diff --git a/demos/06-material.c b/demos/06-material.c
index 00256c0..86615a0 100644
--- a/demos/06-material.c
+++ b/demos/06-material.c
@@ -12,6 +12,10 @@ int main() {
 
     // create camera
     camera_t cam = camera();
+
+    // fx: load all post fx files in all subdirs.
+    fx_load("fx**.fs");
+
     // load video, RGB texture, no audio
     video_t *v = video( "pexels-pachon-in-motion-17486489.mp4", VIDEO_RGB | VIDEO_NO_AUDIO | VIDEO_LOOP ); video_seek(v, 30);
     // load texture
@@ -60,6 +64,7 @@ int main() {
     // load skybox
     scene_get_active()->skybox = skybox_pbr("hdr/Tokyo_BigSight_1k.hdr","hdr/Tokyo_BigSight_Env.hdr");
 
+
     while(window_swap() && !input(KEY_ESC)) {
         // draw environment
         ddraw_grid(0);
@@ -71,7 +76,9 @@ int main() {
         light_teleport(l, cam.position);
 
         // draw scene
+        fx_begin();
         scene_render(SCENE_FOREGROUND|SCENE_BACKGROUND|SCENE_UPDATE_SH_COEF);
+        fx_end();
 
         // fps camera
         bool active = ui_active() || ui_hover() || gizmo_active() ? false : input(MOUSE_L) || input(MOUSE_M) || input(MOUSE_R);
diff --git a/engine/art/shaders/fs_32_4_model.glsl b/engine/art/shaders/fs_32_4_model.glsl
index 85c38e7..f7f953e 100644
--- a/engine/art/shaders/fs_32_4_model.glsl
+++ b/engine/art/shaders/fs_32_4_model.glsl
@@ -1,3 +1,4 @@
+#version 400
 uniform mat4 model, view;
 uniform sampler2D u_texture2d;
 uniform vec3 u_coefficients_sh[9];
@@ -139,10 +140,10 @@ uniform ColorMap map_emissive;  uniform sampler2D map_emissive_tex;
 #define sample_colormap(ColorMap_, uv_) \
     (ColorMap_.has_tex ? texture( ColorMap_##_tex, uv_ ) : ColorMap_.color)
 
-uniform float skysphere_rotation;
+uniform float skysphere_rotation=-90;
 uniform float skysphere_mip_count;
 uniform float exposure=1;
-// uniform uint frame_count;
+uniform uint frame_count;
 uniform float specular_shininess;
 
 uniform sampler2D tex_skysphere;
@@ -687,7 +688,7 @@ void main(void)
     // float dither = random( uvec3( floatBitsToUint( gl_FragCoord.xy ), frame_count ) );
     // color += BOOST_NOISE * vec3( (-1.0/256.) + (2./256.) * dither );
 
-#if 0 // original
+#if 1 // original
     // basic tonemap and gamma correction
     color = color / ( vec3(1.) + color );
     color = pow( color, vec3(1. / 2.2) );
diff --git a/engine/joint/v4k.h b/engine/joint/v4k.h
index edcd68d..b0b1877 100644
--- a/engine/joint/v4k.h
+++ b/engine/joint/v4k.h
@@ -370120,6 +370120,22 @@ unsigned shader(const char *vs, const char *fs, const char *attribs, const char
     return shader_geom(NULL, vs, fs, attribs, fragcolor, defines);
 }
 
+static inline
+char *shader_preprocess(const char *src, const char *defines) {
+    const char *glsl_version = va("#version %s", ifdef(ems, "300 es", "150"));
+
+    if (!src) return NULL;
+
+    // detect GLSL version if set
+    if (src[0] == '#' && src[1] == 'v') {
+        const char *end = strstri(src, "\n");
+        glsl_version = va("%.*s", (int)(end-src), src);
+        src = end+1;
+    }
+
+    return va("%s\n%s\n%s", glsl_version, defines ? defines : "", src);
+}
+
 unsigned shader_geom(const char *gs, const char *vs, const char *fs, const char *attribs, const char *fragcolor, const char *defines) {
     PRINTF(/*"!"*/"Compiling shader\n");
 
@@ -370130,12 +370146,10 @@ unsigned shader_geom(const char *gs, const char *vs, const char *fs, const char
         }
     }
 
-    const char *glsl_version = ifdef(ems, "300 es", "400");
-
     if(gs)
-    gs = gs && gs[0] == '#' && gs[1] == 'v' ? gs : va("#version %s\n%s\n%s", glsl_version, glsl_defines, gs ? gs : "");
-    vs = vs && vs[0] == '#' && vs[1] == 'v' ? vs : va("#version %s\n%s\n%s", glsl_version, glsl_defines, vs ? vs : "");
-    fs = fs && fs[0] == '#' && fs[1] == 'v' ? fs : va("#version %s\n%s\n%s", glsl_version, glsl_defines, fs ? fs : "");
+    gs = shader_preprocess(gs, glsl_defines);
+    vs = shader_preprocess(vs, glsl_defines);
+    fs = shader_preprocess(fs, glsl_defines);
 
 #if is(ems)
     {
@@ -373053,6 +373067,7 @@ void model_set_uniforms(model_t m, int shader, mat44 mv, mat44 proj, mat44 view,
             shader_texture( "tex_skyenv", m.sky_env );
         }
         shader_texture( "tex_brdf_lut", brdf_lut() );
+        shader_uint( "frame_count", (unsigned)window_frame() );
     }
 }
 static
diff --git a/engine/split/v4k_render.c b/engine/split/v4k_render.c
index 6940a77..ad641b5 100644
--- a/engine/split/v4k_render.c
+++ b/engine/split/v4k_render.c
@@ -92,6 +92,22 @@ unsigned shader(const char *vs, const char *fs, const char *attribs, const char
     return shader_geom(NULL, vs, fs, attribs, fragcolor, defines);
 }
 
+static inline
+char *shader_preprocess(const char *src, const char *defines) {
+    const char *glsl_version = va("#version %s", ifdef(ems, "300 es", "150"));
+
+    if (!src) return NULL;
+
+    // detect GLSL version if set
+    if (src[0] == '#' && src[1] == 'v') {
+        const char *end = strstri(src, "\n");
+        glsl_version = va("%.*s", (int)(end-src), src);
+        src = end+1;
+    }
+
+    return va("%s\n%s\n%s", glsl_version, defines ? defines : "", src);
+}
+
 unsigned shader_geom(const char *gs, const char *vs, const char *fs, const char *attribs, const char *fragcolor, const char *defines) {
     PRINTF(/*"!"*/"Compiling shader\n");
 
@@ -102,12 +118,10 @@ unsigned shader_geom(const char *gs, const char *vs, const char *fs, const char
         }
     }
 
-    const char *glsl_version = ifdef(ems, "300 es", "400");
-
     if(gs)
-    gs = gs && gs[0] == '#' && gs[1] == 'v' ? gs : va("#version %s\n%s\n%s", glsl_version, glsl_defines, gs ? gs : "");
-    vs = vs && vs[0] == '#' && vs[1] == 'v' ? vs : va("#version %s\n%s\n%s", glsl_version, glsl_defines, vs ? vs : "");
-    fs = fs && fs[0] == '#' && fs[1] == 'v' ? fs : va("#version %s\n%s\n%s", glsl_version, glsl_defines, fs ? fs : "");
+    gs = shader_preprocess(gs, glsl_defines);
+    vs = shader_preprocess(vs, glsl_defines);
+    fs = shader_preprocess(fs, glsl_defines);
 
 #if is(ems)
     {
@@ -3025,6 +3039,7 @@ void model_set_uniforms(model_t m, int shader, mat44 mv, mat44 proj, mat44 view,
             shader_texture( "tex_skyenv", m.sky_env );
         }
         shader_texture( "tex_brdf_lut", brdf_lut() );
+        shader_uint( "frame_count", (unsigned)window_frame() );
     }
 }
 static
diff --git a/engine/v4k.c b/engine/v4k.c
index 285bc81..ecc4b35 100644
--- a/engine/v4k.c
+++ b/engine/v4k.c
@@ -17266,6 +17266,22 @@ unsigned shader(const char *vs, const char *fs, const char *attribs, const char
     return shader_geom(NULL, vs, fs, attribs, fragcolor, defines);
 }
 
+static inline
+char *shader_preprocess(const char *src, const char *defines) {
+    const char *glsl_version = va("#version %s", ifdef(ems, "300 es", "150"));
+
+    if (!src) return NULL;
+
+    // detect GLSL version if set
+    if (src[0] == '#' && src[1] == 'v') {
+        const char *end = strstri(src, "\n");
+        glsl_version = va("%.*s", (int)(end-src), src);
+        src = end+1;
+    }
+
+    return va("%s\n%s\n%s", glsl_version, defines ? defines : "", src);
+}
+
 unsigned shader_geom(const char *gs, const char *vs, const char *fs, const char *attribs, const char *fragcolor, const char *defines) {
     PRINTF(/*"!"*/"Compiling shader\n");
 
@@ -17276,12 +17292,10 @@ unsigned shader_geom(const char *gs, const char *vs, const char *fs, const char
         }
     }
 
-    const char *glsl_version = ifdef(ems, "300 es", "400");
-
     if(gs)
-    gs = gs && gs[0] == '#' && gs[1] == 'v' ? gs : va("#version %s\n%s\n%s", glsl_version, glsl_defines, gs ? gs : "");
-    vs = vs && vs[0] == '#' && vs[1] == 'v' ? vs : va("#version %s\n%s\n%s", glsl_version, glsl_defines, vs ? vs : "");
-    fs = fs && fs[0] == '#' && fs[1] == 'v' ? fs : va("#version %s\n%s\n%s", glsl_version, glsl_defines, fs ? fs : "");
+    gs = shader_preprocess(gs, glsl_defines);
+    vs = shader_preprocess(vs, glsl_defines);
+    fs = shader_preprocess(fs, glsl_defines);
 
 #if is(ems)
     {
@@ -20199,6 +20213,7 @@ void model_set_uniforms(model_t m, int shader, mat44 mv, mat44 proj, mat44 view,
             shader_texture( "tex_skyenv", m.sky_env );
         }
         shader_texture( "tex_brdf_lut", brdf_lut() );
+        shader_uint( "frame_count", (unsigned)window_frame() );
     }
 }
 static