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#include "internal_shared.hpp"

using namespace cv::gpu;

#ifndef CV_PI
#define CV_PI   3.1415926535897932384626433832795f
#endif

//////////////////////////////////////////////////////////////////////////////////////
// Cart <-> Polar

namespace cv { namespace gpu { namespace mathfunc
{
    struct Nothing
    {
        static __device__ __forceinline__ void calc(int, int, float, float, float*, size_t, float)
        {
        }
    };
    struct Magnitude
    {
        static __device__ __forceinline__ void calc(int x, int y, float x_data, float y_data, float* dst, size_t dst_step, float)
        {
            dst[y * dst_step + x] = sqrtf(x_data * x_data + y_data * y_data);
        }
    };
    struct MagnitudeSqr
    {
        static __device__ __forceinline__ void calc(int x, int y, float x_data, float y_data, float* dst, size_t dst_step, float)
        {
            dst[y * dst_step + x] = x_data * x_data + y_data * y_data;
        }
    };
    struct Atan2
    {
        static __device__ __forceinline__ void calc(int x, int y, float x_data, float y_data, float* dst, size_t dst_step, float scale)
        {
            float angle = atan2f(y_data, x_data);
            angle += (angle < 0) * 2.0 * CV_PI;
            dst[y * dst_step + x] = scale * angle;
        }
    };
    template <typename Mag, typename Angle>
    __global__ void cartToPolar(const float* xptr, size_t x_step, const float* yptr, size_t y_step, 
                                float* mag, size_t mag_step, float* angle, size_t angle_step, float scale, int width, int height)
    {
		const int x = blockDim.x * blockIdx.x + threadIdx.x;
		const int y = blockDim.y * blockIdx.y + threadIdx.y;

        if (x < width && y < height)
        {
            float x_data = xptr[y * x_step + x];
            float y_data = yptr[y * y_step + x];

            Mag::calc(x, y, x_data, y_data, mag, mag_step, scale);
            Angle::calc(x, y, x_data, y_data, angle, angle_step, scale);
        }
    }

    struct NonEmptyMag
    {
        static __device__ __forceinline__ float get(const float* mag, size_t mag_step, int x, int y)
        {
            return mag[y * mag_step + x];
        }
    };
    struct EmptyMag
    {
        static __device__ __forceinline__ float get(const float*, size_t, int, int)
        {
            return 1.0f;
        }
    };
    template <typename Mag>
    __global__ void polarToCart(const float* mag, size_t mag_step, const float* angle, size_t angle_step, float scale,
        float* xptr, size_t x_step, float* yptr, size_t y_step, int width, int height)
    {
		const int x = blockDim.x * blockIdx.x + threadIdx.x;
		const int y = blockDim.y * blockIdx.y + threadIdx.y;

        if (x < width && y < height)
        {
            float mag_data = Mag::get(mag, mag_step, x, y);
            float angle_data = angle[y * angle_step + x];
            float sin_a, cos_a;

            sincosf(scale * angle_data, &sin_a, &cos_a);

            xptr[y * x_step + x] = mag_data * cos_a;
            yptr[y * y_step + x] = mag_data * sin_a;
        }
    }

    template <typename Mag, typename Angle>
    void cartToPolar_caller(const DevMem2Df& x, const DevMem2Df& y, const DevMem2Df& mag, const DevMem2Df& angle, bool angleInDegrees, cudaStream_t stream)
    {
        dim3 threads(32, 8, 1);
        dim3 grid(1, 1, 1);

        grid.x = divUp(x.cols, threads.x);
        grid.y = divUp(x.rows, threads.y);
        
        const float scale = angleInDegrees ? (float)(180.0f / CV_PI) : 1.f;

        cartToPolar<Mag, Angle><<<grid, threads, 0, stream>>>(
            x.data, x.step/x.elemSize(), y.data, y.step/y.elemSize(), 
            mag.data, mag.step/mag.elemSize(), angle.data, angle.step/angle.elemSize(), scale, x.cols, x.rows);
        cudaSafeCall( cudaGetLastError() );

        if (stream == 0)
            cudaSafeCall( cudaDeviceSynchronize() );
    }

    void cartToPolar_gpu(const DevMem2Df& x, const DevMem2Df& y, const DevMem2Df& mag, bool magSqr, const DevMem2Df& angle, bool angleInDegrees, cudaStream_t stream)
    {
        typedef void (*caller_t)(const DevMem2Df& x, const DevMem2Df& y, const DevMem2Df& mag, const DevMem2Df& angle, bool angleInDegrees, cudaStream_t stream);
        static const caller_t callers[2][2][2] = 
        {
            {
                {
                    cartToPolar_caller<Magnitude, Atan2>,
                    cartToPolar_caller<Magnitude, Nothing>
                },
                {
                    cartToPolar_caller<MagnitudeSqr, Atan2>,
                    cartToPolar_caller<MagnitudeSqr, Nothing>,
                }
            },
            {
                {
                    cartToPolar_caller<Nothing, Atan2>,
                    cartToPolar_caller<Nothing, Nothing>
                },
                {
                    cartToPolar_caller<Nothing, Atan2>,
                    cartToPolar_caller<Nothing, Nothing>,
                }
            }
        };

        callers[mag.data == 0][magSqr][angle.data == 0](x, y, mag, angle, angleInDegrees, stream);
    }

    template <typename Mag>
    void polarToCart_caller(const DevMem2Df& mag, const DevMem2Df& angle, const DevMem2Df& x, const DevMem2Df& y, bool angleInDegrees, cudaStream_t stream)
    {
        dim3 threads(32, 8, 1);
        dim3 grid(1, 1, 1);

        grid.x = divUp(mag.cols, threads.x);
        grid.y = divUp(mag.rows, threads.y);
        
        const float scale = angleInDegrees ? (float)(CV_PI / 180.0f) : 1.0f;

        polarToCart<Mag><<<grid, threads, 0, stream>>>(mag.data, mag.step/mag.elemSize(), 
            angle.data, angle.step/angle.elemSize(), scale, x.data, x.step/x.elemSize(), y.data, y.step/y.elemSize(), mag.cols, mag.rows);
        cudaSafeCall( cudaGetLastError() );

        if (stream == 0)
            cudaSafeCall( cudaDeviceSynchronize() );
    }

    void polarToCart_gpu(const DevMem2Df& mag, const DevMem2Df& angle, const DevMem2Df& x, const DevMem2Df& y, bool angleInDegrees, cudaStream_t stream)
    {
        typedef void (*caller_t)(const DevMem2Df& mag, const DevMem2Df& angle, const DevMem2Df& x, const DevMem2Df& y, bool angleInDegrees, cudaStream_t stream);
        static const caller_t callers[2] = 
        {
            polarToCart_caller<NonEmptyMag>,
            polarToCart_caller<EmptyMag>
        };

        callers[mag.data == 0](mag, angle, x, y, angleInDegrees, stream);
    }
}}}