diff --git a/openglcanvas.cpp b/openglcanvas.cpp
index e032944472c04a9e5134deae51245491f171cf42..23c0bed5244fd3e95cf4cd0d1095002459daf7ae 100644
--- a/openglcanvas.cpp
+++ b/openglcanvas.cpp
@@ -22,10 +22,10 @@
 #define VERT_SHADER_FILE "test_vertex_shader.vert"
 #define FRAG_SHADER_FILE "fragment_shader.frag"
 
-#define CONST_PI        3.141592653589793238462
-#define CONST_PI_2      1.57079632679489661923
-#define CONST_PI_F      3.14159265358979f
-#define CONST_PI_2_F    1.570796326794897f // TODO: check this one
+#define CONST_PI        (0x1.921fb54442d18p+1)
+#define CONST_PI_2      (0x1.921fb54442d18p+0)
+#define CONST_PI_F      (0x1.921fb6p+1)
+#define CONST_PI_2_F    (0x1.921fb6p+0)
 
 OpenGLCanvas::OpenGLCanvas(QWidget *parent) :
     QGLWidget(parent)