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ShaderVisitor improvements

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* Adds comments explaining the less-than-obvious aspects.
* Adds comments explaining what to do when adding new stuff.
* Some fixes caused by those comments not historically existing.
* Add a TODO comment to something which may catch fire in the future.
This commit is contained in:
AnyOldName3 2021-12-08 20:44:10 +00:00 committed by glassmancody.info
parent 9389cfaa42
commit 14a330609f
1 changed files with 109 additions and 21 deletions
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130
components/shader/shadervisitor.cpp
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@ -29,6 +29,15 @@
namespace Shader
{
/**
* Miniature version of osg::StateSet used to track state added by the shader visitor which should be ignored when
* it's applied a second time, and removed when shaders are removed.
* Actual StateAttributes aren't kept as they're recoverable from the StateSet this is attached to - we just want
* the TypeMemberPair as that uniquely identifies which of those StateAttributes it was we're tracking.
* Not all StateSet features have been added yet - we implement an equivalently-named method to each of the StateSet
* methods called in createProgram, and implement new ones as they're needed.
* When expanding tracking to cover new things, ensure they're accounted for in ensureFFP.
*/
class AddedState : public osg::Object
{
public:
@ -45,7 +54,6 @@ namespace Shader
void addUniform(const std::string& name) { mUniforms.emplace(name); }
void setMode(osg::StateAttribute::GLMode mode) { mModes.emplace(mode); }
void setAttribute(osg::StateAttribute::TypeMemberPair typeMemberPair) { mAttributes.emplace(typeMemberPair); }
void setTextureMode(int unit, osg::StateAttribute::GLMode mode) { mTextureModes[unit].emplace(mode); }
void setAttribute(const osg::StateAttribute* attribute)
{
@ -63,6 +71,25 @@ namespace Shader
template<typename T>
void setAttributeAndModes(osg::ref_ptr<T> attribute) { setAttributeAndModes(attribute.get()); }
void setTextureMode(unsigned int unit, osg::StateAttribute::GLMode mode) { mTextureModes[unit].emplace(mode); }
void setTextureAttribute(int unit, osg::StateAttribute::TypeMemberPair typeMemberPair) { mTextureAttributes[unit].emplace(typeMemberPair); }
void setTextureAttribute(unsigned int unit, const osg::StateAttribute* attribute)
{
mTextureAttributes[unit].emplace(attribute->getTypeMemberPair());
}
template<typename T>
void setTextureAttribute(unsigned int unit, osg::ref_ptr<T> attribute) { setTextureAttribute(unit, attribute.get()); }
void setTextureAttributeAndModes(unsigned int unit, const osg::StateAttribute* attribute)
{
setTextureAttribute(unit, attribute);
InterrogateModesHelper helper(this, unit);
attribute->getModeUsage(helper);
}
template<typename T>
void setTextureAttributeAndModes(unsigned int unit, osg::ref_ptr<T> attribute) { setTextureAttributeAndModes(unit, attribute.get()); }
bool hasUniform(const std::string& name) { return mUniforms.count(name); }
bool hasMode(osg::StateAttribute::GLMode mode) { return mModes.count(mode); }
bool hasAttribute(const osg::StateAttribute::TypeMemberPair &typeMemberPair) { return mAttributes.count(typeMemberPair); }
@ -77,10 +104,11 @@ namespace Shader
}
const std::set<osg::StateAttribute::TypeMemberPair>& getAttributes() { return mAttributes; }
const std::unordered_map<unsigned int, std::set<osg::StateAttribute::TypeMemberPair>>& getTextureAttributes() { return mTextureAttributes; }
bool empty()
{
return mUniforms.empty() && mModes.empty() && mAttributes.empty() && mTextureModes.empty();
return mUniforms.empty() && mModes.empty() && mAttributes.empty() && mTextureModes.empty() && mTextureAttributes.empty();
}
META_Object(Shader, AddedState)
@ -89,20 +117,26 @@ namespace Shader
class InterrogateModesHelper : public osg::StateAttribute::ModeUsage
{
public:
InterrogateModesHelper(AddedState* tracker) : mTracker(tracker) {}
InterrogateModesHelper(AddedState* tracker, unsigned int textureUnit = 0)
: mTracker(tracker)
, mTextureUnit(textureUnit)
{}
void usesMode(osg::StateAttribute::GLMode mode) override { mTracker->setMode(mode); }
void usesTextureMode(osg::StateAttribute::GLMode mode) override {}
void usesTextureMode(osg::StateAttribute::GLMode mode) override { mTracker->setTextureMode(mTextureUnit, mode); }
private:
AddedState* mTracker;
unsigned int mTextureUnit;
};
using ModeSet = std::unordered_set<osg::StateAttribute::GLMode>;
using AttributeSet = std::set<osg::StateAttribute::TypeMemberPair>;
std::unordered_set<std::string> mUniforms;
ModeSet mModes;
std::set<osg::StateAttribute::TypeMemberPair> mAttributes;
std::unordered_map<int, ModeSet> mTextureModes;
AttributeSet mAttributes;
std::unordered_map<unsigned int, ModeSet> mTextureModes;
std::unordered_map<unsigned int, AttributeSet> mTextureAttributes;
};
ShaderVisitor::ShaderRequirements::ShaderRequirements()
@ -229,6 +263,7 @@ namespace Shader
if (node.getUserValue("shaderRequired", shaderRequired) && shaderRequired)
mRequirements.back().mShaderRequired = true;
// Make sure to disregard any state that came from a previous call to createProgram
osg::ref_ptr<AddedState> addedState = getAddedState(*stateset);
if (!texAttributes.empty())
@ -242,6 +277,8 @@ namespace Shader
const osg::StateAttribute *attr = stateset->getTextureAttribute(unit, osg::StateAttribute::TEXTURE);
if (attr)
{
// If textures ever get removed in createProgram, expand this to check we're operating on main texture attribute list
// rather than the removed list
if (addedState && addedState->hasTextureMode(unit, GL_TEXTURE_2D))
continue;
@ -462,6 +499,22 @@ namespace Shader
return;
}
/**
* The shader visitor is supposed to be idempotent and undoable.
* That means we need to back up state we've removed (so it can be restored and/or considered by further
* applications of the visitor) and track which state we added (so it can be removed and/or ignored by further
* applications of the visitor).
* Before editing writableStateSet in a way that explicitly removes state or might overwrite existing state, it
* should be copied to removedState, another StateSet, unless it's there already or was added by a previous
* application of the visitor (is in previousAddedState).
* If it's a new class of state that's not already handled by ReinstateRemovedStateVisitor::apply, make sure to
* add handling there.
* Similarly, any time new state is added to writableStateSet, the equivalent method should be called on
* addedState.
* If that method doesn't exist yet, implement it - we don't use a full StateSet as we only need to check
* existence, not equality, and don't need to actually get the value as we can get it from writableStateSet
* instead.
*/
osg::Node& node = *reqs.mNode;
osg::StateSet* writableStateSet = nullptr;
if (mAllowedToModifyStateSets)
@ -486,7 +539,10 @@ namespace Shader
}
if (defineMap["diffuseMap"] == "0")
{
writableStateSet->addUniform(new osg::Uniform("useDiffuseMapForShadowAlpha", false));
addedState->addUniform("useDiffuseMapForShadowAlpha");
}
defineMap["parallax"] = reqs.mNormalHeight ? "1" : "0";
@ -495,7 +551,6 @@ namespace Shader
defineMap["alphaFunc"] = std::to_string(reqs.mAlphaFunc);
// back up removed state in case recreateShaders gets rid of the shader later
osg::ref_ptr<osg::StateSet> removedState;
if ((removedState = getRemovedState(*writableStateSet)) && !mAllowedToModifyStateSets)
removedState = new osg::StateSet(*removedState, osg::CopyOp::SHALLOW_COPY);
@ -570,7 +625,7 @@ namespace Shader
osg::ref_ptr<osg::Depth> depth = new SceneUtil::AutoDepth;
depth->setWriteMask(false);
writableStateSet->setAttributeAndModes(depth, osg::StateAttribute::ON|osg::StateAttribute::OVERRIDE);
addedState->setAttribute(depth);
addedState->setAttributeAndModes(depth);
writableStateSet->addUniform(new osg::Uniform("particleSize", reqs.mSoftParticleSize));
addedState->addUniform("particleSize");
@ -579,23 +634,11 @@ namespace Shader
addedState->addUniform("opaqueDepthTex");
writableStateSet->setTextureAttributeAndModes(2, mOpaqueDepthTex, osg::StateAttribute::ON);
addedState->setTextureMode(2, GL_TEXTURE_2D);
addedState->setTextureAttributeAndModes(2, mOpaqueDepthTex);
}
defineMap["softParticles"] = reqs.mSoftParticles ? "1" : "0";
if (!addedState->empty())
{
// user data is normally shallow copied so shared with the original stateset
osg::ref_ptr<osg::UserDataContainer> writableUserData;
if (mAllowedToModifyStateSets)
writableUserData = writableStateSet->getOrCreateUserDataContainer();
else
writableUserData = getWritableUserDataContainer(*writableStateSet);
updateAddedState(*writableUserData, addedState);
}
std::string shaderPrefix;
if (!node.getUserValue("shaderPrefix", shaderPrefix))
shaderPrefix = mDefaultShaderPrefix;
@ -615,6 +658,18 @@ namespace Shader
addedState->addUniform(texIt->second);
}
}
if (!addedState->empty())
{
// user data is normally shallow copied so shared with the original stateset
osg::ref_ptr<osg::UserDataContainer> writableUserData;
if (mAllowedToModifyStateSets)
writableUserData = writableStateSet->getOrCreateUserDataContainer();
else
writableUserData = getWritableUserDataContainer(*writableStateSet);
updateAddedState(*writableUserData, addedState);
}
}
void ShaderVisitor::ensureFFP(osg::Node& node)
@ -627,6 +682,18 @@ namespace Shader
else
writableStateSet = getWritableStateSet(node);
/**
* We might have been using shaders temporarily with the node (e.g. if a GlowUpdater applied a temporary
* environment map for a temporary enchantment).
* We therefore need to remove any state doing so added, and restore any that it removed.
* This is kept track of in createProgram in the StateSet's userdata.
* If new classes of state get added, handling it here is required - not all StateSet features are implemented
* in AddedState yet as so far they've not been necessary.
* Removed state requires no particular special handling as it's dealt with by merging StateSets.
* We don't need to worry about state in writableStateSet having the OVERRIDE flag as if it's in both, it's also
* in addedState, and gets removed first.
*/
// user data is normally shallow copied so shared with the original stateset - we'll need to copy before edits
osg::ref_ptr<osg::UserDataContainer> writableUserData;
@ -661,6 +728,23 @@ namespace Shader
// We don't have access to the function to do that, and can't call removeAttribute with an iterator
for (const auto& [type, member] : addedState->getAttributes())
writableStateSet->removeAttribute(type, member);
for (unsigned int unit = 0; unit < writableStateSet->getTextureModeList().size(); ++unit)
{
for (auto itr = writableStateSet->getTextureModeList()[unit].begin(); itr != writableStateSet->getTextureModeList()[unit].end();)
{
if (addedState->hasTextureMode(unit, itr->first))
writableStateSet->getTextureModeList()[unit].erase(itr++);
else
++itr;
}
}
for (const auto& [unit, attributeList] : addedState->getTextureAttributes())
{
for (const auto& [type, member] : attributeList)
writableStateSet->removeTextureAttribute(unit, type);
}
}
@ -833,6 +917,10 @@ namespace Shader
void ReinstateRemovedStateVisitor::apply(osg::Node& node)
{
// TODO: this may eventually need to remove added state.
// If so, we can migrate from explicitly copying removed state to just calling osg::StateSet::merge.
// Not everything is transferred from removedState yet - implement more when createProgram starts marking more
// as removed.
if (node.getStateSet())
{
osg::ref_ptr<osg::StateSet> removedState = getRemovedState(*node.getStateSet());