/*
 * vertexLists.cpp
 *
 *  Created on: Feb 13, 2013
 *      Author: debure
 */

/* flat and non-flat assemblies of triangles */

#include <stdlib.h>
#include <GL/glut.h>

GLfloat vertices[][3] = { { -1.5, -0.5, 0 }, { -0.5, -0.5, 0 },
		{ -0.5, 0.5, 0 }, { -1.5, 0.5, 0 }, { -1, 0, 0 } };

GLfloat colors[][3] = { { 1.0, 0.0, 0.0 },    // colors[0] = red
		{ 0.0, 0.0, 1.0 } };   // colors[1] = blue

void drawPolygons() {
	glBegin(GL_POLYGON);
		glColor3f(1.0, 0.0, 1.0);
		glVertex3f(1.5, -0.5, 0);
		glVertex3f(0.5, -0.5, 0);
		glVertex3f(1.0, 0.5, 0);
	glEnd();

	glBegin(GL_POLYGON);
		glColor3fv(colors[0]);
		glVertex3fv(vertices[0]);
		glVertex3fv(vertices[1]);
		glVertex3fv(vertices[2]);
	glEnd();

	/*
	glEnableClientState(GL_VERTEX_ARRAY);   //  must have this set to use glDrawElements
	glVertexPointer(3, GL_FLOAT, 0, vertices);   // tells where the array of vertices is located
	GLubyte indices[3]={0,1,2};
	glDrawElements(GL_POLYGON, 3, GL_UNSIGNED_BYTE, indices);  // second parameter is length of array
    */
}

void display() {

	glClear(GL_COLOR_BUFFER_BIT);
    glColor3f(1.0, 1.0, 1.0);

	/* viewing transformation */
	glLoadIdentity();
	gluLookAt(0.0, 0.0, 5.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
	                          // first three values are camera pos
	                          // next three are camera direction
	                          // last three are up vector
	drawPolygons();

	glFlush();
}

void init() {
	glClearColor(0.0, 0.0, 0.0, 0.0);

	glShadeModel(GL_FLAT);
	glMatrixMode(GL_PROJECTION);        // specify which matrices are affected
	glLoadIdentity();                   // start with a new transformation matrix

	// Use an orthographic view
	glOrtho(-2.0, 2.0, -2.0, 2.0, 2.0, 20.0);

	glMatrixMode(GL_MODELVIEW);
}

int main(int argc, char **argv) {
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
	glutInitWindowSize(500, 500);
	glutCreateWindow("Vertex Lists");
    init();
	glutDisplayFunc(display);

	glutMainLoop();
	return 0;
}