Add a simple camera struct and camera controls

1 files changed, 43 insertions, 0 deletions

diff --git a/camera.c b/camera.c
new file mode 100644
index 0000000..6335d0e
--- /dev/null
+++ b/camera.c
@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2018 Tomasz Kramkowski <tk@the-tk.com>
+ * SPDX-License-Identifier: MIT
+ */
+#include <assert.h>
+#include <math.h>
+#include <stdlib.h>
+
+#include "camera.h"
+#include "math.h"
+
+#define PITCH_LIMIT (PI * 0.99)
+
+void camera_clamp(struct camera *cam)
+{
+	assert(cam != NULL);
+
+	cam->yaw = fmod(cam->yaw, 2 * PI);
+	if (cam->pitch > PITCH_LIMIT / 2)
+		cam->pitch = PITCH_LIMIT / 2;
+	else if (cam->pitch < -PITCH_LIMIT / 2)
+		cam->pitch = -PITCH_LIMIT / 2;
+}
+void camera_dir(vec3 out, struct camera *cam)
+{
+	assert(out != NULL);
+	assert(cam != NULL);
+
+	out[0] = cosf(cam->pitch) * cosf(cam->yaw);
+	out[1] = sinf(cam->pitch);
+	out[2] = cosf(cam->pitch) * sinf(cam->yaw);
+}
+void camera_lookat(mat4x4 out, struct camera *cam)
+{
+	vec3 at, dir;
+
+	assert(out != NULL);
+	assert(cam != NULL);
+
+	camera_dir(dir, cam);
+	vec3_add(at, cam->pos, dir);
+	mat4x4_look_at(out, cam->pos, at, (vec3){ 0, 1, 0 });
+}