No shadows in OpenGL?

Wolfgke · Post by **Wolfgke** » Fri Mar 04, 2005 9:10 pm

I looked at the demo of the Irrlicht engine and saw that in the OpenGL renderer there are no realtime shadows. Why is that? And when will it become fixed? I would be very thankful for the answer, because I plan to use Irrlicht (with Dev-C++ where it is complicated to use DirectX) in a private project, but do like the realtime shadows of the demo.

William Finlayson · Post by **William Finlayson** » Fri Mar 04, 2005 9:52 pm

Code: Select all

//! Draws a shadow volume into the stencil buffer. To draw a stencil shadow, do
//! this: Frist, draw all geometry. Then use this method, to draw the shadow
//! volume. Then, use IVideoDriver::drawStencilShadow() to visualize the shadow.
void CVideoOpenGL::drawStencilShadowVolume(const core::vector3df* triangles, s32 count, bool zfail)
{
	if (!StencilBuffer || !count)
		return;
	
	// unset last 3d material
	if (CurrentRenderMode == ERM_3D &&
		Material.MaterialType >= 0 && Material.MaterialType < (s32)MaterialRenderers.size())
	{
		MaterialRenderers[Material.MaterialType]->OnUnsetMaterial();
		ResetRenderStates = true;
	}
	
	// store current OpenGL	state
	glPushAttrib(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_ENABLE_BIT |
		GL_POLYGON_BIT	| GL_STENCIL_BUFFER_BIT	);

	glDisable(GL_LIGHTING);
	glDisable(GL_FOG);
	glDepthMask(GL_FALSE);
	glDepthFunc(GL_LEQUAL);
	glEnable(GL_STENCIL_TEST);
	glColorMask(GL_FALSE, GL_FALSE,	GL_FALSE, GL_FALSE ); // no color buffer drawing
	glStencilFunc(GL_ALWAYS, 1,	0xFFFFFFFFL	);
	glColorMask(0, 0, 0, 0);
	glEnable(GL_CULL_FACE);

	

	if (!zfail)
	{
		// ZPASS Method

		glStencilOp(GL_KEEP, GL_KEEP, GL_INCR);
		glCullFace(GL_BACK);
		glBegin(GL_TRIANGLES);

		s32 i;
		for(i =	0; i < count; ++i)
			glVertex3f(triangles[i].X, triangles[i].Y, triangles[i].Z);

		glEnd();

		glStencilOp(GL_KEEP, GL_KEEP, GL_DECR);
		glCullFace(GL_FRONT);
		
		glBegin(GL_TRIANGLES);
		for(i =	0; i < count; ++i)
			glVertex3f(triangles[i].X, triangles[i].Y, triangles[i].Z);
		
		glEnd();

	}
	else
	{
		// ZFAIL Method

		glStencilOp(GL_KEEP, GL_INCR, GL_KEEP);
		glCullFace(GL_FRONT);
		
		glBegin(GL_TRIANGLES);

		s32 i;
		for(i =	0; i < count; i++)
			glVertex3f(triangles[i].X, triangles[i].Y, triangles[i].Z);
		
		glEnd();

		glStencilOp(GL_KEEP, GL_DECR, GL_KEEP);
		glCullFace(GL_BACK);
		
		glBegin(GL_TRIANGLES);

		for(i =	0; i < count; i++)
			glVertex3f(triangles[i].X, triangles[i].Y, triangles[i].Z);
		
		glEnd();

	}

	glPopAttrib();
}



void CVideoOpenGL::drawStencilShadow(bool clearStencilBuffer, video::SColor leftUpEdge,
			video::SColor rightUpEdge, video::SColor leftDownEdge, video::SColor rightDownEdge)
{
	if (!StencilBuffer)
		return;

		setTexture(0,0); 
		setTexture(1,0);
	glPushAttrib( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_ENABLE_BIT | GL_POLYGON_BIT | GL_STENCIL_BUFFER_BIT );


	glDisable( GL_LIGHTING );
	glDepthMask(GL_FALSE); 
	glDepthFunc( GL_LEQUAL );
	glEnable( GL_STENCIL_TEST );

	glFrontFace( GL_CCW );
	glColorMask( GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE );

	glEnable(GL_BLEND);
	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

	glStencilFunc(GL_NOTEQUAL, 0, 0xFFFFFFFFL);
	glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);

	glDisable(GL_FOG);

	glPushMatrix();
	glLoadIdentity();

	glBegin(GL_TRIANGLE_STRIP);

	glColor4ub (leftUpEdge.getRed(), leftUpEdge.getGreen(), leftUpEdge.getBlue(), leftUpEdge.getAlpha() );
	glVertex3f(-10.1f, 10.1f,0.90f);

	glColor4ub (leftDownEdge.getRed(), leftDownEdge.getGreen(), leftDownEdge.getBlue(), leftDownEdge.getAlpha() );
	glVertex3f(-10.1f,-10.1f,0.90f);

	glColor4ub (rightUpEdge.getRed(), rightUpEdge.getGreen(), rightUpEdge.getBlue(), rightUpEdge.getAlpha() );
	glVertex3f( 10.1f, 10.1f,0.90f);

	glColor4ub (rightDownEdge.getRed(), rightDownEdge.getGreen(), rightDownEdge.getBlue(), rightDownEdge.getAlpha() );
	glVertex3f( 10.1f,-10.1f,0.90f);

	glEnd();

	glPopMatrix();
	glPopAttrib();

	if (clearStencilBuffer)
		glClear(GL_STENCIL_BUFFER_BIT);

	glDepthMask(GL_TRUE); 
	glEnable(GL_DEPTH_TEST); 

}

Replace those functions in CVideoOpenGL.cpp, recompile, and shadows work

Sorry about posting the whole functions, but I couldn't remember what was changed.

AmigaIrr · Post by **AmigaIrr** » Sat Mar 05, 2005 5:15 am

Good man !

But, have you the solution for the DX9 bug ??

I use only DX9c + Dev-C++...

William Finlayson · Post by **William Finlayson** » Sat Mar 05, 2005 11:26 am

I use only OpenGL + Dev-C++...

MikeR · Post by **MikeR** » Sat Mar 05, 2005 12:59 pm

There is a whole long thread in the tools forum talking about directX and dev-cpp.

Murphy · Post by **Murphy** » Sat Mar 05, 2005 4:16 pm

AmigaIrr wrote:But, have you the solution for the DX9 bug ??

What bug?

Wolfgke · Post by **Wolfgke** » Mon Mar 07, 2005 10:00 am

@William Finlayson
Tha code did it. Thanks a lot!

William Finlayson · Post by **William Finlayson** » Mon Mar 07, 2005 4:40 pm

np

You may also find problems with some of the materials in OpenGL. Take a look at the SpecialFX demo, and see if it matches the screenshots. If it isn't working right, I have a fix for that as well, modified from nx++. OpenGL can work just as well as DX in Irrlicht, it just needs a little prod here and there

firefly2442 · Post by **firefly2442** » Wed Mar 09, 2005 2:52 am

Is this changed in irrlicht 0.8? It seems strange to me that shadows are enabled by default in DirectX and not OpenGL.

Murphy · Post by **Murphy** » Wed Mar 09, 2005 7:18 am

firefly2442 wrote:Is this changed in irrlicht 0.8? It seems strange to me that shadows are enabled by default in DirectX and not OpenGL.

It's not a matter of them being enabled, it's a matter of Irrlicht's OpenGL code not being as tuned as its DirectX code -- I think Niko mostly uses DirectX.

So it works on some systems, but not on others. Shadows worked fine in OpenGL on my old GeForce, but on my new Radeon, they don't.