Merge remote-tracking branch 'origin/mirceakitsune/func_train_beizer_curve'

[xonotic/xonotic-data.pk3dir.git] / qcsrc / common / util.qc

diff --git a/qcsrc/common/util.qc b/qcsrc/common/util.qc
index 965431773e3d572162192da7b5ce2a2076c133c8..85efe4144a17355d23cac22ab1ec02dfa37f4070 100644 (file)
--- a/qcsrc/common/util.qc
+++ b/qcsrc/common/util.qc
@@ -2492,6 +2492,28 @@ float cubic_speedfunc_is_sane(float startspeedfactor, float endspeedfactor)
        // (3, [0..3])
        // (3.5, [0.2..2.3])
        // (4, 1)
+
+       /*
+          On another note:
+          inflection point is always at (2s + e - 3) / (3s + 3e - 6).
+
+          s + e - 2 == 0: no inflection
+
+          s + e > 2:
+          0 < inflection < 1 if:
+          0 < 2s + e - 3 < 3s + 3e - 6
+          2s + e > 3 and 2e + s > 3
+
+          s + e < 2:
+          0 < inflection < 1 if:
+          0 > 2s + e - 3 > 3s + 3e - 6
+          2s + e < 3 and 2e + s < 3
+
+          Therefore: there is an inflection point iff:
+          e outside (3 - s)/2 .. 3 - s*2
+          
+          in other words, if (s,e) in triangle (1,1)(0,3)(0,1.5) or in triangle (1,1)(3,0)(1.5,0)
+       */
 }
 
 .float FindConnectedComponent_processing;