void gUpdateSHEnvCoeffs()
{
D3DXSHScale( gEnvSHRScaled, ENV_SH_ORDER, gEnvSHR, gEnvIntensity );
D3DXSHScale( gEnvSHGScaled, ENV_SH_ORDER, gEnvSHG, gEnvIntensity );
D3DXSHScale( gEnvSHBScaled, ENV_SH_ORDER, gEnvSHB, gEnvIntensity );
float* fLight[3] = { gEnvSHRScaled, gEnvSHGScaled, gEnvSHBScaled };
// Lighting environment coefficients
D3DXVECTOR4 vCoefficients[3];
// These constants are described in the article by Peter-Pike Sloan titled
// "Efficient Evaluation of Irradiance Environment Maps" in the book
// "ShaderX 2 - Shader Programming Tips and Tricks" by Wolfgang F. Engel.
static const float s_fSqrtPI = ((float)sqrtf(D3DX_PI));
const float fC0 = 1.0f/(2.0f*s_fSqrtPI);
const float fC1 = (float)sqrt(3.0f)/(3.0f*s_fSqrtPI);
const float fC2 = (float)sqrt(15.0f)/(8.0f*s_fSqrtPI);
const float fC3 = (float)sqrt(5.0f)/(16.0f*s_fSqrtPI);
const float fC4 = 0.5f*fC2;
int iChannel;
for( iChannel=0; iChannel<3; iChannel++ )
{
vCoefficients[iChannel].x = -fC1*fLight[iChannel][3];
vCoefficients[iChannel].y = -fC1*fLight[iChannel][1];
vCoefficients[iChannel].z = fC1*fLight[iChannel][2];
vCoefficients[iChannel].w = fC0*fLight[iChannel][0] - fC3*fLight[iChannel][6];
}
gEnvSHConstAr = vCoefficients[0];
gEnvSHConstAg = vCoefficients[1];
gEnvSHConstAb = vCoefficients[2];
//ep.addVector4( "cAr", vCoefficients[0] );
//ep.addVector4( "cAg", vCoefficients[1] );
//ep.addVector4( "cAb", vCoefficients[2] );
for( iChannel=0; iChannel<3; iChannel++ )
{
vCoefficients[iChannel].x = fC2*fLight[iChannel][4];
vCoefficients[iChannel].y = -fC2*fLight[iChannel][5];
vCoefficients[iChannel].z = 3.0f*fC3*fLight[iChannel][6];
vCoefficients[iChannel].w = -fC2*fLight[iChannel][7];
}
gEnvSHConstBr = vCoefficients[0];
gEnvSHConstBg = vCoefficients[1];
gEnvSHConstBb = vCoefficients[2];
//ep.addVector4( "cBr", vCoefficients[0] );
//ep.addVector4( "cBg", vCoefficients[1] );
//ep.addVector4( "cBb", vCoefficients[2] );
vCoefficients[0].x = fC4*fLight[0][8];
vCoefficients[0].y = fC4*fLight[1][8];
vCoefficients[0].z = fC4*fLight[2][8];
vCoefficients[0].w = 1.0f;
gEnvSHConstC = vCoefficients[0];
//ep.addVector4( "cC", vCoefficients[0] );
}
//--------------------------------------------------------------------------------------
void UpdateLightingEnvironment()
{
// Gather lighting options from the HUD
g_vLightDirection = g_LightControl.GetLightDirection();
g_fLightIntensity = g_SampleUI.GetSlider( IDC_LIGHT_SLIDER )->GetValue() / 100.0f;
g_fEnvIntensity = g_SampleUI.GetSlider( IDC_ENV_SLIDER )->GetValue() / 1000.0f;
// Create the spotlight
D3DXSHEvalConeLight( D3DXSH_MAXORDER, &g_vLightDirection, D3DX_PI / 8.0f,
g_fLightIntensity, g_fLightIntensity, g_fLightIntensity,
m_fRLC, m_fGLC, m_fBLC );
float fSkybox[3][D3DXSH_MAXORDER*D3DXSH_MAXORDER];
// Scale the light probe environment contribution based on input options
D3DXSHScale( fSkybox[0], D3DXSH_MAXORDER, g_fSkyBoxLightSH[0], g_fEnvIntensity );
D3DXSHScale( fSkybox[1], D3DXSH_MAXORDER, g_fSkyBoxLightSH[1], g_fEnvIntensity );
D3DXSHScale( fSkybox[2], D3DXSH_MAXORDER, g_fSkyBoxLightSH[2], g_fEnvIntensity );
// Combine the environment and the spotlight
D3DXSHAdd( m_fRLC, D3DXSH_MAXORDER, m_fRLC, fSkybox[0] );
D3DXSHAdd( m_fGLC, D3DXSH_MAXORDER, m_fGLC, fSkybox[1] );
D3DXSHAdd( m_fBLC, D3DXSH_MAXORDER, m_fBLC, fSkybox[2] );
}
