Beam scenenode

rogerborg · Post by **rogerborg** » Wed Jul 16, 2008 7:45 am

Are you bleeping serious? You'll have to call setStartPoint() with your ships's position (from getAbsolutePosition()), and setEndPoint() with where you want it to end.

If you ask how you calculate the end point, I'm coming for you with a cheese grater and a jar of battery acid.

torleif · Post by **torleif** » Thu Jul 17, 2008 3:02 am

empirepro wrote:How can I get this to shoot from my ship instead of a set location?

instead of

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beam->SetStartPoint( core::vector3df( -500, 0, 0 ) );

use

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beam->SetStartPoint( shipMesh->getPosition());

phoboss · Post by **phoboss** » Sat Aug 30, 2008 11:40 am

When the camera is too near to the beam node, it disappears. Why is it like that?! I'm writing a space shooter and I don't see the lasers I'm shooting

sudi · Post by **sudi** » Sat Aug 30, 2008 1:18 pm

Here is my BeamSceneNode. Works better then the one showed at the beginning.

Header:

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#ifndef CBEAMSCENENODE_H
#define CBEAMSCENENODE_H
#include <irrlicht.h>
namespace irr
{
    namespace scene
    {
        class CBeamNode : public ISceneNode
        {
        public:
        private:
            // The beam material.
            video::SMaterial material;
            video::SMaterial material2;

            // Bounding Box
            core::aabbox3d<f32> Box;

            core::vector3df m_start;
            core::vector3df m_end;
            f32 m_thickness;

        public:

            CBeamNode( scene::ISceneNode* parent, scene::ISceneManager *mgr, s32 id, char* szBeam , char* szBeamFront );

            ~CBeamNode(void);

            virtual void OnRegisterSceneNode(void);

            virtual void OnAnimate(u32 timeMs);

            virtual void render(void);

            virtual const core::aabbox3d<f32>& getBoundingBox() const;

            virtual u32 getMaterialCount();

            virtual video::SMaterial& getMaterial(u32 i);

            void setLine(core::vector3df start, core::vector3df end, f32 thickness);
        };
    }
}
#endif

Source:

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#include "CBeamSceneNode.h"
namespace irr
{
    namespace scene
    {
        CBeamNode::CBeamNode( ISceneNode* parent, ISceneManager *mgr, s32 id, char* szBeam , char* szBeamFront ) : ISceneNode( parent, mgr, id )
        {
            // Setup the beam material
            material.Wireframe = false;
            material.Lighting = false;
            //material.MaterialType = video::EMT_TRANSPARENT_VERTEX_ALPHA;
            //material.MaterialType = video::EMT_TRANSPARENT_ALPHA_CHANNEL;
            material.MaterialType = video::EMT_TRANSPARENT_ADD_COLOR;
            material.Textures[0] = mgr->getVideoDriver( )->getTexture( szBeam );
            //material.Textures[1] = mgr->getVideoDriver( )->getTexture( szBeam );

            material2.Wireframe = false;
            material2.Lighting = false;
            //material.MaterialType = video::EMT_TRANSPARENT_VERTEX_ALPHA;
            //material.MaterialType = video::EMT_TRANSPARENT_ALPHA_CHANNEL;
            material2.MaterialType = video::EMT_TRANSPARENT_ADD_COLOR;
            material2.Textures[0] = mgr->getVideoDriver( )->getTexture( szBeamFront );

            m_thickness = 1.0f;
        }

        CBeamNode::~CBeamNode(void)
        {

        }

        void CBeamNode::OnRegisterSceneNode(void)
        {
            ISceneNode::OnRegisterSceneNode();
        }

        void CBeamNode::OnAnimate(u32 timeMs)
        {

            if ( IsVisible )
            {
                SceneManager->registerNodeForRendering( this );
            }

            ISceneNode::OnAnimate(timeMs);
        }

        void CBeamNode::setLine(core::vector3df start, core::vector3df end, f32 thickness)
        {
            m_start = start;
            m_end = end;
            m_thickness = thickness;
        }

        void CBeamNode::render(void)
        {
            video::IVideoDriver* driver = SceneManager->getVideoDriver();
            driver->setTransform(irr::video::ETS_WORLD, AbsoluteTransformation);

            core::vector3df direction = m_end-m_start;
            direction.normalize();
            core::vector3df savesatrt = m_start;
            AbsoluteTransformation.transformVect(savesatrt);
            core::vector3df lookdir = savesatrt-SceneManager->getActiveCamera()->getAbsolutePosition();
            if(lookdir.getLength() < 20)
                return;
            lookdir.normalize();

            core::vector3df view(SceneManager->getActiveCamera()->getTarget() - SceneManager->getActiveCamera()->getAbsolutePosition());
            view.normalize();

            if(lookdir.dotProduct(direction)/(lookdir.getLength()*direction.getLength()) < .98f && lookdir.dotProduct(direction)/(lookdir.getLength()*direction.getLength()) > -.98f)
            {
                core::vector3df updown = direction.crossProduct(lookdir);
                updown.normalize();
                core::vector3df normal = direction.crossProduct(updown);
                video::S3DVertex vertices[4];
                u16 indices[] = {0,1,2,1,3,2};

                vertices[0] = video::S3DVertex(m_end-updown*m_thickness*0.5f, normal, video::SColor(255,255,255,255), core::vector2d<f32>(0,0));
                vertices[1] = video::S3DVertex(m_end+updown*m_thickness*0.5f, normal, video::SColor(255,255,255,255), core::vector2d<f32>(0,1));
                vertices[2] = video::S3DVertex(m_start-updown*m_thickness*0.5f, normal, video::SColor(255,255,255,255), core::vector2d<f32>(1,0));
                vertices[3] = video::S3DVertex(m_start+updown*m_thickness*0.5f, normal, video::SColor(255,255,255,255), core::vector2d<f32>(1,1));

                driver->setMaterial(material);
                driver->drawIndexedTriangleList(&vertices[0], 4, &indices[0], 2);
                //driver->draw3DLine(m_start, m_end, video::SColor(255,255,0,0));
            }
            else
            {
                //printf("daw dot\n");

                core::vector3df horizontal = SceneManager->getActiveCamera()->getUpVector().crossProduct(view);
                horizontal.normalize();
                horizontal *= 0.5f * m_thickness;

                core::vector3df vertical = horizontal.crossProduct(view);
                vertical.normalize();
                vertical *= 0.5f * m_thickness;
                view *= -1.0f;

                video::S3DVertex vertices[4];
                u16 indices[] = {0,1,2,1,3,2};

                vertices[0] = video::S3DVertex(m_end - horizontal - vertical, view, video::SColor(255,255,255,255), core::vector2d<f32>(0,0));
                vertices[1] = video::S3DVertex(m_end + horizontal - vertical, view, video::SColor(255,255,255,255), core::vector2d<f32>(0,1));
                vertices[2] = video::S3DVertex(m_end - horizontal + vertical, view, video::SColor(255,255,255,255), core::vector2d<f32>(1,0));
                vertices[3] = video::S3DVertex(m_end + horizontal + vertical, view, video::SColor(255,255,255,255), core::vector2d<f32>(1,1));

                driver->setMaterial(material2);
                driver->drawIndexedTriangleList(&vertices[0], 4, &indices[0], 2);
            }
        }

        const core::aabbox3d<f32>& CBeamNode::getBoundingBox() const
        {
            return Box;
        }

        u32 CBeamNode::getMaterialCount()
        {
            return 2;
        }

        video::SMaterial& CBeamNode::getMaterial(u32 i)
        {
            if(i==0)
                return material;
            else if(i==1)
                return material2;
        }
    }
}

Usage:

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scene::CBeamSceneNode* beam = new scene::CBeamNode(parent, smgr, -1, "The texture the beam should have when looking at it from the side , "The texture when looking at the cap" );

//now set the beam
beam->setLine(core::vector3df(0,0,0), core::vector3df(10,10,10), 5.0f);

beam->drop();

phoboss · Post by **phoboss** » Sat Aug 30, 2008 3:10 pm

Thanks Sudi, it works better, but I still see the beams rarely.

sudi · Post by **sudi** » Sat Aug 30, 2008 4:34 pm

maybe u could show some code and tell us what exactly is not working.

rogerborg · Post by **rogerborg** » Sat Aug 30, 2008 5:46 pm

Pennies to pounds he's shooting beams directly away from the camera position.

sudi · Post by **sudi** » Sat Aug 30, 2008 6:54 pm

ahh ok that should work with my beamscenenode when u set the start position a litle bit infront of the camera (farther then the near clipping plane) then u should see a dot bc u can only se th cap of the beam.

rogerborg · Post by **rogerborg** » Sun Aug 31, 2008 1:17 pm

Sudi wrote:ahh ok that should work with my beamscenenode when u set the start position a litle bit infront of the camera (farther then the near clipping plane) then u should see a dot bc u can only se th cap of the beam.

Oh, I've just taken a good look at your code. That's a nice way of doing it: much better than cross polys. Thanks for sharing.

sudi · Post by **sudi** » Sun Aug 31, 2008 1:31 pm

no problem thats what the forum is for

phoboss · Post by **phoboss** » Sun Aug 31, 2008 3:26 pm

Okay, it works now. I had to exchange a custom scene node for a mesh scene node.

rogerborg · Post by **rogerborg** » Mon Sep 01, 2008 12:19 pm

Sudi wrote:no problem thats what the forum is for

Yes, but like a comic at a charity gig, you don't generally give away your A material.

nander · Post by **nander** » Thu Aug 26, 2010 6:00 pm

Hi,

It may be a noobish question, but I'm getting this error:

#LinkToDir#/untitled folder/beam.cpp|15|error: ‘class irr::video::SMaterial’ has no member named ‘Textures’|.
How do I solve this issue?
Is it caused by a change in syntax for 1.7?

hybrid · Post by **hybrid** » Thu Aug 26, 2010 10:12 pm

No, this was a change in Irrlicht 1.4.

freetimecoder · Post by **freetimecoder** » Fri Aug 27, 2010 2:27 pm

Use
SMaterial::TextureLayer[]::Texture instead.

e.g. myMaterial.TextureLayer[0].Texture

greetings