Updated handling glPolygonMode function on GLES

Author: TheMostDiligent

Graphics/GraphicsEngineOpenGL/src/GLContextState.cpp

@@ -426,9 +426,17 @@ namespace Diligent
         {
             if( m_RSState.FillMode != FillMode )
             {
-                auto PolygonMode = FillMode == FILL_MODE_WIREFRAME ? GL_LINE : GL_FILL;
-                glPolygonMode( GL_FRONT_AND_BACK, PolygonMode );
-                CHECK_GL_ERROR( "Failed to set polygon mode" );
+                if(glPolygonMode != nullptr)
+                {
+                    auto PolygonMode = FillMode == FILL_MODE_WIREFRAME ? GL_LINE : GL_FILL;
+                    glPolygonMode( GL_FRONT_AND_BACK, PolygonMode );
+                    CHECK_GL_ERROR( "Failed to set polygon mode" );
+                }
+                else
+                {
+                    if(FillMode != FILL_MODE_SOLID)
+                        LOG_ERROR("This API/device only supports solid fill mode");
+                }
 
                 m_RSState.FillMode = FillMode;
             }

Graphics/GraphicsEngineOpenGL/src/GLStubsAndroid.cpp

@@ -97,7 +97,7 @@
 #endif
 
 #ifdef LOAD_GL_POLYGON_MODE
-    DECLARE_GL_FUNCTION( glPolygonMode, PFNGLPOLYGONMODE, GLenum, GLenum)
+    PFNGLPOLYGONMODE glPolygonMode = nullptr;
 #endif
 
 #ifdef LOAD_GL_ENABLEI
@@ -225,7 +225,7 @@ Func = (FuncType)eglGetProcAddress( #Func );\
 #endif
 
 #ifdef LOAD_GL_POLYGON_MODE
-    LOAD_GL_FUNCTION( glPolygonMode, PFNGLPOLYGONMODE)
+    glPolygonMode = (PFNGLPOLYGONMODE)eglGetProcAddress("glPolygonMode");
 #endif
 
 #ifdef LOAD_GL_ENABLEI

Graphics/GraphicsEngineOpenGL/src/RenderDeviceGLImpl.cpp

@@ -643,6 +643,9 @@ void RenderDeviceGLImpl::TestTextureFormat( TEXTURE_FORMAT TexFormat )
 
 void RenderDeviceGLImpl :: QueryDeviceCaps()
 {
+    if(glPolygonMode == nullptr)
+        m_DeviceCaps.bWireframeFillSupported = false;
+        
     if(m_DeviceCaps.bWireframeFillSupported)
     {
         // Test glPolygonMode() function to check if it fails