try/except bizniss results in big speedup

1 files changed, 35 insertions, 15 deletions

diff --git a/shader-picker.html b/shader-picker.html
index 42d2ca8..177bc76 100644
--- a/shader-picker.html
+++ b/shader-picker.html
@@ -270,14 +270,13 @@ function ready(){
   }
 }
 
-var shader = function(){}
-
 var shader_build = function(){
   var fn_str = document.getElementById('shader').value
   if (!fn_str.length) return
   try {
     var fn = new Function('x','y','t','d', fn_str)
     shader = fn
+    shade = shade_error_handling
   } catch (e) {
     throw Error ("Shader compilation error")
   }
@@ -285,32 +284,50 @@ var shader_build = function(){
 
 var r,g,b,a;
 
-function shade(frame, t){
+function shade_no_error_handling(frame, t){
   if (! t || isNaN(t)) throw Error ("No time specified")
   if (! frame) throw Error ("No frame specified")
 
   var imgData = frame.ctx.getImageData(0,0,w,h)
   var data = imgData.data
-  var clone = frame.cloneData.data
+  var clone = frame.cloneData.data  
+  var realw = w, realh = h, v, index
+
+  for (var x = 0; x < w; x++) {
+    for (var y = 0; y < h; y++) {
+      q = 4*(y*w+x)
+      r = data[q], g = data[q+1], b = data[q+2], a = data[q+3]
+      result = shader(x,y,t,clone)
+      data[q] = r
+      data[q+1] = g
+      data[q+2] = b
+      data[q+3] = a
+      w = realw, h = realh
+    }
+  }
+  cc.putImageData(imgData,0,0)
+}
 
-  var u32 = new Uint32Array(imgData.data.buffer);
+function shade_error_handling(frame, t){
+  if (! t || isNaN(t)) throw Error ("No time specified")
+  if (! frame) throw Error ("No frame specified")
+
+  var imgData = frame.ctx.getImageData(0,0,w,h)
+  var data = imgData.data
+  var clone = frame.cloneData.data
 
   try {
     var realw = w, realh = h, v, index
 
     for (var x = 0; x < w; x++) {
       for (var y = 0; y < h; y++) {
-        index = (y*w+x)
-        a = u32[index] >> 24 & 0xff
-        b = u32[index] >> 16 & 0xff
-        g = u32[index] >> 8  & 0xff;
-        r = u32[index] & 0xff  
+        q = 4*(y*w+x)
+        r = data[q], g = data[q+1], b = data[q+2], a = data[q+3]
         result = shader(x,y,t,clone)
-        u32[index] =
-            (a << 24) |
-            (b << 16) |
-            (g <<  8) |
-             r;
+        data[q] = r
+        data[q+1] = g
+        data[q+2] = b
+        data[q+3] = a
         w = realw, h = realh
       }
     }
@@ -320,8 +337,11 @@ function shade(frame, t){
     throw Error ("Shader execution error")
   }
   cc.putImageData(imgData,0,0)
+  shade = shade_no_error_handling
 }
 
+shade = shade_error_handling
+
 function add_frame(){
   var frame_count = $("#framecount").int()
   if (frame_count < 2) {