#include "camera.h"


void
cameraInitPerspective(camera& cam, glm::vec3 position, glm::vec3 target, glm::vec3 up)
{
	cam.position = position;
	cam.target = target;
	cam.up = up;
	cam.projection = glm::infinitePerspective(glm::radians(FOV), ASPECT_RATIO, NEAR_CLIP_PLANE);

	cam.hAngle = 0;
	cam.vAngle = glm::atan((cam.target.z - cam.position.z) / (cam.target.y - cam.position.y));

	// FIXME: bug, camera always starts with forward pointing at positive 'z' axis
	// 	camera position also changes with change to window size
	cam.forward = glm::normalize(glm::vec3(
			glm::cos(cam.vAngle) * glm::sin(cam.hAngle),
			glm::cos(cam.vAngle) * glm::cos(cam.hAngle),
			glm::sin(cam.vAngle)
		));
	cam.left = glm::normalize(glm::cross(cam.up, cam.forward));
	cam.up = glm::normalize(glm::cross(cam.forward, cam.left)); // get better "up" vector

	cam.view = glm::lookAt(cam.position, cam.position + cam.forward, cam.up);
	cam.model = glm::mat4(1.0f);
	cam.MVP = cam.projection * cam.view * cam.model;
}