Hi! The attached patch adds support for stencil operations in effects. Patches are for simgear's scene/material/Effect.cxx and flightgear's Main/CameraGroup.cxx. I did them with "cvs diff <file>" against latest CVS version. Hope that is correct way.
The format of stencil operations in effect file is following: <stencil> <function>...</function> <value>...</value> <mask>...</mask> <stencil-fail>...</stencil-fail> <z-fail>...</z-fail> <pass>...</pass> </stencil> Where function can be never, always, less, less-or-equal, equal, not-equal, greater-or-equal or greater. Value is the reference value used in stencil operations and mask is the stencil bit mask. Stencil-fail, z-fail and pass are stencil operations if stencil test fails or stencil-test passes but z-test fails or both passes. Possible functions are zero, keep, replace, increase, decrease, invert, increase-wrap and decrease-wrap. I think one has to know something about stencil buffers to use this ;) I also added a new general tag <color-mask type="vec4d">1 0 0 1</color-mask> that allows only writing to certain channel (in this example only to red and alpha channel. As an example, I attached new version of the light-cone.eff I posted few days ago. This one does the same thing but with stencil operations. The .ac model used with this should be almost transparent or it will be too bright. This version has some issue if there is more than 5 light models simultaneously. I don't know if this is a OSG issue about rendering orders or something? But please test and comment. Lauri, a.k.a. Zan -- Lauri Peltonen lauri.pelto...@gmail.com
Index: CameraGroup.cxx =================================================================== RCS file: /var/cvs/FlightGear-0.9/source/src/Main/CameraGroup.cxx,v retrieving revision 1.18 diff -r1.18 CameraGroup.cxx 157c157 < camera->setClearMask(GL_DEPTH_BUFFER_BIT); --- > camera->setClearMask(GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT); 205c205 < camera->setClearMask(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); --- > camera->setClearMask(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT); 216c216 < camera->setClearMask(GL_DEPTH_BUFFER_BIT); --- > camera->setClearMask(GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
Index: Effect.cxx
===================================================================
RCS file: /var/cvs/SimGear-0.3/source/simgear/scene/material/Effect.cxx,v
retrieving revision 1.29
diff -r1.29 Effect.cxx
53a54
> #include <osg/Stencil>
255a257,274
> struct ColorMaskBuilder : PassAttributeBuilder
> {
> void buildAttribute(Effect* effect, Pass* pass, const SGPropertyNode* prop,
> const osgDB::ReaderWriter::Options* options)
> {
> const SGPropertyNode* realProp = getEffectPropertyNode(effect, prop);
> if (!realProp)
> return;
>
> ColorMask *mask = new ColorMask;
> Vec4 m = getColor(realProp);
> mask->setMask(m.r(), m.g(), m.b(), m.a());
> pass->setAttributeAndModes(mask);
> }
> };
>
> InstallAttributeBuilder<ColorMaskBuilder> installColorMask("color-mask");
>
477a497,589
>
> EffectNameValue<Stencil::Function> stencilFunctionInit[] =
> {
> {"never", Stencil::NEVER },
> {"less", Stencil::LESS},
> {"equal", Stencil::EQUAL},
> {"less-or-equal", Stencil::LEQUAL},
> {"greater", Stencil::GREATER},
> {"not-equal", Stencil::NOTEQUAL},
> {"greater-or-equal", Stencil::GEQUAL},
> {"always", Stencil::ALWAYS}
> };
>
> EffectPropertyMap<Stencil::Function> stencilFunction(stencilFunctionInit);
>
> EffectNameValue<Stencil::Operation> stencilOperationInit[] =
> {
> {"keep", Stencil::KEEP},
> {"zero", Stencil::ZERO},
> {"replace", Stencil::REPLACE},
> {"increase", Stencil::INCR},
> {"decrease", Stencil::DECR},
> {"invert", Stencil::INVERT},
> {"increase-wrap", Stencil::INCR_WRAP},
> {"decrease-wrap", Stencil::DECR_WRAP}
> };
>
> EffectPropertyMap<Stencil::Operation> stencilOperation(stencilOperationInit);
>
> struct StencilBuilder : public PassAttributeBuilder
> {
> void buildAttribute(Effect* effect, Pass* pass, const SGPropertyNode* prop,
> const osgDB::ReaderWriter::Options* options)
> {
> if (!isAttributeActive(effect, prop))
> return;
>
> const SGPropertyNode* pmode = getEffectPropertyChild(effect, prop,
> "mode");
> if (pmode && !pmode->getValue<bool>()) {
> pass->setMode(GL_STENCIL, StateAttribute::OFF);
> return;
> }
> const SGPropertyNode* pfunction
> = getEffectPropertyChild(effect, prop, "function");
> const SGPropertyNode* pvalue
> = getEffectPropertyChild(effect, prop, "value");
> const SGPropertyNode* pmask
> = getEffectPropertyChild(effect, prop, "mask");
> const SGPropertyNode* psfail
> = getEffectPropertyChild(effect, prop, "stencil-fail");
> const SGPropertyNode* pzfail
> = getEffectPropertyChild(effect, prop, "z-fail");
> const SGPropertyNode* ppass
> = getEffectPropertyChild(effect, prop, "pass");
>
> Stencil::Function func = Stencil::ALWAYS; // Always pass
> int ref = 0;
> unsigned int mask = ~0u; // All bits on
> Stencil::Operation sfailop = Stencil::KEEP; // Keep the old values as default
> Stencil::Operation zfailop = Stencil::KEEP;
> Stencil::Operation passop = Stencil::KEEP;
>
> Stencil *stencilFunc = new Stencil;
>
> if (pfunction)
> findAttr(stencilFunction, pfunction, func);
> if (pvalue)
> ref = pvalue->getIntValue();
> if (pmask)
> mask = pmask->getIntValue();
>
> if (psfail)
> findAttr(stencilOperation, psfail, sfailop);
> if (pzfail)
> findAttr(stencilOperation, pzfail, zfailop);
> if (ppass)
> findAttr(stencilOperation, ppass, passop);
>
> // Set the stencil operation
> stencilFunc->setFunction(func, ref, mask);
>
> // Set the operation, s-fail, s-pass/z-fail, s-pass/z-pass
> stencilFunc->setOperation(sfailop, zfailop, passop);
>
> // Add the operation to pass
> pass->setAttributeAndModes(stencilFunc);
> }
> };
>
> InstallAttributeBuilder<StencilBuilder> installStencil("stencil");
>
>
light-cone.eff
Description: XML document
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