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openmw/components/sceneutil/shadowsbin.cpp

228 lines
9.0 KiB
C++

#include "shadowsbin.hpp"
#include <osg/AlphaFunc>
#include <osg/Material>
#include <osg/Program>
#include <osg/StateSet>
#include <osgUtil/StateGraph>
#include <unordered_set>
using namespace osgUtil;
namespace
{
template <typename T>
inline void accumulateState(T& currentValue, T newValue, bool& isOverride, unsigned int overrideFlags)
{
if (isOverride && !(overrideFlags & osg::StateAttribute::PROTECTED))
return;
if (overrideFlags & osg::StateAttribute::OVERRIDE)
isOverride = true;
currentValue = newValue;
}
inline void accumulateModeState(const osg::StateSet* ss, bool& currentValue, bool& isOverride, int mode)
{
const osg::StateSet::ModeList& l = ss->getModeList();
osg::StateSet::ModeList::const_iterator mf = l.find(mode);
if (mf == l.end())
return;
unsigned int flags = mf->second;
bool newValue = flags & osg::StateAttribute::ON;
accumulateState(currentValue, newValue, isOverride, flags);
}
inline bool materialNeedShadows(osg::Material* m)
{
// I'm pretty sure this needs to check the colour mode - vertex colours might override this value.
return m->getDiffuse(osg::Material::FRONT).a() > 0.5;
}
}
namespace SceneUtil
{
ShadowsBin::ShadowsBin(const CastingPrograms& castingPrograms)
{
mNoTestStateSet = new osg::StateSet;
mNoTestStateSet->addUniform(new osg::Uniform("useDiffuseMapForShadowAlpha", false));
mNoTestStateSet->addUniform(new osg::Uniform("alphaTestShadows", false));
mShaderAlphaTestStateSet = new osg::StateSet;
mShaderAlphaTestStateSet->addUniform(new osg::Uniform("alphaTestShadows", true));
mShaderAlphaTestStateSet->addUniform(new osg::Uniform("useDiffuseMapForShadowAlpha", true));
mShaderAlphaTestStateSet->setMode(
GL_BLEND, osg::StateAttribute::OFF | osg::StateAttribute::PROTECTED | osg::StateAttribute::OVERRIDE);
for (size_t i = 0; i < castingPrograms.size(); ++i)
{
mAlphaFuncShaders[i] = new osg::StateSet;
mAlphaFuncShaders[i]->setAttribute(castingPrograms[i],
osg::StateAttribute::ON | osg::StateAttribute::PROTECTED | osg::StateAttribute::OVERRIDE);
}
}
StateGraph* ShadowsBin::cullStateGraph(
StateGraph* sg, StateGraph* root, std::unordered_set<StateGraph*>& uninterestingCache, bool cullFaceOverridden)
{
std::vector<StateGraph*> return_path;
State state;
StateGraph* sg_new = sg;
do
{
if (uninterestingCache.find(sg_new) != uninterestingCache.end())
break;
return_path.push_back(sg_new);
sg_new = sg_new->_parent;
} while (sg_new && sg_new != root);
for (auto itr = return_path.rbegin(); itr != return_path.rend(); ++itr)
{
const osg::StateSet* ss = (*itr)->getStateSet();
if (!ss)
continue;
accumulateModeState(ss, state.mAlphaBlend, state.mAlphaBlendOverride, GL_BLEND);
const osg::StateSet::AttributeList& attributes = ss->getAttributeList();
osg::StateSet::AttributeList::const_iterator found
= attributes.find(std::make_pair(osg::StateAttribute::MATERIAL, 0));
if (found != attributes.end())
{
const osg::StateSet::RefAttributePair& rap = found->second;
accumulateState(
state.mMaterial, static_cast<osg::Material*>(rap.first.get()), state.mMaterialOverride, rap.second);
if (state.mMaterial && !materialNeedShadows(state.mMaterial))
state.mMaterial = nullptr;
}
found = attributes.find(std::make_pair(osg::StateAttribute::ALPHAFUNC, 0));
if (found != attributes.end())
{
// As force shaders is on, we know this is really a RemovedAlphaFunc
const osg::StateSet::RefAttributePair& rap = found->second;
accumulateState(state.mAlphaFunc, static_cast<osg::AlphaFunc*>(rap.first.get()),
state.mAlphaFuncOverride, rap.second);
}
if (!cullFaceOverridden)
{
// osg::FrontFace specifies triangle winding, not front-face culling. We can't safely reparent anything
// under it unless GL_CULL_FACE is off or we flip face culling.
found = attributes.find(std::make_pair(osg::StateAttribute::FRONTFACE, 0));
if (found != attributes.end())
state.mImportantState = true;
}
if ((*itr) != sg && !state.interesting())
uninterestingCache.insert(*itr);
}
if (!state.needShadows())
return nullptr;
if (!state.needTexture() && !state.mImportantState)
{
for (RenderLeaf* leaf : sg->_leaves)
{
leaf->_parent = root;
root->_leaves.push_back(leaf);
}
return nullptr;
}
if (state.mAlphaBlend)
{
sg_new = sg->find_or_insert(mShaderAlphaTestStateSet);
sg_new->_leaves = std::move(sg->_leaves);
for (RenderLeaf* leaf : sg_new->_leaves)
leaf->_parent = sg_new;
sg = sg_new;
}
// GL_ALWAYS is set by default by mwshadowtechnique
if (state.mAlphaFunc && state.mAlphaFunc->getFunction() != GL_ALWAYS)
{
sg_new = sg->find_or_insert(mAlphaFuncShaders[state.mAlphaFunc->getFunction() - GL_NEVER]);
sg_new->_leaves = std::move(sg->_leaves);
for (RenderLeaf* leaf : sg_new->_leaves)
leaf->_parent = sg_new;
sg = sg_new;
}
return sg;
}
inline bool ShadowsBin::State::needTexture() const
{
return mAlphaBlend || (mAlphaFunc && mAlphaFunc->getFunction() != GL_ALWAYS);
}
bool ShadowsBin::State::needShadows() const
{
if (mAlphaFunc && mAlphaFunc->getFunction() == GL_NEVER)
return false;
// other alpha func + material combinations might be skippable
if (mAlphaBlend && mMaterial)
return materialNeedShadows(mMaterial);
return true;
}
void ShadowsBin::sortImplementation()
{
// The cull visitor contains a stategraph.
// When a stateset is pushed, it's added/found as a child of the current stategraph node, then that node becomes
// the new current stategraph node. When a drawable is added, the current stategraph node is added to the
// current renderbin (if it's not there already) and the drawable is added as a renderleaf to the stategraph
// This means our list only contains stategraph nodes with directly-attached renderleaves, but they might have
// parents with more state set that needs to be considered.
if (!_stateGraphList.size())
return;
StateGraph* root = _stateGraphList[0];
while (root->_parent)
{
root = root->_parent;
const osg::StateSet* ss = root->getStateSet();
if (ss->getMode(GL_NORMALIZE) & osg::StateAttribute::ON // that is root stategraph of renderingmanager cpp
|| ss->getAttribute(osg::StateAttribute::VIEWPORT)) // fallback to rendertarget's sg just in case
break;
if (!root->_parent)
return;
}
StateGraph* noTestRoot = root->find_or_insert(mNoTestStateSet.get());
// noTestRoot is now a stategraph with useDiffuseMapForShadowAlpha disabled but minimal other state
bool cullFaceOverridden = false;
while (root->_parent)
{
root = root->_parent;
if (!root->getStateSet())
continue;
unsigned int cullFaceFlags = root->getStateSet()->getMode(GL_CULL_FACE);
if (cullFaceFlags & osg::StateAttribute::OVERRIDE && !(cullFaceFlags & osg::StateAttribute::ON))
{
cullFaceOverridden = true;
break;
}
}
noTestRoot->_leaves.reserve(_stateGraphList.size());
StateGraphList newList;
std::unordered_set<StateGraph*> uninterestingCache;
for (StateGraph* graph : _stateGraphList)
{
// Render leaves which shouldn't use the diffuse map for shadow alpha but do cast shadows become children of
// root, so graph is now empty. Don't add to newList. Graphs containing just render leaves which don't cast
// shadows are discarded. Don't add to newList. Graphs containing other leaves need to be in newList.
StateGraph* graphToAdd = cullStateGraph(graph, noTestRoot, uninterestingCache, cullFaceOverridden);
if (graphToAdd)
newList.push_back(graphToAdd);
}
if (!noTestRoot->_leaves.empty())
newList.push_back(noTestRoot);
_stateGraphList = std::move(newList);
}
}