Compute permutation2D at compile time

Change-Id: Ia69913a11aa47a2c37a1c7cb8316cb9d34dffeec
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/113522
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

1 files changed, 43 insertions, 48 deletions

diff --git a/slideshow/source/engine/opengl/TransitionImpl.cxx b/slideshow/source/engine/opengl/TransitionImpl.cxx
index f8d062d34941..d45b17c2e953 100644
--- a/slideshow/source/engine/opengl/TransitionImpl.cxx
+++ b/slideshow/source/engine/opengl/TransitionImpl.cxx
@@ -1431,60 +1431,55 @@ void PermTextureTransition::finishTransition()
     CHECK_GL_ERROR();
 }
 
-int permutation256 [256]= {
-215, 100, 200, 204, 233,  50,  85, 196,
- 71, 141, 122, 160,  93, 131, 243, 234,
-162, 183,  36, 155,   4,  62,  35, 205,
- 40, 102,  33,  27, 255,  55, 214, 156,
- 75, 163, 134, 126, 249,  74, 197, 228,
- 72,  90, 206, 235,  17,  22,  49, 169,
-227,  89,  16,   5, 117,  60, 248, 230,
-217,  68, 138,  96, 194, 170, 136,  10,
-112, 238, 184, 189, 176,  42, 225, 212,
- 84,  58, 175, 244, 150, 168, 219, 236,
-101, 208, 123,  37, 164, 110, 158, 201,
- 78, 114,  57,  48,  70, 142, 106,  43,
-232,  26,  32, 252, 239,  98, 191,  94,
- 59, 149,  39, 187, 203, 190,  19,  13,
-133,  45,  61, 247,  23,  34,  20,  52,
-118, 209, 146, 193, 222,  18,   1, 152,
- 46,  41,  91, 148, 115,  25, 135,  77,
-254, 147, 224, 161,   9, 213, 223, 250,
-231, 251, 127, 166,  63, 179,  81, 130,
-139,  28, 120, 151, 241,  86, 111,   0,
- 88, 153, 172, 182, 159, 105, 178,  47,
- 51, 167,  65,  66,  92,  73, 198, 211,
-245, 195,  31, 220, 140,  76, 221, 186,
-154, 185,  56,  83,  38, 165, 109,  67,
-124, 226, 132,  53, 229,  29,  12, 181,
-121,  24, 207, 199, 177, 113,  30,  80,
-  3,  97, 188,  79, 216, 173,   8, 145,
- 87, 128, 180, 237, 240, 137, 125, 104,
- 15, 242, 119, 246, 103, 143,  95, 144,
-  2,  44,  69, 157, 192, 174,  14,  54,
-218,  82,  64, 210,  11,   6, 129,  21,
-116, 171,  99, 202,   7, 107, 253, 108
-};
+constexpr auto permutation2D = []() constexpr {
+    int permutation256 [256]= {
+    215, 100, 200, 204, 233,  50,  85, 196,
+     71, 141, 122, 160,  93, 131, 243, 234,
+    162, 183,  36, 155,   4,  62,  35, 205,
+     40, 102,  33,  27, 255,  55, 214, 156,
+     75, 163, 134, 126, 249,  74, 197, 228,
+     72,  90, 206, 235,  17,  22,  49, 169,
+    227,  89,  16,   5, 117,  60, 248, 230,
+    217,  68, 138,  96, 194, 170, 136,  10,
+    112, 238, 184, 189, 176,  42, 225, 212,
+     84,  58, 175, 244, 150, 168, 219, 236,
+    101, 208, 123,  37, 164, 110, 158, 201,
+     78, 114,  57,  48,  70, 142, 106,  43,
+    232,  26,  32, 252, 239,  98, 191,  94,
+     59, 149,  39, 187, 203, 190,  19,  13,
+    133,  45,  61, 247,  23,  34,  20,  52,
+    118, 209, 146, 193, 222,  18,   1, 152,
+     46,  41,  91, 148, 115,  25, 135,  77,
+    254, 147, 224, 161,   9, 213, 223, 250,
+    231, 251, 127, 166,  63, 179,  81, 130,
+    139,  28, 120, 151, 241,  86, 111,   0,
+     88, 153, 172, 182, 159, 105, 178,  47,
+     51, 167,  65,  66,  92,  73, 198, 211,
+    245, 195,  31, 220, 140,  76, 221, 186,
+    154, 185,  56,  83,  38, 165, 109,  67,
+    124, 226, 132,  53, 229,  29,  12, 181,
+    121,  24, 207, 199, 177, 113,  30,  80,
+      3,  97, 188,  79, 216, 173,   8, 145,
+     87, 128, 180, 237, 240, 137, 125, 104,
+     15, 242, 119, 246, 103, 143,  95, 144,
+      2,  44,  69, 157, 192, 174,  14,  54,
+    218,  82,  64, 210,  11,   6, 129,  21,
+    116, 171,  99, 202,   7, 107, 253, 108
+    };
+    std::array<unsigned char, 256 * 256> a{};
+    for (int y = 0; y < 256; y++)
+        for (int x = 0; x < 256; x++)
+            a[x + y * 256] = permutation256[(y + permutation256[x]) & 0xff];
+    return a;
+}();
 
 void initPermTexture(GLuint *texID)
 {
     CHECK_GL_ERROR();
     glGenTextures(1, texID);
     glBindTexture(GL_TEXTURE_2D, *texID);
-
-    static bool initialized = false;
-    static unsigned char permutation2D[256*256];
-    if( !initialized ) {
-      int x, y;
-
-      for( y=0; y < 256; y++ )
-          for( x=0; x < 256; x++ )
-              permutation2D[x + y*256] = permutation256[(y + permutation256[x]) & 0xff];
-
-      initialized = true;
-    }
-
-    glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, 256, 256, 0, GL_RED, GL_UNSIGNED_BYTE, permutation2D );
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 256, 256, 0, GL_RED, GL_UNSIGNED_BYTE,
+                 permutation2D.data());
     glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
     glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
     CHECK_GL_ERROR();