Commit 944ee020 authored by Ken Martin's avatar Ken Martin

A number of transparency related issues fixed

A few good fixes in here that are all related. The biggest is a
fix to OpenGLActor to use the more comprehensive GetIsOpaque
method in determining if an actor is opaque. The old code only
looked at the property's opacity. This is why you would see folks
setting somethings opacity to 0.99 to get it treated as translucent
because the actor code wasn't handling it correctly. This change
resulted in 3 new valid images for tests that were rendering
translucent items as if they were opaque. I removed these tests
from the old backend as I did not want to change the behavior
for that backend.

Next up is depth peeling. OpenGL2 depth peeling would render
a number of peels up to the limit and then just stop. Any geometry
left between the opaque layer and the last translucent layer was
just thrown out.  This created very noticable artifacts and was bad.
This change makes it so that when it gets to the last pass, it will
render all remaining geometry using alpha blending. This is much
better. Fix example if you get the limit to 20 layers and 20 was
not enough to render all the geometry, this change renders 19
layers using depth peeling, then in the 20th render it would add
in all the remaining geometry as last layer. That last layer may
have overlapping geometry which is rendered using alpha blending.

Finally some changes to the PointGaussianMapper. It turns out that
the point gaussian mapper is an translucent mapper which means it
needs the first change, and it is a very tough case for depth peeling
resulting in the second change. While at it I modified this mapper
to render far fewer fragments, resulting is far fewer overlapping
layers and fewer artifacts. Really when using PointGaussian you
should turn off depthpeeling as it is not needed and actually makes
it worse, but these changes will make it better if you happen to have
it on.  Also cleaned up the mapper so that the radius is equal to
the standard devisation of the gaussian, previously it was four
standard deviations.

Change-Id: I62d90b6e424ac0e939033387ed10ba8caac66095
parent 0c29a735
......@@ -395,7 +395,7 @@ ballTC.SetInputData(model)
lut = vtk.vtkLookupTable()
lut.SetNumberOfColors(3)
lut.Build()
lut.SetTableValue(0,0,0,0,0)
lut.SetTableValue(0,0,0,0,1)
lut.SetTableValue(1,1,.3,.3,1)
lut.SetTableValue(2,.8,.8,.9,1)
mapper = vtk.vtkDataSetMapper()
......
......@@ -399,7 +399,7 @@ vtkTextureMapToSphere ballTC
vtkLookupTable lut
lut SetNumberOfColors 3
lut Build
lut SetTableValue 0 0 0 0 0
lut SetTableValue 0 0 0 0 1
lut SetTableValue 1 1 .3 .3 1
lut SetTableValue 2 .8 .8 .9 1
......
if(VTK_RENDERING_BACKEND STREQUAL "OpenGL2")
set(extra_opengl2_tests
TestCompositePolyDataMapper2.cxx,NO_DATA
TestAreaSelections.cxx) # incorrect results in OpenGL
# the following produce incorrect results in OpenGL
TestTranslucentLUTAlphaBlending.cxx
TestTranslucentLUTTextureAlphaBlending.cxx
TestAreaSelections.cxx
)
endif()
vtk_add_test_cxx(${vtk-module}CxxTests tests
......@@ -59,9 +63,7 @@ vtk_add_test_cxx(${vtk-module}CxxTests tests
TestTransformCoordinateUseDouble.cxx
TestTranslucentImageActorAlphaBlending.cxx
TestTranslucentImageActorDepthPeeling.cxx
TestTranslucentLUTAlphaBlending.cxx
TestTranslucentLUTDepthPeeling.cxx
TestTranslucentLUTTextureAlphaBlending.cxx
TestTranslucentLUTTextureDepthPeeling.cxx
TestTStripsColorsTCoords.cxx
TestTStripsNormalsColorsTCoords.cxx
......
8687dc14fab46f34e86c8da88aa1dc0e
6c9b293a7537053efa4ed43fdc8a9d96
......@@ -30,7 +30,6 @@
#include "vtkActor.h"
#include "vtkBrownianPoints.h"
#include "vtkCamera.h"
#include "vtkProperty.h"
#include "vtkPointGaussianMapper.h"
......@@ -56,18 +55,13 @@ int TestPointGaussianMapper(int argc, char *argv[])
vtkNew<vtkPointSource> points;
points->SetNumberOfPoints(desiredPoints);
points->SetRadius(pow(desiredPoints,0.33)*5.0);
vtkNew<vtkBrownianPoints> randomVector;
randomVector->SetMinimumSpeed(0);
randomVector->SetMaximumSpeed(1);
randomVector->SetInputConnection(points->GetOutputPort());
points->SetRadius(pow(desiredPoints,0.33)*20.0);
vtkNew<vtkRandomAttributeGenerator> randomAttr;
randomAttr->SetDataTypeToFloat();
randomAttr->GeneratePointScalarsOn();
randomAttr->GeneratePointVectorsOn();
randomAttr->SetInputConnection(randomVector->GetOutputPort());
randomAttr->SetInputConnection(points->GetOutputPort());
randomAttr->Update();
......@@ -87,17 +81,18 @@ int TestPointGaussianMapper(int argc, char *argv[])
ctf->SetColorSpaceToRGB();
mapper->SetLookupTable(ctf.Get());
vtkNew<vtkActor> actor;
actor->SetMapper(mapper.Get());
vtkNew<vtkRenderer> renderer;
renderer->SetBackground(0.0, 0.0, 0.0);
vtkNew<vtkRenderWindow> renderWindow;
renderWindow->SetSize(900, 900);
renderWindow->AddRenderer(renderer.Get());
renderer->AddActor(actor.Get());
vtkNew<vtkRenderWindowInteractor> iren;
iren->SetRenderWindow(renderWindow.Get());
vtkNew<vtkActor> actor;
actor->SetMapper(mapper.Get());
renderer->AddActor(actor.Get());
vtkNew<vtkTimerLog> timer;
timer->StartTimer();
renderWindow->Render();
......@@ -134,5 +129,5 @@ int TestPointGaussianMapper(int argc, char *argv[])
iren->Start();
}
return EXIT_SUCCESS;
return !retVal;
}
71f5af0ed95b703b72ea17c2a471a962
7289527bd2b777a40b853cdfdf8bc826
......@@ -21,14 +21,26 @@ varying vec2 tcoordVC;
uniform sampler2D translucentRGBATexture;
uniform sampler2D currentRGBATexture;
uniform int lastpass;
void main()
{
// current is what is most recently rendered
// translucent is what is in FRONT of it
// we render front to back
vec4 t1Color = texture2D(translucentRGBATexture, tcoordVC);
vec4 t2Color = texture2D(currentRGBATexture, tcoordVC);
gl_FragColor.a = t1Color.a + t2Color.a * (1.0-t1Color.a);
if (gl_FragColor.a > 0.0)
{
gl_FragColor.rgb = (t1Color.rgb*t1Color.a + t2Color.rgb*t2Color.a*(1.0-t1Color.a))/gl_FragColor.a;
if (lastpass == 1)
{
gl_FragColor.rgb = (t1Color.rgb*t1Color.a + t2Color.rgb*(1.0-t1Color.a))/gl_FragColor.a;
}
else
{
gl_FragColor.rgb = (t1Color.rgb*t1Color.a + t2Color.rgb*t2Color.a*(1.0-t1Color.a))/gl_FragColor.a;
}
}
else
{
......
......@@ -59,7 +59,12 @@ void main()
// compute the projected vertex position
vec4 vertexVC = MCVCMatrix * vertexMC;
float radius2 = dot(offsetMC,offsetMC)*0.25;
// the offsets sent down are positioned
// at 2.0*radius*3.0 from the center of the
// gaussian. This has to be consistent
// with the offsets we build into the VBO
float radius = sqrt(dot(offsetMC,offsetMC))/6.0;
// make the triangle face the camera
if (cameraParallel == 0)
......@@ -75,6 +80,6 @@ void main()
vertexVC.xy = vertexVC.xy + offsetMC;
}
offsetVC = offsetMC/sqrt(radius2);
offsetVC = offsetMC/radius;
gl_Position = VCDCMatrix * vertexVC;
}
......@@ -198,7 +198,9 @@ vtkTextureObject *vtkDepthPeelingPassCreateTextureObject(
return result;
}
void vtkDepthPeelingPass::BlendIntermediatePeels(vtkOpenGLRenderWindow *renWin)
void vtkDepthPeelingPass::BlendIntermediatePeels(
vtkOpenGLRenderWindow *renWin,
bool done)
{
this->CurrentRGBATexture->CopyFromFrameBuffer(this->ViewportX, this->ViewportY,
this->ViewportX, this->ViewportY,
......@@ -224,6 +226,8 @@ void vtkDepthPeelingPass::BlendIntermediatePeels(vtkOpenGLRenderWindow *renWin)
"translucentRGBATexture", this->TranslucentRGBATexture->GetTextureUnit());
this->IntermediateBlendProgram->Program->SetUniformi(
"currentRGBATexture", this->CurrentRGBATexture->GetTextureUnit());
this->IntermediateBlendProgram->Program->SetUniformi(
"lastpass", done ? 1 : 0);
glDisable(GL_DEPTH_TEST);
this->CurrentRGBATexture->CopyToFrameBuffer(0, 0,
......@@ -378,7 +382,7 @@ void vtkDepthPeelingPass::Render(const vtkRenderState *s)
this->SetLastRenderingUsedDepthPeeling(s->GetRenderer(), true);
glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
// glClearColor(0.0,0.0,0.0,0.0); // always clear to black
glClearColor(0.0,0.0,0.0,0.0); // always clear to black
// glClearDepth(static_cast<GLclampf>(1.0));
#ifdef GL_MULTISAMPLE
glDisable(GL_MULTISAMPLE);
......@@ -430,7 +434,7 @@ void vtkDepthPeelingPass::Render(const vtkRenderState *s)
#endif
bool done = false;
GLuint nbPixels = 0;
GLuint nbPixels = threshold + 1;
int peelCount = 0;
while(!done)
{
......@@ -445,38 +449,52 @@ void vtkDepthPeelingPass::Render(const vtkRenderState *s)
glBeginQuery(GL_SAMPLES_PASSED,queryId);
#endif
// check if we are going to exceed the max number of peels or if we
// exceeded the pixel threshold last time
peelCount++;
if ((this->MaximumNumberOfPeels && peelCount >= this->MaximumNumberOfPeels) ||
nbPixels <= threshold)
{
done = true;
// if so we do this last render using alpha blending for all
// the stuff that is left
glEnable(GL_BLEND);
glDepthFunc( GL_ALWAYS );
}
this->TranslucentPass->Render(s);
// update translucentZ
this->TranslucentZTexture->CopyFromFrameBuffer(this->ViewportX, this->ViewportY,
this->ViewportX, this->ViewportY,
this->ViewportWidth, this->ViewportHeight);
glDepthFunc( GL_LEQUAL );
glDisable(GL_BLEND);
#if GL_ES_VERSION_2_0 != 1
glEndQuery(GL_SAMPLES_PASSED);
glGetQueryObjectuiv(queryId,GL_QUERY_RESULT,&nbPixels);
if (nbPixels <= threshold)
{
done = true;
}
#endif
peelCount++;
if(this->MaximumNumberOfPeels && peelCount >= this->MaximumNumberOfPeels)
cerr << "Pass " << peelCount << " pixels Drawn " << nbPixels << "\n";
// if something was drawn, blend it in
if (nbPixels > 0)
{
done = true;
}
//cerr << "Pass " << peelCount << " pixels Drawn " << nbPixels << "\n";
// update translucentZ
this->TranslucentZTexture->CopyFromFrameBuffer(this->ViewportX, this->ViewportY,
this->ViewportX, this->ViewportY,
this->ViewportWidth, this->ViewportHeight);
// blend the last two peels together
if (peelCount > 1)
{
this->BlendIntermediatePeels(renWin,done);
}
// blend the last two peels together
if (peelCount > 1)
// update translucent RGBA
this->TranslucentRGBATexture->CopyFromFrameBuffer(this->ViewportX, this->ViewportY,
this->ViewportX, this->ViewportY,
this->ViewportWidth, this->ViewportHeight);
}
else // if we drew nothing we are done
{
this->BlendIntermediatePeels(renWin);
done = true;
}
// update translucent RGBA
this->TranslucentRGBATexture->CopyFromFrameBuffer(this->ViewportX, this->ViewportY,
this->ViewportX, this->ViewportY,
this->ViewportWidth, this->ViewportHeight);
}
// unload the textures we are done with
......
......@@ -178,7 +178,7 @@ public:
vtkTextureObject *CurrentRGBATexture;
std::vector<float> *DepthZData;
void BlendIntermediatePeels(vtkOpenGLRenderWindow *renWin);
void BlendIntermediatePeels(vtkOpenGLRenderWindow *renWin, bool);
void BlendFinalPeel(vtkOpenGLRenderWindow *renWin);
private:
......
......@@ -50,8 +50,8 @@ void vtkOpenGLActor::Render(vtkRenderer *ren, vtkMapper *mapper)
vtkOpenGLClearErrorMacro();
// get opacity
double opacity = this->GetProperty()->GetOpacity();
if (opacity == 1.0)
bool opaque = this->GetIsOpaque();
if (opaque)
{
glDepthMask(GL_TRUE);
}
......@@ -79,7 +79,7 @@ void vtkOpenGLActor::Render(vtkRenderer *ren, vtkMapper *mapper)
// send a render to the mapper; update pipeline
mapper->Render(ren, this);
if (opacity != 1.0)
if (!opaque)
{
glDepthMask(GL_TRUE);
}
......
......@@ -126,10 +126,10 @@ void vtkOpenGLPointGaussianMapperHelper::ReplaceShaderValues(std::string &VSSour
// compute the eye position and unit direction
"//VTK::Color::Impl\n"
" float dist2 = dot(offsetVC.xy,offsetVC.xy);\n"
" float gaussian = exp(-0.5*16.0*dist2);\n"
// " diffuseColor = vertexColor.rgb;\n"
// " ambientColor = vertexColor.rgb;\n"
" if (dist2 > 9.0) { discard; }\n"
" float gaussian = exp(-0.5*dist2);\n"
" opacity = opacity*gaussian;"
// " opacity = opacity*0.5;"
, false);
this->Superclass::ReplaceShaderValues(VSSource,FSSource,GSSource,lightComplexity,ren,actor);
......@@ -216,6 +216,7 @@ void vtkOpenGLPointGaussianMapperHelperPackVBOTemplate2(
pointPtr = points + i*3;
colorPtr = colors ? (colors + i*colorComponents) : white;
float radius = sizes ? sizes[i] : defaultSize;
radius *= 3.0;
// Vertices
*(it++) = pointPtr[0];
......
......@@ -522,11 +522,22 @@ void vtkOpenGLPolyDataMapper::ReplaceShaderValues(std::string &VSSource,
"uniform vec2 screenSize;\n"
"uniform sampler2D opaqueZTexture;\n"
"uniform sampler2D translucentZTexture;\n");
// the .0000001 below is an epsilon. It turns out that
// graphics cards can render the same polygon two times
// in a row with different z values. I suspect it has to
// do with how rasterinzation of the polygon is broken up.
// A different breakup across fragment shaders can result in
// very slightly different z values for some of the pixels.
// The end result is that with depth peeling, you can end up
// counting/accumulating pixels of the same surface twice
// simply due to this randomness in z values. So we introduce
// an epsilon into the transparent test to require some
// minimal z seperation between pixels
substitute(FSSource, "//VTK::DepthPeeling::Impl",
"float odepth = texture2D(opaqueZTexture, gl_FragCoord.xy/screenSize).r;\n"
" if (gl_FragCoord.z >= odepth) { discard; }\n"
" float tdepth = texture2D(translucentZTexture, gl_FragCoord.xy/screenSize).r;\n"
" if (gl_FragCoord.z <= tdepth) { discard; }\n"
" if (gl_FragCoord.z <= tdepth + .0000001) { discard; }\n"
// "gl_FragColor = vec4(odepth*odepth,tdepth*tdepth,gl_FragCoord.z*gl_FragCoord.z,1.0);"
);
}
......
if(VTK_RENDERING_BACKEND STREQUAL "OpenGL2")
set(extra_opengl2_tests
# the following produce incorrect results in OpenGL
TestConeLayoutStrategy.cxx
)
endif()
vtk_add_test_cxx(${vtk-module}CxxTests tests
${extra_opengl2_tests}
TestCoincidentGraphLayoutView.cxx
TestColumnTree.cxx
TestConeLayoutStrategy.cxx
TestDendrogramItem.cxx
TestGraphLayoutView.cxx
TestHeatmapCategoryLegend.cxx
......
e3e1f31b6d238602055f7f58dac034a3
dcedd666812674f4fe4829c3ebc4edc3
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