X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;f=simgear%2Fscreen%2Fcolors.hxx;h=1aa0ef47bc3474ce96dd0413db25a773a3636ec2;hb=dc09a50472890ac706d3c76d8af34cc3682ada0c;hp=197597079de733b06f3e0d72decd28dcfcdd8a43;hpb=94c22fec4668b259e83038f6ba1f098df353c73e;p=simgear.git

diff --git a/simgear/screen/colors.hxx b/simgear/screen/colors.hxx
index 19759707..1aa0ef47 100644
--- a/simgear/screen/colors.hxx
+++ b/simgear/screen/colors.hxx
@@ -30,39 +30,52 @@
 const float system_gamma = 1.4;
 
 #elif defined (sgi)
-const float system_gamma = 1.7;
+const float system_gamma = 2.0/1.7;
 
 #else	// others
 const float system_gamma = 2.5;
 #endif
 
-
 // simple architecture independant gamma correction function.
 inline void gamma_correct_rgb(float *color,
-                          float reff = 2.5, float system = system_gamma)
+                              float reff = 2.5, float system = system_gamma)
 {
-   color[0] = pow(color[0], reff/system);
-   color[1] = pow(color[1], reff/system);
-   color[2] = pow(color[2], reff/system);
+    if (reff == system)
+       return;
+
+    float tmp = reff/system;
+    color[0] = pow(color[0], tmp);
+    color[1] = pow(color[1], tmp);
+    color[2] = pow(color[2], tmp);
 };
 
 inline void gamma_correct_c(float *color,
-                          float reff = 2.5, float system = system_gamma)
+                            float reff = 2.5, float system = system_gamma)
 {
+   if (reff == system)
+      return;
+
    *color = pow(*color, reff/system);
 };
 
 inline void gamma_restore_rgb(float *color,
-                          float reff = 2.5, float system = system_gamma)
+                              float reff = 2.5, float system = system_gamma)
 {
-   color[0] = pow(color[0], system/reff);
-   color[1] = pow(color[1], system/reff);
-   color[2] = pow(color[2], system/reff);
+    if (reff == system)
+       return;
+
+    float tmp = system/reff;
+    color[0] = pow(color[0], tmp);
+    color[1] = pow(color[1], tmp);
+    color[2] = pow(color[2], tmp);
 };
 
 inline void gamma_restore_c(float *color,
-                          float reff = 2.5, float system = system_gamma)
+                            float reff = 2.5, float system = system_gamma)
 {
+   if (reff == system)
+      return;
+
    *color = pow(*color, system/reff);
 };