OpenGL tutorial 15 - functions.cpp

//http://www.youtube.com/user/thecplusplusguy
//Thanks for the typed in code to Tapit85
#include "functions.h"

float camX = 0., camY = 0., camZ = 5.;
float camYaw = 0.;
float camPitch = 0.;
enum {SKY_LEFT = 0, SKY_BACK, SKY_RIGHT, SKY_FRONT, SKY_TOP, SKY_BOTTOM};
unsigned int skybox[6];
#ifndef M_PI
#define M_PI 3.1415926535
#endif

void initSkybox()
{
    skybox[SKY_LEFT] = loadTexture("left.bmp");
    skybox[SKY_BACK] = loadTexture("back.bmp");
    skybox[SKY_RIGHT] = loadTexture("right.bmp");
    skybox[SKY_FRONT] = loadTexture("front.bmp");
    skybox[SKY_TOP] = loadTexture("top.bmp");
    skybox[SKY_BOTTOM] = loadTexture("bottom.bmp");
}

void killskybox()
{
    glDeleteTextures(6,&skybox[0]);
}

void lockCamera()
{
    if(camPitch > 90)
        camPitch = 90;
    if(camPitch < -90)
        camPitch = -90;
    if(camYaw < 0.)
        camYaw += 360.;
    if(camYaw > 360.)
        camYaw -= 360;
}

void moveCamera(float dist, float dir)
{
    float rad = (camYaw+dir)*M_PI/180.;
    camX -= sin(rad)*dist;
    camZ -= cos(rad)*dist;
}

void moveCameraUp(float dist, float dir)
{
    float rad = (camPitch+dir)*M_PI/180.;
    camY += sin(rad)*dist;
}

void Control(float movevel, float mousevel, bool mi)
{
    if(mi)
    {
        int MidX = 320;
        int MidY = 240;
        SDL_ShowCursor(SDL_DISABLE);
        int tmpx, tmpy;
        SDL_GetMouseState(&tmpx, &tmpy);
        camYaw += mousevel*(MidX-tmpx);
        camPitch += mousevel*(MidY-tmpy);
        lockCamera();
        SDL_WarpMouse(MidX, MidY);
        Uint8* state = SDL_GetKeyState(NULL);
        if(state[SDLK_w])
        {
            if(camPitch!=90 && camPitch!=-90)   // comment in if you want to be able to go up and down
                moveCamera(movevel,0.);
            moveCameraUp(movevel,0.);               // comment in if you want to be able to go up and down
        }
        else if(state[SDLK_s])
        {
            if(camPitch!=90 && camPitch!=-90)   // comment in if you want to be able to go up and down
                moveCamera(movevel,180.);
            moveCameraUp(movevel,180.);         // comment in if you want to be able to go up and down
        }
        if(state[SDLK_a])
            moveCamera(movevel,90.);
        else if(state[SDLK_d])
            moveCamera(movevel,270.);
    }
    glRotatef(-camPitch,1.,0.,0.);
    glRotatef(-camYaw,0.,1.,0.);
}

void UpdateCamera()
{
    glTranslatef(-camX,-camY,-camZ);
}

void drawCube(float size)
{
    glBegin(GL_QUADS);
        // front face
        glColor3f(1.0,0.0,0.0);
        glVertex3f(size/2,size/2,size/2);
        glVertex3f(-size/2,size/2,size/2);
        glVertex3f(-size/2,-size/2,size/2);
        glVertex3f(size/2,-size/2,size/2);
        // left face
        glColor3f(0.0,1.0,0.0);
        glVertex3f(-size/2,size/2,size/2);
        glVertex3f(-size/2,-size/2,size/2);
        glVertex3f(-size/2,-size/2,-size/2);
        glVertex3f(-size/2,size/2,-size/2);
        // back face
        glColor3f(0.0,0.0,1.0);
        glVertex3f(size/2,size/2,-size/2);
        glVertex3f(-size/2,size/2,-size/2);
        glVertex3f(-size/2,-size/2,-size/2);
        glVertex3f(size/2,-size/2,-size/2);
        // right face
        glColor3f(1.0,1.0,0.0);
        glVertex3f(size/2,size/2,size/2);
        glVertex3f(size/2,-size/2,size/2);
        glVertex3f(size/2,-size/2,-size/2);
        glVertex3f(size/2,size/2,-size/2);
        // top face
        glColor3f(1.0,0.0,1.0);
        glVertex3f(size/2,size/2,size/2);
        glVertex3f(-size/2,size/2,size/2);
        glVertex3f(-size/2,size/2,-size/2);
        glVertex3f(size/2,size/2,-size/2);
        // bottom face
        glColor3f(0.0,1.0,1.0);
        glVertex3f(size/2,-size/2,size/2);
        glVertex3f(-size/2,-size/2,size/2);
        glVertex3f(-size/2,-size/2,-size/2);
        glVertex3f(size/2,-size/2,-size/2);
    glEnd();
}

void drawSkybox(float size)
{
    glDisable(GL_LIGHTING);
    glDisable(GL_DEPTH_TEST);
    glEnable(GL_TEXTURE_2D);
    glBindTexture(GL_TEXTURE_2D,skybox[SKY_BACK]);
    glBegin(GL_QUADS);
        // back face
        glTexCoord2f(0,0);
        glVertex3f(size/2,size/2,size/2);
        glTexCoord2f(1,0);
        glVertex3f(-size/2,size/2,size/2);
        glTexCoord2f(1,1);
        glVertex3f(-size/2,-size/2,size/2);
        glTexCoord2f(0,1);
        glVertex3f(size/2,-size/2,size/2);
    glEnd();
    glBindTexture(GL_TEXTURE_2D,skybox[SKY_LEFT]);
    glBegin(GL_QUADS);
        // left face
        glTexCoord2f(0,0);
        glVertex3f(-size/2,size/2,size/2);
        glTexCoord2f(0,1);
        glVertex3f(-size/2,-size/2,size/2);
        glTexCoord2f(1,1);
        glVertex3f(-size/2,-size/2,-size/2);
        glTexCoord2f(1,0);
        glVertex3f(-size/2,size/2,-size/2);
    glEnd();
    glBindTexture(GL_TEXTURE_2D,skybox[SKY_FRONT]);
    glBegin(GL_QUADS);
        // front face
        glTexCoord2f(1,0);
        glVertex3f(size/2,size/2,-size/2);
        glTexCoord2f(0,0);
        glVertex3f(-size/2,size/2,-size/2);
        glTexCoord2f(0,1);
        glVertex3f(-size/2,-size/2,-size/2);
        glTexCoord2f(1,1);
        glVertex3f(size/2,-size/2,-size/2);
    glEnd();
    glBindTexture(GL_TEXTURE_2D,skybox[SKY_RIGHT]);
    glBegin(GL_QUADS);
        // right face
        glTexCoord2f(1,0);
        glVertex3f(size/2,size/2,size/2);
        glTexCoord2f(1,1);
        glVertex3f(size/2,-size/2,size/2);
        glTexCoord2f(0,1);
        glVertex3f(size/2,-size/2,-size/2);
        glTexCoord2f(0,0);
        glVertex3f(size/2,size/2,-size/2);
    glEnd();
    glBindTexture(GL_TEXTURE_2D,skybox[SKY_TOP]);
    glBegin(GL_QUADS);
        // top face
        glTexCoord2f(1,0);
        glVertex3f(size/2,size/2,size/2);
        glTexCoord2f(0,0);
        glVertex3f(-size/2,size/2,size/2);
        glTexCoord2f(0,1);
        glVertex3f(-size/2,size/2,-size/2);
        glTexCoord2f(1,1);
        glVertex3f(size/2,size/2,-size/2);
    glEnd();
    glBindTexture(GL_TEXTURE_2D,skybox[SKY_BOTTOM]);
    glBegin(GL_QUADS);
        // bottom face
        glTexCoord2f(1,1);
        glVertex3f(size/2,-size/2,size/2);
        glTexCoord2f(0,1);
        glVertex3f(-size/2,-size/2,size/2);
        glTexCoord2f(0,0);
        glVertex3f(-size/2,-size/2,-size/2);
        glTexCoord2f(1,0);
        glVertex3f(size/2,-size/2,-size/2);
    glEnd();
    glEnable(GL_LIGHTING);
    glEnable(GL_DEPTH_TEST);
    glDisable(GL_TEXTURE_2D);
}

unsigned int loadTexture(const char* filename)
{
    unsigned int num;
    glGenTextures(1,&num);
    SDL_Surface* img = SDL_LoadBMP(filename);
    glBindTexture(GL_TEXTURE_2D,num);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_CLAMP);  // needed if you don't want to see the edges of the skybox
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_CLAMP);  // needed if you don't want to see the edges of the skybox
    glTexImage2D(GL_TEXTURE_2D,0,GL_RGB,img->w,img->h,0,GL_RGB,GL_UNSIGNED_SHORT_5_6_5,img->pixels);
    SDL_FreeSurface(img);
    return num;
}