diff --git a/src/main/kotlin/ru/dbotthepony/kstarbound/client/StarboundClient.kt b/src/main/kotlin/ru/dbotthepony/kstarbound/client/StarboundClient.kt
index c35469c8..c5240402 100644
--- a/src/main/kotlin/ru/dbotthepony/kstarbound/client/StarboundClient.kt
+++ b/src/main/kotlin/ru/dbotthepony/kstarbound/client/StarboundClient.kt
@@ -173,8 +173,8 @@ class StarboundClient : Closeable {
 
 		GLFW.glfwWindowHint(GLFW.GLFW_VISIBLE, GLFW.GLFW_FALSE)
 		GLFW.glfwWindowHint(GLFW.GLFW_RESIZABLE, GLFW.GLFW_TRUE)
-		GLFW.glfwWindowHint(GLFW.GLFW_CONTEXT_VERSION_MAJOR, 4)
-		GLFW.glfwWindowHint(GLFW.GLFW_CONTEXT_VERSION_MINOR, 6)
+		GLFW.glfwWindowHint(GLFW.GLFW_CONTEXT_VERSION_MAJOR, 3)
+		GLFW.glfwWindowHint(GLFW.GLFW_CONTEXT_VERSION_MINOR, 3)
 		GLFW.glfwWindowHint(GLFW.GLFW_OPENGL_PROFILE, GLFW.GLFW_OPENGL_CORE_PROFILE)
 
 		window = GLFW.glfwCreateWindow(800, 600, "KStarbound", MemoryUtil.NULL, MemoryUtil.NULL)
@@ -843,7 +843,6 @@ class StarboundClient : Closeable {
 		ensureSameThread()
 
 		var diff = nextRender - System.nanoTime()
-		var yields = 0
 
 		// try to sleep until next frame as precise as possible
 		while (diff > 0L) {
@@ -851,7 +850,6 @@ class StarboundClient : Closeable {
 				LockSupport.parkNanos(1_000_000L)
 			} else {
 				Thread.yield()
-				yields++
 			}
 
 			diff = nextRender - System.nanoTime()
diff --git a/src/main/kotlin/ru/dbotthepony/kstarbound/client/world/ClientWorld.kt b/src/main/kotlin/ru/dbotthepony/kstarbound/client/world/ClientWorld.kt
index ab533dcb..1d117ede 100644
--- a/src/main/kotlin/ru/dbotthepony/kstarbound/client/world/ClientWorld.kt
+++ b/src/main/kotlin/ru/dbotthepony/kstarbound/client/world/ClientWorld.kt
@@ -90,7 +90,7 @@ class ClientWorld(
 						val tile = view.getTile(x, y) ?: continue
 						val material = tile.material
 
-						if (material != null && !material.isMeta) {
+						if (!material.isMeta) {
 							client.tileRenderers.getMaterialRenderer(material.materialName).tesselate(tile, view, meshes, Vector2i(x, y), background = isBackground)
 						}
 
diff --git a/src/main/resources/shaders/flat.fsh b/src/main/resources/shaders/flat.fsh
index ab68d955..846ac241 100644
--- a/src/main/resources/shaders/flat.fsh
+++ b/src/main/resources/shaders/flat.fsh
@@ -1,5 +1,5 @@
 
-#version 460
+#version 330
 
 uniform vec4 color;
 out vec4 color_out;
diff --git a/src/main/resources/shaders/flat.vsh b/src/main/resources/shaders/flat.vsh
index 707bd488..731d50c4 100644
--- a/src/main/resources/shaders/flat.vsh
+++ b/src/main/resources/shaders/flat.vsh
@@ -1,5 +1,5 @@
 
-#version 460
+#version 330
 
 layout (location = 0) in vec2 pos;
 uniform mat4 transform;
diff --git a/src/main/resources/shaders/flat_color.fsh b/src/main/resources/shaders/flat_color.fsh
index 8eda7992..90d524b7 100644
--- a/src/main/resources/shaders/flat_color.fsh
+++ b/src/main/resources/shaders/flat_color.fsh
@@ -1,5 +1,5 @@
 
-#version 460
+#version 330
 
 in vec4 finalVertexColor;
 
diff --git a/src/main/resources/shaders/flat_color.vsh b/src/main/resources/shaders/flat_color.vsh
index 6989e33f..3e106a27 100644
--- a/src/main/resources/shaders/flat_color.vsh
+++ b/src/main/resources/shaders/flat_color.vsh
@@ -1,5 +1,5 @@
 
-#version 460
+#version 330
 
 layout (location = 0) in vec2 vertexPos;
 layout (location = 1) in vec4 vertexColor;
diff --git a/src/main/resources/shaders/font.fsh b/src/main/resources/shaders/font.fsh
index b97c6ba3..5b6500c5 100644
--- a/src/main/resources/shaders/font.fsh
+++ b/src/main/resources/shaders/font.fsh
@@ -1,5 +1,5 @@
 
-#version 460
+#version 330
 
 in vec2 uv_out;
 out vec4 color_out;
diff --git a/src/main/resources/shaders/font.vsh b/src/main/resources/shaders/font.vsh
index 336af8ec..ac1b45b8 100644
--- a/src/main/resources/shaders/font.vsh
+++ b/src/main/resources/shaders/font.vsh
@@ -1,5 +1,5 @@
 
-#version 460
+#version 330
 
 layout (location = 0) in vec2 pos;
 layout (location = 1) in vec2 uv_in;
diff --git a/src/main/resources/shaders/fragment/texture.glsl b/src/main/resources/shaders/fragment/texture.glsl
index e7663dfb..bd8f867d 100644
--- a/src/main/resources/shaders/fragment/texture.glsl
+++ b/src/main/resources/shaders/fragment/texture.glsl
@@ -1,5 +1,5 @@
 
-#version 460
+#version 330
 
 uniform sampler2D texture0;
 
diff --git a/src/main/resources/shaders/fragment/texture_color.glsl b/src/main/resources/shaders/fragment/texture_color.glsl
index 27680e40..90614da8 100644
--- a/src/main/resources/shaders/fragment/texture_color.glsl
+++ b/src/main/resources/shaders/fragment/texture_color.glsl
@@ -1,5 +1,5 @@
 
-#version 460
+#version 330
 
 uniform sampler2D texture0;
 uniform vec4 color;
diff --git a/src/main/resources/shaders/light.fsh b/src/main/resources/shaders/light.fsh
index 07268458..484d23ce 100644
--- a/src/main/resources/shaders/light.fsh
+++ b/src/main/resources/shaders/light.fsh
@@ -1,5 +1,5 @@
 
-#version 460
+#version 330
 
 in vec2 oUVCoords;
 out vec4 resultColor;
diff --git a/src/main/resources/shaders/light.vsh b/src/main/resources/shaders/light.vsh
index a7d5c597..558f246f 100644
--- a/src/main/resources/shaders/light.vsh
+++ b/src/main/resources/shaders/light.vsh
@@ -1,5 +1,5 @@
 
-#version 460
+#version 330
 
 layout (location = 0) in vec2 vertexPos;
 layout (location = 1) in vec2 uvCoords;
diff --git a/src/main/resources/shaders/liquid.fsh b/src/main/resources/shaders/liquid.fsh
index f8429d5d..4b6daa7d 100644
--- a/src/main/resources/shaders/liquid.fsh
+++ b/src/main/resources/shaders/liquid.fsh
@@ -1,5 +1,5 @@
 
-#version 460
+#version 330
 
 out vec4 resultColor;
 
diff --git a/src/main/resources/shaders/liquid.vsh b/src/main/resources/shaders/liquid.vsh
index ebeb16f6..c5d3e324 100644
--- a/src/main/resources/shaders/liquid.vsh
+++ b/src/main/resources/shaders/liquid.vsh
@@ -1,5 +1,5 @@
 
-#version 460
+#version 330
 
 layout (location = 0) in vec2 vertexPos;
 
diff --git a/src/main/resources/shaders/tile.fsh b/src/main/resources/shaders/tile.fsh
index 85bf822f..1a9f03f4 100644
--- a/src/main/resources/shaders/tile.fsh
+++ b/src/main/resources/shaders/tile.fsh
@@ -1,5 +1,5 @@
 
-#version 460
+#version 330
 
 uniform sampler2D texture0;
 uniform vec4 color;
diff --git a/src/main/resources/shaders/tile.vsh b/src/main/resources/shaders/tile.vsh
index f89073e7..5a0a2815 100644
--- a/src/main/resources/shaders/tile.vsh
+++ b/src/main/resources/shaders/tile.vsh
@@ -1,5 +1,5 @@
 
-#version 460
+#version 330
 
 layout (location = 0) in vec3 pos;
 layout (location = 1) in vec2 uv_in;
diff --git a/src/main/resources/shaders/vertex/2dtexture.glsl b/src/main/resources/shaders/vertex/2dtexture.glsl
index d5227edc..cc741c04 100644
--- a/src/main/resources/shaders/vertex/2dtexture.glsl
+++ b/src/main/resources/shaders/vertex/2dtexture.glsl
@@ -1,5 +1,5 @@
 
-#version 460
+#version 330
 
 layout (location = 0) in vec2 pos;
 layout (location = 1) in vec2 uv_in;
diff --git a/src/main/resources/shaders/vertex/texture.glsl b/src/main/resources/shaders/vertex/texture.glsl
index e916d628..55489e51 100644
--- a/src/main/resources/shaders/vertex/texture.glsl
+++ b/src/main/resources/shaders/vertex/texture.glsl
@@ -1,5 +1,5 @@
 
-#version 460
+#version 330
 
 layout (location = 0) in vec3 pos;
 layout (location = 1) in vec2 uv_in;