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0031597: Visualization, TKOpenGl - allow disabling Alpha component writes within OpenGl_Context::ColorMask()

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Added OpenGl_Caps::buffersOpaqueAlpha option allowing to disable writes
into alpha component of color buffer and keep it opaque.
Added OpenGl_Context::SetColorMaskRGBA() method overriding each color component deliberately.

New option is set within WebGL sample.
This commit is contained in:
kgv 2020-12-12 12:24:50 +03:00 committed by bugmaster
parent 465ffe2840
commit 31174e1a58
8 changed files with 66 additions and 23 deletions
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1
samples/webgl/WasmOcctView.cpp
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@ -227,6 +227,7 @@ bool WasmOcctView::initViewer()
Handle(Aspect_DisplayConnection) aDisp;
Handle(OpenGl_GraphicDriver) aDriver = new OpenGl_GraphicDriver (aDisp, false);
aDriver->ChangeOptions().buffersNoSwap = true; // swap has no effect in WebGL
aDriver->ChangeOptions().buffersOpaqueAlpha = true; // avoid unexpected blending of canvas with page background
if (!aDriver->InitContext())
{
Message::DefaultMessenger()->Send (TCollection_AsciiString ("Error: EGL initialization failed"), Message_Fail);

2
src/OpenGl/OpenGl_Caps.cxx
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@ -38,6 +38,7 @@ OpenGl_Caps::OpenGl_Caps()
#endif
swapInterval (1),
buffersNoSwap (Standard_False),
buffersOpaqueAlpha(Standard_False),
contextStereo (Standard_False),
#ifdef OCCT_DEBUG
contextDebug (Standard_True),
@ -78,6 +79,7 @@ OpenGl_Caps& OpenGl_Caps::operator= (const OpenGl_Caps& theCopy)
useSystemBuffer = theCopy.useSystemBuffer;
swapInterval = theCopy.swapInterval;
buffersNoSwap = theCopy.buffersNoSwap;
buffersOpaqueAlpha= theCopy.buffersOpaqueAlpha;
contextStereo = theCopy.contextStereo;
contextDebug = theCopy.contextDebug;
contextSyncDebug = theCopy.contextSyncDebug;

11
src/OpenGl/OpenGl_Caps.hxx
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@ -48,6 +48,17 @@ public: //! @name context creation parameters
*/
Standard_Boolean buffersNoSwap;
/**
* Specify whether alpha component within color buffer should be written or not.
* With alpha write enabled, background is considered transparent by default
* and overridden by alpha value of last drawn object
* (e.g. it could be opaque or not in case of transparent material).
* With alpha writes disabled, color buffer will be kept opaque.
*
* OFF by default.
*/
Standard_Boolean buffersOpaqueAlpha;
/**
* Request stereoscopic context (with Quad Buffer). This flag requires support in OpenGL driver.
*

20
src/OpenGl/OpenGl_Context.cxx
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@ -4609,17 +4609,29 @@ void OpenGl_Context::DisableFeatures() const
#endif
}
// =======================================================================
// function : SetColorMaskRGBA
// purpose :
// =======================================================================
void OpenGl_Context::SetColorMaskRGBA (const NCollection_Vec4<bool>& theVal)
{
glColorMask (theVal.r() ? GL_TRUE : GL_FALSE,
theVal.g() ? GL_TRUE : GL_FALSE,
theVal.b() ? GL_TRUE : GL_FALSE,
theVal.a() ? GL_TRUE : GL_FALSE);
myColorMask = theVal;
}
// =======================================================================
// function : SetColorMask
// purpose :
// =======================================================================
bool OpenGl_Context::SetColorMask (bool theToWriteColor)
{
const bool anOldValue = myColorMask.r();
myColorMask.SetValues (theToWriteColor, theToWriteColor, theToWriteColor, caps->buffersOpaqueAlpha ? false : theToWriteColor);
const GLboolean toWrite = theToWriteColor ? GL_TRUE : GL_FALSE;
glColorMask (toWrite, toWrite, toWrite, toWrite);
const bool anOldValue = myColorMask;
myColorMask = theToWriteColor;
glColorMask (toWrite, toWrite, toWrite, myColorMask.a() ? GL_TRUE : GL_FALSE);
return anOldValue;
}

11
src/OpenGl/OpenGl_Context.hxx
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@ -805,9 +805,16 @@ public: //! @name methods to alter or retrieve current state
Standard_EXPORT void SetFrameBufferSRGB (bool theIsFbo, bool theIsFboSRgb = true);
//! Return cached flag indicating writing into color buffer is enabled or disabled (glColorMask).
bool ColorMask() const { return myColorMask; }
const NCollection_Vec4<bool>& ColorMaskRGBA() const { return myColorMask; }
//! Enable/disable writing into color buffer (wrapper for glColorMask).
Standard_EXPORT void SetColorMaskRGBA (const NCollection_Vec4<bool>& theToWriteColor);
//! Return cached flag indicating writing into color buffer is enabled or disabled (glColorMask).
bool ColorMask() const { return myColorMask.r(); }
//! Enable/disable writing into color buffer (wrapper for glColorMask).
//! Alpha component writes will be disabled unconditionally in case of caps->buffersOpaqueAlpha.
Standard_EXPORT bool SetColorMask (bool theToWriteColor);
//! Return TRUE if GL_SAMPLE_ALPHA_TO_COVERAGE usage is allowed.
@ -1190,7 +1197,7 @@ private: //! @name fields tracking current state
NCollection_Array1<Standard_Integer>
myDrawBuffers; //!< current draw buffers
unsigned int myDefaultVao; //!< default Vertex Array Object
Standard_Boolean myColorMask; //!< flag indicating writing into color buffer is enabled or disabled (glColorMask)
NCollection_Vec4<bool> myColorMask; //!< flag indicating writing into color buffer is enabled or disabled (glColorMask)
Standard_Boolean myAllowAlphaToCov; //!< flag allowing GL_SAMPLE_ALPHA_TO_COVERAGE usage
Standard_Boolean myAlphaToCoverage; //!< flag indicating GL_SAMPLE_ALPHA_TO_COVERAGE state
Standard_Boolean myIsGlDebugCtx; //!< debug context initialization state

2
src/OpenGl/OpenGl_LayerList.cxx
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@ -883,6 +883,7 @@ void OpenGl_LayerList::renderTransparent (const Handle(OpenGl_Workspace)& theW
static const Standard_Integer aDrawBuffers[] = { GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT0 + 1 };
aCtx->SetDrawBuffers (2, aDrawBuffers);
aCtx->SetColorMaskRGBA (NCollection_Vec4<bool> (true)); // force writes into all components, including alpha
aCtx->core11fwd->glClearColor (0.0f, 0.0f, 0.0f, 1.0f);
aCtx->core11fwd->glClear (GL_COLOR_BUFFER_BIT);
aCtx->core15fwd->glBlendFuncSeparate (GL_ONE, GL_ONE, GL_ZERO, GL_ONE_MINUS_SRC_ALPHA);
@ -917,6 +918,7 @@ void OpenGl_LayerList::renderTransparent (const Handle(OpenGl_Workspace)& theW
static const Standard_Integer aDrawBuffers[] = { GL_COLOR_ATTACHMENT0 };
aCtx->SetDrawBuffers (1, aDrawBuffers);
aCtx->SetColorMask (true); // update writes into alpha component
}
theWorkspace->SetRenderFilter (aPrevFilter | OpenGl_RenderFilter_OpaqueOnly);

27
src/OpenGl/OpenGl_View_Redraw.cxx
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@ -922,20 +922,17 @@ void OpenGl_View::redraw (const Graphic3d_Camera::Projection theProjection,
myWorkspace->UseZBuffer() = Standard_True;
myWorkspace->UseDepthWrite() = Standard_True;
GLbitfield toClear = GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT;
glDepthFunc (GL_LEQUAL);
glDepthMask (GL_TRUE);
glEnable (GL_DEPTH_TEST);
aCtx->core11fwd->glDepthFunc (GL_LEQUAL);
aCtx->core11fwd->glDepthMask (GL_TRUE);
aCtx->core11fwd->glEnable (GL_DEPTH_TEST);
#if !defined(GL_ES_VERSION_2_0)
glClearDepth (1.0);
#else
glClearDepthf (1.0f);
#endif
aCtx->core11fwd->glClearDepth (1.0);
const OpenGl_Vec4 aBgColor = aCtx->Vec4FromQuantityColor (myBgColor);
glClearColor (aBgColor.r(), aBgColor.g(), aBgColor.b(), 0.0f);
glClear (toClear);
aCtx->SetColorMaskRGBA (NCollection_Vec4<bool> (true)); // force writes into all components, including alpha
aCtx->core11fwd->glClearColor (aBgColor.r(), aBgColor.g(), aBgColor.b(), aCtx->caps->buffersOpaqueAlpha ? 1.0f : 0.0f);
aCtx->core11fwd->glClear (toClear);
aCtx->SetColorMask (true); // restore default alpha component write state
render (theProjection, theReadDrawFbo, theOitAccumFbo, Standard_False);
}
@ -1487,12 +1484,10 @@ bool OpenGl_View::blitBuffers (OpenGl_FrameBuffer* theReadFbo,
const Standard_Integer aViewport[4] = { 0, 0, aDrawSizeX, aDrawSizeY };
aCtx->ResizeViewport (aViewport);
#if !defined(GL_ES_VERSION_2_0)
aCtx->core20fwd->glClearDepth (1.0);
#else
aCtx->core20fwd->glClearDepthf (1.0f);
#endif
aCtx->SetColorMaskRGBA (NCollection_Vec4<bool> (true)); // force writes into all components, including alpha
aCtx->core20fwd->glClearDepth (1.0);
aCtx->core20fwd->glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
aCtx->SetColorMask (true); // restore default alpha component write state
const bool toApplyGamma = aCtx->ToRenderSRGB() != aCtx->IsFrameBufferSRGB();
if (aCtx->arbFBOBlit != NULL

15
src/ViewerTest/ViewerTest_ViewerCommands.cxx
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@ -6751,6 +6751,7 @@ static int VCaps (Draw_Interpretor& theDI,
theDI << "Compatible:" << (aCaps->contextCompatible ? "1" : "0") << "\n";
theDI << "Stereo: " << (aCaps->contextStereo ? "1" : "0") << "\n";
theDI << "WinBuffer: " << (aCaps->useSystemBuffer ? "1" : "0") << "\n";
theDI << "OpaqueAlpha: " << (aCaps->buffersOpaqueAlpha ? "1" : "0") << "\n";
theDI << "NoExt:" << (aCaps->contextNoExtensions ? "1" : "0") << "\n";
theDI << "MaxVersion:" << aCaps->contextMajorVersionUpper << "." << aCaps->contextMinorVersionUpper << "\n";
theDI << "CompressTextures: " << (aCaps->compressedTexturesDisable ? "0" : "1") << "\n";
@ -6849,6 +6850,17 @@ static int VCaps (Draw_Interpretor& theDI,
}
aCaps->contextNoAccel = toEnable;
}
else if (anArgCase == "-opaquealpha"
|| anArgCase == "-buffersOpaqueAlpha")
{
Standard_Boolean toEnable = Standard_True;
if (++anArgIter < theArgNb
&& !Draw::ParseOnOff (theArgVec[anArgIter], toEnable))
{
--anArgIter;
}
aCaps->buffersOpaqueAlpha = toEnable;
}
else if (anArgCase == "-winbuffer"
|| anArgCase == "-windowbuffer"
|| anArgCase == "-usewinbuffer"
@ -14519,7 +14531,7 @@ void ViewerTest::ViewerCommands(Draw_Interpretor& theCommands)
theCommands.Add ("vcaps",
"vcaps [-sRGB {0|1}] [-vbo {0|1}] [-sprites {0|1}] [-ffp {0|1}] [-polygonMode {0|1}]"
"\n\t\t: [-compatibleProfile {0|1}] [-compressedTextures {0|1}]"
"\n\t\t: [-vsync {0|1}] [-useWinBuffer {0|1}]"
"\n\t\t: [-vsync {0|1}] [-useWinBuffer {0|1}] [-opaqueAlpha {0|1}]"
"\n\t\t: [-quadBuffer {0|1}] [-stereo {0|1}]"
"\n\t\t: [-softMode {0|1}] [-noupdate|-update]"
"\n\t\t: [-noExtensions {0|1}] [-maxVersion Major Minor]"
@ -14534,6 +14546,7 @@ void ViewerTest::ViewerCommands(Draw_Interpretor& theCommands)
"\n\t\t: arrays to GPU memory)"
"\n\t\t: sprite - use textured sprites instead of bitmaps"
"\n\t\t: vsync - switch VSync on or off"
"\n\t\t: opaqueAlpha - disable writes in alpha component of color buffer"
"\n\t\t: winBuffer - allow using window buffer for rendering"
"\n\t\t: Context creation options:"
"\n\t\t: softMode - software OpenGL implementation"