Question

我想制作一个带有3D图形的XNA游戏，有一件事我想知道。假设我的场景中有10 Model个，我想用相同的光源绘制它们，就像定向光源一样。现在我了解Model有Effect个，Effect有照明信息等等。我的问题是，如何将相同的光源应用于场景中的所有模型，而不是每个模型都有自己的光源？有人告诉我，如果我离开基地。

Answer 1

如果您使用XNA 4.0创建游戏，则需要使用效果。幸运的是，XNA团队包含了一个名为BasicEffect的强大而简单的效果。除非另行指定，否则BasicEffect是渲染模型时使用的默认效果。 BasicEffect最多支持3个定向灯。下面的示例代码可以让您了解如何使用定向光来操作BasicEffect实例进行渲染。

public void DrawModel( Model myModel, float modelRotation, Vector3 modelPosition,
                       Vector3 cameraPosition
     ) {
    // Copy any parent transforms.
    Matrix[] transforms = new Matrix[myModel.Bones.Count];
    myModel.CopyAbsoluteBoneTransformsTo(transforms);

    // Draw the model. A model can have multiple meshes, so loop.
    foreach (ModelMesh mesh in myModel.Meshes)
    {
        // This is where the mesh orientation is set, as well 
        // as our camera and projection.
        foreach (BasicEffect effect in mesh.Effects)
        {
            effect.EnableDefaultLighting();
            effect.World = transforms[mesh.ParentBone.Index] * 
                            Matrix.CreateRotationY(modelRotation) *
                            Matrix.CreateTranslation(modelPosition);
            effect.View = Matrix.CreateLookAt(cameraPosition,
                            Vector3.Zero, Vector3.Up);
            effect.Projection = Matrix.CreatePerspectiveFieldOfView(
                                    MathHelper.ToRadians(45.0f), 1.333f, 
                                    1.0f, 10000.0f);
            effect.LightingEnabled = true; // turn on the lighting subsystem.
            effect.DirectionalLight0.DiffuseColor = new Vector3(0.5f, 0, 0); // a red light
            effect.DirectionalLight0.Direction = new Vector3(1, 0, 0);  // coming along the x-axis
            effect.DirectionalLight0.SpecularColor = new Vector3(0, 1, 0); // with green highlights
        }
        // Draw the mesh, using the effects set above.
        mesh.Draw();
    }
}

XNA - 3D游戏 - 为所有型号应用灯光

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