feat!: implement main using diverge

mandelbrot.c

@@ -1,19 +1,51 @@
 #include "stdio.h"
 #include "math.h"
 #include "stdint.h"
+#include "stdbool.h"
 
 #define MAX_DEPTH 50
-#define WIDTH 3
-#define HEIGHT 2
+#define WIDTH 420
+#define HEIGHT 360
 
-/////////////////////
-// complex numbers //
-/////////////////////
+#define X_MIN -1.0
+#define X_MAX 1.0
+#define Y_MIN -1.0
+#define Y_MAX 1.0
+
+#define SIZE (WIDTH * HEIGHT)
 
 typedef struct Complex {
   double real, imag;
 } Complex;
 
+typedef struct Color {
+  uint8_t r, g, b;
+} Color;
+
+int diverge(Complex c);
+Color color_map(int depth);
+void write_ppm(char *path, Color img[SIZE]);
+
+int main() {
+  Color img[SIZE];
+  for (int i = 0; i < HEIGHT; i++) {
+    for (int j = 0; j < WIDTH; j++) {
+      double x = ((double)j / (double)WIDTH) * (X_MAX - X_MIN) + X_MIN;
+      double y = ((double)i / (double)HEIGHT) * (Y_MAX - Y_MIN) + Y_MIN;
+      Complex c = {.real = x, .imag = y};
+      int depth = diverge(c);
+      img[i * WIDTH + j] = color_map(depth);
+    }
+  }
+  write_ppm("mandelbrot.c.ppm", img);
+
+  return 1;
+}
+
+/////////////////////
+// complex numbers //
+/////////////////////
+
 void cx_print(Complex z) {
   printf("%f + %f i", z.real, z.imag);
 }
@@ -34,28 +66,10 @@ static inline double cx_abs(Complex z) {
 // mandelbrot //
 ////////////////
 
-Complex f(Complex z, Complex c) {
+static inline 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;
@@ -65,11 +79,25 @@ int diverge(Complex c) {
   return counter;
 }
 
-int main() {
-  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}
+Color color_map(int depth) {
+  bool cond = depth % 2 == 0;
+  return (Color){
+    cond ? 255 : 0,
+    cond ? 255 : 0,
+    cond ? 255 : 0
   };
-  write_ppm("test.ppm", img);
-  return 1;
+}
+
+////////////////
+// ppm-writer //
+////////////////
+
+void write_ppm(char *path, Color img[SIZE]) {
+  FILE *fptr;
+  fptr = fopen(path, "w");
+  fprintf(fptr, "P3\n%d %d\n255\n", WIDTH, HEIGHT);
+  for (int i = 0; i < SIZE; i++)
+    fprintf(fptr, "%d %d %d\n", img[i].r, img[i].g, img[i].b);
+  printf("successfully wrote to %s\n", path);
+  fclose(fptr);
 }