diff --git a/lib/init.lua b/lib/init.lua
index 19c862a..2067d54 100644
--- a/lib/init.lua
+++ b/lib/init.lua
@@ -31,18 +31,18 @@ local PostShader = require(_PACKAGE..'postshader')
 local light_world = {}
 light_world.__index = light_world
 
-light_world.image_mask       = love.graphics.newShader(_PACKAGE.."/shaders/image_mask.glsl")
-light_world.shadowShader     = love.graphics.newShader(_PACKAGE.."/shaders/shadow.glsl")
-light_world.refractionShader = love.graphics.newShader(_PACKAGE.."shaders/refraction.glsl")
-light_world.reflectionShader = love.graphics.newShader(_PACKAGE.."shaders/reflection.glsl")
+light_world.image_mask       = util.loadShader(_PACKAGE.."/shaders/image_mask.glsl")
+light_world.shadowShader     = util.loadShader(_PACKAGE.."/shaders/shadow.glsl")
+light_world.refractionShader = util.loadShader(_PACKAGE.."/shaders/refraction.glsl")
+light_world.reflectionShader = util.loadShader(_PACKAGE.."/shaders/reflection.glsl")
 
 local function new(options)
   local obj = {}
 	obj.lights = {}
 	obj.bodies = {}
   obj.post_shader = PostShader()
-  
-  obj.l, obj.t, obj.s      =  0, 0, 1 
+
+  obj.l, obj.t, obj.s      =  0, 0, 1
 	obj.ambient              = {0, 0, 0}
 	obj.refractionStrength   = 8.0
 	obj.reflectionStrength   = 16.0
@@ -273,7 +273,7 @@ function light_world:clear()
   light_world:clearBodies()
 end
 
-function light_world:setTranslation(l, t, s) 
+function light_world:setTranslation(l, t, s)
   self.l, self.t, self.s = l or self.l, t or self.t, s or self.s
 end
 
@@ -296,13 +296,13 @@ function light_world:newCircle(...) return self:newBody("circle", ...) end
 function light_world:newPolygon(...) return self:newBody("polygon", ...) end
 function light_world:newImage(...) return self:newBody("image", ...) end
 
-function light_world:newRefraction(...) 
+function light_world:newRefraction(...)
   self.disableRefraction = false
-  return self:newBody("refraction", ...) 
+  return self:newBody("refraction", ...)
 end
-function light_world:newReflection(normal, ...) 
+function light_world:newReflection(normal, ...)
   self.disableReflection = false
-  return self:newBody("reflection", ...) 
+  return self:newBody("reflection", ...)
 end
 
 -- new body
diff --git a/lib/postshader.lua b/lib/postshader.lua
index efcc6d5..2541e8c 100644
--- a/lib/postshader.lua
+++ b/lib/postshader.lua
@@ -29,12 +29,12 @@ post_shader.__index = post_shader
 
 local files = love.filesystem.getDirectoryItems(_PACKAGE.."/shaders/postshaders")
 local shaders = {}
-	
+
 for i,v in ipairs(files) do
   local name = _PACKAGE.."/shaders/postshaders".."/"..v
   if love.filesystem.isFile(name) then
     local str = love.filesystem.read(name)
-    local effect = love.graphics.newShader(name)
+    local effect = util.loadShader(name)
     local defs = {}
     for vtype, extern in str:gmatch("extern (%w+) (%w+)") do
       defs[extern] = true
@@ -73,14 +73,14 @@ function post_shader:toggleEffect(shaderName, ...)
 end
 
 function post_shader:drawWith(canvas)
-  for shader, args in pairs(self.effects) do 
+  for shader, args in pairs(self.effects) do
     if shader == "bloom" then
       self:drawBloom(canvas, args)
     elseif shader == "blur" then
       self:drawBlur(canvas, args)
     elseif shader == "tilt_shift" then
       self:drawTiltShift(canvas, args)
-    else 
+    else
       self:drawShader(shader, canvas, args)
     end
   end
@@ -126,9 +126,9 @@ function post_shader:drawShader(shaderName, canvas, args)
       effect[1]:send("time", love.timer.getTime())
     elseif def == "palette" then
       effect[1]:send("palette", unpack(process_palette({
-        args[current_arg], 
-        args[current_arg + 1], 
-        args[current_arg + 2], 
+        args[current_arg],
+        args[current_arg + 1],
+        args[current_arg + 2],
         args[current_arg + 3]
       })))
       current_arg = current_arg + 4
diff --git a/lib/shaders/postshaders/black_and_white.glsl b/lib/shaders/postshaders/black_and_white.glsl
index cf90ee8..53d16f2 100644
--- a/lib/shaders/postshaders/black_and_white.glsl
+++ b/lib/shaders/postshaders/black_and_white.glsl
@@ -1,13 +1,13 @@
-extern float exposure = 0.7;
+extern float exposure=0.7;
 extern float brightness = 1.0;
 extern vec3 lumacomponents = vec3(1.0, 1.0, 1.0);
 const vec3 lumcoeff = vec3(0.212671, 0.715160, 0.072169);
 
-vec4 effect(vec4 vcolor, Image texture, vec2 texcoord, vec2 pixel_coords) {	
+vec4 effect(vec4 vcolor, Image texture, vec2 texcoord, vec2 pixel_coords) {
 	vec4 input0 = Texel(texture, texcoord);
 	input0 *= (exp2(input0)*vec4(exposure));
 	vec4 lumacomponents = vec4(lumcoeff * lumacomponents, 0.0 );
 	float luminance = dot(input0,lumacomponents);
 	vec4 luma = vec4(luminance);
 	return vec4(luma.rgb * brightness, 1.0);
-} 
+}
diff --git a/lib/shaders/postshaders/blurh.glsl b/lib/shaders/postshaders/blurh.glsl
index ae58eff..be82cd5 100644
--- a/lib/shaders/postshaders/blurh.glsl
+++ b/lib/shaders/postshaders/blurh.glsl
@@ -3,9 +3,9 @@ extern float steps = 2.0;
 vec4 effect(vec4 color, Image texture, vec2 texture_coords, vec2 pixel_coords) {
 	vec2 pSize = vec2(1.0 / love_ScreenSize.x, 1.0 / love_ScreenSize.y);
 	vec4 col = Texel(texture, texture_coords);
-	for(int i = 1; i <= steps; i++) {
-		col = col + Texel(texture, vec2(texture_coords.x, texture_coords.y - pSize.y * i));
-		col = col + Texel(texture, vec2(texture_coords.x, texture_coords.y + pSize.y * i));
+	for(int i = 1; i <= int(steps); i++) {
+		col = col + Texel(texture, vec2(texture_coords.x, texture_coords.y - pSize.y * float(i)));
+		col = col + Texel(texture, vec2(texture_coords.x, texture_coords.y + pSize.y * float(i)));
 	}
 	col = col / (steps * 2.0 + 1.0);
 	return vec4(col.r, col.g, col.b, 1.0);
diff --git a/lib/shaders/postshaders/blurv.glsl b/lib/shaders/postshaders/blurv.glsl
index 00b929e..e79a40a 100644
--- a/lib/shaders/postshaders/blurv.glsl
+++ b/lib/shaders/postshaders/blurv.glsl
@@ -3,9 +3,9 @@ extern float steps = 2.0;
 vec4 effect(vec4 color, Image texture, vec2 texture_coords, vec2 pixel_coords) {
 	vec2 pSize = vec2(1.0 / love_ScreenSize.x, 1.0 / love_ScreenSize.y);
 	vec4 col = Texel(texture, texture_coords);
-	for(int i = 1; i <= steps; i++) {
-		col = col + Texel(texture, vec2(texture_coords.x - pSize.x * i, texture_coords.y));
-		col = col + Texel(texture, vec2(texture_coords.x + pSize.x * i, texture_coords.y));
+	for(int i = 1; i <= int(steps); i++) {
+		col = col + Texel(texture, vec2(texture_coords.x - pSize.x * float(i), texture_coords.y));
+		col = col + Texel(texture, vec2(texture_coords.x + pSize.x * float(i), texture_coords.y));
 	}
 	col = col / (steps * 2.0 + 1.0);
 	return vec4(col.r, col.g, col.b, 1.0);
diff --git a/lib/shaders/postshaders/four_colors.glsl b/lib/shaders/postshaders/four_colors.glsl
index c68b1cf..96c2e63 100644
--- a/lib/shaders/postshaders/four_colors.glsl
+++ b/lib/shaders/postshaders/four_colors.glsl
@@ -2,7 +2,7 @@ extern vec3 palette[4];
 
 vec4 effect(vec4 color, Image texture, vec2 texture_coords, vec2 pixel_coords){
 	vec4 pixel = Texel(texture, texture_coords);
-	int index = int(min(0.9999, max(0.0001,(pixel.r + pixel.g + pixel.b) / 3.0)) * 4);
+	int index = int(min(0.9999, max(0.0001,(pixel.r + pixel.g + pixel.b) / 3.0)) * 4.0);
 
 	return vec4(palette[index], 1.0);
-}
\ No newline at end of file
+}
diff --git a/lib/shaders/postshaders/monochrome.glsl b/lib/shaders/postshaders/monochrome.glsl
index d4bc55b..9b60f1e 100644
--- a/lib/shaders/postshaders/monochrome.glsl
+++ b/lib/shaders/postshaders/monochrome.glsl
@@ -10,4 +10,4 @@ vec4 effect(vec4 color, Image texture, vec2 texture_coords, vec2 pixel_coords){
 	vec4 pixel = Texel(texture, texture_coords);
 	float intensity = (pixel.r + pixel.g + pixel.b) / 3.0 + (rand(texture_coords, time) - 0.5) * fudge;
 	return vec4(intensity * tint.r, intensity * tint.g, intensity * tint.b, 1.0);
-}
\ No newline at end of file
+}
diff --git a/lib/shaders/postshaders/phosphor.glsl b/lib/shaders/postshaders/phosphor.glsl
index cf58451..b799f9c 100644
--- a/lib/shaders/postshaders/phosphor.glsl
+++ b/lib/shaders/postshaders/phosphor.glsl
@@ -94,22 +94,22 @@ vec4 grid_color( vec2 coords )
 vec2 onex = vec2( 1.0/love_ScreenSize.x, 0.0 );
 vec2 oney = vec2( 0.0, 1.0/love_ScreenSize.y );
 
-vec4 effect(vec4 vcolor, Image texture, vec2 texCoord, vec2 pixel_coords)
+vec4 effect(vec4 vcolor, Image texture, highp vec2 texCoord, vec2 pixel_coords)
 {
-	vec2 coords = (texCoord * love_ScreenSize.xy);
-	vec2 pixel_start = floor(coords);
+	highp vec2 coords = (texCoord * love_ScreenSize.xy);
+	highp vec2 pixel_start = floor(coords);
 	coords -= pixel_start;
-	vec2 pixel_center = pixel_start + vec2(0.5);
-	vec2 texture_coords = pixel_center / love_ScreenSize.xy;
+	highp vec2 pixel_center = pixel_start + vec2(0.5);
+	highp vec2 texture_coords = pixel_center / love_ScreenSize.xy;
 
-	vec4 color = vec4(0.0);
-	vec4 pixel;
-	vec3 centers = vec3(-0.25,-0.5,-0.75);
-	vec3 posx = vec3(coords.x);
-	vec3 hweight;
-	float vweight;
-	float dx,dy;
-	float w;
+	highp vec4 color = vec4(0.0);
+	highp vec4 pixel;
+	highp vec3 centers = vec3(-0.25,-0.5,-0.75);
+	highp vec3 posx = vec3(coords.x);
+	highp vec3 hweight;
+	highp float vweight;
+	highp float dx,dy;
+	highp float w;
 
 	float i,j;
 
diff --git a/lib/shaders/postshaders/phosphorish.glsl b/lib/shaders/postshaders/phosphorish.glsl
index 5449cbd..29bbd5a 100644
--- a/lib/shaders/postshaders/phosphorish.glsl
+++ b/lib/shaders/postshaders/phosphorish.glsl
@@ -5,7 +5,7 @@
 */
 // modified by slime73 for use with love pixeleffects
 
-vec3 to_focus(float pixel)
+vec3 to_focus(highp float pixel)
 {
 	pixel = mod(pixel + 3.0, 3.0);
 	if (pixel >= 2.0) // Blue
@@ -16,24 +16,24 @@ vec3 to_focus(float pixel)
 		return vec3(1.0 - pixel, pixel, 0.0);
 }
 
-vec4 effect(vec4 vcolor, Image texture, vec2 texture_coords, vec2 pixel_coords)
+vec4 effect(vec4 vcolor, Image texture, highp vec2 texture_coords, vec2 pixel_coords)
 {
-	float y = mod(texture_coords.y * love_ScreenSize.y, 1.0);
-	float intensity = exp(-0.2 * y);
+	highp float y = mod(texture_coords.y * love_ScreenSize.y, 1.0);
+	highp float intensity = exp(-0.2 * y);
 
-	vec2 one_x = vec2(1.0 / (3.0 * love_ScreenSize.x), 0.0);
+	highp vec2 one_x = vec2(1.0 / (3.0 * love_ScreenSize.x), 0.0);
 
-	vec3 color = Texel(texture, texture_coords - 0.0 * one_x).rgb;
-	vec3 color_prev = Texel(texture, texture_coords - 1.0 * one_x).rgb;
-	vec3 color_prev_prev = Texel(texture, texture_coords - 2.0 * one_x).rgb;
+	highp vec3 color = Texel(texture, texture_coords - 0.0 * one_x).rgb;
+	highp vec3 color_prev = Texel(texture, texture_coords - 1.0 * one_x).rgb;
+	highp vec3 color_prev_prev = Texel(texture, texture_coords - 2.0 * one_x).rgb;
 
-	float pixel_x = 3.0 * texture_coords.x * love_ScreenSize.x;
+	highp float pixel_x = 3.0 * texture_coords.x * love_ScreenSize.x;
 
-	vec3 focus = to_focus(pixel_x - 0.0);
-	vec3 focus_prev = to_focus(pixel_x - 1.0);
-	vec3 focus_prev_prev = to_focus(pixel_x - 2.0);
+	highp vec3 focus = to_focus(pixel_x - 0.0);
+	highp vec3 focus_prev = to_focus(pixel_x - 1.0);
+	highp vec3 focus_prev_prev = to_focus(pixel_x - 2.0);
 
-	vec3 result =
+	highp vec3 result =
 		0.8 * color * focus +
 		0.6 * color_prev * focus_prev +
 		0.3 * color_prev_prev * focus_prev_prev;
@@ -42,4 +42,3 @@ vec4 effect(vec4 vcolor, Image texture, vec2 texture_coords, vec2 pixel_coords)
 
 	return vec4(intensity * result, 1.0);
 }
-
diff --git a/lib/shaders/postshaders/radialblur.glsl b/lib/shaders/postshaders/radialblur.glsl
index 5c2a032..371be6b 100644
--- a/lib/shaders/postshaders/radialblur.glsl
+++ b/lib/shaders/postshaders/radialblur.glsl
@@ -6,15 +6,15 @@ extern number blurwidth = -0.02; // -1 to 1
 vec4 effect(vec4 vcolor, Image texture, vec2 texture_coords, vec2 pixel_coords)
 {
 	vec4 c = vec4(0.0, 0.0, 0.0, 1.0);
-	
+
 	int i;
 	for (i = 0; i < nsamples; i++)
 	{
-		number scale = blurstart + blurwidth * (i / float(nsamples-1));
+		number scale = blurstart + blurwidth * (float(i) / float(nsamples-1));
 		c.rgb += Texel(texture, texture_coords * scale).rgb;
 	}
-	
-	c.rgb /= nsamples;
-	
+
+	c.rgb /= float(nsamples);
+
 	return c;
 }
diff --git a/lib/shaders/reflection.glsl b/lib/shaders/reflection.glsl
index 16c14e9..90753da 100644
--- a/lib/shaders/reflection.glsl
+++ b/lib/shaders/reflection.glsl
@@ -9,11 +9,11 @@ vec4 effect(vec4 color, Image texture, vec2 texture_coords, vec2 pixel_coords) {
 	if(normal.a > 0.0 && normal.r > 0.0) {
 		vec3 pColor = Texel(backBuffer, texture_coords).rgb;
 		vec4 pColor2;
-		for(int i = 0; i < reflectionStrength; i++) {
-			pColor2 = Texel(texture, vec2(texture_coords.x, texture_coords.y + pSize.y * i));
+		for(int i = 0; i < int(reflectionStrength); i++) {
+			pColor2 = Texel(texture, vec2(texture_coords.x, texture_coords.y + pSize.y * float(i)));
 			if(pColor2.a > 0.0 && pColor2.g > 0.0) {
-				vec3 rColor = Texel(backBuffer, vec2(texture_coords.x, texture_coords.y + pSize.y * i * 2.0)).rgb;
-				return vec4(rColor, (1.0 - i / reflectionStrength) * reflectionVisibility);
+				vec3 rColor = Texel(backBuffer, vec2(texture_coords.x, texture_coords.y + pSize.y * float(i) * 2.0)).rgb;
+				return vec4(rColor, (1.0 - float(i) / reflectionStrength) * reflectionVisibility);
 			}
 		}
 		return vec4(0.0);
diff --git a/lib/shaders/shadow.glsl b/lib/shaders/shadow.glsl
index 5bae828..81b17b7 100644
--- a/lib/shaders/shadow.glsl
+++ b/lib/shaders/shadow.glsl
@@ -32,7 +32,7 @@ vec4 effect(vec4 color, Image texture, vec2 texture_coords, vec2 pixel_coords) {
         pixel.rgb = lightColor * pow(att, lightSmooth);
       }
     } else {
-      vec3 normal = normalize(vec3(normalColor.r,invert_normal ? 1 - normalColor.g : normalColor.g, normalColor.b) * 2.0 - 1.0); 
+      vec3 normal = normalize(vec3(normalColor.r,invert_normal ? 1.0 - normalColor.g : normalColor.g, normalColor.b) * 2.0 - 1.0); 
       //on the normal map, draw normal shadows
       vec3 dir = vec3((lightPosition.xy - pixel_coords.xy) / love_ScreenSize.xy, lightPosition.z);
       dir.x *= love_ScreenSize.x / love_ScreenSize.y;
@@ -47,4 +47,3 @@ vec4 effect(vec4 color, Image texture, vec2 texture_coords, vec2 pixel_coords) {
     return pixel;
   }
 }
-
diff --git a/lib/util.lua b/lib/util.lua
index 7da2d50..d2c7d71 100644
--- a/lib/util.lua
+++ b/lib/util.lua
@@ -2,7 +2,7 @@ local util = {}
 --TODO: the whole stencil/canvas system should be reviewed since it has been changed in a naive way
 
 function util.process(canvas, options)
-  --TODO: now you cannot draw a canvas to itself  
+  --TODO: now you cannot draw a canvas to itself
   temp = love.graphics.newCanvas()
   util.drawCanvasToCanvas(canvas, temp, options)
   util.drawCanvasToCanvas(temp, canvas, options)
@@ -59,4 +59,41 @@ function util.drawto(canvas, x, y, scale, cb)
   love.graphics.pop()
 end
 
+function util.loadShader(name)
+  local shader = ""
+  local externInit = {}
+  for line in love.filesystem.lines(name) do
+
+    if line:sub(1,6) == "extern" then
+      local type, name = line:match("extern (%w+) (%w+)")
+      local value = line:match("=(.*);")
+      if value then
+        externInit[name] = {type=type, val=value}
+        line = line:match("extern %w+ %w+")..";"
+      end
+    end
+    shader = shader.."\n"..line
+  end
+
+  local effect = love.graphics.newShader(shader)
+  for k, v in pairs(externInit) do
+    if v.type == "bool" then
+      effect:send(k, v.val)
+    elseif v.type == "int" or v.type == "uint" then
+      effect:sendInt(k, tonumber(v.val))
+    elseif v.type == "float" or v.type == "double" or v.type == "number" then
+      effect:send(k, tonumber(v.val))
+    elseif v.type:sub(1,3) == "vec" then
+      v.val = v.val:gsub(" ", ""):sub(6):sub(1, -2)
+      local next = v.val:gmatch("([^,]+)")
+      local values = {}
+      for n in next do
+        table.insert(values, tonumber(n))
+      end
+      effect:send(k, values)
+    end
+  end
+  return effect
+end
+
 return util