如何在没有空闲的情况下绘制数百万个立方体，XNA中的模型实例化？

Question

我以“Minecraft”游戏的方式为一个项目工作。

我开始使用“模型实例化”来生成大量具有相同模型的立方体。 到现在为止还挺好。 我的问题是，如果我增加矩阵的大小来绘制[300-1-300]（ 90,000立方米）[500-1-500]（ 250,000立方米< / strong>）我的程序变得非常缓慢。它从60fps到20 ......

我真的不明白为什么。但我正确使用该技术“硬件实例化”。我也在论坛上注意到这种技术允许XNA绘制高达700万立方！ 你对我的问题有什么想法吗？

非常感谢

这是我的函数，用于绘制实例化的模型：

// Draw the 3D map (world) of game 
public void drawWorld(GameTime gameTime)
{
    / * Draw all the structures that make up the world with the instancing system * /
    Array.Resize(ref instanceTransforms, smallListInstance.Count);

    for (int i = 0; i < ListInstance.Count; i++)
    {
        instanceTransforms[i] = ListInstance[i].Transform;
    }

    DrawModelHardwareInstancing(myModel, myTexture2D,instancedModelBones,instanceTransforms, arcadia.camera.View, arcadia.camera.Projection);


}
// ### end function drawWorld

这是我的函数[DrawModelHardwareInstancing] ，它使用microsoft示例中使用的 [Hardware Instancing] 方法绘制模型。

// Function that will draw all the models instantiated in the list
void DrawModelHardwareInstancing(Model model,Texture2D texture, Matrix[] modelBones,
                                 Matrix[] instances, Matrix view, Matrix projection)
{
    Game.GraphicsDevice.SamplerStates[0] = SamplerState.LinearWrap;
    if (instances.Length == 0)
        return;

    // If we have more instances than room in our vertex buffer, grow it to the neccessary size.
    if ((instanceVertexBuffer == null) ||
        (instances.Length > instanceVertexBuffer.VertexCount))
    {
        if (instanceVertexBuffer != null)
            instanceVertexBuffer.Dispose();

        instanceVertexBuffer = new DynamicVertexBuffer(Game.GraphicsDevice, instanceVertexDeclaration,
                                                       instances.Length, BufferUsage.WriteOnly);
    }

    // Transfer the latest instance transform matrices into the instanceVertexBuffer.
    instanceVertexBuffer.SetData(instances, 0, instances.Length, SetDataOptions.Discard);

    foreach (ModelMesh mesh in model.Meshes)
    {
        foreach (ModelMeshPart meshPart in mesh.MeshParts)
        {
            // Tell the GPU to read from both the model vertex buffer plus our instanceVertexBuffer.
            Game.GraphicsDevice.SetVertexBuffers(
                new VertexBufferBinding(meshPart.VertexBuffer, meshPart.VertexOffset, 0),
                new VertexBufferBinding(instanceVertexBuffer, 0, 1)
            );

            Game.GraphicsDevice.Indices = meshPart.IndexBuffer;


            // Set up the instance rendering effect.
            Effect effect = meshPart.Effect;
            //effect.CurrentTechnique = effect.Techniques["HardwareInstancing"];
            effect.Parameters["World"].SetValue(modelBones[mesh.ParentBone.Index]);
            effect.Parameters["View"].SetValue(view);
            effect.Parameters["Projection"].SetValue(projection);
            effect.Parameters["Texture"].SetValue(texture);


            // Draw all the instance copies in a single call.
            foreach (EffectPass pass in effect.CurrentTechnique.Passes)
            {
                pass.Apply();

                Game.GraphicsDevice.DrawInstancedPrimitives(PrimitiveType.TriangleList, 0, 0,
                                                       meshPart.NumVertices, meshPart.StartIndex,
                                                       meshPart.PrimitiveCount, instances.Length);
            }
        }



    }
}
// ### end function DrawModelHardwareInstancing

Answer 1

非常感谢！由于你的建议，我终于解决了我的问题; - ）！

我只绘制了我视野“相机”前面的模型。 仅在需要“编辑”，“新位置等等”时更新模型。

我的最后一步是只绘制6个立方体面中的3个以提高性能。

代码示例仅绘制前面的模型

public BoundingFrustum Frustum {get;私人集; }

//Initialize 
Matrix viewProjection = View * Projection; 
Frustum = new BoundingFrustum(viewProjection); 

//Update 
Matrix viewProjection = View * Projection; 
Frustum.Matrix = viewProjection; 

//Check instance and make the instanceTransformation for draw 
foreach (var object in ListInstance.Where(m => Frustum.Contains(m.BoundingBox) != ContaintmentType.Disjoint) 
{
    instanceTransforms[index].Add(smallListInstance[i].Transform); 

} 
// And now draw ...