History: MadMarx Tutorial 9 - Part 2
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!Foreword.
If you prefer tutorials that come with a framework => check the other wiki tutorial series.
If you prefer tutorials that go step by step without a framework => this page should be ok.
I assume you know C++. If not, this tutorial will probably be hard to understand !
This tutorial presents only a few elements of Ogre3D.
You can download the code and media for this tutorial at the bottom of this wiki page.
This little tutorial is an extract of a bigger project which contains more tutorials & helper classes.
This bigger project is avaible there :
https://sourceforge.net/projects/so3dtools/
Also, make sure you read these tutorials in order!
{maketoc}
!!Tutorial Description
In this program, I create a ((-Texture|texture)), in which I will render the scene.
I create a ((-Material|material)) that uses this ((-Texture|texture)), and I apply it on a mesh.
This ((-technique|technique)) is called a Render-To-((-Texture|Texture)) (RTT).
Please note that depending on your video card driver, you might get very different results.
For example, on my nvidia Geforce 9600M, RTT fails with 'FBO'.
So I modified the SimpleOgreInit.cpp (at the 'step 3'), so that it uses "Copy" instead of FBO.
!!Before root initialisation
{CODE(wrap="0",colors="c++")}
¤ const Ogre::RenderSystemList& lRenderSystemList = mRoot->getAvailableRenderers();
if( lRenderSystemList.size() == 0 )
{
MWARNING("Sorry, no rendersystem was found.");
return result;
}
Ogre::RenderSystem *lRenderSystem = lRenderSystemList.at(0);
{CODE}
In order to have a working RTT, I check if I can select another mode than "FBO".
I suppose that the 'Copy' mode works for everyone under opengl.
{CODE(wrap="0",colors="c++")}
¤ Ogre::ConfigOptionMap& lConfigMap = lRenderSystem->getConfigOptions();
if(lConfigMap.find("RTT Preferred Mode") != lConfigMap.end())
{
lRenderSystem->setConfigOption("RTT Preferred Mode","Copy");
{CODE}
{CODE(wrap="0",colors="c++")}
¤ }
mRoot->setRenderSystem(lRenderSystem);
{CODE}
!!Don't forget the includes
{CODE(wrap="0",colors="c++")}
¤#include "OGRE/OgreRoot.h"
#include "OGRE/OgreRenderSystem.h"
#include "OGRE/OgreRenderWindow.h"
#include "OGRE/OgreWindowEventUtilities.h"
#include "OGRE/OgreManualObject.h"
#include "OGRE/OgreEntity.h"
#include "OGRE/OgreMaterialManager.h"
#include "OGRE/OgreHardwarePixelBuffer.h"
{CODE}
!!After resource loading & viewport creation
Now I create a special ((-Texture|texture)). This ((-Texture|texture)) allows to do what is called a
'render to ((-Texture|texture))'. Which means that you can render your scene into
it, and then use this ((-Texture|texture)) as any other in a ((-Material|material)).
In order to keep a good framerate, I set its number of mipmaps to 0.
{CODE(wrap="0",colors="c++")}
¤ Ogre::TextureManager& lTextureManager = Ogre::TextureManager::getSingleton();
Ogre::String lTextureName = "MyFirstRtt";
bool lGammaCorrection = false;
unsigned int lAntiAliasing = 0;
unsigned int lNumMipmaps = 0;
Ogre::TexturePtr lTextureWithRtt = lTextureManager.createManual(lTextureName, lNameOfResourceGroup,
Ogre::TEX_TYPE_2D, 512, 512, lNumMipmaps,
Ogre::PF_R8G8B8, Ogre::TU_RENDERTARGET, 0, lGammaCorrection, lAntiAliasing);
{CODE}
now I will link this ((-Texture|texture)) to a ((-Camera|camera)), by creating a ((-Viewport|viewport)) in the ((-Texture|texture)).
{CODE(wrap="0",colors="c++")}
¤ Ogre::RenderTexture* lRenderTarget = NULL;
{
Ogre::HardwarePixelBufferSharedPtr lRttBuffer = lTextureWithRtt->getBuffer();
lRenderTarget = lRttBuffer->getRenderTarget();
lRenderTarget->setAutoUpdated(true);
{CODE}
I create a ((-Camera|camera)) so that it has a beautiful '1' aspect ratio.
{CODE(wrap="0",colors="c++")}
¤ Ogre::Camera * lRttCamera = lScene->createCamera("RttCamera");
lRttCamera->setNearClipDistance(1.5f);
lRttCamera->setFarClipDistance(3000.0f);
lRttCamera->setAspectRatio(1.0f);
{CODE}
I attach this ((-Camera|camera)) to the same node than main ((-Camera|camera)).
{CODE(wrap="0",colors="c++")}
¤ lCameraNode->attachObject(lRttCamera);
{CODE}
In the ((-Texture|texture)) I will draw first a Big Blue ((-Viewport|Viewport)).
{CODE(wrap="0",colors="c++")}
¤ Ogre::Viewport* lRttViewport1 = lRenderTarget->addViewport(lRttCamera, 50, 0.00f, 0.00f, 1.0f, 1.0f);
lRttViewport1->setAutoUpdated(true);
Ogre::ColourValue lBgColor1(1.0,0.0,0.0,1.0);
lRttViewport1->setBackgroundColour(lBgColor1);
{CODE}
In the ((-Texture|texture)) I will draw then a more little red ((-Viewport|Viewport)).
The previous ((-Viewport|viewport)) with the ZOrder at 50 will be drawn first (50 < 100).
{CODE(wrap="0",colors="c++")}
¤ Ogre::Viewport* lRttViewport2 = lRenderTarget->addViewport(lRttCamera, 100, 0.05f, 0.05f, 0.9f, 0.9f);
lRttViewport2->setAutoUpdated(true);
Ogre::ColourValue lBgColor2(0.0,0.0,1.0,1.0);
lRttViewport2->setBackgroundColour(lBgColor2);
{CODE}
This will draw a scene, within a scene, within a scene etc...
Because the quad that will be drawn is contained 'inside' the ((-Texture|texture))!
{CODE(wrap="0",colors="c++")}
¤ }
{CODE}
now I create a ((-Material|material)) using this ((-Texture|texture)).
{CODE(wrap="0",colors="c++")}
¤ Ogre::String lMaterialName = "MyRttMaterial";
{
{CODE}
I get a reference on the ((-Material|material)) manager, which is a ((-Singleton|singleton)).
{CODE(wrap="0",colors="c++")}
¤ Ogre::MaterialManager& lMaterialManager = Ogre::MaterialManager::getSingleton();
Ogre::MaterialPtr lMaterial = lMaterialManager.create(lMaterialName, lNameOfResourceGroup);
Ogre::Technique * lTechnique = lMaterial->getTechnique(0);
Ogre::Pass* lPass = lTechnique->getPass(0);
Ogre::TextureUnitState* lTextureUnit = lPass->createTextureUnitState();
lTextureUnit->setTextureName(lTextureName);
{CODE}
I use no mipmap, and I just use some bilinear filtering on the result.
{CODE(wrap="0",colors="c++")}
¤ lTextureUnit->setNumMipmaps(0);
lTextureUnit->setTextureFiltering(Ogre::TFO_BILINEAR);
{CODE}
I make the ((-Texture|texture)) rotate.
The ((-Material|material)) can handle 'special effects' on the ((-Texture|texture)) coordinates.
Here I rotate the ((-Texture|texture)) coordinates.
{CODE(wrap="0",colors="c++")}
¤ float lRotateSpeed = 0.01f;
lTextureUnit->setRotateAnimation(lRotateSpeed);
{CODE}
Uncomment the following line to see something funnier. :-D.
lTextureUnit->setTransformAnimation(Ogre::TextureUnitState::TT_SCALE_U, Ogre::WFT_SINE, 0.9f, 0.5f, 0.0f, 0.2f);
{CODE(wrap="0",colors="c++")}
¤ }
{CODE}
Now I will create a manualobject quad, and convert it to a mesh...
{CODE(wrap="0",colors="c++")}
¤ Ogre::String lNameOfTheMesh = "MyQuad";
{
Ogre::ManualObject * lManualObject = NULL;
Ogre::String lManualObjectName = "SomeQuad";
lManualObject = lScene->createManualObject(lManualObjectName);
{CODE}
Always tell if you want to update the 3D (vertex/index) later or not.
{CODE(wrap="0",colors="c++")}
¤ bool lDoIWantToUpdateItLater = false;
lManualObject->setDynamic(lDoIWantToUpdateItLater);
{CODE}
BaseWhiteNoLighting is the name of a ((-Material|material)) that already exist inside Ogre.
Ogre::RenderOperation::OT_TRIANGLE_LIST is a kind of primitive.
{CODE(wrap="0",colors="c++")}
¤ float lSize = 0.7f;
lManualObject->begin("BaseWhiteNoLighting", Ogre::RenderOperation::OT_TRIANGLE_LIST);
{
float cp = 1.0f * lSize ;
float cm = -1.0f * lSize;
float lNumberOfTiles = 1.0f;
lManualObject->position(cm, cp, 0.0f);// a vertex
lManualObject->textureCoord(0.0f, 0.0f);
lManualObject->position(cp, cp, 0.0f);// a vertex
lManualObject->textureCoord(lNumberOfTiles, 0.0f);
lManualObject->position(cp, cm, 0.0f);// a vertex
lManualObject->textureCoord(lNumberOfTiles, lNumberOfTiles);
lManualObject->position(cm, cm, 0.0f);// a vertex
lManualObject->textureCoord(0.0, lNumberOfTiles);
lManualObject->triangle(2,1,0);
lManualObject->triangle(0,3,2);
}
lManualObject->end();
lManualObject->convertToMesh(lNameOfTheMesh);
lScene->destroyManualObject(lManualObject);
}
{CODE}
Now I will create the corresponding ((-Entity|entity)), and its scenenode.
{CODE(wrap="0",colors="c++")}
¤ {
Ogre::Entity* lEntity = lScene->createEntity(lNameOfTheMesh);
lEntity->setMaterialName(lMaterialName);
{CODE}
Now I attach it to a scenenode, so that it becomes present in the scene.
{CODE(wrap="0",colors="c++")}
¤ Ogre::SceneNode* lNodeWithEntity = lNodeWithEntity = lRootSceneNode->createChildSceneNode();
lNodeWithEntity->attachObject(lEntity);
{CODE}
I move the ((-SceneNode|SceneNode)) so that it is visible to the ((-Camera|camera)).
{CODE(wrap="0",colors="c++")}
¤ lNodeWithEntity->setPosition(0.0f, 0.0f, -1.8f);
}
{CODE}
! main.cpp
{CODE(wrap="0",colors="c++")}
// In this program, I create a texture, in which I will render the scene.
// I create a material that uses this texture, and I apply it on a mesh.
// This technique is called a Render-To-Texture (RTT).
// Please note that depending on your video card driver, you might get very different results.
// For example, on my nvidia Geforce 9600M, RTT fails with 'FBO'.
// So I modified the SimpleOgreInit.cpp (at the 'step 3'), so that it uses "Copy" instead of FBO.
// I will use std::auto_ptr so I need to include 'memory'.
// If you don't know std::auto_ptr, you should check some C++ tutorials/lesson on this matter.
#include <memory>
// I will check for std::exception. If you don't know what exception/try/catch means, you should learn C++ first.
#include <exception>
// These are some files that we need to include to use Ogre3D. Note that you can at the beginnings use directly "Ogre.h", to include lots of commonly used classes.
#include "OGRE/OgreRoot.h"
#include "OGRE/OgreRenderSystem.h"
#include "OGRE/OgreRenderWindow.h"
#include "OGRE/OgreWindowEventUtilities.h"
#include "OGRE/OgreManualObject.h"
#include "OGRE/OgreEntity.h"
#include "OGRE/OgreMaterialManager.h"
#include "OGRE/OgreHardwarePixelBuffer.h"
//Here I include my other files, like the one for SimpleOgreInit...
#include "SimpleOgreInit.h"
#include "EasyDefines.h"
// I declare a function in which I will make my whole application.
// This is easy then to add more things later in that function.
// The main will call this function and take care of the global try/catch.
void AnOgreApplication()
{
// I construct my object that will allow me to initialise Ogre easily.
OgreEasy::SimpleOgreInit lOgreInit;
if(!lOgreInit.initOgre())
{
std::cout<<"Impossible to init Ogre correctly."<<std::endl;
return;
}
//I prefer to be able to access my variables directly.
Ogre::Root* lRoot = lOgreInit.mRoot.get();
Ogre::RenderWindow* lWindow = lOgreInit.mWindow;
// I create a scenemanager. This is like a 'Scene', in which I can put lights, 3d objects, etc...
// The scenemanager contains an arborescent graph of 'SceneNodes'. To manage elements of the scene,
// I will create SceneNodes in the SceneManager, and attach the elements to the scenenodes.
// First parameter : I select a kind of SceneManager. This may have a huge impact on performance.
// Depending on your scene, some are better than other. The default one does no optimization at all.
// Second parameter : I give a name to the scenemanager.
// Note : It is easy to have more than one scenemanager (If you got 2 different scenes for example).
Ogre::SceneManager* lScene = lRoot->createSceneManager(Ogre::ST_GENERIC, "MyFirstSceneManager");
// The 'root SceneNode' is the only scenenode at the beginning in the SceneManager.
// The SceneNodes can be seen as 'transformation' containers <=> it contains scale/position/rotation
// of the objects. There is only 1 root scenenode, and all other scenenode are
// its direct or indirect children.
Ogre::SceneNode* lRootSceneNode = lScene->getRootSceneNode();
// I create a camera. It represent a 'point of view' in the scene.
Ogre::Camera* lCamera = lScene->createCamera("MyFirstCamera");
// I attach the camera to a new SceneNode. It will be easier then to move it in the scene.
Ogre::SceneNode* lCameraNode = lRootSceneNode->createChildSceneNode("MyFirstCameraNode");
lCameraNode->attachObject(lCamera);
// We create a viewport on a part of the window.
// A viewport is the link between 1 camera and 1 drawing surface (here the window).
// I can then call 'update();' on it to make it draw the Scene from the camera.
// You can have several viewports on 1 window.
// Check API for details on parameters.
unsigned short lMainViewportZOrder = 100;
Ogre::Viewport * vp = lWindow->addViewport(lCamera, lMainViewportZOrder);
// I want the viewport to draw the scene automatically
// when I will call lWindow->update();
vp->setAutoUpdated(true);
// I choose a color for this viewport.
// I prefer to have a bright color, to detect holes in geometry etc...
vp->setBackgroundColour(Ogre::ColourValue(1,0,1));
// I choose the visual ratio of the camera. To make it looks real, I want it the same as the viewport.
float ratio = float(vp->getActualWidth()) / float(vp->getActualHeight());
lCamera->setAspectRatio(ratio);
// I choose the clipping far& near planes. if far/near>2000, you can get z buffer problem.
// eg : far/near = 10000/5 = 2000 . it's ok.
// If (far/near)>2000 then you will likely get 'z fighting' issues.
lCamera->setNearClipDistance(1.5f);
lCamera->setFarClipDistance(3000.0f);
// I want my window to be active
lWindow->setActive(true);
// I want to update myself the content of the window, not automatically.
lWindow->setAutoUpdated(false);
// Here I choose a name for a resource group. Then I create it.
// Often, a resourcegroup is a good way to store the data corresponding
// to a level in a game.
Ogre::String lNameOfResourceGroup = "Mission 1 : Deliver Tom";
{
Ogre::ResourceGroupManager& lRgMgr = Ogre::ResourceGroupManager::getSingleton();
lRgMgr.createResourceGroup(lNameOfResourceGroup);
// The function 'initialiseResourceGroup' parses scripts if any in the locations.
lRgMgr.initialiseResourceGroup(lNameOfResourceGroup);
// Files that can be loaded are loaded.
lRgMgr.loadResourceGroup(lNameOfResourceGroup);
}
// Now I create a special texture. This texture allows to do what is called a
// 'render to texture'. Which means that you can render your scene into
// it, and then use this texture as any other in a material.
// In order to keep a good framerate, I set its number of mipmaps to 0.
Ogre::TextureManager& lTextureManager = Ogre::TextureManager::getSingleton();
Ogre::String lTextureName = "MyFirstRtt";
bool lGammaCorrection = false;
unsigned int lAntiAliasing = 0;
unsigned int lNumMipmaps = 0;
Ogre::TexturePtr lTextureWithRtt = lTextureManager.createManual(lTextureName, lNameOfResourceGroup,
Ogre::TEX_TYPE_2D, 512, 512, lNumMipmaps,
Ogre::PF_R8G8B8, Ogre::TU_RENDERTARGET, 0, lGammaCorrection, lAntiAliasing);
// now I will link this texture to a camera, by creating a viewport in the texture.
Ogre::RenderTexture* lRenderTarget = NULL;
{
Ogre::HardwarePixelBufferSharedPtr lRttBuffer = lTextureWithRtt->getBuffer();
lRenderTarget = lRttBuffer->getRenderTarget();
lRenderTarget->setAutoUpdated(true);
// I create a camera so that it has a beautiful '1' aspect ratio.
Ogre::Camera * lRttCamera = lScene->createCamera("RttCamera");
lRttCamera->setNearClipDistance(1.5f);
lRttCamera->setFarClipDistance(3000.0f);
lRttCamera->setAspectRatio(1.0f);
// I attach this camera to the same node than main camera.
lCameraNode->attachObject(lRttCamera);
// In the texture I will draw first a Big Blue Viewport.
Ogre::Viewport* lRttViewport1 = lRenderTarget->addViewport(lRttCamera, 50, 0.00f, 0.00f, 1.0f, 1.0f);
lRttViewport1->setAutoUpdated(true);
Ogre::ColourValue lBgColor1(1.0,0.0,0.0,1.0);
lRttViewport1->setBackgroundColour(lBgColor1);
// In the texture I will draw then a more little red Viewport.
// The previous viewport with the ZOrder at 50 will be drawn first (50 < 100).
Ogre::Viewport* lRttViewport2 = lRenderTarget->addViewport(lRttCamera, 100, 0.05f, 0.05f, 0.9f, 0.9f);
lRttViewport2->setAutoUpdated(true);
Ogre::ColourValue lBgColor2(0.0,0.0,1.0,1.0);
lRttViewport2->setBackgroundColour(lBgColor2);
// This will draw a scene, within a scene, within a scene etc...
// Because the quad that will be drawn is contained 'inside' the texture!
}
// now I create a material using this texture.
Ogre::String lMaterialName = "MyRttMaterial";
{
// I get a reference on the material manager, which is a singleton.
Ogre::MaterialManager& lMaterialManager = Ogre::MaterialManager::getSingleton();
Ogre::MaterialPtr lMaterial = lMaterialManager.create(lMaterialName, lNameOfResourceGroup);
Ogre::Technique * lTechnique = lMaterial->getTechnique(0);
Ogre::Pass* lPass = lTechnique->getPass(0);
Ogre::TextureUnitState* lTextureUnit = lPass->createTextureUnitState();
lTextureUnit->setTextureName(lTextureName);
//I use no mipmap, and I just use some bilinear filtering on the result.
lTextureUnit->setNumMipmaps(0);
lTextureUnit->setTextureFiltering(Ogre::TFO_BILINEAR);
// I make the texture rotate.
// The material can handle 'special effects' on the texture coordinates.
// Here I rotate the texture coordinates.
float lRotateSpeed = 0.01f;
lTextureUnit->setRotateAnimation(lRotateSpeed);
// Uncomment the following line to see something funnier. :-D.
//lTextureUnit->setTransformAnimation(Ogre::TextureUnitState::TT_SCALE_U, Ogre::WFT_SINE, 0.9f, 0.5f, 0.0f, 0.2f);
}
// Now I will create a manualobject quad, and convert it to a mesh...
Ogre::String lNameOfTheMesh = "MyQuad";
{
Ogre::ManualObject * lManualObject = NULL;
Ogre::String lManualObjectName = "SomeQuad";
lManualObject = lScene->createManualObject(lManualObjectName);
// Always tell if you want to update the 3D (vertex/index) later or not.
bool lDoIWantToUpdateItLater = false;
lManualObject->setDynamic(lDoIWantToUpdateItLater);
// BaseWhiteNoLighting is the name of a material that already exist inside Ogre.
// Ogre::RenderOperation::OT_TRIANGLE_LIST is a kind of primitive.
float lSize = 0.7f;
lManualObject->begin("BaseWhiteNoLighting", Ogre::RenderOperation::OT_TRIANGLE_LIST);
{
float cp = 1.0f * lSize ;
float cm = -1.0f * lSize;
float lNumberOfTiles = 1.0f;
lManualObject->position(cm, cp, 0.0f);// a vertex
lManualObject->textureCoord(0.0f, 0.0f);
lManualObject->position(cp, cp, 0.0f);// a vertex
lManualObject->textureCoord(lNumberOfTiles, 0.0f);
lManualObject->position(cp, cm, 0.0f);// a vertex
lManualObject->textureCoord(lNumberOfTiles, lNumberOfTiles);
lManualObject->position(cm, cm, 0.0f);// a vertex
lManualObject->textureCoord(0.0, lNumberOfTiles);
lManualObject->triangle(2,1,0);
lManualObject->triangle(0,3,2);
}
lManualObject->end();
lManualObject->convertToMesh(lNameOfTheMesh);
lScene->destroyManualObject(lManualObject);
}
// Now I will create the corresponding entity, and its scenenode.
{
Ogre::Entity* lEntity = lScene->createEntity(lNameOfTheMesh);
lEntity->setMaterialName(lMaterialName);
// Now I attach it to a scenenode, so that it becomes present in the scene.
Ogre::SceneNode* lNodeWithEntity = lNodeWithEntity = lRootSceneNode->createChildSceneNode();
lNodeWithEntity->attachObject(lEntity);
// I move the SceneNode so that it is visible to the camera.
lNodeWithEntity->setPosition(0.0f, 0.0f, -1.8f);
}
// cleaning of windows events managed by Ogre::WindowEventUtilities::...
// I call it after a 'pause in window updating', in order to maintain smoothness.
// Explanation : if you clicked 2000 times when the windows was being created, there are
// at least 2000 messages created by the OS to listen to. This is made to clean them.
lRoot->clearEventTimes();
// I wait until the window is closed.
// The "message pump" thing is something you will see in most GUI application.
// It allow the binding of messages between the application and the OS.
// These messages are most of the time : keystroke, mouse moved, ... or window closed.
// If I don't do this, the message are never caught, and the window won't close.
while(!lOgreInit.mWindow->isClosed())
{
// Drawings
// the window update its content.
// each viewport that is 'autoupdated' will be redrawn now,
// in order given by its z-order.
lWindow->update(false);
// The drawn surface is then shown on the screen
// (google "double buffering" if you want more details).
// I always use vertical synchro.
bool lVerticalSynchro = true;
lWindow->swapBuffers(lVerticalSynchro);
// This update some internal counters and listeners.
// Each render surface (window/rtt/mrt) that is 'auto-updated' has got its 'update' function called.
lRoot->renderOneFrame();
Ogre::WindowEventUtilities::messagePump();
}
// Let's cleanup!
{
lWindow->removeAllViewports();
}
{
lScene->destroyAllCameras();
lScene->destroyAllManualObjects();
lScene->destroyAllEntities();
lScene->destroyAllLights();
lRootSceneNode->removeAndDestroyAllChildren();
}
{
Ogre::RenderSystem* lRenderSystem = lRoot->getRenderSystem();
lRenderSystem->destroyRenderTarget(lTextureName);
}
{
Ogre::ResourceGroupManager& lRgMgr = Ogre::ResourceGroupManager::getSingleton();
lRgMgr.destroyResourceGroup(lNameOfResourceGroup);
}
return;
}
int main()
{
try
{
AnOgreApplication();
std::cout<<"end of the program"<<std::endl;
}catch(Ogre::Exception &e)
{
MWARNING("!!!!Ogre::Exception!!!!\n"<<e.what());
}catch(std::exception &e)
{
MWARNING("!!!!std::exception!!!!\n"<<e.what());
}
return 0;
}
{CODE}
Full source :
http://sourceforge.net/projects/so3dtools/files/Ogre3DWiki/09_RenderToTexture1.7z/download