#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>

inline int
OK(int x) {
	return x == 0;
}

////RGBImage////

typedef uint8_t  byte;
typedef uint16_t byte2;
typedef uint32_t byte4;

typedef struct _RGB {
	byte r;
	byte g;
	byte b;
} RGB;

void
ARGB_set(RGB* rgb, byte4 color) {
	rgb->r = (0xFF0000 & color) >> 16;
	rgb->g = (0x00FF00 & color) >> 8;
	rgb->b = (0x0000FF & color);
}

typedef struct _RGBImage {
	int width;
	int height;
	RGB* img;
} RGBImage;

RGBImage
RGBImage_new(int width, int height) {
	return (RGBImage){
		.width  = width,
		.height = height,
		.img    = malloc(sizeof(RGB) * width * height)
	};
}

void
RGBImage_free(RGBImage img) {
	free(img.img);
}

void
RGBImage_delete(RGBImage* img) {
	RGBImage_free(*img);
	img->width = img->height = 0;
	img->img = NULL;
}

RGB*
RGBImage_at(RGBImage img, int row, int col) {
	return img.img + (row % img.height) * img.width + col % img.width;
}

int
ppm6_write(FILE* f, RGBImage img) {
	fprintf(f, "P6\n%d %d\n255\n", img.width, img.height);
	fwrite(img.img, sizeof(*img.img), img.width * img.height, f);
	return fflush(f);
}

////main////

int
main() {
	RGBImage frame = RGBImage_new(512, 512);

	for (int frameIndex = 0; frameIndex < 120; ++frameIndex) {

		for (int r = 0; r < frame.width; ++r)
		for (int c = 0; c < frame.height; ++c) {
			RGB* pixel = RGBImage_at(frame, r, c);

			if (((r + frameIndex) / 32 + (c + frameIndex) / 32) % 2 == 0) {
				ARGB_set(pixel, 0x000000);
			}
			else {
				ARGB_set(pixel, 0xFF00FF);
			}
		}

		ppm6_write(stdout, frame);
	}

	RGBImage_delete(&frame);

	return 0;
}