/// <summary>
/// Lazily recomputes the world+view+projection matrix and
/// fog vector based on the current effect parameter settings.
/// </summary>
internal static EffectDirtyFlags SetWorldViewProjAndFog(EffectDirtyFlags dirtyFlags,
ref Matrix world, ref Matrix view, ref Matrix projection, ref Matrix worldView,
bool fogEnabled, float fogStart, float fogEnd,
EffectParameter worldViewProjParam, EffectParameter fogVectorParam)
{
// Recompute the world+view+projection matrix?
if ((dirtyFlags & EffectDirtyFlags.WorldViewProj) != 0)
{
Matrix worldViewProj;
Matrix.Multiply(ref world, ref view, out worldView);
Matrix.Multiply(ref worldView, ref projection, out worldViewProj);
worldViewProjParam.SetValue(worldViewProj);
dirtyFlags &= ~EffectDirtyFlags.WorldViewProj;
}
if (fogEnabled)
{
// Recompute the fog vector?
if ((dirtyFlags & (EffectDirtyFlags.Fog | EffectDirtyFlags.FogEnable)) != 0)
{
SetFogVector(ref worldView, fogStart, fogEnd, fogVectorParam);
dirtyFlags &= ~(EffectDirtyFlags.Fog | EffectDirtyFlags.FogEnable);
}
}
else
{
// When fog is disabled, make sure the fog vector is reset to zero.
if ((dirtyFlags & EffectDirtyFlags.FogEnable) != 0)
{
fogVectorParam.SetValue(Vector4.Zero);
dirtyFlags &= ~EffectDirtyFlags.FogEnable;
}
}
return(dirtyFlags);
}
/// <summary>
/// Lazily recomputes the world inverse transpose matrix and
/// eye position based on the current effect parameter settings.
/// </summary>
internal static EffectDirtyFlags SetLightingMatrices(EffectDirtyFlags dirtyFlags, ref Matrix world, ref Matrix view,
EffectParameter worldParam, EffectParameter worldInverseTransposeParam, EffectParameter eyePositionParam)
{
// Set the world and world inverse transpose matrices.
if ((dirtyFlags & EffectDirtyFlags.World) != 0)
{
Matrix worldTranspose;
Matrix worldInverseTranspose;
Matrix.Invert(ref world, out worldTranspose);
Matrix.Transpose(ref worldTranspose, out worldInverseTranspose);
worldParam.SetValue(world);
worldInverseTransposeParam.SetValue(worldInverseTranspose);
dirtyFlags &= ~EffectDirtyFlags.World;
}
// Set the eye position.
if ((dirtyFlags & EffectDirtyFlags.EyePosition) != 0)
{
Matrix viewInverse;
Matrix.Invert(ref view, out viewInverse);
eyePositionParam.SetValue(viewInverse.TranslationVector);
dirtyFlags &= ~EffectDirtyFlags.EyePosition;
}
return(dirtyFlags);
}
