#include "stdafx.h"

#define GL_PI 3.1415f



GLfloat colors[][3] = { { 0.0, 0.0, 0.0 },{ 1.0, 0.0, 0.0 },
{ 1.0, 1.0, 0.0 },{ 0.0, 1.0, 0.0 },{ 0.0, 0.0, 1.0 },
{ 1.0, 0.0, 1.0 },{ 1.0, 1.0, 1.0 },{ 0.0, 1.0, 1.0 } };

GLfloat pis[4] = { 0., 1., 0., 250. },
foco[4] = { 55., 150., -35., 1.f }, msobmra[16];
GLfloat ALFA = 0.75f;

void unit_square() {
	glBegin(GL_QUADS);
	glVertex2f(-1., -1.);
	glVertex2f(1., -1.);
	glVertex2f(1., 1.);
	glVertex2f(-1., 1.);
	glEnd();
}

void rayas()
{
	glBegin(GL_LINES);
	int i;
	for (i = 0; i<11; i++) {
		glVertex2f(-1., -1. + i*2. / 10.);
		glVertex2f(1., -1. + i*2. / 10.);
	}
	for (i = 0; i<11; i++) {
		glVertex2f(1. - i*2. / 10., -1.);
		glVertex2f(1. - i*2. / 10., 1.);
	}
	glEnd();
}

void piso() {
	glPushMatrix();
	glTranslatef(0, -pis[3], 0);
	glRotatef(270, 1.0f, 0.0f, 0.0f);
	glScalef(150., 150., 150.);
	glColor4f(0.75, 0.75, 0.75, ALFA);
	unit_square();
	glColor4f(0., 0., 0., ALFA);
	rayas();
	glPopMatrix();
}

void luz() {
	glColor4f(1., 1., 0., 1.);
	glPushMatrix();
	glTranslatef(foco[0], foco[1], foco[2]);
	glScalef(10., 10., 10.);
	glutSolidSphere(1, 20, 20);
	glPopMatrix();

}
void colorcube1(void) {
	glPushMatrix();
	glScalef(50., 50., 50.);
	//1a cara
	glPushMatrix();
	glTranslatef(0., 0., 1.);
	glColor3fv(colors[1]);
	unit_square();
	glPopMatrix();
	//2a cara
	glPushMatrix();
	glRotatef(90., 0., 1., 0.);
	glTranslatef(0., 0., 1.);
	glColor3fv(colors[3]);
	unit_square();
	glPopMatrix();

	//etc. ...
	glPopMatrix();
}

void colorcube2(void) {
	glPushMatrix();
	glScalef(50., 50., 50.);
	//1a cara
	glPushMatrix();
	glTranslatef(0., 0., 1.);
	glColor4f(1.0, 0.0, 0.0, ALFA);
	unit_square();
	glPopMatrix();
	//2a cara
	glPushMatrix();
	glRotatef(90., 0., 1., 0.);
	glTranslatef(0., 0., 1.);
	glColor4f(0.0, 1.0, 0.0, ALFA);
	unit_square();
	glPopMatrix();

	//etc. ...
	glPopMatrix();
}

void cubo_sin_color(void) {
	glPushMatrix();
	glScalef(50., 50., 50.);
	//1a cara
	glPushMatrix();
	glTranslatef(0., 0., 1.);

	unit_square();
	glPopMatrix();
	//2a cara
	glPushMatrix();
	glRotatef(90., 0., 1., 0.);
	glTranslatef(0., 0., 1.);

	unit_square();
	glPopMatrix();

	//etc. ...
	glPopMatrix();
}

GLfloat xRot = 0.45f;
GLfloat yRot = 0.35f;
GLboolean bCull = glIsEnabled(GL_CULL_FACE);
GLboolean bDepth = glIsEnabled(GL_DEPTH_TEST);
GLboolean bOutline = (GLboolean)true;

GLenum shademode = GL_FLAT;

GLfloat ex = 0.0f;
GLfloat ey = 100.0f;
GLfloat ez = -700.0f;
GLfloat delta = 0.01f;
GLfloat deltaR = 0.01f;
///////////////////////////////////////////////////////////
void gltMakeShadowMatrix(GLfloat vPlaneEquation[], GLfloat vLightPos[], GLfloat destMat[])
{
	GLfloat dot;

	// Dot product of plane and light position
	dot = vPlaneEquation[0] * vLightPos[0] + vPlaneEquation[1] * vLightPos[1] +
		vPlaneEquation[2] * vLightPos[2] + vPlaneEquation[3] * vLightPos[3];

	// Now do the projection
	// First column
	destMat[0] = dot - vLightPos[0] * vPlaneEquation[0];
	destMat[4] = 0.0f - vLightPos[0] * vPlaneEquation[1];
	destMat[8] = 0.0f - vLightPos[0] * vPlaneEquation[2];
	destMat[12] = 0.0f - vLightPos[0] * vPlaneEquation[3];

	// Second column
	destMat[1] = 0.0f - vLightPos[1] * vPlaneEquation[0];
	destMat[5] = dot - vLightPos[1] * vPlaneEquation[1];
	destMat[9] = 0.0f - vLightPos[1] * vPlaneEquation[2];
	destMat[13] = 0.0f - vLightPos[1] * vPlaneEquation[3];

	// Third Column
	destMat[2] = 0.0f - vLightPos[2] * vPlaneEquation[0];
	destMat[6] = 0.0f - vLightPos[2] * vPlaneEquation[1];
	destMat[10] = dot - vLightPos[2] * vPlaneEquation[2];
	destMat[14] = 0.0f - vLightPos[2] * vPlaneEquation[3];

	// Fourth Column
	destMat[3] = 0.0f - vLightPos[3] * vPlaneEquation[0];
	destMat[7] = 0.0f - vLightPos[3] * vPlaneEquation[1];
	destMat[11] = 0.0f - vLightPos[3] * vPlaneEquation[2];
	destMat[15] = dot - vLightPos[3] * vPlaneEquation[3];
}

void SombraCubo() {
	glPushMatrix();
	gltMakeShadowMatrix(pis, foco, msobmra);
	glMultMatrixf(msobmra);
	glColor4f(0.7, 0.7, 0.7, ALFA);
	cubo_sin_color();
	glPopMatrix();
}
void SetupRC()
{
	// Black background
	glClearColor(0.0f, 0.0f, 0.0f, 1.0f);


	// Set color shading model to flat
	glShadeModel(shademode);

	// Clockwise-wound polygons are front facing; this is reversed
	// because we are using triangle fans
	glFrontFace(GL_CCW);
}


void Stencil_Config() {
	// turning off writing to the color buffer and depth buffer so we only
	// write to stencil buffer
	glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE);
	glDepthMask(GL_FALSE);

	// enable stencil buffer
	glEnable(GL_STENCIL_TEST);

	// write a one to the stencil buffer everywhere we are about to draw
	glStencilFunc(GL_ALWAYS, 1, 0xFFFFFFFF);

	// this is to always pass a one to the stencil buffer where we draw
	glStencilOp(GL_REPLACE, GL_REPLACE, GL_REPLACE);

	// render the plane which the shadow will be on
	// color and depth buffer are disabled, only the stencil buffer
	// will be modified
	piso();
	// turn the color and depth buffers back on
	glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
	glDepthMask(GL_TRUE);
	// until stencil test is diabled, only write to areas where the
	// stencil buffer has a one. This is to draw the shadow only on
	// the floor.
	glStencilFunc(GL_EQUAL, 1, 0xFFFFFFFF);
	// don't modify the contents of the stencil buffer
	glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
}

// Called to draw scene

void RenderScene(void)
{
	// Reset coordinate system

	glLoadIdentity();
	gluLookAt(ex, ey, ez, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);

	GLfloat x, y, angle;         // Storage for coordinates and angles
	int iPivot = 1;            // Used to flag alternating colors

							   // Clear the window and the depth buffer
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
	//glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	// Turn culling on if flag is set
	if (bCull)   glEnable(GL_CULL_FACE);
	else        glDisable(GL_CULL_FACE);

	// Enable depth testing if flag is set
	if (bDepth)  glEnable(GL_DEPTH_TEST);
	else        glDisable(GL_DEPTH_TEST);

	// Draw the front /*back*/ side as a wireframe only, if flag is set
	if (bOutline)glPolygonMode(/*GL_BACK*/GL_FRONT, GL_LINE);
	else        glPolygonMode(/*GL_BACK*/GL_FRONT, GL_FILL);

	glPushMatrix();
	glRotatef(xRot, 1.0f, 0.0f, 0.0f);
	glRotatef(yRot, 0.0f, 1.0f, 0.0f);
	Stencil_Config();

	glFrontFace(GL_CW); //cambio de orientacion
						//para ver objetos reflejados

	glPushMatrix();
	glTranslatef(0., -pis[3], 0.); //trabnsformaciones
	glScalef(1., -1., 1.);         // de
	glTranslatef(0., pis[3], 0.);  //reflejo
	colorcube1();    //dibujar el mundo
	luz();           //en espejo
	glPopMatrix();
	glEnable(GL_BLEND);
	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
	glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
	glDisable(GL_DEPTH_TEST); // para luchar con errores de redondeo
	SombraCubo();       //dibujar sombra mezclandola con reflejo
	if (bDepth)  glEnable(GL_DEPTH_TEST);
	else        glDisable(GL_DEPTH_TEST);
	glDisable(GL_STENCIL_TEST);
	if (bOutline)glPolygonMode(/*GL_BACK*/GL_FRONT, GL_LINE);
	else        glPolygonMode(/*GL_BACK*/GL_FRONT, GL_FILL);

	//floor
	glFrontFace(GL_CCW);
	piso();     //dibujar piso mezclandolo con reflejo+sombra
	glDisable(GL_BLEND);

	colorcube2();/*colorcube1();*/
	luz();
	glPopMatrix();
	// Flush drawing commands
	glFlush();// glutSwapBuffers();
}

// Called by GLUT library when the window has changed size

void ChangeSize(GLsizei w, GLsizei h)
{    // Set Viewport to window dimensions
	glViewport(0, 0, (GLsizei)w, (GLsizei)h);

	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();

	//glOrtho (-100.0, 100.0, -100, 100, -270.0, 270.0);
	//glFrustum (-1.0, 1.0, -1.0, 1.0, 1.5, 20.0);
	gluPerspective(60.0, 1.0, 1.5, 2500.0);
	glMatrixMode(GL_MODELVIEW);
}

void SpecialKeys(int key, int x, int y)
{
	GLfloat dx, dz, dy;


	if (key == GLUT_KEY_UP)
	{//increase distance from camera to origin
		ex *= (1.0f + deltaR);  ey *= (1.0f + deltaR);    ez *= (1.0f + deltaR);
	}

	if (key == GLUT_KEY_DOWN)
	{//reduce distance from camera to origin (close up)
		ex *= (1.0f - deltaR); ey *= (1.0f - deltaR);    ez *= (1.0f - deltaR);
	}

	if (key == GLUT_KEY_LEFT)
		//Rotate camera around origin in Oxz plane
	{
		dx = -ez;     dz = ex;
		GLfloat s = sqrtf(ex*ex + ey*ey + ez*ez);
		ex += delta*dx;       ez += delta*dz;
		GLfloat s1 = sqrtf(ex*ex + ey*ey + ez*ez) / s;
		ex /= s1;    ey /= s1;    ey /= s1;
	}

	if (key == GLUT_KEY_RIGHT)
		//Rotate camera around origin in Oxz plane
	{
		dx = -ez;     dz = ex;
		GLfloat s = sqrtf(ex*ex + ey*ey + ez*ez);
		ex -= delta*dx;          ez -= delta*dz;
		GLfloat s1 = sqrtf(ex*ex + ey*ey + ez*ez) / s;
		ex /= s1;    ey /= s1;    ey /= s1;
	}


	if (key == GLUT_KEY_F1) bCull = !bCull;
	if (key == GLUT_KEY_F2)bDepth = !bDepth;
	if (key == GLUT_KEY_F3)bOutline = !bOutline;
	if (key == GLUT_KEY_F4)
	{
		if (shademode == GL_FLAT) { shademode = GL_SMOOTH; }
		else { if (shademode == GL_SMOOTH) { shademode = GL_FLAT; } };
		glShadeModel(shademode);
	}

	if (key == GLUT_KEY_F5)//Rotate camera around origin in Oyz plane
	{
		dy = -ez;     dz = ey;
		GLfloat s = sqrtf(ex*ex + ey*ey + ez*ez);
		ey -= delta*dy;          ez -= delta*dz;
		GLfloat s1 = sqrtf(ex*ex + ey*ey + ez*ez) / s;
		ex /= s1;    ey /= s1;    ey /= s1;
	}

	if (key == GLUT_KEY_F6)//Rotate camera around origin in Oyz plane
	{
		dy = -ez;     dz = ey;
		GLfloat s = sqrtf(ex*ex + ey*ey + ez*ez);
		ey += delta*dy;          ez += delta*dz;
		GLfloat s1 = sqrtf(ex*ex + ey*ey + ez*ez) / s;
		ex /= s1;    ey /= s1;    ey /= s1;
	}

	// Refresh the Window
	glutPostRedisplay();
}

int main(int argc, char** argv)
{
	glutInit(&argc, argv);
	glutInitDisplayMode(/*GLUT_DOUBLE*/GLUT_SINGLE | GLUT_RGBA | GLUT_STENCIL);
	// glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
	glutInitWindowSize(200, 200);
	glutInitWindowPosition(100, 100);
	glutCreateWindow(argv[0]);
	glutDisplayFunc(RenderScene);
	glutReshapeFunc(ChangeSize);
	glutSpecialFunc(SpecialKeys);

	SetupRC();
	glutMainLoop();
	return 0;
}