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
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