diff --git a/assets/shaders/deferred.frag b/assets/shaders/deferred.frag
index 11ba61e..1f52344 100644
--- a/assets/shaders/deferred.frag
+++ b/assets/shaders/deferred.frag
@@ -1,24 +1,83 @@
 #version 450
 
+#include "shaders://_builtins/constants.glsl"
+#include "shaders://_builtins/PBR.glsl"
+
+struct Light {
+  mat4 tranform;
+  vec4 color;
+  float intensity;
+};
+
+const int MAX_LIGHT_COUNT = 128;
+
+layout( push_constant ) uniform constants
+{
+  uint lightCount;
+} PushConstants;
+
 layout(set = 0, binding = 0) uniform sampler2D positionTexture;
-
 layout(set = 0, binding = 1) uniform sampler2D normalTexture;
-
 layout(set = 0, binding = 2) uniform sampler2D albedoTexture;
-
 layout(set = 0, binding = 3) uniform sampler2D specularTexture;
 
+layout(set = 1, binding = 1) uniform LightBuffer {
+  layout(align = 16) Light lights[MAX_LIGHT_COUNT];
+} LightsBuffer;
+
 layout (location = 0) in vec2 inUV;
+layout(location = 1) in vec3 cameraPos;
 
 layout(location = 0) out vec4 outColor;
 
 void main()
 {
-  vec3 fragPos = texture(positionTexture, inUV).rgb;
+  vec3 position = texture(positionTexture, inUV).rgb;
   vec3 normal = texture(normalTexture, inUV).rgb;
-  vec4 albedo = texture(albedoTexture, inUV);
+  vec3 albedo = texture(albedoTexture, inUV).rgb;
 
-  // outColor = vec4(fragPos, 1.0);
-  // outColor = vec4(normal, 1.0);
-  outColor = albedo;
+  vec3 spec = texture(specularTexture, inUV).rgb;
+  float metallicFactor = spec.b;
+  float roughnessFactor = spec.g;
+  float ao = spec.r;
+
+  vec3 V = normalize(cameraPos - position);
+
+  vec3 Lo = vec3(0);
+  for(int i = 0; i < PushConstants.lightCount; ++i)
+  {
+    Light l = LightsBuffer.lights[i];
+
+    vec3 L = normalize(l.tranform[3].xyz - position);
+    vec3 H = normalize(V + L);
+    float distance    = length(l.tranform[3].xyz - position);
+    float attenuation = 1.0 / (distance * distance);
+    vec3 radiance     = l.color.xyz * attenuation * l.intensity;
+
+    vec3 F0 = vec3(0.04);
+    F0      = mix(F0, albedo, metallicFactor);
+
+    vec3 F  = fresnelSchlick(max(dot(H, V), 0.0), F0);
+    float NDF = DistributionGGX(normal, H, roughnessFactor);
+    float G   = GeometrySmith(normal, V, L, roughnessFactor);
+
+    vec3 numerator    = NDF * G * F;
+    float denominator = 4.0 * max(dot(normal, V), 0.0) * max(dot(normal, L), 0.0);
+    vec3 specular     = numerator / max(denominator, 0.001);
+
+    vec3 kS = F;
+    vec3 kD = vec3(1.0) - kS;
+    kD *= 1.0 - metallicFactor;
+
+    float NdotL = max(dot(normal, L), 0.0);
+    Lo += (kD * albedo / PI + specular) * radiance * NdotL;
+  }
+
+  vec3 ambient = vec3(0.2) * albedo * ao;
+
+  vec3 color   = ambient + Lo;
+  // color += vec3();
+  color = color / (color + vec3(1.0));
+
+  outColor = vec4(color, 1.0);
 }
diff --git a/assets/shaders/deferred.vert b/assets/shaders/deferred.vert
index b9a0e0f..206a683 100644
--- a/assets/shaders/deferred.vert
+++ b/assets/shaders/deferred.vert
@@ -1,9 +1,22 @@
 #version 450
 
+layout( push_constant ) uniform constants
+{
+  uint lightCount;
+} PushConstants;
+
+layout(set = 1, binding = 0) uniform CameraParam {
+  mat4 projection;
+  mat4 view;
+} Camera;
+
 layout (location = 0) out vec2 outUV;
+layout(location = 1) out vec3 cameraPos;
 
 void main()
 {
 	outUV = vec2((gl_VertexIndex << 1) & 2, gl_VertexIndex & 2);
 	gl_Position = vec4(outUV * 2.0f - 1.0f, 0.0f, 1.0f);
+
+  cameraPos = inverse(Camera.view)[3].xyz;
 }
diff --git a/assets/shaders/mrt.frag b/assets/shaders/mrt.frag
index 55caee2..17ba776 100755
--- a/assets/shaders/mrt.frag
+++ b/assets/shaders/mrt.frag
@@ -1,6 +1,10 @@
 #version 450
 #extension GL_EXT_nonuniform_qualifier : require
 
+#include "shaders://_builtins/constants.glsl"
+#include "shaders://_builtins/srgb_ops.glsl"
+#include "shaders://_builtins/PBR.glsl"
+
 struct Material {
   vec4 baseColor;
   uint albedoTexture;
@@ -52,6 +56,7 @@ layout(location = 4) in vec4 outpos;
 layout (location = 0) out vec4 gPosition;
 layout (location = 1) out vec3 gNormal;
 layout (location = 2) out vec3 gAlbedo;
+layout (location = 3) out vec3 gSpecular;
 
 float near = 0.001;
 float far  = 50.0;
@@ -65,32 +70,37 @@ float LinearizeDepth(float depth)
 void main() {
   Material material  = MaterialBuffers.materials[ PushConstants.materialBufferIndex ];
 
-  vec3 out_normal;
+  vec3 outNormal;
   if(material.normalTexture == 0) {
-    out_normal = TBN[2].xyz;
+    outNormal = TBN[2].xyz;
   } else {
-    vec3 sampled_normal = texture(texSampler[material.normalTexture], uv).rgb;
+    vec3 sampled_normal = LinearToSRGB(texture(texSampler[material.normalTexture], uv)).rgb;
     sampled_normal = 2.0 * sampled_normal - vec3(1.0);
-    out_normal = normalize(TBN * sampled_normal);
+    outNormal = normalize(TBN * sampled_normal);
   }
 
+  //float intensity = dot(outNormal, normalize(directional_light)) + 0.2;
 
-  float intensity = dot(out_normal, normalize(directional_light)) + 0.2;
-
-  vec3 inColor;
+  vec3 outColor;
   if(material.albedoTexture == 0) {
-    inColor = material.baseColor.xyz;
+    outColor = material.baseColor.xyz;
   } else {
-    inColor = texture(texSampler[material.albedoTexture], uv).xyz;
+    outColor = texture(texSampler[material.albedoTexture], uv).xyz;
+  }
+
+  vec3 outSpecular;
+  if(material.metallicRoughnessTexture == 0) {
+    outSpecular.b = material.metallicFactor;
+    outSpecular.g = material.roughnessFactor;
+    outSpecular.r = 1;
+  } else {
+    outSpecular = LinearToSRGB(texture(texSampler[material.metallicRoughnessTexture], uv)).xyz;
   }
 
   float depth = LinearizeDepth(gl_FragCoord.z) / far; // divide by far for demonstration
 
   gPosition = outpos;
-  gNormal = out_normal;
-  gAlbedo = inColor;
-  // outColor = vec4(vec3(outpos.z) * 0.5 + 0.5 , 1.0);
-  // outColor = vec4(inColor, 1.0);
-  // outColor = vec4(vec3(intensity), 1.0);
-  // outColor = vec4(out_normal, 1.0);
+  gNormal = outNormal;
+  gAlbedo = outColor;
+  gSpecular = outSpecular;
 }
diff --git a/assets/shaders/skybox.frag b/assets/shaders/skybox.frag
new file mode 100644
index 0000000..bf4c796
--- /dev/null
+++ b/assets/shaders/skybox.frag
@@ -0,0 +1,12 @@
+#version 450
+
+layout (set = 0, binding = 0) uniform samplerCube skybox;
+
+layout(location = 0) in vec3 texCoords;
+
+layout(location = 0) out vec4 outColor;
+
+void main()
+{
+  outColor = texture(skybox, texCoords);
+}
diff --git a/assets/shaders/skybox.vert b/assets/shaders/skybox.vert
new file mode 100644
index 0000000..a716cef
--- /dev/null
+++ b/assets/shaders/skybox.vert
@@ -0,0 +1,61 @@
+#version 450
+
+layout(set = 1, binding = 0) uniform CameraParam {
+  mat4 projection;
+  mat4 view;
+} Camera;
+
+vec3 positions[36] = vec3[](
+    vec3(-1.0f,  1.0f, -1.0f),
+    vec3(-1.0f, -1.0f, -1.0f),
+    vec3( 1.0f, -1.0f, -1.0f),
+    vec3( 1.0f, -1.0f, -1.0f),
+    vec3( 1.0f,  1.0f, -1.0f),
+    vec3(-1.0f,  1.0f, -1.0f),
+
+    vec3(-1.0f, -1.0f,  1.0f),
+    vec3(-1.0f, -1.0f, -1.0f),
+    vec3(-1.0f,  1.0f, -1.0f),
+    vec3(-1.0f,  1.0f, -1.0f),
+    vec3(-1.0f,  1.0f,  1.0f),
+    vec3(-1.0f, -1.0f,  1.0f),
+
+    vec3( 1.0f, -1.0f, -1.0f),
+    vec3( 1.0f, -1.0f,  1.0f),
+    vec3( 1.0f,  1.0f,  1.0f),
+    vec3( 1.0f,  1.0f,  1.0f),
+    vec3( 1.0f,  1.0f, -1.0f),
+    vec3( 1.0f, -1.0f, -1.0f),
+
+    vec3(-1.0f, -1.0f,  1.0f),
+    vec3(-1.0f,  1.0f,  1.0f),
+    vec3( 1.0f,  1.0f,  1.0f),
+    vec3( 1.0f,  1.0f,  1.0f),
+    vec3( 1.0f, -1.0f,  1.0f),
+    vec3(-1.0f, -1.0f,  1.0f),
+
+    vec3(-1.0f,  1.0f, -1.0f),
+    vec3( 1.0f,  1.0f, -1.0f),
+    vec3( 1.0f,  1.0f,  1.0f),
+    vec3( 1.0f,  1.0f,  1.0f),
+    vec3(-1.0f,  1.0f,  1.0f),
+    vec3(-1.0f,  1.0f, -1.0f),
+
+    vec3(-1.0f, -1.0f, -1.0f),
+    vec3(-1.0f, -1.0f,  1.0f),
+    vec3( 1.0f, -1.0f, -1.0f),
+    vec3( 1.0f, -1.0f, -1.0f),
+    vec3(-1.0f, -1.0f,  1.0f),
+    vec3( 1.0f, -1.0f,  1.0f)
+);
+
+layout(location = 0) out vec3 texCoords;
+
+void main()
+{
+  mat4 normalView = mat4(mat3(Camera.view));
+
+  texCoords = positions[gl_VertexIndex];
+  vec4 pos = Camera.projection * normalView * vec4(positions[gl_VertexIndex], 1.0);
+  gl_Position = pos.xyww;
+}
diff --git a/assets/textures/skybox/back.tx b/assets/textures/skybox/back.tx
new file mode 100644
index 0000000..f35261b
Binary files /dev/null and b/assets/textures/skybox/back.tx differ
diff --git a/assets/textures/skybox/bottom.tx b/assets/textures/skybox/bottom.tx
new file mode 100644
index 0000000..c99ee82
Binary files /dev/null and b/assets/textures/skybox/bottom.tx differ
diff --git a/assets/textures/skybox/front.tx b/assets/textures/skybox/front.tx
new file mode 100644
index 0000000..321cc04
Binary files /dev/null and b/assets/textures/skybox/front.tx differ
diff --git a/assets/textures/skybox/left.tx b/assets/textures/skybox/left.tx
new file mode 100644
index 0000000..b2b61d9
Binary files /dev/null and b/assets/textures/skybox/left.tx differ
diff --git a/assets/textures/skybox/right.tx b/assets/textures/skybox/right.tx
new file mode 100644
index 0000000..0f5344d
Binary files /dev/null and b/assets/textures/skybox/right.tx differ
diff --git a/assets/textures/skybox/top.tx b/assets/textures/skybox/top.tx
new file mode 100644
index 0000000..ab911d9
Binary files /dev/null and b/assets/textures/skybox/top.tx differ