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[SOLVED] setting transparency (alpha) for spherescenenode?
Posted: Sat Feb 28, 2015 7:09 pm
by pandoragami
Hi All,
Sorry for asking such a noobish question considering that this has probably been answered before but I did search and found very little on how to do it, including this page
http://irrlicht.sourcearchive.com/docum ... ource.html
Anyways I have this code where I create a sphere and add a texture, what I wanted to do was to create motion trails behind it as it moves along using alpha blending methods but I can't seem to change the alpha (tansparency) of the node itself. I did find this page
http://irrlicht.sourceforge.net/forum/v ... php?t=2179
Where an animated scene node is alpha blended for each frame differently, any suggestions for just a regular sphere node?
Code: Select all
scene::ISceneNode* sphere = smgr->addSphereSceneNode( radius, 32, 0, -1, core::vector3df(0, Y, 0), core::vector3df(0, 0, 0), core::vector3df(1.0f, 1.0f, 1.0f));
sphere->setMaterialFlag(video::EMF_LIGHTING, false);
sphere->setMaterialTexture( 0, driver->getTexture("image.bmp"));
Re: setting transparency (alpha) for spherescenenode?
Posted: Sat Feb 28, 2015 8:36 pm
by CuteAlien
You can try to experiment with IMeshManipulator::setVertexColorAlpha. As each sphere-node has it's own mesh that should work.
Re: setting transparency (alpha) for spherescenenode?
Posted: Sat Feb 28, 2015 10:03 pm
by pandoragami
CuteAlien wrote:You can try to experiment with IMeshManipulator::setVertexColorAlpha. As each sphere-node has it's own mesh that should work.
Thanks so far, I tried this
Code: Select all
scene::IMeshManipulator* mesh = smgr->getMeshManipulator();
mesh->setVertexColorAlpha(sphere, 0);
But the compiler complains that my sphere isn't an IMesh* type?
Code: Select all
error: no matching function for call to 'irr::scene::IMeshManipulator::setVertexColorAlpha(irr::scene::ISceneNode*&, int)'|
Re: setting transparency (alpha) for spherescenenode?
Posted: Sun Mar 01, 2015 2:12 am
by CuteAlien
Use sphere->getMesh() to get the mesh.
Re: setting transparency (alpha) for spherescenenode?
Posted: Sun Mar 01, 2015 2:37 am
by pandoragami
CuteAlien wrote:Use sphere->getMesh() to get the mesh.
Tried but got this error.
Code: Select all
scene::ISceneNode* sphere = smgr->addSphereSceneNode(radius, 32, 0, -1, core::vector3df(0, 0, 0), core::vector3df(0, 0, 0), core::vector3df(1.0f, 1.0f, 1.0f));
sphere->setMaterialFlag(video::EMF_LIGHTING, false);
sphere->setMaterialTexture( 0, driver->getTexture("graph.jpg"));
scene::IMeshManipulator* mesh = smgr->getMeshManipulator();
mesh->setVertexColorAlpha(sphere->getMesh(), 0);
error: 'class irr::scene::ISceneNode' has no member named 'getMesh'|
Re: setting transparency (alpha) for spherescenenode?
Posted: Sun Mar 01, 2015 3:10 am
by CuteAlien
Well, then take a look at the documentation which type addSphereSceneNode does return:
http://irrlicht.sourceforge.net/docu/cl ... 63970cfc04
Maybe you are lucky and it's real type does have such a function ;-)
Re: setting transparency (alpha) for spherescenenode?
Posted: Sun Mar 01, 2015 3:24 am
by pandoragami
It returns a type IMeshSceneNode, but how come ISceneNode works?
Anyways this compiles,
Code: Select all
scene::IMeshSceneNode* sphere = smgr->addSphereSceneNode(radius, 32, 0, -1, core::vector3df(0, 0, 0), core::vector3df(0, 0, 0), core::vector3df(1.0f, 1.0f, 1.0f));
sphere->setMaterialFlag(video::EMF_LIGHTING, false);
sphere->setMaterialTexture( 0, driver->getTexture("graph.jpg"));
scene::IMeshManipulator* mesh = smgr->getMeshManipulator();
mesh->setVertexColorAlpha(sphere->getMesh(), 0);
But I was expecting the sphere to vanish since the second parameter is zero in mesh->setVertexColorAlpha(sphere->getMesh(), 0)
Am I misunderstanding alpha channels? Does this not work with textured meshes?
Re: setting transparency (alpha) for spherescenenode?
Posted: Sun Mar 01, 2015 3:39 am
by CuteAlien
IMeshSceneNode is derived from ISceneNode, meaning it has everything ISceneNode has + some additional stuff. That's why you can always cast safely to the base-classes.
Not sure right now if the alpha value means transparence or opaque, doesn't seem to be documented. Just try it with 255 maybe.
Re: setting transparency (alpha) for spherescenenode?
Posted: Sun Mar 01, 2015 4:23 am
by pandoragami
CuteAlien wrote:IMeshSceneNode is derived from ISceneNode, meaning it has everything ISceneNode has + some additional stuff. That's why you can always cast safely to the base-classes.
Not sure right now if the alpha value means transparence or opaque, doesn't seem to be documented. Just try it with 255 maybe.
Tried both 0 and 255, no luck either way.
Re: setting transparency (alpha) for spherescenenode?
Posted: Sun Mar 01, 2015 4:30 am
by pandoragami
Here's the complete code
Code: Select all
#include <irrlicht.h>
using namespace irr;
class MyEventReceiver : public IEventReceiver
{
public:
struct SMouseState
{
core::position2di Position;
bool LeftButtonDown;
SMouseState() : LeftButtonDown(false) { }
} MouseState;
virtual bool OnEvent(const SEvent& event)
{
if (event.EventType == irr::EET_KEY_INPUT_EVENT)
KeyIsDown[event.KeyInput.Key] = event.KeyInput.PressedDown;
if(event.EventType == EET_MOUSE_INPUT_EVENT)
{
switch(event.MouseInput.Event)
{
case EMIE_LMOUSE_PRESSED_DOWN:
MouseState.LeftButtonDown = true;
break;
case EMIE_LMOUSE_LEFT_UP:
MouseState.LeftButtonDown = false;
break;
case EMIE_MOUSE_MOVED:
MouseState.Position.X = event.MouseInput.X;
MouseState.Position.Y = event.MouseInput.Y;
break;
default:
break;
}
}
return false;
}
// This is used to check whether a key is being held down
virtual bool IsKeyDown(EKEY_CODE keyCode) const
{
return KeyIsDown[keyCode];
}
const SMouseState & GetMouseState(void) const
{
return MouseState;
}
MyEventReceiver()
{
for (u32 i=0; i<KEY_KEY_CODES_COUNT; ++i)
KeyIsDown[i] = false;
}
private:
// We use this array to store the current state of each key
bool KeyIsDown[KEY_KEY_CODES_COUNT];
};
MyEventReceiver receiver;
IrrlichtDevice* device = 0;
const int SCRX = 640;
const int SCRY = 480;
const float radius = 5.0f;
int main()
{
device = createDevice( irr::video::EDT_OPENGL, core::dimension2d<u32>( SCRX, SCRY), 16, false, false, false, &receiver);
if (device == 0)
return 1;
video::IVideoDriver* driver = device->getVideoDriver();
scene::ISceneManager* smgr = device->getSceneManager();
driver->setTextureCreationFlag(video::ETCF_CREATE_MIP_MAPS, true);
scene::ICameraSceneNode* cam = smgr->addCameraSceneNodeFPS( 0, 50.0f, 0.01f, -1, 0, 0, false, 0.0f, false, true);
device->getCursorControl()->setVisible(false);
scene::IMeshSceneNode* sphere = smgr->addSphereSceneNode(radius, 32, 0, -1, core::vector3df(0, 0, 0), core::vector3df(0, 0, 0), core::vector3df(1.0f, 1.0f, 1.0f));
sphere->setMaterialFlag(video::EMF_LIGHTING, false);
sphere->setMaterialTexture( 0, driver->getTexture("graph.jpg"));
scene::IMeshManipulator* mesh = smgr->getMeshManipulator();
mesh->setVertexColorAlpha(sphere->getMesh(), 255);
cam->setPosition( core::vector3df( 0, 0,-15));
cam->setTarget( core::vector3df( 0.0f, 0.0f, 0.0f));
int lastFPS = -1;
while(device->run())
if (device->isWindowActive())
{
driver->beginScene(true, true, video::SColor( 255, 0, 0, 0));
smgr->drawAll();
driver->endScene();
int fps = driver->getFPS();
if (lastFPS != fps)
{
core::stringw str = L"Irrlicht Text Node [";
str += driver->getName();
str += "] FPS:";
str += fps;
device->setWindowCaption(str.c_str());
lastFPS = fps;
}
device->sleep(50);
}
device->drop();
return 0;
}
Re: setting transparency (alpha) for spherescenenode?
Posted: Sun Mar 01, 2015 4:44 am
by CuteAlien
Hm, I really have to sleep, so won't test now. But I suppose it's because the material used in the mesh is solid. Try using any material supporting transparence like video::EMT_TRANSPARENT_ADD_COLOR.
Re: setting transparency (alpha) for spherescenenode?
Posted: Sun Mar 01, 2015 5:08 am
by pandoragami
CuteAlien wrote:Hm, I really have to sleep, so won't test now. But I suppose it's because the material used in the mesh is solid. Try using any material supporting transparence like video::EMT_TRANSPARENT_ADD_COLOR.
Goodnite, thanks so far though, this code below works now except that the texture cannot be alpha blended so it's commented out.
Code: Select all
#include <C:\irrlicht-1.7.2\include\irrlicht.h>
using namespace irr;
class MyEventReceiver : public IEventReceiver
{
public:
struct SMouseState
{
core::position2di Position;
bool LeftButtonDown;
SMouseState() : LeftButtonDown(false) { }
} MouseState;
virtual bool OnEvent(const SEvent& event)
{
if (event.EventType == irr::EET_KEY_INPUT_EVENT)
KeyIsDown[event.KeyInput.Key] = event.KeyInput.PressedDown;
if(event.EventType == EET_MOUSE_INPUT_EVENT)
{
switch(event.MouseInput.Event)
{
case EMIE_LMOUSE_PRESSED_DOWN:
MouseState.LeftButtonDown = true;
break;
case EMIE_LMOUSE_LEFT_UP:
MouseState.LeftButtonDown = false;
break;
case EMIE_MOUSE_MOVED:
MouseState.Position.X = event.MouseInput.X;
MouseState.Position.Y = event.MouseInput.Y;
break;
default:
break;
}
}
return false;
}
// This is used to check whether a key is being held down
virtual bool IsKeyDown(EKEY_CODE keyCode) const
{
return KeyIsDown[keyCode];
}
const SMouseState & GetMouseState(void) const
{
return MouseState;
}
MyEventReceiver()
{
for (u32 i=0; i<KEY_KEY_CODES_COUNT; ++i)
KeyIsDown[i] = false;
}
private:
// We use this array to store the current state of each key
bool KeyIsDown[KEY_KEY_CODES_COUNT];
};
MyEventReceiver receiver;
IrrlichtDevice* device = 0;
const int SCRX = 640;
const int SCRY = 480;
const float radius = 5.0f;
int main()
{
device = createDevice( irr::video::EDT_OPENGL, core::dimension2d<u32>( SCRX, SCRY), 16, false, false, false, &receiver);
if (device == 0)
return 1;
video::IVideoDriver* driver = device->getVideoDriver();
scene::ISceneManager* smgr = device->getSceneManager();
driver->setTextureCreationFlag(video::ETCF_CREATE_MIP_MAPS, true);
scene::ICameraSceneNode* cam = smgr->addCameraSceneNodeFPS( 0, 50.0f, 0.01f, -1, 0, 0, false, 0.0f, false, true);
device->getCursorControl()->setVisible(false);
scene::IMeshSceneNode* sphere = smgr->addSphereSceneNode(radius, 32, 0, -1, core::vector3df(0, 0, 0), core::vector3df(0, 0, 0), core::vector3df(1.0f, 1.0f, 1.0f));
sphere->setMaterialFlag(video::EMF_LIGHTING, false);
//sphere->setMaterialTexture( 0, driver->getTexture("graph.jpg"));
sphere->setMaterialType(video::EMT_TRANSPARENT_ALPHA_CHANNEL);
scene::IMeshManipulator* mesh = smgr->getMeshManipulator();
mesh->setVertexColorAlpha(sphere->getMesh(), 155);
cam->setPosition( core::vector3df( 0, 0,-15));
cam->setTarget( core::vector3df( 0.0f, 0.0f, 0.0f));
int lastFPS = -1;
while(device->run())
if (device->isWindowActive())
{
driver->beginScene(true, true, video::SColor( 255, 0, 0, 0));
smgr->drawAll();
driver->endScene();
int fps = driver->getFPS();
if (lastFPS != fps)
{
core::stringw str = L"Irrlicht Text Node [";
str += driver->getName();
str += "] FPS:";
str += fps;
device->setWindowCaption(str.c_str());
lastFPS = fps;
}
device->sleep(50);
}
device->drop();
return 0;
}
Re: setting transparency (alpha) for spherescenenode?
Posted: Sun Mar 01, 2015 6:25 am
by thanhle
There's a post by an author call feelthat.
I saw a few weeks back, he did transparent even for animated mesh.
I think he fixed other issues he found as well.
Actually there's also lot of posts on the related issue if you search the forum.
http://irrlicht.sourceforge.net/forum/v ... hp?t=31400
Regards
thanh
Re: setting transparency (alpha) for spherescenenode?
Posted: Sun Mar 01, 2015 1:09 pm
by pandoragami
thanhle wrote:There's a post by an author call feelthat.
I saw a few weeks back, he did transparent even for animated mesh.
I think he fixed other issues he found as well.
Actually there's also lot of posts on the related issue if you search the forum.
http://irrlicht.sourceforge.net/forum/v ... hp?t=31400
Regards
thanh
Thanks for the note, I did check his code and he is using "EMT_TRANSPARENT_ALPHA_CHANNEL" just like me in the following code below, but I set the alpha to zero and still the texture doesn't allow it to be transparent? I've tried other enumerators too, if you look you'll notice several, here's all of them
Code: Select all
video::EMT_TRANSPARENT_ALPHA_CHANNEL
video::EMT_TRANSPARENT_ALPHA_CHANNEL_REF
video::EMT_TRANSPARENT_VERTEX_ALPHA
video::EMT_TRANSPARENT_ALPHA_CHANNEL
Code: Select all
#include <irrlicht.h>
using namespace irr;
class MyEventReceiver : public IEventReceiver
{
public:
struct SMouseState
{
core::position2di Position;
bool LeftButtonDown;
SMouseState() : LeftButtonDown(false) { }
} MouseState;
virtual bool OnEvent(const SEvent& event)
{
if (event.EventType == irr::EET_KEY_INPUT_EVENT)
KeyIsDown[event.KeyInput.Key] = event.KeyInput.PressedDown;
if(event.EventType == EET_MOUSE_INPUT_EVENT)
{
switch(event.MouseInput.Event)
{
case EMIE_LMOUSE_PRESSED_DOWN:
MouseState.LeftButtonDown = true;
break;
case EMIE_LMOUSE_LEFT_UP:
MouseState.LeftButtonDown = false;
break;
case EMIE_MOUSE_MOVED:
MouseState.Position.X = event.MouseInput.X;
MouseState.Position.Y = event.MouseInput.Y;
break;
default:
break;
}
}
return false;
}
// This is used to check whether a key is being held down
virtual bool IsKeyDown(EKEY_CODE keyCode) const
{
return KeyIsDown[keyCode];
}
const SMouseState & GetMouseState(void) const
{
return MouseState;
}
MyEventReceiver()
{
for (u32 i=0; i<KEY_KEY_CODES_COUNT; ++i)
KeyIsDown[i] = false;
}
private:
// We use this array to store the current state of each key
bool KeyIsDown[KEY_KEY_CODES_COUNT];
};
MyEventReceiver receiver;
IrrlichtDevice* device = 0;
const int SCRX = 640;
const int SCRY = 480;
const float radius = 5.0f;
int main()
{
device = createDevice( irr::video::EDT_OPENGL, core::dimension2d<u32>( SCRX, SCRY), 16, false, false, false, &receiver);
if (device == 0)
return 1;
video::IVideoDriver* driver = device->getVideoDriver();
scene::ISceneManager* smgr = device->getSceneManager();
driver->setTextureCreationFlag(video::ETCF_CREATE_MIP_MAPS, true);
scene::ICameraSceneNode* cam = smgr->addCameraSceneNodeFPS( 0, 50.0f, 0.01f, -1, 0, 0, false, 0.0f, false, true);
device->getCursorControl()->setVisible(false);
scene::IMeshSceneNode* sphere = smgr->addSphereSceneNode(radius, 32, 0, -1, core::vector3df(0, 0, 0), core::vector3df(0, 0, 0), core::vector3df(1.0f, 1.0f, 1.0f));
sphere->setMaterialFlag(video::EMF_LIGHTING, false);
sphere->setMaterialTexture( 0, driver->getTexture("graph.jpg"));
//sphere->setMaterialType(video::EMT_TRANSPARENT_ALPHA_CHANNEL);
//sphere->setMaterialType(video::EMT_TRANSPARENT_ALPHA_CHANNEL_REF);
//sphere->setMaterialType(video::EMT_TRANSPARENT_VERTEX_ALPHA);
sphere->setMaterialType(video::EMT_TRANSPARENT_ALPHA_CHANNEL);
scene::IMeshManipulator* mesh = smgr->getMeshManipulator();
mesh->setVertexColorAlpha(sphere->getMesh(), 0);
cam->setPosition( core::vector3df( 0, 0,-15));
cam->setTarget( core::vector3df( 0.0f, 0.0f, 0.0f));
int lastFPS = -1;
while(device->run())
if (device->isWindowActive())
{
driver->beginScene(true, true, video::SColor( 255, 0, 0, 0));
smgr->drawAll();
driver->endScene();
int fps = driver->getFPS();
if (lastFPS != fps)
{
core::stringw str = L"Irrlicht Text Node [";
str += driver->getName();
str += "] FPS:";
str += fps;
device->setWindowCaption(str.c_str());
lastFPS = fps;
}
device->sleep(50);
}
device->drop();
return 0;
}
Re: setting transparency (alpha) for spherescenenode?
Posted: Sun Mar 01, 2015 1:48 pm
by mongoose7
Code: Select all
Meshbuffer->Material.DiffuseColor.setAlpha( (s32)(value * 255) );
Meshbuffer->Material.MaterialType = video::EMT_TRANSPARENT_VERTEX_ALPHA;
