SDL2 + OpenGL - Collision detection script

CollisionDetection.cpp

#include <SDL2/SDL.h>
#include <SDL2/SDL_opengl.h>

float MOVEMENT_SPEED=0.08;

const Uint8 *key=SDL_GetKeyboardState(NULL);

SDL_Window *window;
SDL_Event event;
SDL_GLContext glContext;

struct WindowData{
        int WIDTH=800, HEIGHT=800;
        int POS_X=SDL_WINDOWPOS_CENTERED, POS_Y=SDL_WINDOWPOS_CENTERED;
        const char *TITLE="TEST";
        int FLAG=SDL_WINDOW_OPENGL;
        SDL_Color FILLCOLOR={0, 0, 0, 1};
} WindowData;

struct CharacterData{
        int WIDTH=100, HEIGHT=100;
        float POS_X=WindowData.WIDTH/2-WIDTH/2, POS_Y=WindowData.HEIGHT/2-HEIGHT/2;
        SDL_Color FILLCOLOR={255, 0, 0, 255};
} CharacterData;

struct ObjectData{
        int WIDTH=100, HEIGHT=100;
        float POS_X=100, POS_Y=100;
        SDL_Color FILLCOLOR={0, 0, 255, 255};
} ObjectData;

bool getCollisionX(float x, float y){
        if(CharacterData.POS_X>=ObjectData.POS_X-(CharacterData.WIDTH-x)&&
           CharacterData.POS_X<=ObjectData.POS_X+(ObjectData.WIDTH-y))
                return true;
        else
                return false;
}

bool getCollisionY(float x, float y){
        if(CharacterData.POS_Y>=ObjectData.POS_Y-(CharacterData.HEIGHT-x)&&
           CharacterData.POS_Y<=ObjectData.POS_Y+(ObjectData.HEIGHT-y))
                return true;
        else
                return false;
}

bool collisionWasDetected(float x, float y, float _x, float _y){
        if(getCollisionY(_x, _y)&&getCollisionX(x, y))
                return true;
        else
                return false;
}

void controller(){
        if(key[SDL_SCANCODE_D]){

                if(collisionWasDetected(0, ObjectData.WIDTH, 0.5, 0.5)){
                        MOVEMENT_SPEED=0.04;
                        if(ObjectData.POS_X<=WindowData.WIDTH-ObjectData.WIDTH)
                                ObjectData.POS_X+=0.04;
                }
                else
                        MOVEMENT_SPEED=0.08;
                if(!collisionWasDetected(0, ObjectData.WIDTH, 0.5, 0.5)){
                        if(CharacterData.POS_X<=WindowData.WIDTH-CharacterData.WIDTH)
                                CharacterData.POS_X+=MOVEMENT_SPEED;
                }
                else{
                        if(CharacterData.POS_X<=WindowData.WIDTH-(CharacterData.WIDTH+ObjectData.WIDTH))
                                CharacterData.POS_X+=MOVEMENT_SPEED;
                }
        }
        if(key[SDL_SCANCODE_A]){
                if(collisionWasDetected(ObjectData.WIDTH, 0, 0.5, 0.5)){
                        MOVEMENT_SPEED=0.04;
                        if(ObjectData.POS_X>=0)
                                ObjectData.POS_X-=0.04;
                }
                else
                        MOVEMENT_SPEED=0.08;
                if(!collisionWasDetected(ObjectData.WIDTH, 0, 0.5, 0.5)){
                        if(CharacterData.POS_X>=0)
                                CharacterData.POS_X-=MOVEMENT_SPEED;
                }
                else{
                        if(CharacterData.POS_X>=ObjectData.WIDTH)
                                CharacterData.POS_X-=MOVEMENT_SPEED;
                }
        }
        if(key[SDL_SCANCODE_W]){
                if(collisionWasDetected(0.5, 0.5, ObjectData.HEIGHT, 0)){
                        MOVEMENT_SPEED=0.04;
                        if(ObjectData.POS_Y>=0)
                                ObjectData.POS_Y-=0.04;
                }
                else
                        MOVEMENT_SPEED=0.08;
                if(!collisionWasDetected(0.5, 0.5, ObjectData.HEIGHT, 0)){
                        if(CharacterData.POS_Y>=0)
                                CharacterData.POS_Y-=MOVEMENT_SPEED;
                }
                else{
                        if(CharacterData.POS_Y>=ObjectData.HEIGHT)
                                CharacterData.POS_Y-=MOVEMENT_SPEED;
                }
        }
        if(key[SDL_SCANCODE_S]){
                if(collisionWasDetected(0.5, 0.5, 0, ObjectData.HEIGHT)){
                        MOVEMENT_SPEED=0.04;
                        if(ObjectData.POS_Y<=WindowData.HEIGHT-ObjectData.HEIGHT)
                                ObjectData.POS_Y+=0.04;
                }
                else
                        MOVEMENT_SPEED=0.08;
                if(!collisionWasDetected(0.5, 0.5, 0, ObjectData.HEIGHT)){
                        if(CharacterData.POS_Y<=WindowData.HEIGHT-CharacterData.HEIGHT)
                                CharacterData.POS_Y+=MOVEMENT_SPEED;
                }
                else{
                        if(CharacterData.POS_Y<=WindowData.HEIGHT-(CharacterData.HEIGHT+ObjectData.HEIGHT))
                                CharacterData.POS_Y+=MOVEMENT_SPEED;
                }
        }
}

int main(){
        window=SDL_CreateWindow(WindowData.TITLE, WindowData.POS_X, WindowData.POS_Y, WindowData.WIDTH, WindowData.HEIGHT, WindowData.FLAG);

        SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 2);
        SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);

        glContext=SDL_GL_CreateContext(window);

        SDL_GL_SetSwapInterval(SDL_FALSE);

        while(window!=NULL){
                while(SDL_PollEvent(&event)){
                        switch(event.type){
                                case SDL_QUIT:
                                        window=NULL;
                                        break;
                        }
                }

                glClearColor(WindowData.FILLCOLOR.r,
                                         WindowData.FILLCOLOR.g,
                                         WindowData.FILLCOLOR.b,
                                         WindowData.FILLCOLOR.a);
                glClear(GL_COLOR_BUFFER_BIT);

                controller();

                glViewport(0, 0, WindowData.WIDTH, WindowData.HEIGHT);
                glMatrixMode(GL_PROJECTION);
                glLoadIdentity();
                glOrtho(0, WindowData.WIDTH, WindowData.HEIGHT, 0, -10, 10);

                glPushMatrix();
                glEnable(GL_BLEND);
                glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
                glTranslatef(CharacterData.POS_X, CharacterData.POS_Y, 0);
                glBegin(GL_QUADS);
                        glColor4ub(CharacterData.FILLCOLOR.r, CharacterData.FILLCOLOR.g, 
                                           CharacterData.FILLCOLOR.b, CharacterData.FILLCOLOR.a);
                        glVertex2f(0,                                      0);
                        glVertex2f(CharacterData.WIDTH,                                    0);
                        glVertex2f(CharacterData.WIDTH, CharacterData.HEIGHT);
                        glVertex2f(0,                                   CharacterData.HEIGHT);
                glEnd();
                glDisable(GL_BLEND);
                glPopMatrix();

                glPushMatrix();
                glEnable(GL_BLEND);
                glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
                glTranslatef(ObjectData.POS_X, ObjectData.POS_Y, 0);
                glBegin(GL_QUADS);
                        glColor4ub(ObjectData.FILLCOLOR.r, ObjectData.FILLCOLOR.g, 
                                           ObjectData.FILLCOLOR.b, ObjectData.FILLCOLOR.a);
                        glVertex2f(0,                                                            0);
                        glVertex2f(ObjectData.WIDTH,                             0);
                        glVertex2f(ObjectData.WIDTH, ObjectData.HEIGHT);
                        glVertex2f(0,                            ObjectData.HEIGHT);
                glEnd();
                glDisable(GL_BLEND);
                glPopMatrix();

                if(key[SDL_SCANCODE_ESCAPE])
                        window=NULL;

                SDL_GL_SwapWindow(window);
        }
}