source: trunk/VUT/chcdemo/Geometry.cpp @ 10

#include "Geometry.h"
#include "glInterface.h"
#include "stdio.h"
#include "teapot.h"
#include <math.h>

#define NO_LIST    -1
#define STRIP_END  -1

int Geometry::num_torus_indices;
int Geometry::num_torus_vertices;
int Geometry::num_torus_normals;

const int Geometry::torus_precision = 24;
const int Geometry::sphere_precision = 24;

float *Geometry::torus_vertices;
float *Geometry::torus_normals;
int *Geometry::torus_indices;

// choose size so the glut-rendered sphere is approximately
// as big as the other objects
const float Geometry::sphere_radius = 1.0 / 9.0f;
const float Geometry::torus_inner_radius = 0.05;
const float Geometry::torus_outer_radius = 0.07;

int Geometry::sDisplayList[NUM_OBJECTS];

bool Geometry::sIsInitialised = Init();

Geometry::Geometry(): 
mXRotation(0), mYRotation(0), mZRotation(0), mScale(1.0), mObjectType(TEAPOT)
{
        copyVector3Values(mTranslation, 0, 0, 0);
        
        SetAmbientColor(0.1745, 0.01175, 0.01175);
        SetDiffuseColor(0.61424, 0.04136, 0.04136);
        SetSpecularColor(0.727811, 0.626959, 0.626959);
        
        CalcBoundingVolume();
        CalcTransform();
        GenerateList();
}

Geometry::Geometry(Vector3 translation, float xRot, float yRot, float zRot, float scale, int objectType):
mXRotation(xRot), mYRotation(yRot), mZRotation(zRot), mScale(scale), mObjectType(objectType)
{
        copyVector3(mTranslation, translation);

        SetAmbientColor(0.1745, 0.01175, 0.01175);
        SetDiffuseColor(0.61424, 0.04136, 0.04136);
        SetSpecularColor(0.727811, 0.626959, 0.626959);
        
        CalcBoundingVolume();
        CalcTransform();
        GenerateList();
}

void Geometry::ResetLists()
{
        for(int i = 0; i < NUM_OBJECTS; i++)
        {
        if(sDisplayList[i] == NO_LIST)
                        glDeleteLists(sDisplayList[i], 1);

                sDisplayList[i] = NO_LIST;
        }
}

void Geometry::CleanUp()
{
        ResetLists();

        delete [] torus_vertices;
        delete [] torus_normals;
        delete [] torus_indices;
}


bool Geometry::Init()
{
        for(int i=0; i < NUM_OBJECTS; i++)
                sDisplayList[i] = NO_LIST;

        // parameters chosen so torus is approximately as big as teapot
        CreateTorus(torus_inner_radius, torus_outer_radius, torus_precision);

        return true;
}

void Geometry::GenerateList()
{
        if(sDisplayList[mObjectType] == NO_LIST)
        {
                sDisplayList[mObjectType] = glGenLists(1);
                glNewList(sDisplayList[mObjectType], GL_COMPILE);

                switch(mObjectType)
                {
                        case TEAPOT:
                                RenderTeapot();
                                break;
                        case TORUS:
                                RenderTorus();
                                break;
                        case SPHERE:    
                                RenderSphere();
                                break;
                        
                        default:
                                break;
                }
                glEndList();
        }
}

void Geometry::Render()
{
        glMaterialfv(GL_FRONT, GL_AMBIENT, mAmbientColor);
        glMaterialfv(GL_FRONT, GL_DIFFUSE, mDiffuseColor);
        glMaterialfv(GL_FRONT, GL_SPECULAR, mSpecularColor);
        
        glPushMatrix();
        
        Transform();
        
        glCallList(sDisplayList[mObjectType]);

        glPopMatrix();
}


//! sets rotations around the three axis: executed in the order specified here
void Geometry::SetRotations(float xRot, float yRot, float zRot)
{
        mXRotation = xRot;
        mYRotation = yRot;
        mZRotation = zRot;

        CalcBoundingVolume();
        CalcTransform();
}


void Geometry::SetTranslation(Vector3 translation)
{
        copyVector3(mTranslation, translation);

        CalcBoundingVolume();
        CalcTransform();
}


void Geometry::SetScale(float scale)
{
        mScale = scale;
        CalcTransform();

        CalcBoundingVolume();
}


void Geometry::SetAmbientColor(float ambientR, float ambientG, float ambientB)
{
        mAmbientColor[0] = ambientR;
        mAmbientColor[1] = ambientG;
        mAmbientColor[2] = ambientB;
}


void Geometry::SetDiffuseColor(float diffuseR, float diffuseG, float diffuseB)
{
        mDiffuseColor[0] = diffuseR;
        mDiffuseColor[1] = diffuseG;
        mDiffuseColor[2] = diffuseB;
}


void Geometry::SetSpecularColor(float specularR, float specularG, float specularB)
{
        mSpecularColor[0] = specularR;
        mSpecularColor[1] = specularG;
        mSpecularColor[2] = specularB;
}


float Geometry::GetScale()
{
        return mScale;
}


void Geometry::GetTranslation(Vector3 translation)
{
        copyVector3(translation, mTranslation);
}


void Geometry::GetRotations(float &xRot, float &yRot, float &zRot)
{
        xRot = mXRotation;
        yRot = mYRotation;
        zRot = mZRotation;
}

        
const AABox &Geometry::GetBoundingVolume()
{
        return mBoundingBox;
}


void Geometry::SetLastVisited(int lastVisited)
{
        mLastVisited = lastVisited;
}


int Geometry::GetLastVisited()
{
        return mLastVisited;
}


void Geometry::SetObjectType(int type)
{
        mObjectType = type;
        GenerateList();
}


void Geometry::RenderTeapot()
{
        int i = 0;

        while(i < num_teapot_indices)
        {
                glBegin(GL_TRIANGLE_STRIP);
                        while(teapot_indices[i] != STRIP_END)
                        {       
                                int index = teapot_indices[i] * 3;
                                
                                glNormal3fv(teapot_normals + index);
                                glVertex3fv(teapot_vertices + index);
                                
                                i++;            
                        }
                glEnd();
                
                i++; // skip strip end flag
        }
}

void Geometry::CalcBoundingVolume()
{
    switch(mObjectType)
        {
                case TORUS:
                        CalcBoundingVolume(torus_vertices, num_torus_vertices);
                        break;
                case SPHERE:
                        CalcSphereBoundingVolume();
                        break;
                case TEAPOT:
                        CalcBoundingVolume(teapot_vertices, num_teapot_vertices);
                        break;
                default:
                        break;
        }
}


void Geometry::CalcBoundingVolume(float *vertices, const int num_vertices)
{
        Vector3 *rotatedPoints = new Vector3[num_vertices];
        
        for(int i = 0; i < num_vertices; i++)
        {
                copyVector3Values(rotatedPoints[i], vertices[i * 3],
                                                  vertices[i * 3 + 1], vertices[i * 3 + 2]);
        
                rotateVectorZ(rotatedPoints[i], mZRotation * PI_180);
                rotateVectorY(rotatedPoints[i], mYRotation * PI_180);
                rotateVectorX(rotatedPoints[i], mXRotation * PI_180);
        }

        calcCubicHull(mBoundingBox.min, mBoundingBox.max, rotatedPoints, num_vertices);

        for(int i=0; i< 3; i++)
        {
                mBoundingBox.min[i] *= mScale;
                mBoundingBox.max[i] *= mScale;
        }

        addVector3(mBoundingBox.min, mTranslation, mBoundingBox.min);
    addVector3(mBoundingBox.max, mTranslation, mBoundingBox.max);

        delete [] rotatedPoints;
}


void Geometry::CalcSphereBoundingVolume()
{
        float len = mScale * sphere_radius;
        Vector3 size = {len, len, len};
                                        
        diffVector3(mBoundingBox.min, mTranslation, size);
        addVector3(mBoundingBox.max, mTranslation, size);
}


void Geometry::RenderTorus()
{
        glVertexPointer(3, GL_FLOAT, sizeof(float), torus_vertices);
        glEnableClientState(GL_VERTEX_ARRAY);

        glNormalPointer(GL_FLOAT, sizeof(float), torus_normals);
        glEnableClientState(GL_NORMAL_ARRAY);

    glDrawElements(GL_TRIANGLES, num_torus_indices, GL_UNSIGNED_INT, torus_indices);

        glDisableClientState(GL_VERTEX_ARRAY);
        glDisableClientState(GL_NORMAL_ARRAY);
}

/*
        creates a torus with specified radii, with number of rings and ring
        subdivision = precision.
*/
void Geometry::CreateTorus(float innerRadius, float outerRadius, int precision)
{
        num_torus_vertices = num_torus_normals = (precision + 1) * (precision + 1);
        num_torus_indices = 2 * precision * precision * 3;

        torus_vertices = new float[num_torus_vertices * 3];
        torus_normals = new float[num_torus_normals * 3];
        torus_indices = new int[num_torus_indices];

        for(int i=0; i<precision+1; i++)
        {
                int index = i * 3;

                Vector3 currentVertex = {innerRadius, 0.0f, 0.0f};
                rotateVectorZ(currentVertex, ((float)i * 2.0 * PI) / (float)precision);

                currentVertex[0] += outerRadius;
                
                Vector3 sTangent = {0.0f, 0.0f, -1.0f};
                Vector3 tTangent = {0, -1, 0};
                rotateVectorZ(tTangent, ((float)i * 2.0 * PI) / (float)precision);

        Vector3 currentNormal;

                cross(currentNormal, tTangent, sTangent);

                torus_normals[index + 0] = currentNormal[0];
                torus_normals[index + 1] = currentNormal[1];
                torus_normals[index + 2] = currentNormal[2];
                
                torus_vertices[index + 0] = currentVertex[0];
                torus_vertices[index + 1] = currentVertex[1];
                torus_vertices[index + 2] = currentVertex[2];
        }

        for(int i_rng=1; i_rng<precision+1; ++i_rng)
        {
                for(int i=0; i<precision+1; ++i)
                {
                        int index = 3 * (i_rng * (precision + 1) + i);

                        Vector3 currentVertex = {torus_vertices[i*3], torus_vertices[i*3+1], torus_vertices[i*3+2]};
                        
                        rotateVectorY(currentVertex, ((float)i_rng * 2.0 * PI) / (float)precision);
                                                
                        Vector3 currentNormal = {torus_normals[i*3], torus_normals[i*3+1], torus_normals[i*3+2]};
                        
                        rotateVectorY(currentNormal, ((float)i_rng * 2.0 * PI) / (float)precision);

                        torus_normals[index + 0] = currentNormal[0];
                        torus_normals[index + 1] = currentNormal[1];
                        torus_normals[index + 2] = currentNormal[2];
                
                        torus_vertices[index + 0] = currentVertex[0];
                        torus_vertices[index + 1] = currentVertex[1];
                        torus_vertices[index + 2] = currentVertex[2];
                }
        }

        for(i_rng=0; i_rng<precision; ++i_rng)
        {
                for(i=0; i<precision; ++i)
                {
                        int index = ((i_rng * precision + i) * 2) * 3;

                        torus_indices[index+0] = (i_rng     * (precision+1) + i)*3;
                        torus_indices[index+1] = ((i_rng+1) * (precision+1) + i)*3;
                        torus_indices[index+2] = (i_rng     * (precision+1) + i + 1)*3;

                        index = ((i_rng * precision + i) * 2 + 1) * 3;

                        torus_indices[index+0] = (i_rng     * (precision+1) + i + 1)*3;
                        torus_indices[index+1] = ((i_rng+1) * (precision+1) + i)*3;
                        torus_indices[index+2] = ((i_rng+1) * (precision+1) + i + 1)*3;
                }
        }
}

/**
        counts the triangles of the teapot.
        traverses through all the triangle strips.
*/
int Geometry::CountTeapotTriangles()
{
        int result = 0;
        int i=0;
        // n - 2 triangles are drawn for a strip
        while(i < num_teapot_indices)
        {
                while(teapot_indices[i] != STRIP_END)
                {       
                        result ++;;
                        i++;            
                }
                result -= 2;
                i++; // skip STRIP_END
        }
        return result;
}

/**
        counts the triangles of the torus
*/
int Geometry::CountTorusTriangles()
{
        // every 3 indices specify one triangle
        return num_torus_indices / 3;
}

/**
        counts the triangles of the sphere.
        sphere_precision / 2 + 1 strips with sphere_precision * 2 - 2 triangles each
*/
int Geometry::CountSphereTriangles()
{
        return sphere_precision * sphere_precision;
}


int Geometry::CountTriangles(int objectType)
{
        int result = 0;

        switch(objectType)
        {
                case TEAPOT:
                        result = CountTeapotTriangles();
                        break;
                case TORUS:
                        result = CountTorusTriangles();
                        break;
                case SPHERE:    
                        result = CountSphereTriangles();
                        break;
                default:
                        break;
        }
        return result;
}


void Geometry::Transform()
{
        glMultMatrixd(mTransform);
}

void Geometry::CalcTransform()
{
        Matrix4x4 scale;
        Matrix4x4 xrot;
        Matrix4x4 yrot;
        Matrix4x4 zrot;
        Matrix4x4 transl;

        makeScaleMtx(scale, mScale, mScale, mScale);
        makeTranslationMtx(transl, mTranslation);
        makeRotationXMtx(xrot, mXRotation * PI_180);
        makeRotationYMtx(yrot, mYRotation * PI_180);
        makeRotationZMtx(zrot, mZRotation * PI_180);

        copyMatrix(mTransform, IDENTITY);
        mult(mTransform, mTransform, transl);
        mult(mTransform, mTransform, xrot);
        mult(mTransform, mTransform, yrot);
        mult(mTransform, mTransform, zrot);
        mult(mTransform, mTransform, scale);
}

/**
   renders a sphere with sphere_precision subdivisions.
   note: works only for even sphere_precision
*/
void Geometry::RenderSphere()
{
        Vector3 vertex;

        // this algorithm renders the triangles clockwise
        glFrontFace(GL_CW);

        for (int j = 0; j < sphere_precision/2; ++j) 
        {
                double alpha = j * PI * 2.0 / (double)sphere_precision - PI_2;
                double beta = (j + 1) * PI * 2.0 / (double)sphere_precision - PI_2;

                glBegin(GL_TRIANGLE_STRIP);

                for (int i = 0; i <= sphere_precision; ++i) 
                {
                        double gamma = i * PI * 2.0 / (double)sphere_precision;
        
                        vertex[0] = sphere_radius * cos(beta) * cos(gamma);
                        vertex[1] = sphere_radius * sin(beta);
                        vertex[2] = sphere_radius * cos(beta) * sin(gamma);

                        glNormal3dv(vertex);
                        glVertex3dv(vertex);

                        vertex[0] = sphere_radius * cos(alpha) * cos(gamma);
                        vertex[1] = sphere_radius * sin(alpha);
                        vertex[2] = sphere_radius * cos(alpha) * sin(gamma);

                    glNormal3dv(vertex);
                        glVertex3dv(vertex);

                }
                glEnd();
        }
        glFrontFace(GL_CCW);
}