24 BasicEffect
Chuck Walbourn редактировал(а) эту страницу 2022-08-14 17:56:09 -07:00
DirectXTK Effects

This is a native Direct3D 11 implementation of the built-in BasicEffect from XNA Game Studio 4 (Microsoft.Xna.Framework.Graphics.BasicEffect) which supports texture mapping, vertex coloring, directional vertex lighting, directional per-pixel lighting, and fog.

BasicEffect image

Related tutorials: Simple rendering, Line drawing and anti-aliasing, 3D shapes

classDiagram
class IEffect{
    <<Interface>>
    +Apply()
    +GetVertexShaderBytecode()
}
class IEffectMatrices{
    <<Interface>>
    +SetWorld()
    +SetView()
    +SetProjection()
    +SetMatrices()
}
class IEffectLights{
    <<Interface>>
    +SetLightingEnabled()
    +SetPerPixelLighting()
    +SetAmbientLightColor()
    +SetLightEnabled()
    +SetLightDirection()
    +SetLightDiffuseColor()
    +SetLightSpecularColor()
    +EnableDefaultLighting()
}
class IEffectFog{
    <<Interface>>
    +SetFogEnabled()
    +SetFogStart()
    +SetFogEnd()
    +SetFogColor()
}
class BasicEffect{
    +SetDiffuseColor()
    +SetEmissiveColor()
    +SetSpecularColor()
    +SetSpecularPower()
    +DisableSpecular()
    +SetAlpha()
    +SetColorAndAlpha()
    +SetVertexColorEnabled()
    +SetBiasedVertexNormals()
    +SetTextureEnabled()
    +SetTexture()
}
BasicEffect --|> IEffect
BasicEffect --|> IEffectMatrices
BasicEffect --|> IEffectLights
BasicEffect --|> IEffectFog

Header

#include <Effects.h>

Initialization

Construction requires a Direct3D 11 device.

std::unique_ptr<BasicEffect> effect;
effect = std::make_unique<BasicEffect>(device);

For exception safety, it is recommended you make use of the C++ RAII pattern and use a std::unique_ptr or std::shared_ptr

Interfaces

BasicEffect supports IEffect, IEffectMatrices, IEffectLights, and IEffectFog

Input layout

This effect requires SV_Position, NORMAL if lighting is enabled, COLOR if per-vertex colors are enabled, and TEXCOORD0 if texturing is enabled.

Properties

  • SetDiffuseColor: Sets the diffuse color of the effect. Defaults to white (1,1,1). Alpha channel (.w component) is ignored.

  • SetEmissiveColor: Sets the emissive color of the effect. Defaults to black (0,0,0).

  • SetSpecularColor: Sets the specular color of the effect. Defaults to white (1,1,1).

  • SetSpecularPower: Sets the specular power of the effect. Defaults to 16. Settings power to 0 can cause strange rendering artifacts.

  • DisableSpecular: Disables the specular lighting for the effect. Sets the color to black (0,0,0) and power to 1.

  • SetAlpha: Sets the alpha (transparency) of the effect. Defaults to 1 (fully opaque). This value is also used for binning opaque vs. transparent geometry.

  • SetColorAndAlpha: Sets the diffuse color of the effect and the alpha (transparency).

  • SetVertexColorEnabled: Enables per-vertex color. Defaults to false. Modifying this setting requires recreating associated input layouts, and enabling it requires COLOR.

  • SetTextureEnabled: Enables texturing. Defaults to false. Modifying this setting requires recreating associated input layouts, and enabling it requires TEXCOORD0.

  • SetTexture: Associates a texture shader resource view with the effect. Can be set to nullptr to remove a reference. Can optionally include an alpha channel as well.

  • SetBiasedVertexNormals: Enables support for compressed vertex normals which require *2 - 1 biasing at runtime such as DXGI_FORMAT_R10G10B10A2_UNORM.

Example

Here is an example of creating and using a basic effect instance:

std::unique_ptr<DirectX::BasicEffect> basicEffect;

When creating device-dependent resources:

basicEffect = std::make_unique<BasicEffect>(device);

basicEffect->EnableDefaultLighting();
basicEffect->SetDiffuseColor(Colors::Red);
basicEffect->SetFogColor(Colors::CornflowerBlue);
basicEffect->SetFogStart(fogstart);
basicEffect->SetFogEnd(fogend);
basicEffect->SetTexture( texture.Get() );

When the window size is changed is where you typically set the projection:

basicEffect->SetProjection(projection);

A view matrix is computed based on user input and camera settings:

basicEffect->SetView(view);

Then to render:

basicEffect->SetWorld(world);
basicEffect->Apply(context);

context->OMSetBlendState(states->AlphaBlend(), Colors::White, 0xFFFFFFFF);
context->OMSetDepthStencilState(states->DepthDefault(), 0);
context->RSSetState(states->None());

ID3D11SamplerState* samplers[] = { states->LinearWrap() };
context->PSSetSamplers(0, 1, samplers);

context->IASetVertexBuffers(...);
context->IASetIndexBuffer(...);
context->IASetPrimitiveTopology(...);
context->DrawIndexed(...);

When dealing with lost device (if required):

basicEffect.reset();

Remarks

This effect implements the classic diffuse Lambertian shading with Phong specular highlights lighting model.

See Microsoft Docs

Further reading

BasicEffect optimizations in XNA Game Studio 4.0
SpriteBatch and BasicEffect for C++ Direct3D 11
BasicEffect: a misnomer?