//
// Created by ary on 19.07.2026.
//

#include "examples.h"
#include "structs.h"
#include "vectorOp.h"
#include "raytrace.h"
#include <stdlib.h>

void example_color(int width, int height, int channels, unsigned char *image) {
    for (int i = 0; i < height * width; i++) {
        int step = i *channels;
        int x = i % width;
        int y = i / width;
        image[step] = 0 + (int)((((double)x)/width) * 255);
        image[step+1] = 0 + (int)((((double)y)/width) * 255);
        image[step+2] = 0;
        if (channels == 4) {
            image[step+3] = 255;
        }
    }
}

void exampleSphere( int width, int height, int channels, unsigned char *image) {
    camera cam1;
    cam1.origin.x = 0;
    cam1.origin.y = 0;
    cam1.origin.z = 0;
    cam1.direction.x = 0;
    cam1.direction.y = 0;
    cam1.direction.z = 1;
    cam1.resolutionX = width;
    cam1.resolutionY = height;
    cam1.screenDistance = 1;
    cam1.width = 1.920;
    cam1.height = 1.080;
    vec3 sphereOrigin = (vec3){0,0,5};
    double sphereRadius = 2.0;
    sphere obj = (sphere){sphereOrigin, sphereRadius};

    vec3 worldUp = (vec3){0, 1, 0};
    vec3 screenX = vec3Cross(worldUp, cam1.direction);
    vec3 screenY = vec3Cross(screenX, cam1.direction);
    vec3 screenMiddlePoint = vec3Add(cam1.origin, vec3Scale(cam1.direction, cam1.screenDistance));
    vec3 screenTopLeft = vec3Add(
        vec3Add(screenMiddlePoint,
            vec3Scale(screenY, -cam1.height/2.0)),
        vec3Scale(screenX, -cam1.width/2.0)
        );
    double pixelStepX = cam1.width / cam1.resolutionX;
    double pixelStepY = cam1.height / cam1.resolutionY;
    vec3 vecPixelStepX = vec3Scale(screenX, pixelStepX);
    vec3 vecPixelStepY = vec3Scale(screenY, pixelStepY);
    for (int i = 0; i < height * width; i++) {
        int step = i *channels;
        int x = i % width;
        int y = i / width;
        RGBA pixelColor;

        vec3 *pixelOrigin = (vec3 *)malloc(sizeof(vec3));
        *pixelOrigin = vec3Add(screenTopLeft,
            vec3Add(
                vec3Scale(vecPixelStepX, x),
                vec3Scale(vecPixelStepY, y)
                )
        );

        ray *lightRay = (ray *)malloc(sizeof(ray));;
        lightRay->origin = cam1.origin;

        lightRay->direction = vec3Normalize(vec3Subtract(*pixelOrigin, cam1.origin));

        pixelColor = raytraceSphere(&obj, lightRay);
        free(pixelOrigin);
        free(lightRay);

        image[step] = (int)(pixelColor.r * 255.0);
        image[step+1] = 0;
        image[step+2] = 0;
        if (channels == 4) {
            image[step+3] = 255;
        }
    }
}