天行健 君子當(dāng)自強(qiáng)而不息

Creating In−Game Cinematic Sequences

Using time−based animation is crucial to achieving smooth playback, but what good could using time−based movement possibly do? Sure, moving a few objects around a set path is neat, but is that all you can do? The answer is a resounding no! There's much more you can do with time−based movement, including creating in−game cinematic sequences, like those from games such as Silicon Knights' Eternal Darkness: Sanity's Requiem In Eternal Darkness, the player is treated to animation sequences that play out using the game's 3D engine.

To use a cinematic camera, you can rely on the techniques you read about earlier in this chapter, and you can use the pre−calculated animation sequences, it's only a matter of plotting out the path that your camera will follow over time. Mix that with a complete
pre−calculated animation, and you've got yourself a complete in−game cinematic engine!

Rather than reiterate what you already saw in this chapter, I'll leave it up to you to check out the Cinematic demo, which shows a small cinematic sequence. In a nutshell, the demo merely loads a series of keys (using the .X path parser class) that represent the paths the camera follows. In every frame, the position of the camera is calculated using the keys, and the viewport is oriented. Then the pre−calculated animation is updated and the entire scene is rendered.

As shown in Figure 2.12, you get to see how complex routes can be applied to cameras in order to traverse a 3D scene in real time. This technique of moving a camera is perfect to use for an in−game cinematic system.

Figure 2.12: The cinematic camera demo adds a moving camera to the Route demo.

Route.x:

xof 0303txt 0032

template Path {
  <F8569BED-53B6-4923-AF0B-59A09271D556>
  DWORD Type;        // 0=straight, 1=curved
  Vector Start;
  Vector Point1;
  Vector Point2;
  Vector End;
}

template Route {
  <18AA1C92-16AB-47a3-B002-6178F9D2D12F>
  DWORD NumPaths;
  array Path Paths[NumPaths];
}

Route Robot {
  5;  // 5 paths

  0; // Straight path type
  0.0, 10.0,   0.0;  // Start
  0.0,  0.0,   0.0;  // Unused
  0.0,  0.0,   0.0;  // Unused
  0.0, 10.0, 150.0;, // End

  1; // Curved path type
    0.0, 10.0, 150.0;  // Start
   75.0, 10.0, 150.0;  // Point1
  150.0, 10.0,  75.0;  // Point2
  150.0, 10.0,   0.0;, // End

  1; // Curved path type
  150.0, 10.0,    0.0;  // Start
  150.0, 10.0,  -75.0;  // Point1
   75.0, 10.0, -150.0;  // Point2
    0.0, 10.0, -150.0;, // End

  0; // Straight path type
     0.0, 10.0, -150.0;  // Start
     0.0,  0.0,    0.0;  // Unused
     0.0,  0.0,    0.0;  // Unused
  -150.0, 10.0,   75.0;, // End

  0; // Straight path type
  -150.0, 10.0,  75.0;  // Start
     0.0, 10.0,   0.0;  // Unused
     0.0, 10.0,   0.0;  // Unused
     0.0, 10.0,   0.0;; // End
}

Route Camera {
  4;  // 4 paths

  1;  // Curved path type
    0.0, 80.0, 300.0;   // Start
  150.0, 80.0, 300.0;   // Point1
  300.0, 80.0, 150.0;   // Point2
  300.0, 80.0,   0.0;,  // End

  1;  // Curved path type
  300.0, 80.0,    0.0;   // Start
  300.0, 80.0, -150.0;   // Point1
  151.0, 80.0, -300.0;   // Point2
    0.0, 80.0, -300.0;,  // End

  1;  // Curved path type
     0.0, 80.0, -300.0;   // Start
  -150.0, 80.0, -300.0;   // Point1
  -300.0, 80.0, -150.0;   // Point2
  -300.0, 80.0,    0.0;,  // End

  1;  // Curved path type
  -300.0, 80.0,   0.0;   // Start
  -300.0, 80.0, 150.0;   // Point1
  -150.0, 80.0, 300.0;   // Point2
     0.0, 80.0, 300.0;;  // End
}

Route Target {
  5;  // 5 paths

  0; // Straight path type
  0.0, 10.0,   0.0;  // Start
  0.0,  0.0,   0.0;  // Unused
  0.0,  0.0,   0.0;  // Unused
  0.0, 10.0, 150.0;, // End

  1; // Curved path type
    0.0, 10.0, 150.0;  // Start
   75.0, 10.0, 150.0;  // Point1
  150.0, 10.0,  75.0;  // Point2
  150.0, 10.0,   0.0;, // End

  1; // Curved path type
  150.0, 10.0,    0.0;  // Start
  150.0, 10.0,  -75.0;  // Point1
   75.0, 10.0, -150.0;  // Point2
    0.0, 10.0, -150.0;, // End

  0; // Straight path type
     0.0, 10.0, -150.0;  // Start
     0.0,  0.0,    0.0;  // Unused
     0.0,  0.0,    0.0;  // Unused
  -150.0, 10.0,   75.0;, // End

  0; // Straight path type
  -150.0, 10.0,  75.0;  // Start
     0.0, 10.0,   0.0;  // Unused
     0.0, 10.0,   0.0;  // Unused
     0.0, 10.0,   0.0;; // End
}

WinMain.cpp:

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