Improve windows build.

Don't report error when `in_normal` is not used in the shader.

examples/glview/README.md

@@ -15,10 +15,15 @@ Simple OpenGL viewer for glTF geometry.
     > premake4 gmake
     $ make
 
-### Windows(not tested)
+### Windows(not tested well)
+
+Edit glew and glfw path in `premake4.lua`, then
 
     > premake5.exe vs2013
-    Open .sln in Visual Studio 2013
+
+Open .sln in Visual Studio 2013
+
+When running .exe, glew and glfw dll must exist in the working directory.
 
 ## TODO
 

examples/glview/glview.cc

@@ -360,12 +360,15 @@ void DrawMesh(tinygltf::Scene &scene, const tinygltf::Mesh &mesh) {
       if ((it->first.compare("POSITION") == 0) ||
           (it->first.compare("NORMAL") == 0) ||
           (it->first.compare("TEXCOORD_0") == 0)) {
-        glVertexAttribPointer(
-            gGLProgramState.attribs[it->first], count, accessor.componentType,
-            GL_FALSE, accessor.byteStride, BUFFER_OFFSET(accessor.byteOffset));
-        CheckErrors("vertex attrib pointer");
-        glEnableVertexAttribArray(gGLProgramState.attribs[it->first]);
-        CheckErrors("enable vertex attrib array");
+
+		if (gGLProgramState.attribs[it->first] >= 0) {
+			glVertexAttribPointer(
+				gGLProgramState.attribs[it->first], count, accessor.componentType,
+				GL_FALSE, accessor.byteStride, BUFFER_OFFSET(accessor.byteOffset));
+			CheckErrors("vertex attrib pointer");
+			glEnableVertexAttribArray(gGLProgramState.attribs[it->first]);
+			CheckErrors("enable vertex attrib array");
+		}
       }
     }
 
@@ -403,7 +406,9 @@ void DrawMesh(tinygltf::Scene &scene, const tinygltf::Mesh &mesh) {
         if ((it->first.compare("POSITION") == 0) ||
             (it->first.compare("NORMAL") == 0) ||
             (it->first.compare("TEXCOORD_0") == 0)) {
-          glDisableVertexAttribArray(gGLProgramState.attribs[it->first]);
+		  if (gGLProgramState.attribs[it->first] >= 0) {
+	        glDisableVertexAttribArray(gGLProgramState.attribs[it->first]);
+		  }
         }
       }
     }
@@ -497,7 +502,7 @@ int main(int argc, char **argv) {
   glfwSetMouseButtonCallback(window, clickFunc);
   glfwSetCursorPosCallback(window, motionFunc);
 
-  glewExperimental = true;
+  glewExperimental = true; // This may be only true for linux environment.
   if (glewInit() != GLEW_OK) {
     std::cerr << "Failed to initialize GLEW." << std::endl;
     return -1;
@@ -523,17 +528,12 @@ int main(int argc, char **argv) {
   CheckErrors("link");
 
   {
+    // At least `in_vertex` should be used in the shader.
     GLint vtxLoc = glGetAttribLocation(progId, "in_vertex");
     if (vtxLoc < 0) {
       printf("vertex loc not found.\n");
       exit(-1);
     }
-
-    GLint tnLoc = glGetAttribLocation(progId, "in_normal");
-    if (tnLoc < 0) {
-      printf("normal loc not found.\n");
-      exit(-1);
-    }
   }
 
   glUseProgram(progId);

examples/glview/premake4.lua

@@ -1,36 +1,41 @@
 solution "glview"
-	-- location ( "build" )
-	configurations { "Debug", "Release" }
-	platforms {"native", "x64", "x32"}
-	
-	project "glview"
+   -- location ( "build" )
+   configurations { "Debug", "Release" }
+   platforms {"native", "x64", "x32"}
+   
+   project "glview"
 
-		kind "ConsoleApp"
-		language "C++"
-		files { "glview.cc", "trackball.cc" }
-		includedirs { "./" }
-		includedirs { "../../" }
+      kind "ConsoleApp"
+      language "C++"
+      files { "glview.cc", "trackball.cc" }
+      includedirs { "./" }
+      includedirs { "../../" }
 
-		configuration { "linux" }
-			 linkoptions { "`pkg-config --libs glfw3`" }
-			 links { "GL", "GLU", "m", "GLEW", "X11", "Xrandr", "Xinerama", "Xi", "Xxf86vm", "Xcursor", "dl" }
+      configuration { "linux" }
+         linkoptions { "`pkg-config --libs glfw3`" }
+         links { "GL", "GLU", "m", "GLEW", "X11", "Xrandr", "Xinerama", "Xi", "Xxf86vm", "Xcursor", "dl" }
 
-		configuration { "windows" }
-			 links { "glfw3", "gdi32", "winmm", "user32", "GLEW", "glu32","opengl32", "kernel32" }
-			 defines { "_CRT_SECURE_NO_WARNINGS" }
+      configuration { "windows" }
+         -- Edit path to glew and GLFW3 fit to your environment.
+         includedirs { "../../../../local/glew-1.13.0/include/" }
+         includedirs { "../../../../local/glfw-3.2.bin.WIN32/include/" }
+         libdirs { "../../../../local/glew-1.13.0/lib/Release/Win32/" }
+         libdirs { "../../../../local/glfw-3.2.bin.WIN32/lib-vc2013/" }
+         links { "glfw3", "gdi32", "winmm", "user32", "glew32", "glu32","opengl32", "kernel32" }
+         defines { "_CRT_SECURE_NO_WARNINGS" }
 
-		configuration { "macosx" }
+      configuration { "macosx" }
          includedirs { "/usr/local/include" }
          buildoptions { "-Wno-deprecated-declarations" }
          libdirs { "/usr/local/lib" }
-			links { "glfw3", "GLEW" }
-			linkoptions { "-framework OpenGL", "-framework Cocoa", "-framework IOKit", "-framework CoreVideo" }
+         links { "glfw3", "GLEW" }
+         linkoptions { "-framework OpenGL", "-framework Cocoa", "-framework IOKit", "-framework CoreVideo" }
 
-		configuration "Debug"
-			defines { "DEBUG" }
-			flags { "Symbols", "ExtraWarnings"}
+      configuration "Debug"
+         defines { "DEBUG" }
+         flags { "Symbols", "ExtraWarnings"}
 
-		configuration "Release"
-			defines { "NDEBUG" }
-			flags { "Optimize", "ExtraWarnings"}
+      configuration "Release"
+         defines { "NDEBUG" }
+         flags { "Optimize", "ExtraWarnings"}