Downloads: Generating Outlines in OpenGL

outline_mode_demo.zip

OGLDemo.exe

outline_mode_src.zip

include

CGLImage.h

CGLTexture.h

CRGBSurface.h

CWGL.h

Jconfig.h

jmorecfg.h

Jpeglib.h

OGLT.h

StdAfx.h

intro.txt

lib

Jpegmt.lib

OGLDemo

ChildFrm.cpp

ChildFrm.h

MainFrm.cpp

MainFrm.h

OGLDemo.cpp

OGLDemo.dsp

OGLDemo.h

OGLDemo.rc

OGLDemo.vcproj

OGLDemoDoc.cpp

OGLDemoDoc.h

OGLDemoView.cpp

OGLDemoView.h

res

OGLDemo.ico

OGLDemo.rc2

OGLDemoDoc.ico

Toolbar.bmp

resource.h

StdAfx.cpp

StdAfx.h

OGLTDoc

Doc

HTML - English

index.chm

OGLTools.sln

OGLTools.vcproj

src

CGLImage.cpp

CGLTexture.cpp

CRGBSurface.cpp

CWGL.cpp

README.ijg.txt

StdAfx.cpp

// OGLDemoView.cpp : implementation of the COGLDemoView class
//

#include "stdafx.h"
#include <math.h>

#include "OGLDemo.h"

#include "OGLDemoDoc.h"
#include "OGLDemoView.h"
#include ".\ogldemoview.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

#define M_PI       3.14159265358979323846

/////////////////////////////////////////////////////////////////////////////
// COGLDemoView

IMPLEMENT_DYNCREATE(COGLDemoView, CView)

BEGIN_MESSAGE_MAP(COGLDemoView, CView)
	//{{AFX_MSG_MAP(COGLDemoView)
	ON_WM_SIZE()
	ON_WM_ERASEBKGND()
	ON_WM_DESTROY()
	//}}AFX_MSG_MAP
	ON_COMMAND(ID_RENDER_POLYGONOFFSET, OnRenderPolygonoffset)
	ON_COMMAND(ID_RENDER_STENCILBUFFER, OnRenderStencilbuffer)
	ON_COMMAND(ID_RENDER_STENCILBUFFERWITHDISPLAYLIST, OnRenderStencilbufferwithdisplaylist)
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// COGLDemoView construction/destruction

COGLDemoView::COGLDemoView()
: m_rtri(0), m_rquad(0), m_bResizing(true), m_listCreated( false ), m_renderType( eRenderPolygon )
{
	// TODO: add construction code here
}

COGLDemoView::~COGLDemoView()
{
}

BOOL COGLDemoView::PreCreateWindow(CREATESTRUCT& cs)
{
	// TODO: Modify the Window class or styles here by modifying
	//  the CREATESTRUCT cs

	return CView::PreCreateWindow(cs);
}

/////////////////////////////////////////////////////////////////////////////
// COGLDemoView drawing

void COGLDemoView::OnDraw(CDC* pDC)
{
	COGLDemoDoc* pDoc = GetDocument();
	ASSERT_VALID(pDoc);
	// TODO: add draw code for native data here

	
	m_wgl.Begin(pDC);
		if (m_bResizing)
		{
			CRect rect;
			GetClientRect(&rect);

			glViewport(0,0, rect.Width(), rect.Height());
			glMatrixMode(GL_PROJECTION);
			glLoadIdentity();
			gluPerspective(35,rect.Width()/(double)rect.Height(),1,100);
			gluLookAt(0,0,0,0,0,-10,0,1,0);
			glMatrixMode(GL_MODELVIEW);
		}

		glDisable( GL_DITHER );
		glEnable( GL_DEPTH_TEST );
		GLfloat pos[4] = { 3.0f, 5.0f, 2.0f, 1.0f };
		GLfloat white[4] = { 1.0f, 1.0f, 1.0f, 1.0f };
		GLfloat black[4] = { 0.0f, 0.0f, 0.0f, 0.0f };
		glDisable( GL_LIGHTING );
		glEnable( GL_LIGHT1 );
		glLightfv( GL_LIGHT1, GL_POSITION, pos );
		glLightfv( GL_LIGHT1, GL_DIFFUSE, white );
		glLightfv( GL_LIGHT1, GL_SPECULAR, black );
		glEnable( GL_COLOR_MATERIAL );
		glColorMaterial( GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE );
		glMaterialfv( GL_FRONT_AND_BACK, GL_SPECULAR, black );

		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
		if ( !m_listCreated )
			CreateDisplayLists();
		switch ( m_renderType )
		{
		case eRenderPolygon:
			DrawGLScenePolygonOffset();
			break;
		case eRenderStencilBuffer:
			DrawGLSceneStencil();
			break;
		case eRenderStencilBufferWithDisplayList:
			DrawGLSceneStencilDisplayList();
			break;
		}
		
	m_wgl.End();
}

/////////////////////////////////////////////////////////////////////////////
// COGLDemoView diagnostics

#ifdef _DEBUG
void COGLDemoView::AssertValid() const
{
	CView::AssertValid();
}

void COGLDemoView::Dump(CDumpContext& dc) const
{
	CView::Dump(dc);
}

COGLDemoDoc* COGLDemoView::GetDocument() // non-debug version is inline
{
	ASSERT(m_pDocument->IsKindOf(RUNTIME_CLASS(COGLDemoDoc)));
	return (COGLDemoDoc*)m_pDocument;
}
#endif //_DEBUG

/////////////////////////////////////////////////////////////////////////////
// COGLDemoView message handlers

int COGLDemoView::DrawGLScenePolygonOffset()
{
	glLoadIdentity();						// Reset The View
	glTranslatef(-1.5f,0.0f,-6.0);			// Move Left And Into The Screen

	glRotatef(m_rtri,0.0f,1.0f,0.0f);		// Rotate The Pyramid On It's Y Axis

	// Render Object 3
	glPushAttrib( GL_ALL_ATTRIB_BITS );
	glEnable( GL_POLYGON_OFFSET_FILL );
	glPolygonOffset( -2.5f, -2.5f );
	glPolygonMode( GL_FRONT_AND_BACK, GL_LINE );
	glLineWidth( 3.0f );
	glColor3f( 1.0f, 1.0f, 1.0f );
	RenderMesh3();

	glPolygonMode( GL_FRONT_AND_BACK, GL_FILL );
	glEnable( GL_LIGHTING );
	glColor3f( 0.0f, 0.0f, 0.0f );
	RenderMesh3();
	glPopAttrib();

	glLoadIdentity();
	glTranslatef(1.5f,0.0f,-7.0f);				// Move Right And Into The Screen
	glRotatef(m_rquad,1.0f,1.0f,1.0f);			// Rotate The Cube On X, Y & Z

	// Render Object 2
	glPushAttrib( GL_ALL_ATTRIB_BITS );
	glEnable( GL_POLYGON_OFFSET_FILL );
	glPolygonOffset( -2.5f, -2.5f );
	glPolygonMode( GL_FRONT_AND_BACK, GL_LINE );
	glLineWidth( 3.0f );
	glColor3f( 1.0f, 1.0f, 1.0f );
	RenderMesh2();

	glPolygonMode( GL_FRONT_AND_BACK, GL_FILL );
	glEnable( GL_LIGHTING );
	glColor3f( 0.0f, 0.0f, 0.0f );
	RenderMesh2();
	glPopAttrib();

	m_rtri+=0.5f;						// Increase The Rotation Variable For The Triangle 
	m_rquad-=0.4f;						// Decrease The Rotation Variable For The Quad 
	return TRUE;						// Keep Going
}

int COGLDemoView::DrawGLSceneStencil()
{
	glLoadIdentity();						// Reset The View
	glTranslatef(-1.5f,0.0f,-6.0);			// Move Left And Into The Screen

	glRotatef(m_rtri,0.0f,1.0f,0.0f);		// Rotate The Pyramid On It's Y Axis

	// Render object 3
	glPushAttrib( GL_ALL_ATTRIB_BITS );
	glEnable( GL_LIGHTING );
	glClearStencil(0);
	glClear( GL_STENCIL_BUFFER_BIT );
	glEnable( GL_STENCIL_TEST );
	glStencilFunc( GL_ALWAYS, 1, 0xFFFF );
	glStencilOp( GL_KEEP, GL_KEEP, GL_REPLACE );
	glPolygonMode( GL_FRONT_AND_BACK, GL_FILL );
	glColor3f( 0.0f, 0.0f, 0.0f );
	RenderMesh3();
	glDisable( GL_LIGHTING );
	glStencilFunc( GL_NOTEQUAL, 1, 0xFFFF );
	glStencilOp( GL_KEEP, GL_KEEP, GL_REPLACE );
	glLineWidth( 3.0f );
	glPolygonMode( GL_FRONT_AND_BACK, GL_LINE );
	glColor3f( 1.0f, 1.0f, 1.0f );
	RenderMesh3();
	glPopAttrib();

	glLoadIdentity();
	glTranslatef(1.5f,0.0f,-7.0f);				// Move Right And Into The Screen
	glRotatef(m_rquad,1.0f,1.0f,1.0f);			// Rotate The Cube On X, Y & Z

	// Render object 2
	glPushAttrib( GL_ALL_ATTRIB_BITS );
	glEnable( GL_LIGHTING );
	glClearStencil(0);
	glClear( GL_STENCIL_BUFFER_BIT );
	glEnable( GL_STENCIL_TEST );
	glStencilFunc( GL_ALWAYS, 1, -1 );
	glStencilOp( GL_KEEP, GL_KEEP, GL_REPLACE );
	glPolygonMode( GL_FRONT_AND_BACK, GL_FILL );
	glColor3f( 0.0f, 0.0f, 0.0f  );
	RenderMesh2();
	glDisable( GL_LIGHTING );
	glStencilFunc( GL_NOTEQUAL, 1, -1 );
	glStencilOp( GL_KEEP, GL_KEEP, GL_REPLACE );
	glLineWidth( 3.0f );
	glPolygonMode( GL_FRONT_AND_BACK, GL_LINE );
	glColor3f( 1.0f, 1.0f, 1.0f );
	RenderMesh2();
	glPopAttrib();

	m_rtri+=0.5f;						// Increase The Rotation Variable For The Triangle 
	m_rquad-=0.4f;						// Decrease The Rotation Variable For The Quad 
	return TRUE;
}

int COGLDemoView::DrawGLSceneStencilDisplayList()
{
	glLoadIdentity();						// Reset The View
	glTranslatef(-1.5f,0.0f,-6.0);			// Move Left And Into The Screen

	glRotatef(m_rtri,0.0f,1.0f,0.0f);		// Rotate The Pyramid On It's Y Axis

	// Render object 3
	glCallList( 1 );

	glLoadIdentity();
	glTranslatef(1.5f,0.0f,-7.0f);				// Move Right And Into The Screen
	glRotatef(m_rquad,1.0f,1.0f,1.0f);			// Rotate The Cube On X, Y & Z

	// Render object 2
	glCallList( 2 );

	m_rtri+=0.5f;						// Increase The Rotation Variable For The Triangle 
	m_rquad-=0.4f;						// Decrease The Rotation Variable For The Quad 
	return TRUE;
}

int COGLDemoView::CreateDisplayLists()
{
	glNewList( 1, GL_COMPILE );
	glPushAttrib( GL_ALL_ATTRIB_BITS );
	glEnable( GL_LIGHTING );
	glClearStencil(0);
	glClear( GL_STENCIL_BUFFER_BIT );
	glEnable( GL_STENCIL_TEST );
	glStencilFunc( GL_ALWAYS, 1, 0xFFFF );
	glStencilOp( GL_KEEP, GL_KEEP, GL_REPLACE );
	glPolygonMode( GL_FRONT_AND_BACK, GL_FILL );
	glColor3f( 0.2f, 0.2f, 1.0f );
	RenderMesh3();
	glDisable( GL_LIGHTING );
	glStencilFunc( GL_NOTEQUAL, 1, 0xFFFF );
	glStencilOp( GL_KEEP, GL_KEEP, GL_REPLACE );
	glLineWidth( 3.0f );
	glPolygonMode( GL_FRONT_AND_BACK, GL_LINE );
	glColor3f( 1.0f, 1.0f, 1.0f );
	RenderMesh3();
	glPopAttrib();
	glEndList();

	glNewList( 2, GL_COMPILE );
	glPushAttrib( GL_ALL_ATTRIB_BITS );
	glEnable( GL_LIGHTING );
	glClearStencil(0);
	glClear( GL_STENCIL_BUFFER_BIT );
	glEnable( GL_STENCIL_TEST );
	glStencilFunc( GL_ALWAYS, 1, -1 );
	glStencilOp( GL_KEEP, GL_KEEP, GL_REPLACE );
	glPolygonMode( GL_FRONT_AND_BACK, GL_FILL );
	glColor3f( 0.2f, 0.2f, 1.0f );
	RenderMesh2();
	glDisable( GL_LIGHTING );
	glStencilFunc( GL_NOTEQUAL, 1, -1 );
	glStencilOp( GL_KEEP, GL_KEEP, GL_REPLACE );
	glLineWidth( 3.0f );
	glPolygonMode( GL_FRONT_AND_BACK, GL_LINE );
	glColor3f( 1.0f, 1.0f, 1.0f );
	RenderMesh2();
	glPopAttrib();
	glEndList();

	m_listCreated = true;

	return TRUE;
}

void COGLDemoView::RenderMesh1()
{
	glBegin(GL_TRIANGLES);					// Start Drawing The Pyramid
	
	glVertex3f( 0.0f, 1.0f, 0.0f);			// Top Of Triangle (Front)
	glVertex3f(-1.0f,-1.0f, 1.0f);			// Left Of Triangle (Front)
	glVertex3f( 1.0f,-1.0f, 1.0f);			// Right Of Triangle (Front)

	glVertex3f( 0.0f, 1.0f, 0.0f);			// Top Of Triangle (Right)
	glVertex3f( 1.0f,-1.0f, 1.0f);			// Left Of Triangle (Right)
	glVertex3f( 1.0f,-1.0f, -1.0f);			// Right Of Triangle (Right)

	glVertex3f( 0.0f, 1.0f, 0.0f);			// Top Of Triangle (Back)
	glVertex3f( 1.0f,-1.0f, -1.0f);			// Left Of Triangle (Back)
	glVertex3f(-1.0f,-1.0f, -1.0f);			// Right Of Triangle (Back)

	glVertex3f( 0.0f, 1.0f, 0.0f);			// Top Of Triangle (Left)
	glVertex3f(-1.0f,-1.0f,-1.0f);			// Left Of Triangle (Left)
	glVertex3f(-1.0f,-1.0f, 1.0f);			// Right Of Triangle (Left)

	glEnd();						// Done Drawing The Pyramid
}

void COGLDemoView::RenderMesh2()
{
	glBegin(GL_QUADS);					// Start Drawing The Cube

	glVertex3f( 1.0f, 1.0f,-1.0f);			// Top Right Of The Quad (Top)
	glVertex3f(-1.0f, 1.0f,-1.0f);			// Top Left Of The Quad (Top)
	glVertex3f(-1.0f, 1.0f, 1.0f);			// Bottom Left Of The Quad (Top)
	glVertex3f( 1.0f, 1.0f, 1.0f);			// Bottom Right Of The Quad (Top)

	glVertex3f( 1.0f,-1.0f, 1.0f);			// Top Right Of The Quad (Bottom)
	glVertex3f(-1.0f,-1.0f, 1.0f);			// Top Left Of The Quad (Bottom)
	glVertex3f(-1.0f,-1.0f,-1.0f);			// Bottom Left Of The Quad (Bottom)
	glVertex3f( 1.0f,-1.0f,-1.0f);			// Bottom Right Of The Quad (Bottom)

	glVertex3f( 1.0f, 1.0f, 1.0f);			// Top Right Of The Quad (Front)
	glVertex3f(-1.0f, 1.0f, 1.0f);			// Top Left Of The Quad (Front)
	glVertex3f(-1.0f,-1.0f, 1.0f);			// Bottom Left Of The Quad (Front)
	glVertex3f( 1.0f,-1.0f, 1.0f);			// Bottom Right Of The Quad (Front)

	glVertex3f( 1.0f,-1.0f,-1.0f);			// Bottom Left Of The Quad (Back)
	glVertex3f(-1.0f,-1.0f,-1.0f);			// Bottom Right Of The Quad (Back)
	glVertex3f(-1.0f, 1.0f,-1.0f);			// Top Right Of The Quad (Back)
	glVertex3f( 1.0f, 1.0f,-1.0f);			// Top Left Of The Quad (Back)

	glVertex3f(-1.0f, 1.0f, 1.0f);			// Top Right Of The Quad (Left)
	glVertex3f(-1.0f, 1.0f,-1.0f);			// Top Left Of The Quad (Left)
	glVertex3f(-1.0f,-1.0f,-1.0f);			// Bottom Left Of The Quad (Left)
	glVertex3f(-1.0f,-1.0f, 1.0f);			// Bottom Right Of The Quad (Left)
   
	glVertex3f( 1.0f, 1.0f,-1.0f);			// Top Right Of The Quad (Right)
	glVertex3f( 1.0f, 1.0f, 1.0f);			// Top Left Of The Quad (Right)
	glVertex3f( 1.0f,-1.0f, 1.0f);			// Bottom Left Of The Quad (Right)
	glVertex3f( 1.0f,-1.0f,-1.0f);			// Bottom Right Of The Quad (Right)

	glEnd();						// Done Drawing The Quad
}

void COGLDemoView::RenderMesh3()
{
	float radius = 1.0f;
	static const int uDensity = 10;
	static const int vDensity = 20;
	float points[uDensity+1][vDensity+1][3];
	for ( int uu = 0; uu <= uDensity; ++uu )
	{
		for ( int vv = 0; vv <=	vDensity; ++vv )
		{
			float theta = (float) ( M_PI * uu / uDensity );
			float phi = (float) ( 2 * M_PI * vv / vDensity );
			points[uu][vv][0] = radius * cos( theta );
			points[uu][vv][1] = radius * sin( theta ) * cos( phi );
			points[uu][vv][2] = radius * sin( theta ) * sin( phi );
		}
	}
	glBegin( GL_TRIANGLES );

	for ( int ii = 0; ii < uDensity; ++ii )
	{
		for ( int jj = 0; jj < vDensity; ++jj )
		{
			glNormal3f( points[ii][jj][0], points[ii][jj][1], points[ii][jj][2] );
			glVertex3f( points[ii][jj][0], points[ii][jj][1], points[ii][jj][2] );
			glNormal3f( points[ii][jj+1][0], points[ii][jj+1][1], points[ii][jj+1][2] );
			glVertex3f( points[ii][jj+1][0], points[ii][jj+1][1], points[ii][jj+1][2] );
			glNormal3f( points[ii+1][jj][0], points[ii+1][jj][1], points[ii+1][jj][2] );
			glVertex3f( points[ii+1][jj][0], points[ii+1][jj][1], points[ii+1][jj][2] );
			glNormal3f( points[ii][jj+1][0], points[ii][jj+1][1], points[ii][jj+1][2] );
			glVertex3f( points[ii][jj+1][0], points[ii][jj+1][1], points[ii][jj+1][2] );
			glNormal3f( points[ii+1][jj][0], points[ii+1][jj][1], points[ii+1][jj][2] );
			glVertex3f( points[ii+1][jj][0], points[ii+1][jj][1], points[ii+1][jj][2] );
			glNormal3f( points[ii+1][jj+1][0], points[ii+1][jj+1][1], points[ii+1][jj+1][2] );
			glVertex3f( points[ii+1][jj+1][0], points[ii+1][jj+1][1], points[ii+1][jj+1][2] );
		}
	}
	glEnd();

}

void COGLDemoView::OnSize(UINT nType, int cx, int cy) 
{
	CView::OnSize(nType, cx, cy);
	
	m_bResizing = true;
}

void COGLDemoView::OnInitialUpdate() 
{
	CView::OnInitialUpdate();
	
	CClientDC dc(this);

	m_wgl.Begin(&dc);
		
		glShadeModel(GL_SMOOTH);						// Enable Smooth Shading
		glClearColor(0.0f, 0.0f, 0.0f, 0.5f);			// Black Background
		glClearDepth(1.0f);								// Depth Buffer Setup
		glEnable(GL_DEPTH_TEST);						// Enables Depth Testing
		glDepthFunc(GL_LEQUAL);							// The Type Of Depth Testing To Do
		glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);			// Really Nice Perspective Calculations

	m_wgl.End();
	
	((COGLDemoApp*)AfxGetApp())->m_pIdleView = this;
}

BOOL COGLDemoView::OnEraseBkgnd(CDC* pDC) 
{
	return true;
}

void COGLDemoView::OnDestroy() 
{
	CView::OnDestroy();
	
	((COGLDemoApp*)AfxGetApp())->m_pIdleView = NULL;

}

void COGLDemoView::OnRenderPolygonoffset()
{
	m_renderType = eRenderPolygon;
}

void COGLDemoView::OnRenderStencilbuffer()
{
	m_renderType = eRenderStencilBuffer;
}

void COGLDemoView::OnRenderStencilbufferwithdisplaylist()
{
	m_renderType = eRenderStencilBufferWithDisplayList;
}

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About the Author

Dave Handley

Web Developer

United Kingdom

Member

I started programming on 8 bit machines as a teenager, writing my first compiled programming language before I was 16. I went on to study Engineering and Computer Science at Oxford University, getting a first and the University Prize for the best results in Computer Science. Since then I have worked in a variety of roles, involving systems management and development management on a wide variety of platforms. Now I manage a software development company producing CAD software for Windows using C++.

My 3 favourite reference books are: Design Patterns, Gamma et al; The C++ Standard Library, Josuttis; and Computer Graphics, Foley et al.

Outside computers, I am also the drummer in a band, The Unbelievers and we have just released our first album. I am a pretty good juggler and close up magician, and in my more insane past, I have cycled from Spain to Eastern Turkey, and cycled across the Namib desert.

Using multi-pass techniques to generate outlines in OpenGL.

Type	Article
Licence
First Posted	7 Oct 2004
Views	129,964
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