#include "stdafx.h"
#define GL_PI 3.1415f

#define ALTP -150.f
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 = 0.0f;
GLfloat ez = -600.0f;
GLfloat delta = 0.01f;
GLfloat deltaR = 0.01f;

GLfloat vP[] = { 0.f, 1.f, 0.f, -ALTP };
GLfloat vluz[] = { 0.f, 250.f, -50.f, 1.f };
GLfloat msombra[16];
///////////////////////////////////////////////////////////

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 SetupRC()
{
	// Black background
	glClearColor(0.0f, 0.0f, 0.0f, 1.0f);

	// Set drawing color to green
	glColor3f(0.0f, 1.0f, 0.0f);

	// 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_CW);
}


void cuadro_sin_color(){

	glBegin(GL_QUADS);
	glVertex3f(1.0f, 1.0f, .0f);
	glVertex3f(1.0f, -1.0f, .0f);
	glVertex3f(-1.0f, -1.0f, .0f);
	glVertex3f(-1.0f, 1.0f, .0f);

	glEnd();
}

// Called to draw scene
void luz(){
	glColor3f(1.f, 1.f, .0f);
	glPushMatrix();
	glTranslatef(vluz[0]/*0.f*/, vluz[1]/*250.f*/,
		vluz[2]/*-50.f*/);
	glScalef(5.f, 5.f, 5.f); //piso 3 veces mas ancho que cubo
	glutSolidSphere(1., 20, 20);
	glPopMatrix();
}
void piso(){   /*función agregada 23/05/2018*/
	glColor3f(.7f, .7f, .7f);
	glPushMatrix();
	glTranslatef(0.f, -vP[3]/*-150.f*/, 50.f);
	glRotatef(270.f, 1.f, 0.f, 0.f);     //la version          glRotatef(90.f, 1.f, 0.f, 0.f);     
	// voltea el piso al la cara invisible
	glScalef(250.f, 250.f, 250.f); //piso 3 veces mas ancho que cubo
	cuadro_sin_color();
	glPopMatrix();
}

void objetos_mundo_sin_color(){
	//primera cara    
	glPushMatrix();
	glTranslatef(0.f, 0.f, 50.f);
	glScalef(50.f, 50.f, 50.f);
	cuadro_sin_color();
	glPopMatrix();

	//2a cara     
	glPushMatrix();
	glRotatef(90.f, 0.f, 1.f, 0.f);
	glPushMatrix();
	glTranslatef(0.f, 0.f, 50.f);
	glScalef(50.f, 50.f, 50.f);
	cuadro_sin_color();
	glPopMatrix();
	glPopMatrix();

	//3a cara     
	glPushMatrix();
	glRotatef(180.f, 0.f, 1.f, 0.f);
	glPushMatrix();
	glTranslatef(0.f, 0.f, 50.f);
	glScalef(50.f, 50.f, 50.f);
	cuadro_sin_color();
	glPopMatrix();
	glPopMatrix();
}

void SombradeMiMundo(){
	glPushMatrix();
	gltMakeShadowMatrix(vP/*GLfloat vPlaneEquation[]*/,
		vluz/*GLfloat vLightPos[]*/, msombra/*GLfloat destMat[]*/);
	glMultMatrixf(msombra);
	objetos_mundo_sin_color();
	glPopMatrix();
}


void objetos_mundo(){
	//primera cara
	glColor3f(0.0f, 1.0f, 0.0f);
	glPushMatrix();
	glTranslatef(0.f, 0.f, 50.f);
	glScalef(50.f, 50.f, 50.f);
	cuadro_sin_color();
	glPopMatrix();

	//2a cara
	glColor3f(1.0f, 1.0f, 0.0f);
	glPushMatrix();
	glRotatef(90.f, 0.f, 1.f, 0.f);
	glPushMatrix();
	glTranslatef(0.f, 0.f, 50.f);
	glScalef(50.f, 50.f, 50.f);
	cuadro_sin_color();
	glPopMatrix();
	glPopMatrix();

	//3a cara
	glColor3f(1.0f, .0f, 0.0f);
	glPushMatrix();
	glRotatef(180.f, 0.f, 1.f, 0.f);
	glPushMatrix();
	glTranslatef(0.f, 0.f, 50.f);
	glScalef(50.f, 50.f, 50.f);
	cuadro_sin_color();
	glPopMatrix();
	glPopMatrix();
}


void RenderScene(void)
{
	// Reset coordinate system

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

	// Clear the window and the depth buffer
	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 back side as a wireframe only, if flag is set
	if (bOutline)glPolygonMode(GL_BACK, GL_LINE);
	else        glPolygonMode(GL_BACK, GL_FILL);

	// Save matrix state and do the rotation
	glPushMatrix();
	glRotatef(xRot, 1.0f, 0.0f, 0.0f);
	glRotatef(yRot, 0.0f, 1.0f, 0.0f);

	luz();

	piso();

	objetos_mundo();
	glColor3f(0.5f, 0.5f, 0.5f);

	glDisable(GL_DEPTH_TEST);
	SombradeMiMundo();
	if (bDepth)  glEnable(GL_DEPTH_TEST);

	glPopMatrix();

	// Flush drawing commands
	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, 1500.0);
	glMatrixMode(GL_MODELVIEW);
}

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


	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);
	}
	// Refresh the Window
	glutPostRedisplay();

	// Refresh the Window
	glutPostRedisplay();
}



int main(int argc, char** argv)
{
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
	glutInitWindowSize(200, 200);
	glutInitWindowPosition(100, 100);
	glutCreateWindow(argv[0]);
	glutDisplayFunc(RenderScene);
	glutReshapeFunc(ChangeSize);
	glutSpecialFunc(SpecialKeys);
	SetupRC();
	glutMainLoop();
	return 0;
}