Programowanie CUDA (Visual Studio 2019)

#pragma comment(lib, "D:/cuda/lib/glut64.lib")
#pragma comment(lib, "D:/cuda/lib/glut32.lib")
#include "D:/cuda/common/book.h"
#include "D:/cuda/common/cpu_bitmap.h"
#include <cuda.h>
#include <cuda_runtime.h>
#include <device_launch_parameters.h>
#include <stdio.h>


#define DIM 1000

struct cuComplex {
	float   r;
	float   i;
	__device__ cuComplex(float a, float b) : r(a), i(b) {}
	__device__ float magnitude2(void) {
		return r * r + i * i;
	}
	__device__ cuComplex operator*(const cuComplex& a) {
		return cuComplex(r * a.r - i * a.i, i * a.r + r * a.i);
	}
	__device__ cuComplex operator+(const cuComplex& a) {
		return cuComplex(r + a.r, i + a.i);
	}
};

__device__ int julia(int x, int y) {
	const float scale = 1.5;
	float jx = scale * (float)(DIM / 2 - x) / (DIM / 2);
	float jy = scale * (float)(DIM / 2 - y) / (DIM / 2);

	cuComplex c(-0.8, 0.156);
	cuComplex a(jx, jy);

	int i = 0;
	for (i = 0; i < 200; i++) {
		a = a * a + c;
		if (a.magnitude2() > 1000)
			return 0;
	}

	return 1;
}

__global__ void kernel(unsigned char* ptr) {
	// Odwzorowanie z blockIdx na położenie piksela
	int x = blockIdx.x;
	int y = blockIdx.y;
	int offset = x + y * gridDim.x;

	// Obliczenie wartości dla tego miejsca
	int juliaValue = julia(x, y);
	ptr[offset * 4 + 0] = 255 * juliaValue;
	ptr[offset * 4 + 1] = 0;
	ptr[offset * 4 + 2] = 0;
	ptr[offset * 4 + 3] = 255;
}

// Wartości wymagane przez procedurę aktualizującą
struct DataBlock {
	unsigned char* dev_bitmap;
};

int main(void) {
	DataBlock   data;
	CPUBitmap bitmap(DIM, DIM, &data);
	unsigned char* dev_bitmap;

	HANDLE_ERROR(cudaMalloc((void**)&dev_bitmap, bitmap.image_size()));
	data.dev_bitmap = dev_bitmap;

	dim3    grid(DIM, DIM);
	kernel << <grid, 1 >> > (dev_bitmap);

	HANDLE_ERROR(cudaMemcpy(bitmap.get_ptr(), dev_bitmap,
		bitmap.image_size(),
		cudaMemcpyDeviceToHost));

	HANDLE_ERROR(cudaFree(dev_bitmap));

	bitmap.display_and_exit();
}