Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Primitive : do not write opengl depth when using polygon offset #1268

Closed
wants to merge 1 commit into from
Closed

Primitive : do not write opengl depth when using polygon offset #1268

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
73 changes: 64 additions & 9 deletions src/IECoreGL/Primitive.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -208,9 +208,28 @@ void Primitive::render( State *state ) const
// render the shaded primitive if requested
///////////////////////////////////////////

if( state->get<Primitive::DrawSolid>()->value() )
// we draw the primitive in various different drawing modes
// for modes other than solid we use polygon offset to prevent z-fighting, however
// the actual offset that opengl applies is based on implementation defined values
// which makes performing a reliable manual depth test hard. So we only write depth
// once from the first mode that does not use polygon offset. We only use polygon
// offset for modes after the first mode that has written depth. After drawing in
// solid mode we never write depth.
bool depthWritten = false;
const bool drawSolid = state->get<Primitive::DrawSolid>()->value();
if( drawSolid )
{
glDepthMask( !depthSortRequested( state ) );
const bool writeDepth = ! depthSortRequested( state );
if( writeDepth )
{
glDepthMask( GL_TRUE );
depthWritten = true;
}
else
{
glDepthMask( GL_FALSE );
}

// the state itself will have a shader with some nice uniform parameter
// values. we are responsible for binding this setup. unless we're performing
// an id render for selection, in which case we're responsible for binding an
Expand Down Expand Up @@ -245,10 +264,10 @@ void Primitive::render( State *state ) const
// then perform wireframe shading etc as requested
//////////////////////////////////////////////////

bool drawOutline = state->get<Primitive::DrawOutline>()->value();
bool drawWireframe = state->get<Primitive::DrawWireframe>()->value();
bool drawPoints = state->get<Primitive::DrawPoints>()->value();
bool drawBound = state->get<Primitive::DrawBound>()->value();
const bool drawOutline = state->get<Primitive::DrawOutline>()->value();
const bool drawWireframe = state->get<Primitive::DrawWireframe>()->value();
const bool drawPoints = state->get<Primitive::DrawPoints>()->value();
const bool drawBound = state->get<Primitive::DrawBound>()->value();
if( !(drawOutline || drawWireframe || drawPoints || drawBound) )
{
return;
Expand Down Expand Up @@ -277,7 +296,19 @@ void Primitive::render( State *state ) const
{
glPolygonMode( GL_FRONT_AND_BACK, GL_LINE );
float width = state->get<Primitive::WireframeWidth>()->value();
glEnable( GL_POLYGON_OFFSET_LINE );
if( drawSolid || depthWritten )
{
glDepthMask( GL_FALSE );
( depthWritten )
? glEnable( GL_POLYGON_OFFSET_LINE )
: glDisable( GL_POLYGON_OFFSET_LINE );
}
else
{
glDepthMask( GL_TRUE );
glDisable( GL_POLYGON_OFFSET_LINE );
depthWritten = true;
}
glPolygonOffset( -1 * width, -1 );
glLineWidth( width );
if( csIndex >= 0 )
Expand All @@ -293,7 +324,19 @@ void Primitive::render( State *state ) const
{
glPolygonMode( GL_FRONT_AND_BACK, GL_POINT );
float width = state->get<Primitive::PointWidth>()->value();
glEnable( GL_POLYGON_OFFSET_POINT );
if( drawSolid || depthWritten )
{
glDepthMask( GL_FALSE );
( depthWritten )
? glEnable( GL_POLYGON_OFFSET_POINT )
: glDisable( GL_POLYGON_OFFSET_POINT );
}
else
{
glDepthMask( GL_TRUE );
glDisable( GL_POLYGON_OFFSET_POINT );
depthWritten = true;
}
glPolygonOffset( -2 * width, -1 );
glPointSize( width );
if( csIndex >= 0 )
Expand All @@ -308,8 +351,20 @@ void Primitive::render( State *state ) const
if( drawOutline )
{
glPolygonMode( GL_FRONT_AND_BACK, GL_LINE );
glEnable( GL_POLYGON_OFFSET_LINE );
float width = 2 * state->get<Primitive::OutlineWidth>()->value();
if( drawSolid || depthWritten )
{
glDepthMask( GL_FALSE );
( depthWritten )
? glEnable( GL_POLYGON_OFFSET_LINE )
: glDisable( GL_POLYGON_OFFSET_LINE );
}
else
{
glDepthMask( GL_TRUE );
glDisable( GL_POLYGON_OFFSET_LINE );
depthWritten = true;
}
glPolygonOffset( 2 * width, 1 );
glLineWidth( width );
if( csIndex >= 0 )
Expand Down