//----------------------------------------------------------------------------
void SMShadowEffect::Draw (Renderer* renderer, const VisibleSet& visibleSet)
{
const int numVisible = visibleSet.GetNumVisible();
for (int j = 0; j < numVisible; ++j)
{
// Replace the object's effect instance by the shadow-effect instance.
Visual* visual = (Visual*)visibleSet.GetVisible(j);
VisualEffectInstancePtr save = visual->GetEffectInstance();
visual->SetEffectInstance(mInstance);
// Draw the object using the shadow effect.
renderer->Draw(visual);
// Restore the object's effect instance.
visual->SetEffectInstance(save);
}
}
//----------------------------------------------------------------------------
void PlanarShadowEffect::Draw (Renderer* renderer,
const VisibleSet& visibleSet)
{
// Draw the potentially visible portions of the shadow caster.
const int numVisible = visibleSet.GetNumVisible();
int j;
for (j = 0; j < numVisible; ++j)
{
renderer->Draw((const Visual*)visibleSet.GetVisible(j));
}
// Save the current global state overrides for restoration later.
const DepthState* saveDState = renderer->GetOverrideDepthState();
const StencilState* saveSState = renderer->GetOverrideStencilState();
// Override the global state to support this effect.
renderer->SetOverrideDepthState(mDepthState);
renderer->SetOverrideStencilState(mStencilState);
// Get the camera to store post-world transformations.
Camera* camera = renderer->GetCamera();
for (int i = 0; i < mNumPlanes; ++i)
{
// Enable depth buffering. NOTE: The plane object should not have a
// ZBufferState object that changes the current settings.
mDepthState->Enabled = true;
mDepthState->Writable = true;
mDepthState->Compare = DepthState::CM_LEQUAL;
// Enable the stencil buffer so that the shadow can be clipped by the
// plane. The stencil values are set whenever the corresponding
// plane pixels are visible.
mStencilState->Enabled = true;
mStencilState->Compare = StencilState::CM_ALWAYS;
mStencilState->Reference = (unsigned int)(i + 1);
mStencilState->OnFail = StencilState::OT_KEEP; // irrelevant
mStencilState->OnZFail = StencilState::OT_KEEP; // invisible to 0
mStencilState->OnZPass = StencilState::OT_REPLACE; // visible to i+1
// Draw the plane.
renderer->Draw(mPlanes[i]);
// Blend the shadow color with the pixels drawn on the projection
// plane. The blending equation is
// (rf,gf,bf) = as*(rs,gs,bs) + (1-as)*(rd,gd,bd)
// where (rf,gf,bf) is the final color to be written to the frame
// buffer, (rs,gs,bs,as) is the shadow color, and (rd,gd,bd) is the
// current color of the frame buffer.
const AlphaState* saveAState = renderer->GetOverrideAlphaState();
renderer->SetOverrideAlphaState(mAlphaState);
mAlphaState->BlendEnabled = true;
mAlphaState->SrcBlend = AlphaState::SBM_SRC_ALPHA;
mAlphaState->DstBlend = AlphaState::DBM_ONE_MINUS_SRC_ALPHA;
mMaterial->Diffuse = mShadowColors[i];
// Disable the depth buffer reading so that no depth-buffer fighting
// occurs. The drawing of pixels is controlled solely by the stencil
// value.
mDepthState->Enabled = false;
// Only draw where the plane has been drawn.
mStencilState->Enabled = true;
mStencilState->Compare = StencilState::CM_EQUAL;
mStencilState->Reference = (unsigned int)(i + 1);
mStencilState->OnFail = StencilState::OT_KEEP; // invisible kept 0
mStencilState->OnZFail = StencilState::OT_KEEP; // irrelevant
mStencilState->OnZPass = StencilState::OT_ZERO; // visible set to 0
// Get the projection matrix relative to the projector (light).
HMatrix projection;
if (!GetProjectionMatrix(i, projection))
{
continue;
}
camera->SetPreViewMatrix(projection);
// Draw the caster again, but temporarily use a material effect so
// that the shadow color is blended onto the plane. TODO: This
// drawing pass should use a VisibleSet relative to the projector so
// that objects that are out of view (i.e. culled relative to the
// camera and not in the camera's VisibleSet) can cast shadows.
for (j = 0; j < numVisible; ++j)
{
Visual* visual = (Visual*)visibleSet.GetVisible(j);
VisualEffectInstancePtr save = visual->GetEffectInstance();
visual->SetEffectInstance(mMaterialEffectInstance);
renderer->Draw(visual);
visual->SetEffectInstance(save);
}
camera->SetPreViewMatrix(HMatrix::IDENTITY);
renderer->SetOverrideAlphaState(saveAState);
}
// Restore the global state that existed before this function call.
renderer->SetOverrideStencilState(saveSState);
renderer->SetOverrideDepthState(saveDState);
}