add sky

assets/fs/shaders/sky.f.glsl

@@ -0,0 +1,7 @@
+
+varying vec3 color_i;
+
+void main(void)
+{
+    gl_FragColor = vec4(color_i, 1);
+}

assets/fs/shaders/sky.v.glsl

@@ -0,0 +1,14 @@
+
+uniform mat4 projection;
+uniform mat4 modelview;
+
+attribute vec3 pos;
+attribute vec3 color;
+
+varying vec3 color_i;
+
+void main(void)
+{
+    gl_Position = projection * modelview * vec4(pos, 1);
+    color_i = color;
+}