, node2);

// execute the pipe defined pipe

// 1st template parameter defines if VisionCpp back-end fuses the expression

// 2nd & 3rd shared memory sizes ( column, row )

// 4th & 5th local work group size ( column , row )

visioncpp::execute<visioncpp::policy::Fuse, 1, 1, 1, 1>(pipe, dev);

} // destroy the expression tree to bring the data back to host

printf("RGB: %u %u %u \nGrey: %f \n", in_rgb.get()[0], in_rgb.get()[1],

in_rgb.get()[2], out_grey.get()[0]);

}

visioncpp/examples/hello_world.cpp at master · codeplaysoftware/visioncpp · GitHub

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