Method update

samples/_opengl/ClothSimulation/src/ClothSimulationApp.cpp:196–235

}

void ClothSimulationApp::update()
{
	updateParams();

	if( ! mUpdate ) return;
	
	gl::ScopedGlslProg	scopeGlsl( mUpdateGlsl );
	gl::ScopedState		scopeState( GL_RASTERIZER_DISCARD, true );
	
	for( auto i = mIterationsPerFrame; i != 0; --i ) {
		// Bind the vao that has the original vbo attached,
		// these buffers will be used to read from.
		gl::ScopedVao scopedVao( mVaos[mIterationIndex & 1] );
		// Bind the BufferTexture, which contains the positions
		// of the first vbo. We'll cycle through the neighbors
		// using the connection buffer so that we can derive our
		// next position and velocity to write to Transform Feedback
		gl::ScopedTextureBind scopeTex( mPositionBufTexs[mIterationIndex & 1]->getTarget(), mPositionBufTexs[mIterationIndex & 1]->getId() );
		
		// We iterate our index so that we'll be using the
		// opposing buffers to capture the data
		mIterationIndex++;
		
		// Now bind our opposing buffers to the correct index
		// so that we can capture the values coming from the shader
		gl::bindBufferBase( GL_TRANSFORM_FEEDBACK_BUFFER, POSITION_INDEX, mPositions[mIterationIndex & 1] );
		gl::bindBufferBase( GL_TRANSFORM_FEEDBACK_BUFFER, VELOCITY_INDEX, mVelocities[mIterationIndex & 1] );
		
		// Begin Transform feedback with the correct primitive,
		// In this case, we want GL_POINTS, because each vertex
		// exists by itself
		gl::beginTransformFeedback( GL_POINTS );
		// Now we issue our draw command which puts all of the
		// setup in motion and processes all the vertices
		gl::drawArrays( GL_POINTS, 0, POINTS_TOTAL );
		// After that we issue an endTransformFeedback command
		// to tell OpenGL that we're finished capturing vertices
		gl::endTransformFeedback();
	}
}

void ClothSimulationApp::draw()
{