Updated GLWater

#define WIN32_LEAN_AND_MEAN
#define WIN32_EXTRA_LEAN
#include <windows.h>
#include <cmath>
#include <gl/gl.h>
#include <gl/glu.h>
#include "GLWater.h"

#define MAP_WIDTH       20
#define MAP_HEIGHT      20
#define MAP_SCALE       1
#define WAVE_Y_SCALE    0.15f

float terrain[MAP_WIDTH][MAP_HEIGHT][3];
float deformData[MAP_WIDTH][MAP_HEIGHT];
DWORD lastTime;
float timeCoefficient = 0.0f;

float x_pos = 0.0f;
float y_pos = 5.0f;
float z_pos = 20.0f;
float x_look = 0.0f;
float y_look = -5.0f;


///////////////////////////////////////////////////////////////////////////////
// Fast lookup table
#define MAX_CIRCLE_ANGLE            512
#define HALF_MAX_CIRCLE_ANGLE       256
#define RECIP_HALF_MAX_CIRCLE_ANGLE 0.00390625f
#define QUARTER_MAX_CIRCLE_ANGLE    128
#define MASK_MAX_CIRCLE_ANGLE       511
#define PI                          3.1415926535897932f
#define PI_RECIPRICAL               0.3183098861837907f

float fast_cossin_table[MAX_CIRCLE_ANGLE];

float FAST_SIN(float n) {
    float f = n * HALF_MAX_CIRCLE_ANGLE * PI_RECIPRICAL;
    int i = int(f);
    if (i < 0)
        return fast_cossin_table[(-((-i)&MASK_MAX_CIRCLE_ANGLE)) + MAX_CIRCLE_ANGLE];
    return fast_cossin_table[i&MASK_MAX_CIRCLE_ANGLE];
}

float FAST_COS(float n) {
    float f = n * HALF_MAX_CIRCLE_ANGLE * PI_RECIPRICAL;
    int i = int(f);
    if (i < 0)
        return fast_cossin_table[((-i) + QUARTER_MAX_CIRCLE_ANGLE)&MASK_MAX_CIRCLE_ANGLE];
    return fast_cossin_table[(i + QUARTER_MAX_CIRCLE_ANGLE)&MASK_MAX_CIRCLE_ANGLE];
}

inline void SetupSinCosLookupTable() {
    for (int i = 0 ; i < MAX_CIRCLE_ANGLE ; i++) {
        fast_cossin_table[i] = (float)sin((double)i * PI * RECIP_HALF_MAX_CIRCLE_ANGLE);
    }
}
///////////////////////////////////////////////////////////////////////////////


void Initialize() {
    SetupSinCosLookupTable();

    glPolygonMode( GL_FRONT_AND_BACK, GL_LINE );
    timeCoefficient = 0.0f;

    for (int z = 0; z < MAP_WIDTH; ++z) {
        for (int x = 0; x < MAP_HEIGHT; ++x) {
            deformData[x][z] = (x == 0) ? 0.0f : float(FAST_SIN(x)) * WAVE_Y_SCALE;
            deformData[x][z] += (z == 0) ? 0.0f : float(FAST_SIN(z)) * WAVE_Y_SCALE;

            terrain[x][z][0] = -10.0f +  x * MAP_SCALE;
            terrain[x][z][1] = deformData[x][z];
            terrain[x][z][2] = -1.0f * (-10.0f + z) * MAP_SCALE;
        }
    }

    lastTime = GetTickCount();
}

void RenderWater() {
    for (int z = 0; z < MAP_WIDTH - 1; ++z) {
        glBegin(GL_TRIANGLE_STRIP);
        for (int x = 0; x < MAP_HEIGHT - 1; ++x) {
            glColor3f(1.0f, 0.0f, 0.0f);
            glVertex3f(terrain[x][z][0], terrain[x][z][1], terrain[x][z][2]);

            glColor3f(1.0f, 0.0f, 0.0f);
            glVertex3f(terrain[x + 1][z][0], terrain[x + 1][z][1], terrain[x + 1][z][2]);

            glColor3f(1.0f, 0.0f, 0.0f);
            glVertex3f(terrain[x][z + 1][0], terrain[x][z + 1][1], terrain[x][z + 1][2]);

            glColor3f(1.0f, 0.0f, 0.0f);
            glVertex3f(terrain[x + 1][z + 1][0], terrain[x + 1][z + 1][1], terrain[x + 1][z + 1][2]);
        }
        glEnd();
    }
}

void Update() {
    DWORD thisTime = GetTickCount();
    float deltaTime = (float)(thisTime - lastTime) * 0.001f;
    lastTime = thisTime;

    timeCoefficient += deltaTime;

    for (int z = 0; z < MAP_WIDTH; ++z) {
        for (int x = 0; x < MAP_HEIGHT; ++x) {
            deformData[x][z] = float(FAST_SIN(x + timeCoefficient)) * WAVE_Y_SCALE;
            deformData[x][z] += float(FAST_SIN(z + timeCoefficient)) * WAVE_Y_SCALE;

            terrain[x][z][1] = deformData[x][z];
        }
    }

    if (GetAsyncKeyState('W')) z_pos -= deltaTime * 3.0f;
    else if (GetAsyncKeyState('S')) z_pos += deltaTime * 3.0f;
    if (GetAsyncKeyState('A')) x_pos += deltaTime * 3.0f;
    else if (GetAsyncKeyState('D')) x_pos -= deltaTime * 3.0f;
    if (GetAsyncKeyState('Q')) y_pos += deltaTime * 3.0f;
    else if (GetAsyncKeyState('E')) y_pos -= deltaTime * 3.0f;
    if (GetAsyncKeyState('R')) y_look += deltaTime * 3.0f;
    else if (GetAsyncKeyState('F')) y_look -= deltaTime * 3.0f;
    if (GetAsyncKeyState('Z')) x_look += deltaTime * 3.0f;
    else if (GetAsyncKeyState('X')) x_look -= deltaTime * 3.0f;
    if (GetAsyncKeyState('C')) x_look = 0.0f;
    if (GetAsyncKeyState('V')) y_look = -5.0f;
}

void Shutdown() {

}

void Suspend(bool paused) {

}

void Render() {
    glClearColor(0.5f, 0.5f, 0.5f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);

    glMatrixMode(GL_MODELVIEW);
    glPushMatrix();
    glLoadIdentity();

    gluLookAt(x_pos, y_pos, z_pos, x_pos + x_look, y_pos + y_look, z_pos - 20.0f, 0.0f, 1.0f, 0.0f);

    RenderWater();

    glPopMatrix();
}