add missing premake file

btgui/OpenGLWindow/premake4.lua

@@ -0,0 +1,64 @@
+	
+
+		project "OpenGL_rendertest"
+
+	
+		language "C++"
+				
+		kind "ConsoleApp"
+		targetdir "../../bin"
+
+
+		initOpenGL()
+		initGlew()
+
+		includedirs {
+		 	"..",
+		 	"../../src",
+		}
+		
+		links {
+			"gwen"
+		}
+		
+		files {
+			"main.cpp",
+			"renderscene.cpp",
+			"renderscene.h",
+			"GLInstancingRenderer.cpp",
+			"GLInstancingRenderer.h",
+			"GLPrimitiveRenderer.h",
+			"GLPrimitiveRenderer.cpp",
+			"LoadShader.cpp",
+			"LoadShader.h",
+			"gwenWindow.cpp",
+			"gwenWindow.h",
+			"TwFonts.cpp",
+			"TwFonts.h",
+      "GwenOpenGL3CoreRenderer.h",
+      "../FontFiles/OpenSans.cpp",
+			"../OpenGLTrueTypeFont/fontstash.cpp",
+			"../OpenGLTrueTypeFont/fontstash.h",
+			"../OpenGLTrueTypeFont/opengl_fontstashcallbacks.cpp",
+ 			"../OpenGLTrueTypeFont/opengl_fontstashcallbacks.h",
+			"../../src/BulletGeometry/btConvexHullComputer.cpp",
+			"../../src/BulletGeometry/btConvexHullComputer.h",
+			"../../src/BulletCommon/btAlignedAllocator.cpp",
+			"../../src/BulletCommon/btQuickprof.cpp",
+			"../../src/BulletCommon/btQuickprof.h"
+		}
+
+		if os.is("Windows") then 
+			files{  
+				"Win32OpenGLWindow.cpp",
+      	"Win32OpenGLWindow.h",
+      	"Win32Window.cpp",
+      	"Win32Window.h",
+			}
+		end
+		if os.is("Linux") then
+			files {
+				"X11OpenGLWindow.cpp",
+				"X11OpenGLWindows.h"
+			}
+		end