Adds gl::ScopedColorMask and gl::ScopedStencilMask. (cinder#2324)

* Adds gl::ScopedColorMask and gl::ScopedStencilMask. * Changed the implementation of gl::ScopedColorMask and gl::ScopedStencilMask to use gl::Context instead of querying the OpenGL state. --------- Co-authored-by: paulhoux <[email protected]>
paulhoux · Jan 8, 2024 · 18e1214 · 18e1214
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diff --git a/include/cinder/gl/Context.h b/include/cinder/gl/Context.h
@@ -170,6 +170,28 @@ class CI_API Context {
 	void					popFrontFace( bool forceRestore = false );
 	//! Returns the winding order defining front-facing polygons, either \c GL_CW or \c GL_CCW (the default).
 	GLenum					getFrontFace();
+
+	//! Set the current color mask, which enables and disables writing of frame buffer color components.
+	void					colorMask( bool red, bool green, bool blue, bool alpha );
+	//! Push the current color mask, which enables and disables writing of frame buffer color components.
+	void					pushColorMask( bool red, bool green, bool blue, bool alpha );
+	//! Pops the current color mask, which enables and disables writing of frame buffer color components.
+	void					popColorMask( bool forceRestore = false );
+	//! Returns the current color mask, which enables and disables writing of frame buffer color components. Default is \c GL_TRUE for all 4 components (red, green, blue, alpha).
+	glm::bvec4				getColorMask();
+
+	//! Set the current stencil mask, which controls the front and back writing of individual bits in the stencil planes (front and back).
+	void					stencilMask( GLuint mask );
+	//! Set the current stencil mask, which controls the front and back writing of individual bits in the stencil planes (front and back).
+	void					stencilMask( GLuint front, GLuint back );
+	//! Push the current stencil mask, which controls the front and back writing of individual bits in the stencil planes (front and back).
+	void					pushStencilMask( GLuint mask );
+	//! Push the current stencil mask, which controls the front and back writing of individual bits in the stencil planes (front and back).
+	void					pushStencilMask( GLuint front, GLuint back );
+	//! Pops the current stencil mask, which controls the front and back writing of individual bits in the stencil planes (front and back).
+	void					popStencilMask( bool forceRestore = false );
+	//! Returns the current stencil mask, which controls the front and back writing of individual bits in the stencil planes (front and back). 
+	glm::u8vec2				getStencilMask();
 
 #if ! defined( CINDER_GL_ES )
 	//! Analogous to glLogicOp( \a mode ). Valid arguments are \c GL_CLEAR, \c GL_SET, \c GL_COPY, \c GL_COPY_INVERTED, \c GL_NOOP, \c GL_INVERT, \c GL_AND, \c GL_NAND, \c GL_OR, \c GL_NOR, \c GL_XOR, \c GL_EQUIV, \c GL_AND_REVERSE, \c GL_AND_INVERTED, \c GL_OR_REVERSE, or \c GL_OR_INVERTED.
@@ -535,6 +557,9 @@ class CI_API Context {
 	std::vector<GLenum>			mCullFaceStack;
 	std::vector<GLenum>			mFrontFaceStack;
 
+	std::vector<glm::bvec4>		mColorMaskStack;
+	std::vector<glm::u8vec2>	mStencilMaskStack;
+
 #if ! defined( CINDER_GL_ES )
 	std::vector<GLenum>			mLogicOpStack;
 	std::vector<GLenum>			mPolygonModeStack;

diff --git a/include/cinder/gl/scoped.h b/include/cinder/gl/scoped.h
@@ -360,6 +360,30 @@ struct CI_API ScopedFrontFace : private Noncopyable {
 	Context		*mCtx;
 };
 
+//! Scopes writing of frame buffer color components
+class ScopedColorMask : private Noncopyable {
+  public:
+	//! Values for \a red, \a green, \a blue and \a alpha may be \c GL_TRUE or \c GL_FALSE
+	ScopedColorMask( GLboolean red, GLboolean green, GLboolean blue, GLboolean alpha );
+	~ScopedColorMask();
+
+  private:
+	Context *mCtx;
+};
+
+//! Scopes the front and back writing of individual bits in the stencil planes (front and back)
+class ScopedStencilMask : private Noncopyable {
+  public:
+	//! Values for \a mask may be between \c 0x00 and \c 0xFF
+	ScopedStencilMask( GLuint mask );
+	//! Values for \a front and \a back may be between \c 0x00 and \c 0xFF
+	ScopedStencilMask( GLuint front, GLuint back );
+	~ScopedStencilMask();
+
+  private:
+	Context *mCtx;
+};
+
 #if defined( CINDER_GL_HAS_KHR_DEBUG )
 
 //! Scopes debug group message

diff --git a/src/cinder/gl/Context.cpp b/src/cinder/gl/Context.cpp
@@ -87,6 +87,12 @@ Context::Context( const std::shared_ptr<PlatformData> &platformData )
 #endif
 	mDefaultArrayVboIdx = 0;
 
+	// initial state for color mask is enabled
+	mColorMaskStack.emplace_back( GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE );
+
+	// initial state for stencil mask is all bits enabled
+	mStencilMaskStack.emplace_back( 0xFF, 0xFF );
+
 	// initial state for depth mask is enabled
 	mBoolStateStack[GL_DEPTH_WRITEMASK] = vector<GLboolean>();
 	mBoolStateStack[GL_DEPTH_WRITEMASK].push_back( GL_TRUE );
@@ -470,6 +476,101 @@ GLenum Context::getFrontFace()
 	return mFrontFaceStack.back();
 }
 
+//////////////////////////////////////////////////////////////////
+// ColorMask
+void Context::colorMask( bool red, bool green, bool blue, bool alpha )
+{
+	if( setStackState( mColorMaskStack, glm::bvec4( red, green, blue, alpha ) ) ) {
+		glColorMask( red, green, blue, alpha );
+	}
+}
+
+void Context::pushColorMask( bool red, bool green, bool blue, bool alpha )
+{
+	if( pushStackState( mColorMaskStack, glm::bvec4( red, green, blue, alpha ) ) ) {
+		glColorMask( red, green, blue, alpha );
+	}
+}
+
+void Context::popColorMask( bool forceRestore )
+{
+	if( mColorMaskStack.empty() )
+		CI_LOG_E( "Color mask stack underflow" );
+	else if( popStackState( mColorMaskStack ) || forceRestore ) {
+		const auto mask = getColorMask();
+		glColorMask( mask.r, mask.g, mask.b, mask.a );
+	}
+}
+
+glm::bvec4 Context::getColorMask()
+{
+	if( mColorMaskStack.empty() ) {
+		GLboolean queriedBool[4];
+		glGetBooleanv( GL_COLOR_WRITEMASK, queriedBool );
+		mColorMaskStack.emplace_back( queriedBool[0], queriedBool[1], queriedBool[2], queriedBool[3] ); // push twice
+		mColorMaskStack.emplace_back( queriedBool[0], queriedBool[1], queriedBool[2], queriedBool[3] );
+	}
+
+	return mColorMaskStack.back();
+}
+
+//////////////////////////////////////////////////////////////////
+// StencilMask
+void Context::stencilMask( GLuint mask )
+{
+	if( setStackState( mStencilMaskStack, glm::u8vec2( mask, mask ) ) ) {
+		glStencilMask( mask );
+	}
+}
+
+void Context::stencilMask( GLuint front, GLuint back )
+{
+	if( setStackState( mStencilMaskStack, glm::u8vec2( front, back ) ) ) {
+		glStencilMaskSeparate( GL_FRONT, front );
+		glStencilMaskSeparate( GL_BACK, back );
+	}
+}
+
+void Context::pushStencilMask( GLuint mask )
+{
+	if( pushStackState( mStencilMaskStack, glm::u8vec2( mask, mask ) ) ) {
+		glStencilMask( mask );
+	}
+}
+
+void Context::pushStencilMask( GLuint front, GLuint back )
+{
+	if( pushStackState( mStencilMaskStack, glm::u8vec2( front, back ) ) ) {
+		glStencilMaskSeparate( GL_FRONT, front );
+		glStencilMaskSeparate( GL_BACK, back );
+	}
+}
+
+void Context::popStencilMask( bool forceRestore )
+{
+	if( mStencilMaskStack.empty() )
+		CI_LOG_E( "Stencil mask stack underflow" );
+	else if( popStackState( mStencilMaskStack ) || forceRestore ) {
+		const auto mask = getStencilMask();
+		glStencilMaskSeparate( GL_FRONT, mask[0] );
+		glStencilMaskSeparate( GL_BACK, mask[1] );
+	}
+}
+
+glm::u8vec2 Context::getStencilMask()
+{
+	if( mStencilMaskStack.empty() ) {
+		GLint queriedIntFront;
+		GLint queriedIntBack;
+		glGetIntegerv( GL_STENCIL_WRITEMASK, &queriedIntFront );
+		glGetIntegerv( GL_STENCIL_BACK_WRITEMASK, &queriedIntBack );
+		mStencilMaskStack.emplace_back( queriedIntFront, queriedIntBack ); // push twice
+		mStencilMaskStack.emplace_back( queriedIntFront, queriedIntBack );
+	}
+
+	return mStencilMaskStack.back();
+}
+
 //////////////////////////////////////////////////////////////////
 // LogicOp
 #if ! defined( CINDER_GL_ES )

diff --git a/src/cinder/gl/scoped.cpp b/src/cinder/gl/scoped.cpp
@@ -513,6 +513,38 @@ ScopedFrontFace::~ScopedFrontFace()
 	mCtx->popFrontFace();
 }
 
+///////////////////////////////////////////////////////////////////////////////////////////
+// ScopedColorMask
+ScopedColorMask::ScopedColorMask( GLboolean red, GLboolean green, GLboolean blue, GLboolean alpha )
+	: mCtx( gl::context() )
+{
+	mCtx->pushColorMask( red, green, blue, alpha );
+}
+
+ScopedColorMask::~ScopedColorMask()
+{
+	mCtx->popColorMask();
+}
+
+///////////////////////////////////////////////////////////////////////////////////////////
+// ScopedStencilMask
+ScopedStencilMask::ScopedStencilMask( GLuint mask )
+	: mCtx( gl::context() )
+{
+	mCtx->pushStencilMask( mask );
+}
+
+ScopedStencilMask::ScopedStencilMask( GLuint front, GLuint back )
+	: mCtx( gl::context() )
+{
+	mCtx->pushStencilMask( front, back );
+}
+
+ScopedStencilMask::~ScopedStencilMask()
+{
+	mCtx->popStencilMask();
+}
+
 ///////////////////////////////////////////////////////////////////////////////////////////
 // ScopedDebugGroup
 #if defined( CINDER_GL_HAS_KHR_DEBUG )