lab3.cpp

#include "initShaders.h"
#include <cstdlib>
using namespace std;

void rotate(GLuint locate);

GLuint vaoID,vboID[2],eboID;
GLuint program;

GLfloat pit,yaw,scalar=1;
glm::vec3 triTran;

GLfloat size=10;

GLfloat vertexarray[]={
	-size, -size, size,
	size, size, size,
	size, -size, -size,
	-size, size, -size
};

GLfloat colorarray[]={
	0.0f,0.0f,1.0f,1.0f,
	1.0f,1.0f,1.0f,1.0f,
	1.0f,0.0f,1.0f,1.0f,
	0.0f,1.0f,0.0f,1.0f
};
											
 GLubyte elems[]={
	0,1,2,3,0,1
};

void init(){
	 glEnable(GL_DEPTH_TEST);
	 glViewport(0, 0, 600, 600);
	
	glGenVertexArrays(1,&vaoID);
	glBindVertexArray(vaoID);
	
	glGenBuffers(2, vboID);
	glBindBuffer(GL_ARRAY_BUFFER,vboID[0]);
	glBufferData(GL_ARRAY_BUFFER,sizeof(vertexarray),vertexarray,GL_STATIC_DRAW);
	glVertexAttribPointer(0,3,GL_FLOAT,GL_FALSE,0,(void*)0);
	
	glBindBuffer(GL_ARRAY_BUFFER, vboID[1]);
  glBufferData(GL_ARRAY_BUFFER,sizeof(colorarray),colorarray,GL_STATIC_DRAW);
  glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, 0, (void*)0);
  
  glGenBuffers(1,&eboID);
  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,eboID);
  glBufferData(GL_ELEMENT_ARRAY_BUFFER,sizeof(elems),elems,GL_STATIC_DRAW);

	ShaderInfo shaders[]={
  { GL_VERTEX_SHADER , "vertexshader.glsl"},
  { GL_FRAGMENT_SHADER , "fragmentshader.glsl"}, 
  { GL_NONE , NULL} 
  };
		
  program=initShaders(shaders);
  
  glEnableVertexAttribArray(0);
  glEnableVertexAttribArray(1);
  
}


void display(SDL_Window* screen){
	glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
	
	glm::mat4 trans;
	
	trans=glm::translate(trans,triTran);//translate the triangle
  trans=glm::rotate(trans,pit,glm::vec3(1,0,0));//rotate the triangle around the x axis
  trans=glm::rotate(trans,yaw,glm::vec3(0,1,0));//rotate the triangle arround the y axis
  trans=glm::scale(trans,glm::vec3(scalar));//scaling the triangle
    
  GLint tempLoc = glGetUniformLocation(program,"modelMatrix");//Matrix that handle the transformations
	glUniformMatrix4fv(tempLoc,1,GL_FALSE,&trans[0][0]);
	
	glDrawElements(GL_TRIANGLE_STRIP,24,GL_UNSIGNED_BYTE,NULL);
	glFlush();
	SDL_GL_SwapWindow(screen);
}

void input(SDL_Window* screen){

SDL_Event event;

	while (SDL_PollEvent(&event)){//Handling the keyboard
		switch (event.type){
			case SDL_QUIT:exit(0);break;
			case SDL_KEYDOWN:
				switch(event.key.keysym.sym){
					case SDLK_ESCAPE:exit(0);
					case SDLK_w:triTran.y+=2;break;
					case SDLK_s:triTran.y-=2;break;
					case SDLK_a:triTran.x-=2;break;
					case SDLK_d:triTran.x+=2;break;
					case SDLK_e:scalar+=.1f;break;
					case SDLK_q:scalar-=.1f;break;
					case SDLK_i:pit+=2;break;
					case SDLK_k:pit-=2;break;
					case SDLK_j:yaw+=2;break;
					case SDLK_l:yaw-=2;break;
				}
		/*case SDL_MOUSEMOTION:
				yaw+=((event.motion.x)-300)/10.0;
				pit+=((event.motion.y)-300)/10.0;
				SDL_WarpMouseInWindow(screen,300,300);
				
			}
			*/
		}
	}
}


int main(int argc, char **argv){
	
	//SDL window and context management
	SDL_Window *window;
	
	if(SDL_Init(SDL_INIT_VIDEO)<0){//initilizes the SDL video subsystem
		fprintf(stderr,"Unable to create window: %s\n", SDL_GetError());
    SDL_Quit();
    exit(1);//die on error
	}

	//create window
	window = SDL_CreateWindow(
		"Schwarz - Lab 3", //Window title
		SDL_WINDOWPOS_UNDEFINED, //initial x position
		SDL_WINDOWPOS_UNDEFINED, //initial y position
		500,							//width, in pixels
		500,							//height, in pixels
		SDL_WINDOW_OPENGL	//flags to be had
	);
	
	//check window creation
	if(window==NULL){
		fprintf(stderr,"Unable to create window: %s\n",SDL_GetError());
	}
	

	//creates opengl context associated with the window
	SDL_GLContext glcontext=SDL_GL_CreateContext(window);
	
	//initializes glew
  glewExperimental=GL_TRUE;
  if(glewInit()){
    fprintf(stderr, "Unable to initalize GLEW");
    exit(EXIT_FAILURE);
  }
  
	init();
	
	while(true){
	  input(window);//keyboard controls
		display(window);//displaying
	}

	SDL_GL_DeleteContext(glcontext);
  SDL_DestroyWindow(window);
  SDL_Quit();
 
  return 0;
}