HydroSDL/oGL_graphics/wave_z_compute_byHand.cpp

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struct seaDatas
{
        float *z;
        float *R;
        float *G;
        float *B;
        int N;
        float L;
};


#include <math.h>

#include "Sea.h"


#define pi 3.14159265358979
#define LUTLEN 64
#define LUTLENF 64.0f


float sinLUT[LUTLEN]; 
float cosLUT[LUTLEN]; 

seaDatas seaDat;
seaDatas *sd = &seaDat;




void fillWaveLuts()
{
        int k;
        for (k=0; k<LUTLEN; k++)
        {
                sinLUT[k] = sin(((float)k)*(2.0f*pi)/(LUTLENF-1.0f));
                cosLUT[k] = cos(((float)k)*(2.0f*pi)/(LUTLENF-1.0f));
        }
}



__inline float Wcos(float xarg)
{
        float x;
        x = xarg/(2*pi);
        if (x<0) x=-x;
        x = x - (float (int (x)));
        x *= LUTLENF;
        return cosLUT[int(x)];
}



__inline float Wsin(float xarg)
{
        return Wcos(xarg-pi/2.0f);
}



void wave_init()//graphicDatas *gd)
{
        long k;
        int N;

        sd->N = 64;
        sd->L = 150.0;//100

        N = sd->N;

        sd->z = new float [N*N];
        sd->R = new float [N*N];
        sd->G = new float [N*N];
        sd->B = new float [N*N];

        for (k=0; k<N*N; k++) sd->z[k]=0.0f;

        //Fill LUTs:
        fillWaveLuts();
}


void wave_z_compute(datas *d)//, graphicDatas *gd)
{
        float x,y, a,b;
        long i, j, iN, k;
        long N;
        float L;

        N=sd->N;
        L=sd->L;
        
        x = (float)d->x;
        y = (float)d->y;

        for (i=0; i<N; i++)
        {
                iN=i*N;
                a = x - (L/2.0f)+i*(L/((float)N-1.0f));
                for (j=0; j<N; j++)
                {
                        b = y - (L/2.0f)+j*(L/((float)N-1.0f));
                        k = iN+j;

                        //sd->z[k] = d->Wave_amp0*sin(2.0*pi*(a*cos(d->Wave_angle0)/d->Lambda0+b*sin(d->Wave_angle0)/d->Lambda0+d->V_wave0/d->Lambda0*d->t))+d->Wave_amp1*sin(2.0*pi*(a*cos(d->Wave_angle1)/d->Lambda1+b*sin(d->Wave_angle1)/d->Lambda1+d->V_wave1/d->Lambda1*d->t))+d->Wave_amp2*sin(2.0*pi*(a*cos(d->Wave_angle2)/d->Lambda2+b*sin(d->Wave_angle2)/d->Lambda2+d->V_wave2/d->Lambda2*d->t)); 
                        sd->z[k] = d->Wave_amp0*Wsin(2.0*pi*(a*Wcos(d->Wave_angle0)/d->Lambda0+b*Wsin(d->Wave_angle0)/d->Lambda0+d->V_wave0/d->Lambda0*d->t))+d->Wave_amp1*Wsin(2.0*pi*(a*Wcos(d->Wave_angle1)/d->Lambda1+b*Wsin(d->Wave_angle1)/d->Lambda1+d->V_wave1/d->Lambda1*d->t))+d->Wave_amp2*Wsin(2.0*pi*(a*Wcos(d->Wave_angle2)/d->Lambda2+b*Wsin(d->Wave_angle2)/d->Lambda2+d->V_wave2/d->Lambda2*d->t)); 
                        //sd->z[k] = 0.0f;
                }
        }

}



void free_wave_variables()//graphicDatas *gd)
{

        delete [] sd->z;
        delete [] sd->R;
        delete [] sd->G;
        delete [] sd->B;
}



void Draw_sea()//graphicDatas *gd)
{
        float x,y, a,b, dl;
        long i, j, iN, k;
        long N;
        float L;

        N=sd->N;
        L=sd->L;


        dl = L/((float)N-1);

        glEnable(GL_BLEND) ;
        glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA) ; 
        
        glBegin(GL_QUADS);
        for (i=0; i<(N-1); i++)
        {
                iN=i*N;
                a = 0.0 - (L/2.0f)+i*(L/((float)N-1.0f));//a = x - (L/2.0f)+i*(L/((float)N-1.0f));
                for (j=0; j<(N-1); j++)
                {
                        b = 0.0 - (L/2.0f)+j*(L/((float)N-1.0f));//b = y - (L/2.0f)+j*(L/((float)N-1.0f));
                        k = iN+j;
                        glNormal3f(0.0,0.0,1.0);
                        glColor4f(0.0f,0.1f*(sd->z[k]+2.0f),0.5f*(sd->z[k]+2.0f),0.7f);
                                glVertex3f(a,    b ,   sd->z[k]);       
                        glColor4f(0.0f,0.1f*(sd->z[k+N]+2.0f),0.5f*(sd->z[k+N]+2.0f),0.7f);
                                glVertex3f(a+dl, b ,   sd->z[k+N]);     
                        glColor4f(0.0f,0.1f*(sd->z[k+N+1]+2.0f),0.5f*(sd->z[k+N+1]+2.0f),0.7f);
                                glVertex3f(a+dl, b+dl, sd->z[k+N+1]);
                        glColor4f(0.0f,0.1f*(sd->z[k+1]+2.0f),0.5f*(sd->z[k+1]+2.0f),0.7f);
                                glVertex3f(a,    b+dl, sd->z[k+1]);
                }
        }
        glEnd();
}

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