The clipping you are seeing is probably due to osg's computation of
the near and far clipping planes.
You'll need to implement computeBound so osg knows about your object.
Have a look in ShapeDrawable.cpp
2009/8/10 Andrew Thompson <andyb1...@yahoo.co.uk>:
> Hi Chris,
>
> Thanks for the heads up, I was digging around and found the
> drawImplementation method in Drawable myself so decided to give it a go.
> However I've had less than spectacular results!
>
> My first test was to take the code from ShapeDrawable that draws a box. Here
> it is for completeness sake
>
>
> Code:
>
>
> void drawImplementation(osg::RenderInfo & renderInfo) const
> {
> // evaluate hints
> bool createBody = true;
> bool createTop = true;
> bool createBottom = true;
>
> float dx = 3;
> float dy = 3;
> float dz = 3;
>
> glColor3ub(60,60,60);
> glPushMatrix();
>
> glTranslatef(10,10,10);
>
> glBegin(GL_QUADS);
>
> if (createBody) {
> // -ve y plane
> glNormal3f(0.0f,-1.0f,0.0f);
>
> glTexCoord2f(0.0f,1.0f);
> glVertex3f(-dx,-dy,dz);
>
> glTexCoord2f(0.0f,0.0f);
> glVertex3f(-dx,-dy,-dz);
>
> glTexCoord2f(1.0f,0.0f);
> glVertex3f(dx,-dy,-dz);
>
> glTexCoord2f(1.0f,1.0f);
> glVertex3f(dx,-dy,dz);
>
> // +ve y plane
> glNormal3f(0.0f,1.0f,0.0f);
>
> glTexCoord2f(0.0f,1.0f);
> glVertex3f(dx,dy,dz);
>
> glTexCoord2f(0.0f,0.0f);
> glVertex3f(dx,dy,-dz);
>
> glTexCoord2f(1.0f,0.0f);
> glVertex3f(-dx,dy,-dz);
>
> glTexCoord2f(1.0f,1.0f);
> glVertex3f(-dx,dy,dz);
>
> // +ve x plane
> glNormal3f(1.0f,0.0f,0.0f);
>
> glTexCoord2f(0.0f,1.0f);
> glVertex3f(dx,-dy,dz);
>
> glTexCoord2f(0.0f,0.0f);
> glVertex3f(dx,-dy,-dz);
>
> glTexCoord2f(1.0f,0.0f);
> glVertex3f(dx,dy,-dz);
>
> glTexCoord2f(1.0f,1.0f);
> glVertex3f(dx,dy,dz);
>
> // -ve x plane
> glNormal3f(-1.0f,0.0f,0.0f);
>
> glTexCoord2f(0.0f,1.0f);
> glVertex3f(-dx,dy,dz);
>
> glTexCoord2f(0.0f,0.0f);
> glVertex3f(-dx,dy,-dz);
>
> glTexCoord2f(1.0f,0.0f);
> glVertex3f(-dx,-dy,-dz);
>
> glTexCoord2f(1.0f,1.0f);
> glVertex3f(-dx,-dy,dz);
> }
>
> if (createTop) {
> // +ve z plane
> glNormal3f(0.0f,0.0f,1.0f);
>
> glTexCoord2f(0.0f,1.0f);
> glVertex3f(-dx,dy,dz);
>
> glTexCoord2f(0.0f,0.0f);
> glVertex3f(-dx,-dy,dz);
>
> glTexCoord2f(1.0f,0.0f);
> glVertex3f(dx,-dy,dz);
>
> glTexCoord2f(1.0f,1.0f);
> glVertex3f(dx,dy,dz);
> }
>
> if (createBottom) {
> // -ve z plane
> glNormal3f(0.0f,0.0f,-1.0f);
>
> glTexCoord2f(0.0f,1.0f);
> glVertex3f(dx,dy,-dz);
>
> glTexCoord2f(0.0f,0.0f);
> glVertex3f(dx,-dy,-dz);
>
> glTexCoord2f(1.0f,0.0f);
> glVertex3f(-dx,-dy,-dz);
>
> glTexCoord2f(1.0f,1.0f);
> glVertex3f(-dx,dy,-dz);
> }
>
> glEnd();
> glPopMatrix();
> }
>
>
>
>
>
> This results in a gray box drawn at the location 10,10,10 of size 3,3,3.
>
> [Image: http://i137.photobucket.com/albums/q217/andyb1979/drawImpBefore.png ]
>
> However, if I add other objects to my scene, then the box renders incorrectly.
>
> [Image: http://i137.photobucket.com/albums/q217/andyb1979/drawImpAfter.png ]
>
> At this point the subgraph looks like this, the additional objects from the
> position attitude transforms (labelled PAT) onwards are added when the cones
> are in the scene.
>
> [Image: http://i137.photobucket.com/albums/q217/andyb1979/Subgraph.png ]
>
> Another example, what I actually want to do is draw a subdividing grid that
> extends to the horizon. The code for this (at present) is included below
>
>
> Code:
>
> void drawImplementation(osg::RenderInfo & renderInfo) const
> {
> currentState->applyMode(GL_LIGHTING, false);
> glColor3ub(60,60,60);
>
> //render floor grid
> glLineWidth(1.0f);
> glBegin(GL_LINES);
>
> // Compute the Z location of the grid
> int zg = (int)0;
> int ystep = 100;
> int xstep = 100;
>
> // Compute the Y-Step depending on the current zoom factor
> if(m_zoom < 1.5)
> ystep = xstep = 10;
> if(m_zoom < 0.8)
> ystep = xstep = 5;
> if(m_zoom < 0.4)
> ystep = xstep = 2;
> if(m_zoom < 0.2)
> ystep = xstep = 1;
>
> // Compute the min/max X and Y values for each line
> float miny = (m_posY-(m_vHeight/2*m_zoom));
> float maxy = (m_posY+(m_vHeight/2*m_zoom));
> float minx = (m_posX-(m_vWidth/2*m_zoom));
> float maxx = (m_posX+(m_vWidth/2*m_zoom));
>
> // Draw lines in the Y direction
> for(int yg = (int)(miny - ((int)miny%ystep)); yg <= (int)(maxy -
> ((int)maxy%ystep)); yg+=ystep){
> glColor3ub(60,60,60);
> if(yg%10 == 0){
> glEnd();
> glColor3ub(100,100,100);
> glLineWidth(2.0f);
> glBegin(GL_LINES);
> }
> if(yg%100 == 0)
> glColor3ub(180,180,180);
> glVertex3f(minx, (GLfloat)yg, (GLfloat)zg);
> glVertex3f(maxx, (GLfloat)yg, (GLfloat)zg);
> if(yg%10 == 0){
> glEnd();
> glLineWidth(1.0f);
> glBegin(GL_LINES);
> }
> }
>
> // Draw lines in the X direction
> for(int xg = (int)(minx - ((int)minx%xstep)); xg <= (int)(maxx -
> ((int)maxx%xstep)); xg+=xstep){
> glColor3ub(60,60,60);
> if(xg%10 == 0){
> glEnd();
> glColor3ub(100,100,100);
> glLineWidth(2.0f);
> glBegin(GL_LINES);
> }
> if(xg%100 == 0)
> glColor3ub(180,180,180);
> glVertex3f((GLfloat)xg, miny, (GLfloat)zg);
> glVertex3f((GLfloat)xg, maxy, (GLfloat)zg);
> if(xg%10 == 0){
> glEnd();
> glLineWidth(1.0f);
> glBegin(GL_LINES);
> }
> }
>
> glEnd();
>
> // Re-enable lightning
> currentState->applyMode(GL_LIGHTING, true);
> }
>
>
>
>
> The subgrpah is the same as above, and the result with and without external
> objects is this
>
> [Image: http://i137.photobucket.com/albums/q217/andyb1979/drawImpBefore2.png ]
>
> [Image: http://i137.photobucket.com/albums/q217/andyb1979/drawImpAfter2.png ]
>
> Does anyone know what I'm doing wrong in my drawImplementation code?
>
> Thank you for your time,
> Andrew
>
> ------------------
> Read this topic online here:
> http://forum.openscenegraph.org/viewtopic.php?p=16032#16032
>
>
>
>
>
> _______________________________________________
> osg-users mailing list
> osg-users@lists.openscenegraph.org
> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
>
--
http://www.ssTk.co.uk
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