camera not passes through terrain

Graphics and GPU Programming Programming

Started by chench September 14, 2011 03:10 PM

4 comments, last by chench 12 years, 7 months ago

chench

100

Author

September 14, 2011 03:10 PM

I don't want to let the camera passes through terrain.

here my code:





 float fHeight = m_pTerrain->GetHeight((int)m_pCamera->GetPosition().x, 

  (int)m_pCamera->GetPosition().z);



 if ( fHeight > m_pCamera->GetPosition().y )

 {

  m_pCamera->SetPosition(m_pCamera->GetPosition().x, fHeight + 4.0f,

   m_pCamera->GetPosition().z);

 }

I know it is not work!

1. the function GetHeight(int x, int z), and the paramer x and z is the terrain, not the camera,
but i don't know how to get the terrain's point

2.





m_pCamera->SetPosition(m_pCamera->GetPosition().x, fHeight + 4.0f,

   m_pCamera->GetPosition().z);

do not know if there is wrong

Nanoha

2,682

September 14, 2011 03:17 PM

It looks reasonable enough, what happening exactly? This bit:

if ( fHeight > m_pCamera->GetPosition().y )

You should change it to:

if ( fHeight + 4.0 > m_pCamera->GetPosition().y )

Since the camera should always be 4 units above the terrain (from what your code does). Otherwise it can get very close to the terrain before finally jumping up 4 units which wouldn't look as good.

Interested in Fractals? Check out my App, Fractal Scout, free on the Google Play store.

chench

100

Author

September 14, 2011 03:41 PM

It looks reasonable enough, what happening exactly? This bit:

if ( fHeight > m_pCamera->GetPosition().y )

You should change it to:

if ( fHeight + 4.0 > m_pCamera->GetPosition().y )

Since the camera should always be 4 units above the terrain (from what your code does). Otherwise it can get very close to the terrain before finally jumping up 4 units which wouldn't look as good.

thanks, it is not jumping up now, but still under the terrain

gsamour

141

September 14, 2011 04:03 PM

thanks, it is not jumping up now, but still under the terrain

Can you post the code for the terrain's GetHeight() ?

Nanoha

2,682

September 14, 2011 06:08 PM

thanks, it is not jumping up now, but still under the terrain

All I can think of is GetHeight is not working as it should. Simplest thing to try is to reverse the x/z you pass in so its:

float fHeight = m_pTerrain->GetHeight((int)m_pCamera->GetPosition().z, (int)m_pCamera->GetPosition().x);

Interested in Fractals? Check out my App, Fractal Scout, free on the Google Play store.

chench

100

Author

September 15, 2011 01:18 PM

[quote name='chench' timestamp='1316014861' post='4861594']
thanks, it is not jumping up now, but still under the terrain

Can you post the code for the terrain's GetHeight() ?
[/quote]







float CTerrain::GetHeight(int x, int z)

{

 x += (int)( m_position.x + m_vfScale.x*m_cxDIB/2.0f );

 z += (int)( m_position.z + m_vfScale.z*m_czDIB/2.0f );



 float rx, rz;

 rx = x/m_vfScale.x;

 rz = m_czDIB - z/m_vfScale.z;



 long col1, row1, col2, row2;

 float h1, h2, h3, h4, ha, hb;



 col1 = (DWORD)rx;

 row1 = (DWORD)rz;



 if ( col1 > m_cxDIB || col1 < 0 || row1 > m_czDIB || row1 < 0)

 {

  return 0;

 }

 else

 {



  col2 = ( col1 == m_cxDIB )? col1 : col1 + 1;

  row2 = ( row1 == m_czDIB )? row1 : row1 + 1;



  h1 = ( m_pHeightMap[ row1*m_cxDIB + col1 ].position.y );

  h2 = ( m_pHeightMap[ row1*m_cxDIB + col2 ].position.y );

  h3 = ( m_pHeightMap[ row2*m_cxDIB + col1 ].position.y );

  h4 = ( m_pHeightMap[ row2*m_cxDIB + col2 ].position.y );



  ha = ( h2*(rx - col1) + h1*(col2 - rx) );

  hb = ( h4*(rx - col1) + h3*(col2 - rx) );



  return ( hb*(rz - row1) + ha*(row2 - rz) );

 }



}

TerrainVertex* m_pHeightMap





typedef struct TerrainVertex

{

 D3DXVECTOR3   position;          

 D3DXVECTOR3   normal;           

 D3DXVECTOR2   texture1;        

 D3DXVECTOR2   texture2;



}TerrainVertex;

camera not passes through terrain

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