Method _updateScreenGeometry

Engine/source/postFx/postEffect.cpp:475–533

}

void PostEffect::_updateScreenGeometry(   const Frustum &frustum,
                                          GFXVertexBufferHandle<PFXVertex> *outVB )
{
   outVB->set( GFX, 4, GFXBufferTypeVolatile );

   const Point3F *frustumPoints = frustum.getPoints();
   const Point3F& cameraPos = frustum.getPosition();

   // Perform a camera offset.  We need to manually perform this offset on the postFx's
   // polygon, which is at the far plane.
   const Point2F& projOffset = frustum.getProjectionOffset();
   Point3F cameraOffsetPos = cameraPos;
   if(!projOffset.isZero())
   {
      // First we need to calculate the offset at the near plane.  The projOffset
      // given above can be thought of a percent as it ranges from 0..1 (or 0..-1).
      F32 nearOffset = frustum.getNearRight() * projOffset.x;

      // Now given the near plane distance from the camera we can solve the right
      // triangle and calcuate the SIN theta for the offset at the near plane.
      // SIN theta = x/y
      F32 sinTheta = nearOffset / frustum.getNearDist();

      // Finally, we can calcuate the offset at the far plane, which is where our sun (or vector)
      // light's polygon is drawn.
      F32 farOffset = frustum.getFarDist() * sinTheta;

      // We can now apply this far plane offset to the far plane itself, which then compensates
      // for the project offset.
      MatrixF camTrans = frustum.getTransform();
      VectorF offset = camTrans.getRightVector();
      offset *= farOffset;
      cameraOffsetPos += offset;
   }

   PFXVertex *vert = outVB->lock();

   vert->point.set(-1.0, 1.0, 0.0);
   vert->texCoord.set(0.0f, 0.0f);
   vert->wsEyeRay = frustumPoints[Frustum::FarTopLeft] - cameraOffsetPos;
   vert++;

   vert->point.set(1.0, 1.0, 0.0);
   vert->texCoord.set(1.0f, 0.0f);
   vert->wsEyeRay = frustumPoints[Frustum::FarTopRight] - cameraOffsetPos;
   vert++;

   vert->point.set(-1.0, -1.0, 0.0);
   vert->texCoord.set(0.0f, 1.0f);
   vert->wsEyeRay = frustumPoints[Frustum::FarBottomLeft] - cameraOffsetPos;
   vert++;

   vert->point.set(1.0, -1.0, 0.0);
   vert->texCoord.set(1.0f, 1.0f);
   vert->wsEyeRay = frustumPoints[Frustum::FarBottomRight] - cameraOffsetPos;
   vert++;

   outVB->unlock();