Jump to content
  • Advertisement

Archived

This topic is now archived and is closed to further replies.

Todd Casey

Texturing a Sphere

This topic is 6644 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

Advertisement
Here''s some code to build a sphere with texture coordinates in the verticies. (It''s stolen directly from the DX8 bumpearth sample code, so I take no blame or credit for it.)

    
// Get the World-View(WV) matrix set
D3DXMATRIX matWorld, matView, matWorldView;
m_pd3dDevice->GetTransform( D3DTS_WORLD, &matWorld );
m_pd3dDevice->GetTransform( D3DTS_VIEW, &matView );
D3DXMatrixMultiply( &matWorldView, &matWorld, &matView );

// Lock the vertex buffer

BUMPVERTEX* vtx;
m_pEarthVB->Lock( 0, 0, (BYTE**)&vtx, 0 );

// Establish constants used in sphere generation

DWORD dwNumSphereRings = m_bHighTesselation ? 15 : 5;
DWORD dwNumSphereSegments = m_bHighTesselation ? 30 : 10;
FLOAT fDeltaRingAngle = ( D3DX_PI / dwNumSphereRings );
FLOAT fDeltaSegAngle = ( 2.0f * D3DX_PI / dwNumSphereSegments );

D3DXVECTOR4 vT;
FLOAT fScale;

// Generate the group of rings for the sphere

for( DWORD ring = 0; ring < dwNumSphereRings; ring++ )
{
FLOAT r0 = sinf( (ring+0) * fDeltaRingAngle );
FLOAT r1 = sinf( (ring+1) * fDeltaRingAngle );
FLOAT y0 = cosf( (ring+0) * fDeltaRingAngle );
FLOAT y1 = cosf( (ring+1) * fDeltaRingAngle );

// Generate the group of segments for the current ring

for( DWORD seg = 0; seg < (dwNumSphereSegments+1); seg++ )
{
FLOAT x0 = r0 * sinf( seg * fDeltaSegAngle );
FLOAT z0 = r0 * cosf( seg * fDeltaSegAngle );
FLOAT x1 = r1 * sinf( seg * fDeltaSegAngle );
FLOAT z1 = r1 * cosf( seg * fDeltaSegAngle );

// Add two vertices to the strip which makes up the sphere

(*vtx).p = (*vtx).n = D3DXVECTOR3(x0,y0,z0);
(*vtx).tu1 = (*vtx).tu2 = -((FLOAT)seg)/dwNumSphereSegments;
(*vtx).tv1 = (*vtx).tv2 = (ring+0)/(FLOAT)dwNumSphereRings;

// Use the transformed normal to generate texture coords

D3DXVec3Transform( &vT, &(*vtx).n, &matWorldView );
fScale = 1.37f / D3DXVec4Length( &vT );
(*vtx).tu1 = 0.5f + fScale*vT.x;
(*vtx).tv1 = 0.5f - fScale*vT.y;
vtx++;

(*vtx).p = (*vtx).n = D3DXVECTOR3(x1,y1,z1);
(*vtx).tu1 = (*vtx).tu2 = -((FLOAT)seg)/dwNumSphereSegments;
(*vtx).tv1 = (*vtx).tv2 = (ring+1)/(FLOAT)dwNumSphereRings;

// Use the transformed normal to generate texture coords

D3DXVec3Transform( &vT, &(*vtx).n, &matWorldView );
fScale = 1.37f / D3DXVec4Length( &vT );
(*vtx).tu1 = 0.5f + fScale*vT.x;
(*vtx).tv1 = 0.5f - fScale*vT.y;
vtx++;
}
}

m_pEarthVB->Unlock();

Share this post


Link to post
Share on other sites

  • Advertisement
×

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

We are the game development community.

Whether you are an indie, hobbyist, AAA developer, or just trying to learn, GameDev.net is the place for you to learn, share, and connect with the games industry. Learn more About Us or sign up!

Sign me up!