Create material abstraction

include/material.h

@@ -0,0 +1,40 @@
+#ifndef MATERIAL_H
+#define MATERIAL_H
+
+#include "ray.h"
+#include "rng.h"
+
+#define LAMBERTIAN(r, g, b) \
+	{ \
+		.scatter = scatter_lambertian, \
+		.params = { .lambertian = { .albedo = { r, g, b } } }, \
+	}
+
+typedef struct {
+	vec3_t point, normal;
+	double t;
+	bool front;
+} hit_t;
+
+typedef struct {
+	vec3_t albedo;
+} lambertian_params_t;
+
+typedef union {
+	lambertian_params_t lambertian;
+} material_params_t;
+
+typedef bool scatter_fn_t(
+    material_params_t params, hit_t hit, rng_t *rng, ray_t *ray,
+    vec3_t *atten_out);
+
+typedef struct {
+	scatter_fn_t *scatter;
+	material_params_t params;
+} material_t;
+
+bool scatter_lambertian(
+    material_params_t params, hit_t hit, rng_t *rng, ray_t *ray,
+    vec3_t *atten_out);
+
+#endif