diff --git a/shader/root/rt.glsl b/shader/root/rt.glsl
index 7445cc1..0d48e0b 100644
--- a/shader/root/rt.glsl
+++ b/shader/root/rt.glsl
@@ -1,20 +1,23 @@
 #version 430
 
-layout (location = 1) uniform vec4 t;
+// TODO: do i actually need explicit location descriptors?
+layout (location = 1)   uniform vec4 _t;
 
-layout (location = 2) uniform vec3 _w;                       // view space axes
-layout (location = 3) uniform vec3 _u;
-layout (location = 4) uniform vec3 _v;
+layout (location = 2)   uniform vec3 _w;                        // view space axes
+layout (location = 3)   uniform vec3 _u;
+layout (location = 4)   uniform vec3 _v;
 
-layout (location = 5) uniform mat4 _cameraInverseProjection;
-layout (location = 6) uniform vec3 _camh;
-layout (location = 7) uniform vec3 _camv;
-layout (location = 8) uniform vec3 _camll;
+layout (location = 5)   uniform mat4 _cameraInverseProjection;
+layout (location = 6)   uniform vec3 _camh;
+layout (location = 7)   uniform vec3 _camv;
+layout (location = 8)   uniform vec3 _camll;
+layout (location = 9)   uniform vec3 _cpos;
+layout (location = 10)  uniform vec3 _tpos;                     // target
 
-layout(local_size_x = 1, local_size_y = 1) in;              // size of local work group - 1 pixel
-layout(rgba32f, binding = 0) uniform image2D img_output;    // rgba32f defines internal format, image2d for random write to output texture
+layout(local_size_x = 1, local_size_y = 1) in;                  // size of local work group - 1 pixel
+layout(rgba32f, binding = 0) uniform image2D img_output;        // rgba32f defines internal format, image2d for random write to output texture
 
-const float INF = 20.0;
+const float INF = 30.0;
 
 #include sphere.glsl
 
@@ -57,6 +60,8 @@ Ray createCameraRay(vec2 uv)
     uv = uv*0.5+0.5;
     //uv.x=1-uv.x;
 
+    vec3 target = vec3(0,0,0);
+
     // transform camera origin to world space
     // TODO: c2w matrix!! for now we just assume the camera is at the origin
     // float3 origin = mul(_CameraToWorld, float4(0.0,0.0,0.0,1.0)).xyz;
@@ -79,11 +84,11 @@ Ray createCameraRay(vec2 uv)
     float max_y = 5.0;
 
     Ray ray;
-    ray.origin = vec3(0.0,0.0,0.0);
+    ray.origin = _cpos;
     ray.direction = dir;
 
     return ray;
-}
+};
 
 void main()
 {
@@ -106,26 +111,30 @@ void main()
     hit.normal = vec3(0.0,0.0,0.0);
     hit.albedo = vec3(0.0,0.0,0.0);
 
-    vec3 spheresCenter = _w*-10.0;
+    vec3 spheresCenter = vec3(0.0,0.0,0.0);
 
+    float t = _t.x;
     Sphere s1;
-    s1.center = spheresCenter+vec3(sin(t.x),0.0,cos(t.x))*2.5;
+    s1.center = spheresCenter+vec3(sin(t),0.0,cos(t))*2.5;
     s1.radius = 2.0;
     s1.albedo = vec3(1.0,0.0,0.0);
 
+    t+=3.1415/1.5;
     Sphere s2;
-    s2.center = spheresCenter-vec3(sin(t.x),0.0,cos(t.x))*2.5;
+    s2.center = spheresCenter+vec3(sin(t),0.0,cos(t))*2.5;
     s2.radius = 2.0;
-    s2.albedo = vec3(0.0,0.0,1.0);
+    s2.albedo = vec3(0.0,1.0,0.0);
 
-    Sphere sphere;
-    sphere.center = _w*-10.0;
-    sphere.center += vec3(0.0,0.0,t.y);
-    sphere.radius = 4.0;
+    t+=3.1415/1.5;
+    Sphere s3;
+    s3.center = spheresCenter+vec3(sin(t),0.0,cos(t))*2.5;
+    s3.radius = 2.0;
+    s3.albedo = vec3(0.0,0.0,1.0);
 
     // ray-sphere intersection
     intersectSphere(ray, hit, s1);
     intersectSphere(ray, hit, s2);
+    intersectSphere(ray, hit, s3);
 
     // TODO: write depth to texture
     float depth = hit.distance/INF;
diff --git a/src/main.c b/src/main.c
index 45f249b..6f1d782 100644
--- a/src/main.c
+++ b/src/main.c
@@ -66,7 +66,7 @@ void updateUniforms(GLuint shaderProgram)
 {
     float t = time();                                           // time
     float sin_t = sin(t);
-    int tLocation = glGetUniformLocation(shaderProgram, "t");
+    int tLocation = glGetUniformLocation(shaderProgram, "_t");
     glUniform4f(tLocation, t, sin_t, (1.0 + sin_t)*0.5, 0.0f);
 
     updateCameraUniforms(shaderProgram);
@@ -85,10 +85,31 @@ void updateCameraUniforms(GLuint shaderProgram)
     int inverseProjLocation = glGetUniformLocation(shaderProgram, "_cameraInverseProjection");
     glUniformMatrix4fv(inverseProjLocation, 1, GL_FALSE, proji[0]);
 
+    float t = time();
+
+    vec3 cdir, cright, cup;
+    vec3 up = {0.1*sin(t),1.0,0.2*cos(t)};                                    // world up
+    glm_vec3_normalize(up);
+
+    // lookat vector and view matrix
+    float d = 10.0 + sin(t);
+    vec3 cpos = {sin(-t)*d,cos(0.5*t)*5.0,cos(-t)*d};                        // camera pos
+    vec3 tpos = {0.0,0.0,0.0};                                  // target pos
+    glm_vec3_sub(cpos,tpos,cdir);                               // look dir (inverted cause opengl noises)
+    glm_vec3_normalize(cdir); 
+    glm_vec3_cross(up,cdir,cright);                             // camera right
+    glm_vec3_normalize(cright);                                 
+    glm_vec3_cross(cdir,cright,cup);                            // camera up
+    glm_vec3_normalize(cup);
+    mat4 view;
+    glm_lookat(cpos,tpos,cup,view);
+    int cposLocation = glGetUniformLocation(shaderProgram, "_cpos");
+    glUniform3f(cposLocation, cpos[0],cpos[1],cpos[2]);
+
     // form view space axes
-    vec3 u,v;
-    vec3 up = {0.0,1.0,0.0};
-    vec3 w = {0.0,0.0,-1.0};
+    vec3 w,u,v;
+    glm_vec3_copy(cdir,w);
+
     glm_vec3_norm(w);
     glm_vec3_cross(up,w,u);
     glm_vec3_norm(u);
@@ -98,8 +119,9 @@ void updateCameraUniforms(GLuint shaderProgram)
     glUniform3f(wLocation+1, u[0], u[1], u[2]);                 // u
     glUniform3f(wLocation+2, v[0], v[1], v[2]);                 // v
 
+
     // get camera properties
-    float theta = glm_rad(fovy);                                    // convert fovy to radians
+    float theta = glm_rad(fovy);                                // convert fov to radians
     float h = tan(theta*0.5);
     float vph = 2.0*h;                                          // viewport height
     float vpw = aspect*vph;                                     // viewport width
diff --git a/todo.md b/todo.md
index 3d59c31..048504d 100644
--- a/todo.md
+++ b/todo.md
@@ -10,6 +10,7 @@
     * [x] pass uniforms to texture to animate it
     * [-] ray tracing time
         * [x] perspective
+        * [x] camera lookat
         * [-] depth
             * [x] acquire value
             * [ ] depth texture