Fix wrong flash rectangle size after window resize

src/gl/data/gl_vertexbuffer.cpp

@@ -213,6 +213,20 @@ FFlatVertexBuffer::~FFlatVertexBuffer()
 	map = nullptr;
 }
 
+void FFlatVertexBuffer::OutputResized(int width, int height)
+{
+	vbo_shadowdata[4].Set(0, 0, 0, 0, 0);
+	vbo_shadowdata[5].Set(0, (float)height, 0, 0, 0);
+	vbo_shadowdata[6].Set((float)width, 0, 0, 0, 0);
+	vbo_shadowdata[7].Set((float)width, (float)height, 0, 0, 0);
+	
+	if (gl.buffermethod == BM_DEFERRED)
+	{
+		Map();
+		memcpy(map, &vbo_shadowdata[0], mNumReserved * sizeof(FFlatVertex));
+		Unmap();
+	}
+}
 
 void FFlatVertexBuffer::BindVBO()
 {

src/gl/data/gl_vertexbuffer.h

@@ -131,6 +131,8 @@ public:
 	FFlatVertexBuffer(int width, int height);
 	~FFlatVertexBuffer();
 
+	void OutputResized(int width, int height);
+
 	void BindVBO();
 
 	void CreateVBO();

src/gl/system/gl_framebuffer.cpp

@@ -192,6 +192,7 @@ void OpenGLFrameBuffer::Update()
 		{
 			Resize(clientWidth, clientHeight);
 			V_OutputResized(Width, Height);
+			GLRenderer->mVBO->OutputResized(Width, Height);
 		}
 	}