Fix clang -Wc++11-narrowing warnings.

Clang compiler gives warning to implicit conversions of
literal structure fields, although the compiler generated
implicit conversions are what we want in these cases.

Change-Id: I8f04e7f2fa1db0ed1d1937135d9091532eec3d5b
diff --git a/opengl/tests/linetex/linetex.cpp b/opengl/tests/linetex/linetex.cpp
index 7921f80..5ad695b 100644
--- a/opengl/tests/linetex/linetex.cpp
+++ b/opengl/tests/linetex/linetex.cpp
@@ -80,9 +80,11 @@
      // default pack-alignment is 4
      const uint16_t t16[64] = { 0xFFFF, 0, 0xF800, 0, 0x07E0, 0, 0x001F, 0 };
 
+     const GLfloat fh = h;
+     const GLfloat fw2 = w/2;
      const GLfloat vertices[4][2] = {
-             { w/2,  0 },
-             { w/2,  h }
+             { fw2,  0  },
+             { fw2,  fh }
      };
 
      const GLfloat texCoords[4][2] = {