#define STB_IMAGE_IMPLEMENTATION
#define STB_IMAGE_WRITE_IMPLEMENTATION
#define STBI_MSC_SECURE_CRT
#define M_PI 3.14159265358979323846

#include "stb_image.h"
#include "stb_image_write.h"

#include <cmath>
#include <algorithm>
#include <iostream>
#include <cstdint>

extern "C"
{
    void blur(uint32_t* source, uint32_t* target, float* kernel, uint32_t width, uint32_t height, uint32_t kernel_size, float weight_sum);
}

int main()
{
    int width = 0, height = 0, channels = 0;
    uint32_t* source = new uint32_t[width*height];//(uint32_t*)stbi_load("test.jpg", &width, &height, &channels, 4);
    uint32_t* target = new uint32_t[width*height];

    const float sigma = 50 / 2.57;
    const int radius = ceil(50);
    const float exp_denom = 2 * sigma * sigma;
    const float gauss_denom = sqrt(M_PI * 2 * sigma * sigma);

    float* weight = new float[2 * radius + 1];
    float weight_sum = 0;
    for (int i = 0; i < 2 * radius + 1; i++)
    {
        const int numerator = (i - radius) * (i - radius);
        weight[i] = exp(-numerator / exp_denom) / gauss_denom;
        weight_sum += weight[i];
    }

    blur((int*)1, (int*)2, (float*)3, 4, 5, 6, 7);

    blur(source, target, weight, width, height, 2*radius, 1/weight_sum);
    stbi_write_jpg("test_output.jpg", width, height, 4, target, 100);

    return 0;
}