c++ - 渲染到小 map 的纹理，directX

Question

我正在尝试将 3d 环境的鸟瞰图渲染为纹理，并将该纹理绘制为 HUD 以表示迷你 map ，就好像它是从上方俯视游戏的相机。我在 3D 编程和 DirextX API 方面还很陌生，所以我需要这方面的帮助。通过使用一些示例和教程，这就是我所拥有的，但仍然没有成功。

我几乎不知道如何将纹理作为 HUD 正确地绘制到屏幕上。引擎会运行 beginProjectScene() 和 endProjectScene() 方法，然后运行 ​​beginSuperImpose() 方法。

beginProjectScene() 创建一个纹理来绘制，创建适当的 View 和投影矩阵和后台缓冲区以及一个新的视口(viewport)，并在备份当前视口(viewport)后设置它们。它还设置适当的渲染目标。

endProjectScene() 恢复备份的矩阵、视口(viewport)、后台缓冲区。

beginSuperImpose() 应该将纹理 (texH) 绘制到屏幕上。

还有一些其他方法通过显示设备 (d3dd) 调用到 D3D API 方法来实现这一点。但这似乎不起作用，实际上什么也没有发生，我不确定为什么。之前，在将渲染目标恢复到 endProjectScene() 中的备份后备缓冲区之前，屏幕刚刚变黑(原因很明显)。我相信我的大部分问题都与多个视口(viewport)有关，而且很多概念都是相对较新的，我仍在努力完全掌握。

此外，在恢复后备缓冲区后调用 SetTexture(0, texH) 时，我的白色球体会变成蓝色。

我稍微提到了这个:http://www.two-kings.de/tutorials/dxgraphics/dxgraphics16.html

主引擎循环:

int Engine::run() { 

  ....

  // update the model components
  design->update(rightNow);
  Viewing->update(rightNow);
  audio->update(rightNow);
  lighting->update();
  hud->update(rightNow);

  //NEW CODE FOR HUD BEGIN
  // create the projection here - this part is new

  display->beginProjectScene();

  // draw the opaque scene objects
  scene->draw(true);
  // then the translucent/transparent objects
  display->alphaBlendOn();
  scene->draw(false);
  display->alphaBlendOff();
  display->endProjectScene();

  //NEW CODE FOR HUD END

  // draw the scene
  display->beginDraw();
  // draw the opaque scene objects
  scene->draw(true);
  // then the translucent/transparent objects
  display->alphaBlendOn();
  scene->draw(false);
  display->alphaBlendOff();

  // draw the HUD
  display->beginSuperimpose();
  hud->draw();
  display->endDraw();

  ....
}

显示:

void Display::beginProjectScene() {

    // create the texture COM object on which to draw
    // if the texture COM object does not yet exist
    //
    if (!texH && FAILED(D3DXCreateTexture(d3dd, TEXTURE_WIDTH,
     TEXTURE_HEIGHT, 0, D3DUSAGE_RENDERTARGET | D3DUSAGE_AUTOGENMIPMAP,
  D3DFMT_R5G6B5, D3DPOOL_DEFAULT, &texH)))
        error(L"Projection::11 Failed to create projection texture");

    // get the interface to the surface for the texture - GetSurfaceLevel
    // increases the reference count by 1 so we will have
    // to Release the interface when done
    //

    if (texH && SUCCEEDED(texH->GetSurfaceLevel(0, &textureSurface))) {

    // build the view matrix
    //
    // define position, heading, and up direction of camera and
    // create a view matrix and set the view transformationf
    //TEMPORTY VALUES
    Vector up(0,1,0);
    Vector heading(0,0,0); 
    Vector position(0.5,1,0.5);
    Vector view(1,0,0);

    // the look at point from the virtual camera
    Vector lookAt = position + heading;
    Matrix viewH = 
       ::view(view, position+heading, up);


   // build the projection matrix
   // ...TEST VALUES
   Matrix projectionProjection =
      ::projection(FIELD_OF_VIEW, aspect, NEAR_CLIPPING, 
         FAR_CLIPPING);


  // back up the projection matrix and the viewport, and back buffer
  d3dd->GetTransform(D3DTS_PROJECTION, &projBak);
  d3dd->GetViewport(&viewportBak);
  d3dd->GetRenderTarget(0, &pBackBuffer);

  // associate the backbuffer with the texture surface
  d3dd->SetRenderTarget(0, textureSurface);

  // project the scene onto the texture
  d3dd->Clear(0, NULL, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER,
   D3DCOLOR_ARGB(100, 100, 100, alpha), 1.0f, 0);

  d3dd->BeginScene();

  //d3dd->SetTexture(0, texH);

  d3dd->SetTransform(D3DTS_VIEW, (D3DXMATRIX*)&viewH);
  d3dd->SetTransform(D3DTS_PROJECTION, (D3DMATRIX*)&projectionProjection);

  // define the viewport for the texture
  D3DVIEWPORT9 viewport;
  viewport.X = 0;
  viewport.Y = 0;
  viewport.Width  = TEXTURE_WIDTH;
  viewport.Height = TEXTURE_HEIGHT;
  viewport.MinZ = 0.0f;
  viewport.MaxZ = 1.0f;
  d3dd->SetViewport(&viewport);

  //d3dd->EndScene();

 }
}

void Display::endProjectScene() {

  d3dd->SetRenderTarget(0, pBackBuffer);
  d3dd->Clear(0, NULL, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER,
   D3DCOLOR_ARGB(100, 100, 100, alpha), 1.0f, 0);


  //d3dd->BeginScene();

  //d3dd->SetTexture(0, texH);

  // restore the projection and viewport
  d3dd->SetTransform(D3DTS_PROJECTION, &projBak);
  d3dd->SetViewport(&viewportBak);

  d3dd->EndScene();


  // release the backbuffer associated with the texture
  textureSurface->Release();
  pBackBuffer->Release();
  //texH->Release();

} 

void Display::beginSuperimpose() {

   // prepare to draw the hud
   //
   if (spriteManager_){
     // start the sprite manager
     spriteManager_->Begin(D3DXSPRITE_ALPHABLEND);


     //NEW CODE FOR HUD
     Vector topRight(width() * 0.01f, height() * 0.01f, 0);

     spriteManager_->Draw(texH, NULL, NULL, (D3DXVECTOR3*)&topRight,
     D3DCOLOR_RGBA(SPRITEH_R, SPRITEH_G, SPRITEH_B,  1));
 }
}

Answer 1

尝试在对 Draw 的调用中将 , 1 更改为 , 255。 D3DCOLOR_RGBA 取值范围为 0 到 255。alpha 值为 1 几乎是透明的。