1 /** Example 007 Collision
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3 We will describe 2 methods: Automatic collision detection for moving through
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4 3d worlds with stair climbing and sliding, and manual scene node and triangle
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5 picking using a ray. In this case, we will use a ray coming out from the
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6 camera, but you can use any ray.
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8 To start, we take the program from tutorial 2, which loads and displays a
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9 quake 3 level. We will use the level to walk in it and to pick triangles from.
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10 In addition we'll place 3 animated models into it for triangle picking. The
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11 following code starts up the engine and loads the level, as per tutorial 2.
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13 #include <irrlicht.h>
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14 #include "driverChoice.h"
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15 #include "exampleHelper.h"
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17 using namespace irr;
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20 #pragma comment(lib, "Irrlicht.lib")
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25 // I use this ISceneNode ID to indicate a scene node that is
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26 // not pickable by getSceneNodeAndCollisionPointFromRay()
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27 ID_IsNotPickable = 0,
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29 // I use this flag in ISceneNode IDs to indicate that the
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30 // scene node can be picked by ray selection.
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31 IDFlag_IsPickable = 1 << 0,
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33 // I use this flag in ISceneNode IDs to indicate that the
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34 // scene node can be highlighted. In this example, the
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35 // homonids can be highlighted, but the level mesh can't.
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36 IDFlag_IsHighlightable = 1 << 1
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41 // ask user for driver
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42 video::E_DRIVER_TYPE driverType=driverChoiceConsole();
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43 if (driverType==video::EDT_COUNT)
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48 IrrlichtDevice *device =
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49 createDevice(driverType, core::dimension2d<u32>(640, 480), 16, false);
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52 return 1; // could not create selected driver.
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55 If we want to receive information about the material of a hit triangle we have to get
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56 collisions per meshbuffer. The only disadvantage of this is that getting them per
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57 meshbuffer can be a little bit slower than per mesh, but usually that's not noticeable.
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58 If you set this to false you will no longer get material names in the title bar.
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60 const bool separateMeshBuffers = true;
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62 video::IVideoDriver* driver = device->getVideoDriver();
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63 scene::ISceneManager* smgr = device->getSceneManager();
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65 const io::path mediaPath = getExampleMediaPath();
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67 device->getFileSystem()->addFileArchive(mediaPath + "map-20kdm2.pk3");
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69 scene::IAnimatedMesh* q3levelmesh = smgr->getMesh("20kdm2.bsp");
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70 scene::IMeshSceneNode* q3node = 0;
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72 // The Quake mesh is pickable, but doesn't get highlighted.
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74 q3node = smgr->addOctreeSceneNode(q3levelmesh->getMesh(0), 0, IDFlag_IsPickable);
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77 So far so good, we've loaded the quake 3 level like in tutorial 2. Now,
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78 here comes something different: We create a triangle selector. A
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79 triangle selector is a class which can fetch the triangles from scene
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80 nodes for doing different things with them, for example collision
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81 detection. There are different triangle selectors, and all can be
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82 created with the ISceneManager. In this example, we create an
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83 OctreeTriangleSelector, which optimizes the triangle output a little
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84 bit by reducing it like an octree. This is very useful for huge meshes
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85 like quake 3 levels. After we created the triangle selector, we attach
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86 it to the q3node. This is not necessary, but in this way, we do not
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87 need to care for the selector, for example dropping it after we do not
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91 scene::ITriangleSelector* selector = 0;
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95 q3node->setPosition(core::vector3df(-1350,-130,-1400));
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98 There is currently no way to split an octree by material.
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99 So if we need material infos we have to create one octree per
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100 meshbuffer and put them together in a MetaTriangleSelector.
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102 if ( separateMeshBuffers && q3node->getMesh()->getMeshBufferCount() > 1)
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104 scene::IMetaTriangleSelector * metaSelector = smgr->createMetaTriangleSelector();
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105 for ( irr::u32 m=0; m < q3node->getMesh()->getMeshBufferCount(); ++m )
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107 scene::ITriangleSelector*
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108 bufferSelector = smgr->createOctreeTriangleSelector(
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109 q3node->getMesh()->getMeshBuffer(m), m, q3node);
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110 if ( bufferSelector )
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112 metaSelector->addTriangleSelector( bufferSelector );
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113 bufferSelector->drop();
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116 selector = metaSelector;
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120 // If you don't need material infos just create one octree for the
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122 selector = smgr->createOctreeTriangleSelector(
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123 q3node->getMesh(), q3node, 128);
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125 q3node->setTriangleSelector(selector);
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126 // We're not done with this selector yet, so don't drop it.
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131 We add a first person shooter camera to the scene so that we can see and
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132 move in the quake 3 level like in tutorial 2. But this, time, we add a
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133 special animator to the camera: A collision response animator. This
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134 animator modifies the scene node to which it is attached in order to
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135 prevent it from moving through walls and to add gravity to the node. The
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136 only things we have to tell the animator is how the world looks like,
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137 how big the scene node is, how much gravity to apply and so on. After the
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138 collision response animator is attached to the camera, we do not have to do
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139 anything else for collision detection, it's all done automatically.
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140 The rest of the collision detection code below is for picking. And please
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141 note another cool feature: The collision response animator can be
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142 attached also to all other scene nodes, not only to cameras. And it can
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143 be mixed with other scene node animators. In this way, collision
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144 detection and response in the Irrlicht engine is really easy.
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146 Now we'll take a closer look on the parameters of
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147 createCollisionResponseAnimator(). The first parameter is the
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148 TriangleSelector, which specifies how the world, against which collision
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149 detection is done, looks like. The second parameter is the scene node,
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150 which is the object which is affected by collision detection - in our
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151 case it is the camera. The third defines how big the object is, it is
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152 the radius of an ellipsoid. Try it out and change the radius to smaller
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153 values, the camera will be able to move closer to walls after this. The
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154 next parameter is the direction and speed of gravity. We'll set it to
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155 (0, -1000, 0), which approximates realistic gravity (depends on the units
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156 which are used in the scene model). You could set it to (0,0,0) to disable
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157 gravity. And the last value is just an offset: Without it the ellipsoid with
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158 which collision detection is done would be around the camera and the camera
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159 would be in the middle of the ellipsoid. But as human beings, we are used to
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160 have our eyes on top of the body, not in the middle of it. So we place the
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161 scene node 50 units over the center of the ellipsoid with this parameter.
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162 And that's it, collision detection works now.
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165 // Set a jump speed of 300 units per second, which gives a fairly realistic jump
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166 // when used with the gravity of (0, -1000, 0) in the collision response animator.
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167 scene::ICameraSceneNode* camera =
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168 smgr->addCameraSceneNodeFPS(0, 100.0f, .3f, ID_IsNotPickable, 0, 0, true, 300.f);
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169 camera->setPosition(core::vector3df(50,50,-60));
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170 camera->setTarget(core::vector3df(-70,30,-60));
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174 scene::ISceneNodeAnimatorCollisionResponse * anim = smgr->createCollisionResponseAnimator(
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175 selector, camera, core::vector3df(30,50,30),
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176 core::vector3df(0,-1000,0), core::vector3df(0,30,0));
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177 selector->drop(); // As soon as we're done with the selector, drop it.
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178 camera->addAnimator(anim);
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179 anim->drop(); // And likewise, drop the animator when we're done referring to it.
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182 // Now I create three animated characters which we can pick, a dynamic light for
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183 // lighting them, and a billboard for drawing where we found an intersection.
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185 // First, let's get rid of the mouse cursor. We'll use a billboard to show
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186 // what we're looking at.
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187 device->getCursorControl()->setVisible(false);
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189 // Add the billboard.
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190 scene::IBillboardSceneNode * bill = smgr->addBillboardSceneNode();
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191 bill->setMaterialType(video::EMT_TRANSPARENT_ADD_COLOR );
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192 bill->setMaterialTexture(0, driver->getTexture(mediaPath + "particle.bmp"));
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193 bill->setMaterialFlag(video::EMF_LIGHTING, false);
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194 bill->setMaterialFlag(video::EMF_ZBUFFER, false);
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195 bill->setSize(core::dimension2d<f32>(20.0f, 20.0f));
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196 bill->setID(ID_IsNotPickable); // This ensures that we don't accidentally ray-pick it
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198 /* Add 3 animated hominids, which we can pick using a ray-triangle intersection.
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199 They all animate quite slowly, to make it easier to see that accurate triangle
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200 selection is being performed. */
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201 scene::IAnimatedMeshSceneNode* node = 0;
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203 video::SMaterial material;
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205 // Add an MD2 node, which uses vertex-based animation.
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206 node = smgr->addAnimatedMeshSceneNode(smgr->getMesh(mediaPath + "faerie.md2"),
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207 0, IDFlag_IsPickable | IDFlag_IsHighlightable);
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208 node->setPosition(core::vector3df(-90,-15,-140)); // Put its feet on the floor.
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209 node->setScale(core::vector3df(1.6f)); // Make it appear realistically scaled
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210 node->setMD2Animation(scene::EMAT_POINT);
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211 node->setAnimationSpeed(20.f);
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212 material.setTexture(0, driver->getTexture(mediaPath + "faerie2.bmp"));
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213 material.Lighting = true;
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214 material.NormalizeNormals = true;
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215 node->getMaterial(0) = material;
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217 // Now create a triangle selector for it. The selector will know that it
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218 // is associated with an animated node, and will update itself as necessary.
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219 selector = smgr->createTriangleSelector(node, separateMeshBuffers);
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220 node->setTriangleSelector(selector);
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221 selector->drop(); // We're done with this selector, so drop it now.
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223 // And this B3D file uses skinned skeletal animation.
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224 node = smgr->addAnimatedMeshSceneNode(smgr->getMesh(mediaPath + "ninja.b3d"),
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225 0, IDFlag_IsPickable | IDFlag_IsHighlightable);
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226 node->setScale(core::vector3df(10));
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227 node->setPosition(core::vector3df(-75,-66,-80));
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228 node->setRotation(core::vector3df(0,90,0));
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229 node->setAnimationSpeed(8.f);
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230 node->getMaterial(0).NormalizeNormals = true;
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231 node->getMaterial(0).Lighting = true;
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232 // Just do the same as we did above.
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233 selector = smgr->createTriangleSelector(node, separateMeshBuffers);
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234 node->setTriangleSelector(selector);
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237 // This X files uses skeletal animation, but without skinning.
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238 node = smgr->addAnimatedMeshSceneNode(smgr->getMesh(mediaPath + "dwarf.x"),
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239 0, IDFlag_IsPickable | IDFlag_IsHighlightable);
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240 node->setPosition(core::vector3df(-70,-66,-30)); // Put its feet on the floor.
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241 node->setRotation(core::vector3df(0,-90,0)); // And turn it towards the camera.
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242 node->setAnimationSpeed(20.f);
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243 node->getMaterial(0).Lighting = true;
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244 selector = smgr->createTriangleSelector(node, separateMeshBuffers);
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245 node->setTriangleSelector(selector);
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248 // And this mdl file uses skinned skeletal animation.
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249 node = smgr->addAnimatedMeshSceneNode(smgr->getMesh(mediaPath + "yodan.mdl"),
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250 0, IDFlag_IsPickable | IDFlag_IsHighlightable);
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251 node->setPosition(core::vector3df(-90,-25,20));
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252 node->setScale(core::vector3df(0.8f));
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253 node->getMaterial(0).Lighting = true;
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254 node->setAnimationSpeed(20.f);
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256 // Just do the same as we did above.
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257 selector = smgr->createTriangleSelector(node, separateMeshBuffers);
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258 node->setTriangleSelector(selector);
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261 material.setTexture(0, 0);
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262 material.Lighting = false;
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264 // Add a light, so that the unselected nodes aren't completely dark.
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265 scene::ILightSceneNode * light = smgr->addLightSceneNode(0, core::vector3df(-60,100,400),
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266 video::SColorf(1.0f,1.0f,1.0f,1.0f), 600.0f);
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267 light->setID(ID_IsNotPickable); // Make it an invalid target for selection.
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269 // Remember which scene node is highlighted
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270 scene::ISceneNode* highlightedSceneNode = 0;
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271 scene::ISceneCollisionManager* collMan = smgr->getSceneCollisionManager();
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273 // draw the selection triangle only as wireframe
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274 material.Wireframe=true;
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276 while(device->run())
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277 if (device->isWindowActive())
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279 driver->beginScene(video::ECBF_COLOR | video::ECBF_DEPTH, video::SColor(0));
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282 // Unlight any currently highlighted scene node
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283 if (highlightedSceneNode)
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285 highlightedSceneNode->setMaterialFlag(video::EMF_LIGHTING, true);
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286 highlightedSceneNode = 0;
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289 // All intersections in this example are done with a ray cast out from the camera to
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290 // a distance of 1000. You can easily modify this to check (e.g.) a bullet
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291 // trajectory or a sword's position, or create a ray from a mouse click position using
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292 // ISceneCollisionManager::getRayFromScreenCoordinates()
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293 core::line3d<f32> ray;
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294 ray.start = camera->getPosition();
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295 ray.end = ray.start + (camera->getTarget() - ray.start).normalize() * 1000.0f;
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298 // This call is all you need to perform ray/triangle collision on every scene node
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299 // that has a triangle selector, including the Quake level mesh. It finds the nearest
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300 // collision point/triangle, and returns the scene node containing that point.
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301 // Irrlicht provides other types of selection, including ray/triangle selector,
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302 // ray/box and ellipse/triangle selector, plus associated helpers.
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303 // You might also want to check the other methods of ISceneCollisionManager.
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305 irr::io::SNamedPath hitTextureName;
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306 scene::SCollisionHit hitResult;
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307 scene::ISceneNode * selectedSceneNode =collMan->getSceneNodeAndCollisionPointFromRay(
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308 hitResult, // Returns all kind of info about the collision
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310 IDFlag_IsPickable, // This ensures that only nodes that we have
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311 // set up to be pickable are considered
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312 0); // Check the entire scene (this is actually the implicit default)
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315 // If the ray hit anything, move the billboard to the collision position
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316 // and draw the triangle that was hit.
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317 if(selectedSceneNode)
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319 bill->setPosition(hitResult.Intersection); // Show the current intersection point with the level or a mesh
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321 // We need to reset the transform before doing our own rendering.
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322 driver->setTransform(video::ETS_WORLD, core::matrix4());
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323 driver->setMaterial(material);
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324 driver->draw3DTriangle(hitResult.Triangle, video::SColor(0,255,0,0)); // Show which triangle has been hit
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326 // We can check the flags for the scene node that was hit to see if it should be
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327 // highlighted. The animated nodes can be highlighted, but not the Quake level mesh
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328 if((selectedSceneNode->getID() & IDFlag_IsHighlightable) == IDFlag_IsHighlightable)
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330 highlightedSceneNode = selectedSceneNode;
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332 // Highlighting in this case means turning lighting OFF for this node,
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333 // which means that it will be drawn with full brightness.
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334 highlightedSceneNode->setMaterialFlag(video::EMF_LIGHTING, false);
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337 // When separateMeshBuffers is set to true we can now find out which material was hit
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338 if ( hitResult.MeshBuffer && hitResult.Node && hitResult.Node->getMaterial(hitResult.MaterialIndex).TextureLayer[0].Texture )
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340 // Note we are interested in the node material and not in the meshbuffer material.
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341 // Otherwise we wouldn't get the fairy2 texture which is only set on the node.
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342 hitTextureName = hitResult.Node->getMaterial(hitResult.MaterialIndex).TextureLayer[0].Texture->getName();
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346 // We're all done drawing, so end the scene.
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347 driver->endScene();
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349 // Show some info in title-bar
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350 int fps = driver->getFPS();
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351 static core::stringw lastString;
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352 core::stringw str = L"Collision detection example - Irrlicht Engine [";
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353 str += driver->getName();
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356 if ( !hitTextureName.getInternalName().empty() )
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359 irr::io::path texName(hitTextureName.getInternalName());
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360 str += core::deletePathFromFilename(texName);
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362 if ( str != lastString ) // changing caption is somewhat expensive, so don't when nothing changed
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364 device->setWindowCaption(str.c_str());
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