#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;
#define ALPHA 0.75f
#define DELTATRANS        0.05f

GLenum shademode = GL_FLAT;

GLfloat ex = 0.0f;
GLfloat ey = 0.0f;
GLfloat ez = -600.0f;

GLfloat cx = 0.0f;
GLfloat cy = 0.0f;
GLfloat cz = 0.0f;
GLfloat deltatrans = DELTATRANS;
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 wluz[4];
GLfloat msombra[16];

#define    checkImageWidth 256
#define    checkImageHeight 256
#define subImageWidth 64
#define subImageHeight 64
static GLubyte checkImage[checkImageHeight][checkImageWidth][4];
//static GLubyte otherImage[checkImageHeight][checkImageWidth][4];
static GLubyte subImage[subImageHeight][subImageWidth][4];
static GLuint texName[1];
///////////////////////////////////////////////////////////

void makeCheckImages(void)
{
	int i, j, c;

	for (i = 0; i < checkImageHeight; i++) {
		for (j = 0; j < checkImageWidth; j++) {
			c = ((((i & 0x8) == 0) ^ ((j & 0x8)) == 0)) * 255;
			checkImage[i][j][0] = (GLubyte)c;
			checkImage[i][j][1] = (GLubyte)c;
			checkImage[i][j][2] = (GLubyte)c;
			checkImage[i][j][3] = (GLubyte)255;

			//c = ((((i&0x10)==0)^((j&0x10))==0))*255;
			//      otherImage[i][j][0] = (GLubyte) 0;
			//      otherImage[i][j][1] = (GLubyte) 0;
			//      otherImage[i][j][2] = (GLubyte) c;
			//      otherImage[i][j][3] = (GLubyte) 255;
		}
	}

	for (i = 0; i < subImageHeight; i++) {
		for (j = 0; j < subImageWidth; j++) {
			c = ((((i & 0x4) == 0) ^ ((j & 0x4)) == 0)) * 255;
			subImage[i][j][0] = (GLubyte)c;
			subImage[i][j][1] = (GLubyte)0;
			subImage[i][j][2] = (GLubyte)0;
			subImage[i][j][3] = (GLubyte)255;
		}
	}
}


void Buff_Light()
{
	wluz[0] = vluz[0];
	wluz[1] = vluz[1];
	wluz[2] = vluz[2];
	wluz[3] = vluz[3];
}

void SetLightPos()
{
	vluz[0] = wluz[0];  vluz[1] = wluz[1];
	vluz[2] = wluz[2];  vluz[3] = wluz[3];
	//glLightfv(GL_LIGHT0, GL_POSITION, lightPos);
	//gltMakeShadowMatrix(vGroundPlane, lightPos, shadowMat);
}

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 color shading model to flat
	glShadeModel(shademode);

	makeCheckImages();
	glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

	glGenTextures(1, texName);
	glBindTexture(GL_TEXTURE_2D, texName[0]);

	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, checkImageWidth, checkImageHeight,
		0, GL_RGBA, GL_UNSIGNED_BYTE, checkImage);

	glTexSubImage2D(GL_TEXTURE_2D, 0, 48, 170, subImageWidth,
		subImageHeight, GL_RGBA, GL_UNSIGNED_BYTE, subImage);
	glTexSubImage2D(GL_TEXTURE_2D, 0, 48, 48, subImageWidth,
		subImageHeight, GL_RGBA, GL_UNSIGNED_BYTE, subImage);
	glTexSubImage2D(GL_TEXTURE_2D, 0, 170, 48, subImageWidth,
		subImageHeight, GL_RGBA, GL_UNSIGNED_BYTE, subImage);
	glTexSubImage2D(GL_TEXTURE_2D, 0, 170, 170, subImageWidth,
		subImageHeight, GL_RGBA, GL_UNSIGNED_BYTE, subImage);


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


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();
}

void cuadro_con_texture(){
	glEnable(GL_TEXTURE_2D);
	glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
	glBindTexture(GL_TEXTURE_2D, texName[0]);
	glBegin(GL_QUADS);

	glTexCoord2f(0.0, 0.0);  glVertex3f(1.0f, 1.0f, .0f); //glVertex3f( 400.0f, -150.0f, -700.0f); //glVertex3f(-2.0, -1.0, 0.0);
	glTexCoord2f(0.0, 1.0);  glVertex3f(1.0f, -1.0f, .0f); //glVertex3f(-400.0f, -150.0f, -700.0f); //glVertex3f(-2.0, 1.0, 0.0);
	glTexCoord2f(1.0, 1.0);  glVertex3f(-1.0f, -1.0f, .0f); //glVertex3f(-400.0f, -150.0f, 200.0f); //glVertex3f(0.0, 1.0, 0.0);
	glTexCoord2f(1.0, 0.0);  glVertex3f(-1.0f, 1.0f, .0f); //glVertex3f(400.0f, -150.0f, 200.0f);//glVertex3f(0.0, -1.0, 0.0);

	glEnd();
	// glFlush();
	glDisable(GL_TEXTURE_2D);

	//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();
}

void rayas_sobre_cuadro_sin_color(){

	glBegin(GL_LINES);
	int i;
	for (i = 0; i <= 10; i++)
	{
		glVertex3f(1.0f - i / 5.f, 1.0f, .0f);
		glVertex3f(1.0f - i / 5.f, -1.0f, .0f);
	}

	for (i = 0; i <= 10; i++)
	{
		glVertex3f(1.0f, 1.0f - i / 5.f, .0f);
		glVertex3f(-1.0f, 1.0f - i / 5.f, .0f);
	}
	glEnd();
}



// Called to draw scene
void luz(){
	glColor4f(1.f, 1.f, .0f, 1.f);
	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*/
	glColor4f(.7f, .7f, .7f, ALPHA);
	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();
	glColor4f(.0f, .0f, .0f, ALPHA);
	glDisable(GL_DEPTH_TEST);
	rayas_sobre_cuadro_sin_color();
	if (bDepth)  glEnable(GL_DEPTH_TEST);
	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();

	//4a cara     
	glPushMatrix();
	glRotatef(270.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
	glColor4f(0.0f, 1.0f, 0.0f, ALPHA);
	glPushMatrix();
	glTranslatef(0.f, 0.f, 50.f);
	glScalef(50.f, 50.f, 50.f);
	cuadro_sin_color();
	glPopMatrix();

	//2a cara
	glColor4f(1.0f, 1.0f, 0.0f, ALPHA);
	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
	glColor4f(1.0f, .0f, 0.0f, ALPHA);
	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();

	//4a cara     
	glPushMatrix();
	glRotatef(270.f, 0.f, 1.f, 0.f);
	glPushMatrix();
	glTranslatef(0.f, 0.f, 50.f);
	glScalef(50.f, 50.f, 50.f);
	cuadro_con_texture();
	glPopMatrix();
	glPopMatrix();
}
void StencilConfig()
{// step 1
	// 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);
	// end step 1
}


void RenderScene(void)
{
	// Reset coordinate system

	glLoadIdentity();
	gluLookAt(ex, ey, ez, cx, cy, cz, 0.0, 1.0, 0.0);

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

		///////////
		glFrontFace(GL_CW);      // cambiar orientacion de poligonos para invertir los lados delanteros y traseros
		glPushMatrix();                  // recordar la matriz actual

			/*  dibujar mundo invertido */

			glScalef(1.0f, -1.0f, 1.0f);
			glTranslatef(0.0f, -2.0f*ALTP/*-? */, 0.0f);
			StencilConfig();
			luz();
			objetos_mundo();
			glDisable(GL_STENCIL_TEST);
			/*   restaurar el mundo normal*/
		glPopMatrix();      //restaurar matriz
		glFrontFace(GL_CCW);      // restaurar orientación

		//////////
		glEnable(GL_BLEND);
		glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
		piso();
		glDisable(GL_BLEND);

		luz();

		objetos_mundo();
		glColor4f(0.3f, 0.3f, 0.3f, ALPHA);

		glEnable(GL_BLEND);
		glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
		glDisable(GL_DEPTH_TEST);
		StencilConfig();
		SombradeMiMundo();
		glDisable(GL_STENCIL_TEST);
		glDisable(GL_BLEND);

		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, dy, dz;


	if (key == GLUT_KEY_F7)//Move light toward the center of ground
	{
		Buff_Light();
		dx = cx - wluz[0]; dy = cy - wluz[1];    dz = cz - wluz[2];
		dx *= (1.0 - deltatrans); dy *= (1.0 - deltatrans);
		dz *= (1.0 - deltatrans);
		wluz[0] = cx - dx;  wluz[1] = cy - dy; wluz[2] = cz - dz;

		SetLightPos();
		// Calculate new projection matrix to draw shadow on the ground

		glutPostRedisplay(); return;
	}
	if (key == GLUT_KEY_F8)//Move light outward the center of ground
	{
		Buff_Light();

		dx = cx - wluz[0]; dy = cy - wluz[1];    dz = cz - wluz[2];

		dx /= (1.0 - deltatrans); dy /= (1.0 - deltatrans);
		dz /= (1.0 - deltatrans);
		wluz[0] = cx - dx;  wluz[1] = cy - dy; wluz[2] = cz - dz;

		SetLightPos();
		// Calculate new projection matrix to draw shadow on the ground

		glutPostRedisplay(); return;
	}


	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();
}



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