implement write_ppm

mandelbrot.c

@@ -1,11 +1,17 @@
 #include "stdio.h"
 #include "math.h"
+#include "stdint.h"
 
 #define MAX_DEPTH 50
+#define WIDTH 3
+#define HEIGHT 2
 
-typedef struct {
-  double real;
-  double imag;
+/////////////////////
+// complex numbers //
+/////////////////////
+
+typedef struct Complex {
+  double real, imag;
 } Complex;
 
 void cx_print(Complex z) {
@@ -24,10 +30,32 @@ static inline double cx_abs(Complex z) {
   return sqrt(z.real * z.real + z.imag * z.imag);
 }
 
+////////////////
+// mandelbrot //
+////////////////
+
 Complex f(Complex z, Complex c) {
   return cx_add(cx_square(z), c);
 }
 
+////////////////
+// ppm-writer //
+////////////////
+
+typedef struct Color {
+  uint8_t r, g, b;
+} Color;
+
+void write_ppm(char *path, Color img[HEIGHT * WIDTH]) {
+  FILE *fptr;
+  fptr = fopen(path, "w");
+  fprintf(fptr, "P3\n%d %d\n255\n", WIDTH, HEIGHT);
+  for (int i = 0; i < WIDTH * HEIGHT; i++) {
+    fprintf(fptr, "%d %d %d\n", img[i].r, img[i].g, img[i].b);
+  }
+  fclose(fptr);
+}
+
 // return iteration count, MAX_DEPTH if diverge
 int diverge(Complex c) {
   int counter = 0;
@@ -38,7 +66,10 @@ int diverge(Complex c) {
 }
 
 int main() {
-  Complex z = {2.0, 4.0};
-  cx_print(z);
+  Color img[WIDTH * HEIGHT] = {
+    (Color){255, 0, 0}, (Color){0, 255, 0}, (Color){0, 0, 255},
+    (Color){255, 0, 0}, (Color){0, 255, 0}, (Color){0, 0, 255}
+  };
+  write_ppm("test.ppm", img);
   return 1;
 }