neo pipelines; postfx fix

src/extras/shaders/simple.frag

@@ -0,0 +1,16 @@
+uniform sampler2D tex0;
+
+in vec4 v_color;
+in vec2 v_tex0;
+in float v_fog;
+
+out vec4 color;
+
+void
+main(void)
+{
+	color = v_color*texture(tex0, vec2(v_tex0.x, 1.0-v_tex0.y));
+	color.rgb = mix(u_fogColor.rgb, color.rgb, v_fog);
+	DoAlphaTest(color.a);
+}
+