diff --git a/README b/README
index 4d39492..d0a27e9 100644
--- a/README
+++ b/README
@@ -13,7 +13,7 @@ TODO:
 	add input abstraction for SDL
 	store meshes separately from entities for reuse
 	add a function to update camera transforms only once per frame, per shader
-	fix example Makefile dependenies
+	update camera to use quaternions for rotation
 
 Dependencies:
 	assimp >= 5.0.0
diff --git a/include/camera.h b/include/camera.h
index b545645..8346416 100644
--- a/include/camera.h
+++ b/include/camera.h
@@ -30,16 +30,37 @@ enum projection_type
 };
 
 
-v2f cameraUnproject(camera& cam, int x, int y, int vp_width, int vp_height);
+v2f
+cameraUnproject(camera& cam, int x, int y, int vp_width, int vp_height);
 
-v3f cameraCreateRay(camera& cam, v2i vp_coords, v2i vp_dims);
+v3f
+cameraCreateRay(camera& cam, v2i vp_coords, v2i vp_dims);
 
-bool cameraIntersectPlane(camera& cam, v3f ray, v3f plane_origin, v3f plane_normal, v3f& intersection);
+bool
+cameraIntersectPlane(camera& cam,
+	v3f ray,
+	v3f plane_origin,
+	v3f plane_normal,
+	v3f& intersection);
 
-void cameraInitPerspective(camera& cam, glm::vec3 position, glm::vec3 target, glm::vec3 world_up);
+void
+cameraInitPerspective(camera& cam,
+	glm::vec3 position,
+	glm::vec3 target,
+	glm::vec3 world_up,
+	float aspect_ratio = 16.f / 9.f);
 
-void cameraMove(camera& cam, bool up, bool left, bool down, bool right, bool forward, bool backward);
+void
+cameraMove(camera& cam,
+	bool up,
+	bool left,
+	bool down,
+	bool right,
+	bool forward,
+	bool backward);
 
-void cameraRotate(camera& cam, int32	xrel, int32 yrel);
+void
+cameraRotate(camera& cam, int32	xrel, int32 yrel);
 
-void cameraRoll(camera& cam, bool CW, bool CCW);
+void
+cameraRoll(camera& cam, bool CW, bool CCW);
diff --git a/include/renderer.h b/include/renderer.h
index cf7916c..52b3388 100644
--- a/include/renderer.h
+++ b/include/renderer.h
@@ -92,3 +92,6 @@ renAddLight(render_state* rs,
 	glm::vec3 color = glm::vec3(1, 1, 1),
 	float intensity = 1.0);
 
+glm::vec2
+renGetWindowDims(render_state* rs);
+
diff --git a/src/camera.cpp b/src/camera.cpp
index 0fa34f0..e89b563 100644
--- a/src/camera.cpp
+++ b/src/camera.cpp
@@ -1,4 +1,6 @@
 
+#include <cassert>
+
 #include <GL/glew.h>
 
 #include "camera.h"
@@ -8,7 +10,6 @@
 #define ROTATE_SPEED 0.005f
 #define CAMERA_Z_CLAMP_ANGLE 85.f
 #define FOV 60.f
-#define ASPECT_RATIO 16.f/9.f
 #define NEAR_CLIP_PLANE 20.f
 
 
@@ -19,20 +20,29 @@ inline glm::vec3 convertv3f(v3f v);
 // interface
 
 void
-cameraInitPerspective(camera& cam, glm::vec3 position, glm::vec3 target, glm::vec3 world_up)
+cameraInitPerspective(camera& cam,
+	glm::vec3 position,
+	glm::vec3 target,
+	glm::vec3 world_up,
+	float aspect_ratio)
 {
+	assert(aspect_ratio > 0);
+
 	cam.position = position;
 	cam.target = target;
 	cam.world_up = world_up;
-	cam.projection = glm::infinitePerspective(glm::radians(FOV), ASPECT_RATIO, NEAR_CLIP_PLANE);
+	cam.projection = glm::infinitePerspective(glm::radians(FOV),
+		aspect_ratio,
+		NEAR_CLIP_PLANE);
 
 	cam.forward = glm::normalize(target - position);
 	cam.left = glm::normalize(glm::cross(cam.world_up, cam.forward));
 	cam.up = glm::normalize(glm::cross(cam.forward, cam.left));
 
 	cam.hAngle = glm::atan(cam.forward.x, cam.forward.y);
-	// NOTE: using pythagoras' to get absolute value of relative axis for vAngle component
-	real32 len = glm::sqrt(glm::pow(cam.forward.y, 2) + glm::pow(cam.forward.x, 2));
+	// NOTE: get absolute value of relative axis for vAngle component
+	real32 len = glm::sqrt(glm::pow(cam.forward.y, 2) +
+		glm::pow(cam.forward.x, 2));
 	cam.vAngle = glm::atan(cam.forward.z, len);
 
 	cam.view = glm::lookAt(cam.position, cam.position + cam.forward, cam.up);
diff --git a/src/renderer.cpp b/src/renderer.cpp
index d287e47..064f243 100644
--- a/src/renderer.cpp
+++ b/src/renderer.cpp
@@ -164,6 +164,15 @@ renAddLight(render_state* rs, glm::vec3 pos, glm::vec3 color, float intensity)
 	return true;
 }
 
+glm::vec2
+renGetWindowDims(render_state* rs)
+{
+	int x = 0, y = 0;
+	SDL_GetWindowSize(rs->handles->window, &x, &y);
+	glm::vec2 dims(x, y);
+	return dims;
+}
+
 
 // internal