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MARS_999

Irrlicht and render a polygon with a texture

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I am trying to render a arbitrary shape that starts out as a triangle and grows into a circle. I am not getting my math and/or Irrlicht's rendering calls correct to be able to do this.

 

Here is the code, hope it helps someone to help me solve my problem...

 

class ShapeAbstract
{
private:
    std::vector<irr::video::S3DVertex> vertex;
    std::vector<irr::u16> index;
    
public:
    ShapeAbstract(unsigned int level = 3,
                  const irr::video::SColor& color = irr::video::SColor(255, 255, 255, 255))
    {
        CalculateVertices(level, color);
        CalculateIndices(level);
    }
    ~ShapeAbstract(){}
    inline void Draw(NX::Object* obj,
                     irr::video::IVideoDriver *driver, irr::video::ITexture* texture,
                     irr::core::rect<irr::s32> sourceRect,
                     irr::core::position2d<irr::s32> position,
                     irr::core::position2d<irr::s32> rotationPoint,
                     irr::f32 rotation,
                     bool useAlphaChannel,
                     const irr::video::SColor& color)
    {
        irr::core::matrix4 oldProjMat = driver->getTransform(irr::video::ETS_PROJECTION);
        driver->setTransform(irr::video::ETS_PROJECTION, irr::core::matrix4());
        irr::core::matrix4 oldViewMat = driver->getTransform(irr::video::ETS_VIEW);
        driver->setTransform(irr::video::ETS_VIEW, irr::core::matrix4());

        irr::core::vector2df corner[4];
        corner[0] = irr::core::vector2df((irr::f32)position.X, (irr::f32)position.Y);
        corner[1] = irr::core::vector2df((irr::f32)position.X + sourceRect.getWidth(), (irr::f32)position.Y);
        corner[2] = irr::core::vector2df((irr::f32)position.X, (irr::f32)position.Y + sourceRect.getHeight());
        corner[3] = irr::core::vector2df((irr::f32)position.X + sourceRect.getWidth(), (irr::f32)position.Y + sourceRect.getHeight());

        for(int x = 0; x < 4; ++x)
            corner[x].rotateBy(rotation, irr::core::vector2df((irr::f32)rotationPoint.X, (irr::f32)rotationPoint.Y));

        irr::core::vector2df uvCorner[4];    
        uvCorner[0] = irr::core::vector2df(0,0);
        uvCorner[1] = irr::core::vector2df(0,1);
        uvCorner[2] = irr::core::vector2df(1,0);
        uvCorner[3] = irr::core::vector2df(1,1);
                
        //if(obj->GetLevel() < 12)
        //    CalculateVertices(obj->GetLevel()+1, color);

        //static irr::u16 indices[6] = {0, 1, 2, 3 ,2 ,1};
                
        //Using indices like this: 0 1 2   0 2 3   0 3 4  ... for a fan list
        
         /*
        std::vector<irr::u16> indices;
        for(int x = 0; x < obj->GetLevel(); ++x)
        {
            indices.push_back(x);
        }
        */
        
        //irr::core::matrix4 translate;
        //irr::core::matrix4 rot;
        //rot.setRotationDegrees(irr::core::vector3df(0.0f, 0.0f, 60.0f));
        //translate.setTranslation(irr::core::vector3df(screenPosX, screenPosY, 1));
        //translate.transformVect(vertex[x].Pos);
        //rot.rotateVect(v);
        float screenWidth  = (irr::f32)driver->getScreenSize().Width;
        float screenHeight = (irr::f32)driver->getScreenSize().Height;
        for(int x = 0; x < vertex.size(); ++x)
        {
            float screenPosX  = ((corner[x].X/screenWidth) -0.5f)* 2.0f;
            float screenPosY  = ((corner[x].Y/screenHeight)-0.5f)*-2.0f;
            //vertex[x].Pos     = irr::core::vector3df(screenPosX, screenPosY, 1);    
            //think I need to do a translation of this point from vertex.pos from the screenPoX, screenPosY, 1 point
            vertex[x].TCoords = uvCorner[x];
            vertex[x].Color   = color;            
        }

        irr::video::SMaterial material;
        material.Lighting     = false;
        material.ZWriteEnable = false;
        material.UseMipMaps   = true;
        material.AntiAliasing = irr::video::EAAM_FULL_BASIC;
        material.TextureLayer[0].Texture           = texture;
        material.TextureLayer[0].AnisotropicFilter = 16;
        material.TextureLayer[0].TrilinearFilter   = true;
        material.TextureLayer[0].TextureWrapU      = irr::video::ETC_CLAMP;
        material.TextureLayer[0].TextureWrapV      = irr::video::ETC_CLAMP;
    
        if(useAlphaChannel)
            material.MaterialType = irr::video::EMT_TRANSPARENT_ALPHA_CHANNEL;
        else
            material.MaterialType = irr::video::EMT_SOLID;

        driver->setMaterial(material);
        driver->drawIndexedTriangleFan(&vertex[0],vertex.size(),
                                       &index[0], index.size() - 2);
        /*driver->drawIndexedTriangleList(&vertex[0],vertex.size(),
                                          &index[0], index.size() / 3);
        */
        driver->setTransform(irr::video::ETS_PROJECTION, oldProjMat);
        driver->setTransform(irr::video::ETS_VIEW, oldViewMat);
    }
    inline void CalculateVertices(unsigned int sides, const irr::video::SColor& color)
    {
        //X=SIN(RADIANS(angle))* radius
        //Y=COS(RADIANS(angle))* radius
        //float angle  = 180.0f - (360.0f/float(level));
        vertex.clear();
        //vertex.push_back(irr::video::S3DVertex(.5f, .5f, 1.0f, 0.0f, 0.0f, 0.0f, color, 0.0f, 0.0f));
        unsigned int angle = 360 / sides;
        for(unsigned int i = 0.0f; i < 360.0f; i+=angle)
        {
            irr::video::S3DVertex v(sinf(irr::core::degToRad(float(i))),
                                    cosf(irr::core::degToRad(float(i))),
                                    0.0f,
                                    0.0f, 0.0f, 0.0f,
                                    color,
                                    0.0f, 0.0f);
            vertex.push_back(v);
        }
    }
    inline void CalculateIndices(unsigned int sides)
    {
        index.clear();
        for(unsigned int n = 2; n < sides; ++n)
        {
            index.push_back(0);
            index.push_back(n - 1);
            index.push_back(n);
        }
    }
};
Edited by MARS_999

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