Displaying 3D surface.

OpenGL OpenGL: Basic Coding
1

Hi,
I am code to determine the surface texture.
Through this code i am getting x,y,z values.
Now using these values I have to display a 3D surface.
I have written a program for displaying it using triangles and have also written a code for calculating the normals.Basically I am having the Z value in 2D array while x and y in 1D array…

glBegin ( GL_TRIANGLES ) ;

	for(i=1;i<=100;i++)
	{
		for(j=1;j<=100;j++)
		{
			n1=check.CCalNormal(i,j,1);
			glNormal3f(n1.x,n1.z,n1.y);
			glVertex3f (xw[i],zw[i][j],yw[j]) ;
			glVertex3f (xw[i+1],zw[i+1][j],yw[j]) ;
			glVertex3f (xw[i+1],zw[i+1][j+1],yw[j+1]) ;

			n2=check.CCalNormal(i,j,2);
			
			glNormal3f(n2.x,n2.z,n2.y);;
			glVertex3f (xw[i],zw[i][j],yw[j]) ;
			glVertex3f (xw[i],zw[i][j+1],yw[j+1]) ;
			glVertex3f (xw[i+1],zw[i+1][j+1],yw[j+1]) ;
		
		}
	}
	glEnd();

I would like to know whether this is good way to draw that surface…or in other words can i enhance this code …

One more question my Z values variation is very less for eg its between 100 and 99.5.
But X & Y values varies from 1 to 100…( Can be treated as length of the cube).
Now i want to display the top surface…i.e the surface having values like 100 ,99.5 ,99.75…etc in much better way i.e I am more intrested in the displaying the differnce in these values .How can I do that…

Thanks in advance
aus

2

Hi,
Can any body help me with the method to display 3D surface using triangle strips.

I am posting this message because nobody replied to the last message…

thanks
aus

3

One reason why nobodoy might have replied is because you missed to formulate your problem in clear sentences with good structure so that everyone understands it on first sight.

4

Here is my code for rendering a heightfield:

static int const SKIP = 1;

static void DrawTerrain()
{
int const sx = s_pTerrain->GetSizeX();
int const sy = s_pTerrain->GetSizeY();
HeightField::Vertex const * pData = s_pTerrain->GetData();
float const d = s_pTerrain->GetXYScale();
float const x0 = -( sx - 1 ) * .5f * d;
float const y0 = -( sy - 1 ) * .5f * d;

s_pTerrainMaterial->Apply();

glEnableClientState( GL_NORMAL_ARRAY );
glNormalPointer( GL_FLOAT, sizeof( *s_paTerrainNormals ), s_paTerrainNormals );

for ( int i = 0; i < sy-SKIP; i += SKIP )
{
glBegin( GL_TRIANGLE_STRIP );

  for ( int j = 0; j < sx; j += SKIP )
  {
  	float const	x	= x0 + j * d;
  	float const	tx	= float( j );//float( j ) / float( sx - 1 );

  	HeightField::Vertex const * const	pa	= &pData[ i * sx + j ];
  	HeightField::Vertex const * const	pb	= pa + SKIP * sx;

  	float const	yb	= y0 + ( i + SKIP ) * d;
  	float const	tyb	= float( i + SKIP );//float( i + SKIP ) / float( sy - 1 );
  	float const	zb	= pb->m_Z;

  	glTexCoord2f( tx, tyb );
  	glArrayElement( ( i + SKIP ) * sx + j );

// glNormal3fv( pb->m_Normal.m_V );
glVertex3f( x, yb, zb );

  	float const	ya	= y0 + i * d;
  	float const	tya	= float( i );//float( i ) / float( sy - 1 );
  	float const	za	= pa->m_Z;

  	glTexCoord2f( tx, tya );
  	glArrayElement( i * sx + j );

// glNormal3fv( pa->m_Normal.m_V );
glVertex3f( x, ya, za );
}

  glEnd();

}

glDisableClientState( GL_NORMAL_ARRAY );

}

5

Oy!