[Bf-blender-cvs] SVN commit: /data/svn/bf-blender [55644] trunk/blender/source/blender: Fix #34782: Video Editor - Substract after transform fails

[Sergey Sharybin]

Revision: 55644
          http://projects.blender.org/scm/viewvc.php?view=rev&root=bf-blender&revision=55644
Author:   nazgul
Date:     2013-03-28 08:21:29 +0000 (Thu, 28 Mar 2013)
Log Message:
-----------
Fix #34782: Video Editor - Substract after transform fails

Couple of precision issues here:

- Interpolation was rounding trunkcating colors, and because
  of some precision issues value 254.999 became 254 leading
  to troubles later.

  Now color interpolaiton will do rounding to nearest int.

- Subtract was setting channels to something negative which
  confused color management (especially negative alpha),

  Now subtract effect will clamp channels to 0 from bottom
  and also do some tricks to prevent small alpha which
  could also confuse color management.

Modified Paths:
--------------
    trunk/blender/source/blender/blenkernel/intern/seqeffects.c
    trunk/blender/source/blender/blenlib/intern/math_interp.c

Modified: trunk/blender/source/blender/blenkernel/intern/seqeffects.c
===================================================================
--- trunk/blender/source/blender/blenkernel/intern/seqeffects.c	2013-03-28 06:36:09 UTC (rev 55643)
+++ trunk/blender/source/blender/blenkernel/intern/seqeffects.c	2013-03-28 08:21:29 UTC (rev 55644)
@@ -965,11 +965,14 @@
 			straight_uchar_to_premul_float(rt1, cp1);
 			straight_uchar_to_premul_float(rt2, cp2);
 
-			tempc[0] = rt1[0] - fac1 * rt2[0];
-			tempc[1] = rt1[1] - fac1 * rt2[1];
-			tempc[2] = rt1[2] - fac1 * rt2[2];
-			tempc[3] = rt1[3] - fac1 * rt2[3];
+			tempc[0] = max_ff(rt1[0] - fac1 * rt2[0], 0.0f);
+			tempc[1] = max_ff(rt1[1] - fac1 * rt2[1], 0.0f);
+			tempc[2] = max_ff(rt1[2] - fac1 * rt2[2], 0.0f);
+			tempc[3] = max_ff(rt1[3] - fac1 * rt2[3], 0.0f);
 
+			if (tempc[3] < 1e-6)
+				tempc[3] = 0.0f;
+
 			premul_float_to_straight_uchar(rt, tempc);
 
 			cp1 += 4; cp2 += 4; rt += 4;
@@ -984,11 +987,14 @@
 			straight_uchar_to_premul_float(rt1, cp1);
 			straight_uchar_to_premul_float(rt2, cp2);
 
-			tempc[0] = rt1[0] - fac3 * rt2[0];
-			tempc[1] = rt1[1] - fac3 * rt2[1];
-			tempc[2] = rt1[2] - fac3 * rt2[2];
-			tempc[3] = rt1[3] - fac3 * rt2[3];
+			tempc[0] = max_ff(rt1[0] - fac3 * rt2[0], 0.0f);
+			tempc[1] = max_ff(rt1[1] - fac3 * rt2[1], 0.0f);
+			tempc[2] = max_ff(rt1[2] - fac3 * rt2[2], 0.0f);
+			tempc[3] = max_ff(rt1[3] - fac3 * rt2[3], 0.0f);
 
+			if (tempc[3] < 1e-6)
+				tempc[3] = 0.0f;
+
 			premul_float_to_straight_uchar(rt, tempc);
 
 			cp1 += 4; cp2 += 4; rt += 4;
@@ -1011,22 +1017,34 @@
 	fac3 = facf1;
 
 	while (y--) {
-		x = xo * 4;
+		x = xo;
 		while (x--) {
-			*rt = *rt1 - fac1 * (*rt2);
+			rt[0] = max_ff(rt1[0] - fac1 * rt2[0], 0.0f);
+			rt[1] = max_ff(rt1[1] - fac1 * rt2[1], 0.0f);
+			rt[2] = max_ff(rt1[2] - fac1 * rt2[2], 0.0f);
+			rt[3] = max_ff(rt1[3] - fac1 * rt2[3], 0.0f);
 
-			rt1++; rt2++; rt++;
+			if (rt[3] < 1e-6)
+				rt[3] = 0.0f;
+
+			rt1 += 4; rt2 += 4; rt += 4;
 		}
 
 		if (y == 0)
 			break;
 		y--;
 
-		x = xo * 4;
+		x = xo;
 		while (x--) {
-			*rt = *rt1 - fac3 * (*rt2);
+			rt[0] = max_ff(rt1[0] - fac3 * rt2[0], 0.0f);
+			rt[1] = max_ff(rt1[1] - fac3 * rt2[1], 0.0f);
+			rt[2] = max_ff(rt1[2] - fac3 * rt2[2], 0.0f);
+			rt[3] = max_ff(rt1[3] - fac3 * rt2[3], 0.0f);
 
-			rt1++; rt2++; rt++;
+			if (rt[3] < 1e-6)
+				rt[3] = 0.0f;
+
+			rt1 += 4; rt2 += 4; rt += 4;
 		}
 	}
 }

Modified: trunk/blender/source/blender/blenlib/intern/math_interp.c
===================================================================
--- trunk/blender/source/blender/blenlib/intern/math_interp.c	2013-03-28 06:36:09 UTC (rev 55643)
+++ trunk/blender/source/blender/blenlib/intern/math_interp.c	2013-03-28 08:21:29 UTC (rev 55644)
@@ -215,18 +215,18 @@
 	}
 	else {
 		if (components == 1) {
-			byte_output[0] = out[0];
+			byte_output[0] = out[0] + 0.5f;
 		}
 		else if (components == 3) {
-			byte_output[0] = out[0];
-			byte_output[1] = out[1];
-			byte_output[2] = out[2];
+			byte_output[0] = out[0] + 0.5f;
+			byte_output[1] = out[1] + 0.5f;
+			byte_output[2] = out[2] + 0.5f;
 		}
 		else {
-			byte_output[0] = out[0];
-			byte_output[1] = out[1];
-			byte_output[2] = out[2];
-			byte_output[3] = out[3];
+			byte_output[0] = out[0] + 0.5f;
+			byte_output[1] = out[1] + 0.5f;
+			byte_output[2] = out[2] + 0.5f;
+			byte_output[3] = out[3] + 0.5f;
 		}
 	}
 }
@@ -322,18 +322,18 @@
 		a_b = a * b; ma_b = (1.0f - a) * b; a_mb = a * (1.0f - b); ma_mb = (1.0f - a) * (1.0f - b);
 
 		if (components == 1) {
-			byte_output[0] = ma_mb * row1[0] + a_mb * row3[0] + ma_b * row2[0] + a_b * row4[0];
+			byte_output[0] = ma_mb * row1[0] + a_mb * row3[0] + ma_b * row2[0] + a_b * row4[0] + 0.5f;
 		}
 		else if (components == 3) {
-			byte_output[0] = ma_mb * row1[0] + a_mb * row3[0] + ma_b * row2[0] + a_b * row4[0];
-			byte_output[1] = ma_mb * row1[1] + a_mb * row3[1] + ma_b * row2[1] + a_b * row4[1];
-			byte_output[2] = ma_mb * row1[2] + a_mb * row3[2] + ma_b * row2[2] + a_b * row4[2];
+			byte_output[0] = ma_mb * row1[0] + a_mb * row3[0] + ma_b * row2[0] + a_b * row4[0] + 0.5f;
+			byte_output[1] = ma_mb * row1[1] + a_mb * row3[1] + ma_b * row2[1] + a_b * row4[1] + 0.5f;
+			byte_output[2] = ma_mb * row1[2] + a_mb * row3[2] + ma_b * row2[2] + a_b * row4[2] + 0.5f;
 		}
 		else {
-			byte_output[0] = ma_mb * row1[0] + a_mb * row3[0] + ma_b * row2[0] + a_b * row4[0];
-			byte_output[1] = ma_mb * row1[1] + a_mb * row3[1] + ma_b * row2[1] + a_b * row4[1];
-			byte_output[2] = ma_mb * row1[2] + a_mb * row3[2] + ma_b * row2[2] + a_b * row4[2];
-			byte_output[3] = ma_mb * row1[3] + a_mb * row3[3] + ma_b * row2[3] + a_b * row4[3];
+			byte_output[0] = ma_mb * row1[0] + a_mb * row3[0] + ma_b * row2[0] + a_b * row4[0] + 0.5f;
+			byte_output[1] = ma_mb * row1[1] + a_mb * row3[1] + ma_b * row2[1] + a_b * row4[1] + 0.5f;
+			byte_output[2] = ma_mb * row1[2] + a_mb * row3[2] + ma_b * row2[2] + a_b * row4[2] + 0.5f;
+			byte_output[3] = ma_mb * row1[3] + a_mb * row3[3] + ma_b * row2[3] + a_b * row4[3] + 0.5f;
 		}
 	}
 }