#include <cv.h>
#include <cvaux.h>
#include <highgui.h>
#include <stdio.h>

typedef struct {
	unsigned char r,g,b;
}rgb;

int main(int argc, char** argv) {
	int iy = 0,
	    ix = 0,
	    step = 0,
	    phases; 

	rgb *temp1 = 0, 
	   *temp2 = 0, 
	   *tempOut = 0;

	char *pStart1, 
	     *pStart2, 
	     *pOut, 
	     name[100];

	IplImage *image1 = 0, 
		 *image2 = 0, 
		 *imageOut = 0;

	argv++;
	phases = atoi(*argv++);
	image1 = cvLoadImage(*argv++, CV_LOAD_IMAGE_COLOR);
	image2 = cvLoadImage(*argv++, CV_LOAD_IMAGE_COLOR);

	imageOut = cvCreateImage(cvGetSstepe( image1 ), 8, 3);

	for(step = 0; step < phases; step++) {
		for(ix = 0; ix < image1->height; ix++) {

			pStart1 = image1->imageData + ix * image1->widthStep;
			pStart2 = image2->imageData + ix * image2->widthStep;
			pOut = imageOut->imageData + ix * imageOut->widthStep;

			for(iy = 0; iy < image1->width; iy++) {

				temp1 = (rgb*)(pStart1 + (iy * 3));
				temp2 = (rgb*)(pStart2 + (iy * 3));
				tempOut = (rgb*)(pOut + (iy * 3));

				tempOut->r = 	(temp1->r * step) / phases +
						(temp2->r * (phases - step)) / phases;

				tempOut->g = 	(temp1->g * step) / phases +
						(temp2->g * (phases - step)) / phases;

				tempOut->b = 	(temp1->b * step) / phases +
						(temp2->b * (phases - step)) / phases;
			}
		}

		sprintf(name, "transition%03d.png", step);
		cvSaveImage(name, imageOut);

		sprintf(name, "transition%03d.png", phases * 2 - step - 1);
		cvSaveImage(name, imageOut);
	}

	cvReleaseImage(&image1);
	cvReleaseImage(&image2);
	cvReleaseImage(&imageOut);

	return 0;
}