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/** Example 010 Shaders
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This tutorial shows how to use shaders for D3D8, D3D9, and OpenGL with the
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engine and how to create new material types with them. It also shows how to
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disable the generation of mipmaps at texture loading, and how to use text scene
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This tutorial does not explain how shaders work. I would recommend to read the
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D3D or OpenGL documentation, to search a tutorial, or to read a book about
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At first, we need to include all headers and do the stuff we always do, like in
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nearly all other tutorials:
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#include "driverChoice.h"
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#pragma comment(lib, "Irrlicht.lib")
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Because we want to use some interesting shaders in this tutorials, we need to
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set some data for them to make them able to compute nice colors. In this
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example, we'll use a simple vertex shader which will calculate the color of the
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vertex based on the position of the camera.
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For this, the shader needs the following data: The inverted world matrix for
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transforming the normal, the clip matrix for transforming the position, the
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camera position and the world position of the object for the calculation of the
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angle of light, and the color of the light. To be able to tell the shader all
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this data every frame, we have to derive a class from the
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IShaderConstantSetCallBack interface and override its only method, namely
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OnSetConstants(). This method will be called every time the material is set.
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The method setVertexShaderConstant() of the IMaterialRendererServices interface
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is used to set the data the shader needs. If the user chose to use a High Level
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shader language like HLSL instead of Assembler in this example, you have to set
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the variable name as parameter instead of the register index.
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IrrlichtDevice* device = 0;
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bool UseHighLevelShaders = false;
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class MyShaderCallBack : public video::IShaderConstantSetCallBack
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virtual void OnSetConstants(video::IMaterialRendererServices* services,
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video::IVideoDriver* driver = services->getVideoDriver();
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// set inverted world matrix
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// if we are using highlevel shaders (the user can select this when
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// starting the program), we must set the constants by name.
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core::matrix4 invWorld = driver->getTransform(video::ETS_WORLD);
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invWorld.makeInverse();
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if (UseHighLevelShaders)
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services->setVertexShaderConstant("mInvWorld", invWorld.pointer(), 16);
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services->setVertexShaderConstant(invWorld.pointer(), 0, 4);
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core::matrix4 worldViewProj;
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worldViewProj = driver->getTransform(video::ETS_PROJECTION);
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worldViewProj *= driver->getTransform(video::ETS_VIEW);
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worldViewProj *= driver->getTransform(video::ETS_WORLD);
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if (UseHighLevelShaders)
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services->setVertexShaderConstant("mWorldViewProj", worldViewProj.pointer(), 16);
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services->setVertexShaderConstant(worldViewProj.pointer(), 4, 4);
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// set camera position
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core::vector3df pos = device->getSceneManager()->
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getActiveCamera()->getAbsolutePosition();
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if (UseHighLevelShaders)
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services->setVertexShaderConstant("mLightPos", reinterpret_cast<f32*>(&pos), 3);
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services->setVertexShaderConstant(reinterpret_cast<f32*>(&pos), 8, 1);
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video::SColorf col(0.0f,1.0f,1.0f,0.0f);
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if (UseHighLevelShaders)
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services->setVertexShaderConstant("mLightColor",
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reinterpret_cast<f32*>(&col), 4);
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services->setVertexShaderConstant(reinterpret_cast<f32*>(&col), 9, 1);
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// set transposed world matrix
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core::matrix4 world = driver->getTransform(video::ETS_WORLD);
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world = world.getTransposed();
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if (UseHighLevelShaders)
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services->setVertexShaderConstant("mTransWorld", world.pointer(), 16);
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services->setVertexShaderConstant(world.pointer(), 10, 4);
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The next few lines start up the engine just like in most other tutorials
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before. But in addition, we ask the user if he wants to use high level shaders
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in this example, if he selected a driver which is capable of doing so.
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// ask user for driver
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video::E_DRIVER_TYPE driverType=driverChoiceConsole();
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if (driverType==video::EDT_COUNT)
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// ask the user if we should use high level shaders for this example
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if (driverType == video::EDT_DIRECT3D9 ||
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driverType == video::EDT_OPENGL)
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printf("Please press 'y' if you want to use high level shaders.\n");
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UseHighLevelShaders = true;
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device = createDevice(driverType, core::dimension2d<u32>(640, 480));
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return 1; // could not create selected driver.
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video::IVideoDriver* driver = device->getVideoDriver();
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scene::ISceneManager* smgr = device->getSceneManager();
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gui::IGUIEnvironment* gui = device->getGUIEnvironment();
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Now for the more interesting parts. If we are using Direct3D, we want
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to load vertex and pixel shader programs, if we have OpenGL, we want to
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use ARB fragment and vertex programs. I wrote the corresponding
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programs down into the files d3d8.ps, d3d8.vs, d3d9.ps, d3d9.vs,
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opengl.ps and opengl.vs. We only need the right filenames now. This is
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done in the following switch. Note, that it is not necessary to write
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the shaders into text files, like in this example. You can even write
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the shaders directly as strings into the cpp source file, and use later
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addShaderMaterial() instead of addShaderMaterialFromFiles().
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io::path vsFileName; // filename for the vertex shader
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io::path psFileName; // filename for the pixel shader
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case video::EDT_DIRECT3D8:
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psFileName = "../../media/d3d8.psh";
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vsFileName = "../../media/d3d8.vsh";
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case video::EDT_DIRECT3D9:
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if (UseHighLevelShaders)
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psFileName = "../../media/d3d9.hlsl";
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vsFileName = psFileName; // both shaders are in the same file
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psFileName = "../../media/d3d9.psh";
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vsFileName = "../../media/d3d9.vsh";
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case video::EDT_OPENGL:
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if (UseHighLevelShaders)
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psFileName = "../../media/opengl.frag";
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vsFileName = "../../media/opengl.vert";
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psFileName = "../../media/opengl.psh";
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vsFileName = "../../media/opengl.vsh";
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In addition, we check if the hardware and the selected renderer is
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capable of executing the shaders we want. If not, we simply set the
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filename string to 0. This is not necessary, but useful in this
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example: For example, if the hardware is able to execute vertex shaders
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but not pixel shaders, we create a new material which only uses the
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vertex shader, and no pixel shader. Otherwise, if we would tell the
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engine to create this material and the engine sees that the hardware
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wouldn't be able to fullfill the request completely, it would not
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create any new material at all. So in this example you would see at
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least the vertex shader in action, without the pixel shader.
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if (!driver->queryFeature(video::EVDF_PIXEL_SHADER_1_1) &&
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!driver->queryFeature(video::EVDF_ARB_FRAGMENT_PROGRAM_1))
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device->getLogger()->log("WARNING: Pixel shaders disabled "\
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"because of missing driver/hardware support.");
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if (!driver->queryFeature(video::EVDF_VERTEX_SHADER_1_1) &&
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!driver->queryFeature(video::EVDF_ARB_VERTEX_PROGRAM_1))
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device->getLogger()->log("WARNING: Vertex shaders disabled "\
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"because of missing driver/hardware support.");
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Now lets create the new materials. As you maybe know from previous
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examples, a material type in the Irrlicht engine is set by simply
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changing the MaterialType value in the SMaterial struct. And this value
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is just a simple 32 bit value, like video::EMT_SOLID. So we only need
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the engine to create a new value for us which we can set there. To do
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this, we get a pointer to the IGPUProgrammingServices and call
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addShaderMaterialFromFiles(), which returns such a new 32 bit value.
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The parameters to this method are the following: First, the names of
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the files containing the code of the vertex and the pixel shader. If
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you would use addShaderMaterial() instead, you would not need file
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names, then you could write the code of the shader directly as string.
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The following parameter is a pointer to the IShaderConstantSetCallBack
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class we wrote at the beginning of this tutorial. If you don't want to
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set constants, set this to 0. The last paramter tells the engine which
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material it should use as base material.
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To demonstrate this, we create two materials with a different base
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material, one with EMT_SOLID and one with EMT_TRANSPARENT_ADD_COLOR.
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video::IGPUProgrammingServices* gpu = driver->getGPUProgrammingServices();
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s32 newMaterialType1 = 0;
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s32 newMaterialType2 = 0;
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MyShaderCallBack* mc = new MyShaderCallBack();
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// create the shaders depending on if the user wanted high level
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// or low level shaders:
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if (UseHighLevelShaders)
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// create material from high level shaders (hlsl or glsl)
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newMaterialType1 = gpu->addHighLevelShaderMaterialFromFiles(
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vsFileName, "vertexMain", video::EVST_VS_1_1,
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psFileName, "pixelMain", video::EPST_PS_1_1,
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mc, video::EMT_SOLID);
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newMaterialType2 = gpu->addHighLevelShaderMaterialFromFiles(
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vsFileName, "vertexMain", video::EVST_VS_1_1,
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psFileName, "pixelMain", video::EPST_PS_1_1,
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mc, video::EMT_TRANSPARENT_ADD_COLOR);
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// create material from low level shaders (asm or arb_asm)
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newMaterialType1 = gpu->addShaderMaterialFromFiles(vsFileName,
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psFileName, mc, video::EMT_SOLID);
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newMaterialType2 = gpu->addShaderMaterialFromFiles(vsFileName,
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psFileName, mc, video::EMT_TRANSPARENT_ADD_COLOR);
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Now it's time for testing the materials. We create a test cube and set
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the material we created. In addition, we add a text scene node to the
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cube and a rotation animator to make it look more interesting and
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// create test scene node 1, with the new created material type 1
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scene::ISceneNode* node = smgr->addCubeSceneNode(50);
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node->setPosition(core::vector3df(0,0,0));
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node->setMaterialTexture(0, driver->getTexture("../../media/wall.bmp"));
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node->setMaterialFlag(video::EMF_LIGHTING, false);
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node->setMaterialType((video::E_MATERIAL_TYPE)newMaterialType1);
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smgr->addTextSceneNode(gui->getBuiltInFont(),
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L"PS & VS & EMT_SOLID",
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video::SColor(255,255,255,255), node);
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scene::ISceneNodeAnimator* anim = smgr->createRotationAnimator(
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core::vector3df(0,0.3f,0));
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node->addAnimator(anim);
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Same for the second cube, but with the second material we created.
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// create test scene node 2, with the new created material type 2
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node = smgr->addCubeSceneNode(50);
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node->setPosition(core::vector3df(0,-10,50));
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node->setMaterialTexture(0, driver->getTexture("../../media/wall.bmp"));
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node->setMaterialFlag(video::EMF_LIGHTING, false);
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node->setMaterialFlag(video::EMF_BLEND_OPERATION, true);
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node->setMaterialType((video::E_MATERIAL_TYPE)newMaterialType2);
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smgr->addTextSceneNode(gui->getBuiltInFont(),
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L"PS & VS & EMT_TRANSPARENT",
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video::SColor(255,255,255,255), node);
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anim = smgr->createRotationAnimator(core::vector3df(0,0.3f,0));
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node->addAnimator(anim);
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Then we add a third cube without a shader on it, to be able to compare
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// add a scene node with no shader
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node = smgr->addCubeSceneNode(50);
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node->setPosition(core::vector3df(0,50,25));
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node->setMaterialTexture(0, driver->getTexture("../../media/wall.bmp"));
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node->setMaterialFlag(video::EMF_LIGHTING, false);
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smgr->addTextSceneNode(gui->getBuiltInFont(), L"NO SHADER",
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video::SColor(255,255,255,255), node);
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And last, we add a skybox and a user controlled camera to the scene.
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For the skybox textures, we disable mipmap generation, because we don't
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driver->setTextureCreationFlag(video::ETCF_CREATE_MIP_MAPS, false);
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smgr->addSkyBoxSceneNode(
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driver->getTexture("../../media/irrlicht2_up.jpg"),
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driver->getTexture("../../media/irrlicht2_dn.jpg"),
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driver->getTexture("../../media/irrlicht2_lf.jpg"),
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driver->getTexture("../../media/irrlicht2_rt.jpg"),
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driver->getTexture("../../media/irrlicht2_ft.jpg"),
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driver->getTexture("../../media/irrlicht2_bk.jpg"));
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driver->setTextureCreationFlag(video::ETCF_CREATE_MIP_MAPS, true);
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// add a camera and disable the mouse cursor
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scene::ICameraSceneNode* cam = smgr->addCameraSceneNodeFPS();
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cam->setPosition(core::vector3df(-100,50,100));
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cam->setTarget(core::vector3df(0,0,0));
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device->getCursorControl()->setVisible(false);
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Now draw everything. That's all.
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if (device->isWindowActive())
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driver->beginScene(true, true, video::SColor(255,0,0,0));
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int fps = driver->getFPS();
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core::stringw str = L"Irrlicht Engine - Vertex and pixel shader example [";
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str += driver->getName();
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device->setWindowCaption(str.c_str());
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Compile and run this, and I hope you have fun with your new little shader
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examples/10.Shaders/main.cpp
