add clouds shader

res/shaders/clouds.glslf

@@ -0,0 +1,31 @@
+layout (location = 0) out vec4 f_color;
+layout (location = 1) out vec4 f_position;
+layout (location = 2) out vec4 f_normal;
+layout (location = 3) out vec4 f_emission;
+
+#include <world_fragment_header>
+
+in vec4 a_torchLight;
+
+uniform sampler2D u_texture0;
+uniform vec3 u_sunDir;
+
+// flags
+uniform bool u_alphaClip;
+uniform bool u_debugLights;
+uniform bool u_debugNormals;
+uniform vec4 u_tint;
+
+void main() {
+    f_color.rgb = max(a_torchLight.rgb, a_skyLight);
+    f_color.a = 1.0;
+    f_color *= u_tint;
+
+#ifndef ADVANCED_RENDER
+    vec3 fogColor = texture(u_skybox, a_dir).rgb;
+    f_color = mix(f_color, vec4(fogColor, 1.0), a_fog);
+#endif
+    f_position = vec4(a_position, 1.0);
+    f_normal = vec4(a_normal, 1.0);
+    f_emission = vec4(vec3(a_emission), 1.0);
+}