[SOLVED] Difference between DynamicVertexBuffer and VertexBuffer ?

NayGames · July 9, 2020, 8:37pm

I need to know what is the difference between DynamicVertexBuffer and VertexBuffer because in the two cases we can setData all times.

markus · July 9, 2020, 8:58pm

API-wise they are basically the same. DynamicVertexBuffer inherits from VertexBuffer and just adds two additional SetData functions:

github.com

MonoGame/MonoGame/blob/develop/MonoGame.Framework/Graphics/Vertices/DynamicVertexBuffer.cs

// MonoGame - Copyright (C) The MonoGame Team
// This file is subject to the terms and conditions defined in
// file 'LICENSE.txt', which is part of this source code package.

using System;
using MonoGame.Utilities;

namespace Microsoft.Xna.Framework.Graphics
{
	public class DynamicVertexBuffer : VertexBuffer
    {
        /// <summary>
        /// Special offset used internally by GraphicsDevice.DrawUserXXX() methods.
        /// </summary>
        internal int UserOffset;

        public bool IsContentLost { get { return false; } }

        public DynamicVertexBuffer(GraphicsDevice graphicsDevice, VertexDeclaration vertexDeclaration, int vertexCount, BufferUsage bufferUsage)
            : base(graphicsDevice, vertexDeclaration, vertexCount, bufferUsage, true)

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It’s about optimization. By creating a DynamicVertexBuffer you are telling OpenGL/DirectX/MonoGame that you intend to change the contents frequently, so they can optimize for that use case, which should lead to better performance.

Kwyrky · July 9, 2020, 9:40pm

Use DynamicVertexBuffer only when you need to recalculate your Vertex Buffer very often as the data of the Vertex Buffer is sent over the bus to the gpu every frame this way as far as I know.
Under normal circumstances the VertexBuffer is the right choice since the Vertex Buffer will be sent one time. Transformations are applied to the vertices using Matrices (world matrix).