Add vectors, points and colors

build.sh

@@ -2,7 +2,7 @@
 
 CC=${CC:-"gcc"}
 CFLAGS=${CFLAGS:-"-Wall -Wextra -std=c18 -g"}
-LDFLAGS=${LDFLAGS:-""}
+LDFLAGS=${LDFLAGS:-"-lm"}
 MAIN_FILE=${MAIN_FILE:-"main.c"}
 
 # Write out compile_flags.txt for clangd

color.c

@@ -0,0 +1,7 @@
+#include "color.h"
+#include <stdio.h>
+
+void color_write(FILE *out, color c) {
+  fprintf(out, "%d %d %d\n", (int)(255.999 * c.r), (int)(255.999 * c.g),
+          (int)(255.999 * c.b));
+}

color.h

@@ -0,0 +1,12 @@
+#ifndef INCLUDED_COLOR_H
+#define INCLUDED_COLOR_H
+
+#include <stdio.h>
+
+typedef struct color {
+  double r, g, b;
+} color;
+
+void color_write(FILE *out, color c);
+
+#endif /* INCLUDED_COLOR_H */

main.c

@@ -1,5 +1,7 @@
 #include <stdio.h>
 
+#include "color.h"
+
 int main(void) {
   const int image_width = 256;
   const int image_height = 256;
@@ -9,15 +11,12 @@ int main(void) {
   for (int j = image_height - 1; j >= 0; --j) {
     fprintf(stderr, "\rScanlines remaining: %d      ", j);
     for (int i = 0; i < image_width; ++i) {
-      double r = (double)(i) / (image_width - 1);
-      double g = (double)(j) / (image_height - 1);
-      double b = 0.25;
-
-      int ir = (int)(255.999 * r);
-      int ig = (int)(255.999 * g);
-      int ib = (int)(255.999 * b);
-
-      printf("%d %d %d\n", ir, ig, ib);
+      color pixel_color = {
+          .r = (double)(i) / (image_width - 1),
+          .g = (double)(j) / (image_height - 1),
+          .b = 0.25,
+      };
+      color_write(stdout, pixel_color);
     }
   }
 
@@ -25,3 +24,7 @@ int main(void) {
 
   return 0;
 }
+
+#include "color.c"
+#include "point3.c"
+#include "vec3.c"

point3.c

@@ -0,0 +1,9 @@
+#include "point3.h"
+
+point3 point3_add(point3 p, vec3 v) {
+  return (point3){p.x + v.x, p.y + v.y, p.z + v.z};
+}
+
+vec3 point3_sub(point3 p1, point3 p2) {
+  return (vec3){p1.x - p2.x, p1.y - p2.y, p1.z - p2.z};
+}

point3.h

@@ -0,0 +1,13 @@
+#ifndef INCLUDED_POINT3_H
+#define INCLUDED_POINT3_H
+
+#include "vec3.h"
+
+typedef struct point3 {
+  double x, y, z;
+} point3;
+
+point3 point3_add(point3 p, vec3 v);
+vec3 point3_sub(point3 p1, point3 p2);
+
+#endif /* INCLUDED_POINT3_H */

vec3.c

@@ -0,0 +1,35 @@
+#include "vec3.h"
+
+#include <math.h>
+
+vec3 vec3_neg(vec3 v) { return (vec3){-v.x, -v.y, -v.z}; }
+
+vec3 vec3_add(vec3 v1, vec3 v2) {
+  return (vec3){v1.x + v2.x, v1.y + v2.y, v1.z + v2.z};
+}
+
+vec3 vec3_sub(vec3 v1, vec3 v2) {
+  return (vec3){v1.x - v2.x, v1.y - v2.y, v1.z - v2.z};
+}
+
+vec3 vec3_mul(double c, vec3 v) { return (vec3){c * v.x, c * v.y, c * v.z}; }
+
+vec3 vec3_div(vec3 v, double c) { return (vec3){v.x / c, v.y / c, v.z / c}; }
+
+double vec3_length(vec3 v) { return sqrt(vec3_length2(v)); }
+
+double vec3_length2(vec3 v) { return v.x * v.x + v.y * v.y + v.z * v.z; }
+
+vec3 vec3_normalize(vec3 v) { return vec3_div(v, vec3_length(v)); }
+
+double vec3_dot(vec3 v1, vec3 v2) {
+  return v1.x * v2.x + v1.y * v2.y + v1.z * v2.z;
+}
+
+vec3 vec3_cross(vec3 v1, vec3 v2) {
+  return (vec3){
+      v1.y * v2.z - v1.z * v2.y,
+      v1.z * v2.x - v1.x * v2.z,
+      v1.x * v2.y - v1.y * v2.x,
+  };
+}

vec3.h

@@ -0,0 +1,22 @@
+#ifndef INCLUDED_VEC3_H
+#define INCLUDED_VEC3_H
+
+typedef struct vec3 {
+  double x, y, z;
+} vec3;
+
+vec3 vec3_neg(vec3 v);
+vec3 vec3_add(vec3 v1, vec3 v2);
+vec3 vec3_sub(vec3 v1, vec3 v2);
+vec3 vec3_mul(double c, vec3 v);
+vec3 vec3_div(vec3 v, double c);
+
+double vec3_length(vec3 v);
+double vec3_length2(vec3 v);
+
+vec3 vec3_normalize(vec3 v);
+
+double vec3_dot(vec3 v1, vec3 v2);
+vec3 vec3_cross(vec3 v1, vec3 v2);
+
+#endif /* INCLUDED_VEC3_H */