expose fxaa params

README.md

@@ -1,7 +1,7 @@
-This is a port of NVIDIA's original FXAA v2 shader (the console version), with further pre-compute optimizations added by Matt DesLauriers. In short, FXAA is a single-pass, 1:1 anti-aliasing post-processing effect. Compared to straight super-sampling or MSAA, it has a lower quality, but is much faster. Love2D's MSAA was too slow for a project I'm working on, so I quickly hacked this together based on Matt's glslify shader.
+This is a port of NVIDIA's original FXAA v2 shader (the console version), with further pre-compute optimizations added by Matt DesLauriers. In short, FXAA is a single-pass, 1:1 anti-aliasing post-processing effect. Compared to straight super-sampling or MSAA, it has a lower quality, but is much faster. Love2D's MSAA was too slow for a project I'm working on, so I quickly hacked this together based on Matt's glslify shader. I've added an optional sharpening stage, which uses a very simple algorithm.
 
-I found that (on my linux machine with NVIDIA drivers), the shader *must* be applied to a canvas if `window.setMode` is used *at all*. Don't ask me why. You can finetune the FXAA params in the shader code (or convert them to sent values to allow runtime changes). Read the paper to learn what they mean.
+`main.moon` contains an example class `FXAACanvas`, which wraps canvas draw calls and applies FXAA and sharpening on `render`. You can fine tune all FXAA params and the sharpening strength, as well as the number of FXAA passes (uses nested canvas render targets).
 
-Here's a screenshot of the demo file (single pass, left is FXAA, right is original):
+Here's a screenshot of the demo file (click to view full size):
 
 ![](/screenshot.png)

fxaa.glsl

@@ -56,15 +56,19 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  * EVEN IF NVIDIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
  */
 
-#ifndef FXAA_REDUCE_MIN
-  #define FXAA_REDUCE_MIN   (1.0/ 128.0)
-#endif
-#ifndef FXAA_REDUCE_MUL
-  #define FXAA_REDUCE_MUL   (1.0 / 8.0)
-#endif
-#ifndef FXAA_SPAN_MAX
-  #define FXAA_SPAN_MAX     8.0
-#endif
+// #ifndef fxaa_reduce_min
+//   #define fxaa_reduce_min   (1.0/ 128.0)
+// #endif
+// #ifndef fxaa_reduce_mul
+//   #define fxaa_reduce_mul   (1.0 / 8.0)
+// #endif
+// #ifndef fxaa_span_max
+//   #define fxaa_span_max     8.0
+// #endif
+
+uniform float fxaa_reduce_min;
+uniform float fxaa_reduce_mul;
+uniform float fxaa_span_max;
 
 varying vec2 v_rgbNW;
 varying vec2 v_rgbNE;
@@ -142,11 +146,11 @@ vec4 fxaa(
   dir.y =  ((lumaNW + lumaSW) - (lumaNE + lumaSE));
 
   float dirReduce = max((lumaNW + lumaNE + lumaSW + lumaSE) *
-                        (0.25 * FXAA_REDUCE_MUL), FXAA_REDUCE_MIN);
+                        (0.25 * fxaa_reduce_mul), fxaa_reduce_min);
 
   float rcpDirMin = 1.0 / (min(abs(dir.x), abs(dir.y)) + dirReduce);
-  dir = min(vec2(FXAA_SPAN_MAX, FXAA_SPAN_MAX),
-            max(vec2(-FXAA_SPAN_MAX, -FXAA_SPAN_MAX),
+  dir = min(vec2(fxaa_span_max, fxaa_span_max),
+            max(vec2(-fxaa_span_max, -fxaa_span_max),
             dir * rcpDirMin)) * inverseVP;
 
   vec3 rgbA = 0.5 * (

main.lua

@@ -54,6 +54,12 @@ do
       end
       self.sharpen = sharpen
       self.shader_fxaa = love.graphics.newShader('fxaa.glsl')
+      do
+        local _with_0 = self.shader_fxaa
+        _with_0:send('fxaa_reduce_min', (1.0 / 128.0))
+        _with_0:send('fxaa_reduce_mul', (1.0 / 8.0))
+        _with_0:send('fxaa_span_max', 8.0)
+      end
       self.shader_sharpen = love.graphics.newShader('sharpen.glsl')
       self.layers = { }
       for stage = 1, stages do
@@ -81,7 +87,7 @@ love.load = function()
   love.window.setMode(1024, 1024, {
     borderless = true
   })
-  return love.window.setTitle("Mobile FXAA (by NVIDIA/Timothy L. & Meincraft/Armin Ronacher) - Left: FXAA on, Right: Original")
+  return love.window.setTitle("Mobile FXAA (by NVIDIA/Timothy L. & Meincraft/Armin Ronacher)")
 end
 local cv = FXAACanvas(512, 512)
 local cv2 = FXAACanvas(512, 512, 2)

main.moon

@@ -1,9 +1,13 @@
 image = love.graphics.newImage('download.png')
 
 class FXAACanvas
-
-  new: (width, height, stages = 1, @sharpen = 0) =>
+  new: (width, height, stages = 1, @sharpen = 0, reduce_min = 1/128, reduce_mul = 1/8, span_max = 8) =>
     @shader_fxaa = love.graphics.newShader('fxaa.glsl')
+    with @shader_fxaa
+      \send('fxaa_reduce_min', reduce_min)
+      \send('fxaa_reduce_mul', reduce_mul)
+      \send('fxaa_span_max', span_max)
+
     @shader_sharpen = love.graphics.newShader('sharpen.glsl')
 
     @layers = { }
@@ -53,7 +57,7 @@ love.load = ->
     -- vsync: false
   })
 
-  love.window.setTitle("Mobile FXAA (by NVIDIA/Timothy L. & Meincraft/Armin Ronacher) - Left: FXAA on, Right: Original")
+  love.window.setTitle("Mobile FXAA (by NVIDIA/Timothy L. & Meincraft/Armin Ronacher)")
 
 
 cv = FXAACanvas(512, 512)