#include "stdafx.h"

#define checkImageHeight 256
#define checkImageWidth 256
#define subImageHeight 64
#define subImageWidth 64
static GLubyte checkImage[checkImageHeight][checkImageWidth][4];
static GLubyte otherImage[checkImageHeight][checkImageWidth][4];

static GLubyte subImage[subImageHeight][subImageWidth][4];
static GLuint texName[2];

GLfloat ALFA = 0.3;

GLfloat colors[][3] = { { .3,.30,0.30 },{ 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 } };

#define GL_PI 3.1415f

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 = 50.0f;
GLfloat ez = -120.0f;
GLfloat delta = 0.01f;
GLfloat deltaR = 0.01f;

GLfloat datos_luz[4] = { 15., 55., 0., 1. };
GLfloat datos_piso[4] = { 0., 1. , 0., 50. };
GLfloat MatrizSombra[16];

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 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);

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

	makeCheckImages();
	glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

	glGenTextures(2, 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);

	glBindTexture(GL_TEXTURE_2D, texName[1]);
	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,
		otherImage);
}


void cuadrado_con_textura() {
	glEnable(GL_TEXTURE_2D);
	glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
	
	glBindTexture(GL_TEXTURE_2D, texName[0]);
	glBegin(GL_POLYGON);
	glTexCoord2f(0.0, 0.0); glVertex3f(-1., -1., 0);
	glTexCoord2f(0.0, 1.0); glVertex3f(-1., 1., 0);
	glTexCoord2f(1.0, 1.0);   glVertex3f(1., 1., 0);
	glTexCoord2f(1.0, 0.0); glVertex3f(1., -1., 0);
	glEnd();

	glDisable(GL_TEXTURE_2D);
}
void cuadrado_unitario() {
	glBegin(GL_POLYGON);
	glVertex3f(-1., -1., 0);
	glVertex3f(-1., 1., 0);
	glVertex3f(1., 1., 0);
	glVertex3f(1., -1., 0);
	glEnd();
}
#define NUMLIN 10
void lineas() {
	glColor3f(1., 1., 1.);
	glBegin(GL_LINES);
	for (int i = 0; i < NUMLIN; i++)
	{
		glVertex3f(-1. + i * 2. / (NUMLIN - 1.), -1., 0);
		glVertex3f(-1. + i * 2. / (NUMLIN - 1.), 1., 0);

		glVertex3f(-1., 1. - i * 2. / (NUMLIN - 1.), 0);
		glVertex3f(1., 1. - i * 2. / (NUMLIN - 1.), 0);
	}
	glEnd();
}

void colorcube2(void)
{
	/* map vertices to faces */
	glPushMatrix();
	glScalef(10., 10., 10.);
	//cara1
	glColor3fv(colors[0]);
	glPushMatrix();
	glTranslatef(0., 0, 1.);
	cuadrado_con_textura();
	//cuadrado_unitario();
	glPopMatrix();
	//cara2
	glColor3fv(colors[1]);
	glPushMatrix();
	glRotatef(90., 0., 1., 0.);
	glTranslatef(0., 0, 1.);
	cuadrado_unitario();
	glPopMatrix();
	//cara3
	glColor3fv(colors[2]);
	glPushMatrix();
	glRotatef(180., 0., 1., 0.);
	glTranslatef(0., 0, 1.);
	cuadrado_unitario();
	glPopMatrix();

	//cara4
	glColor3fv(colors[3]);
	glPushMatrix();
	glRotatef(270., 0., 1., 0.);
	glTranslatef(0., 0, 1.);
	cuadrado_unitario();
	glPopMatrix();

	//cara5
	glColor3fv(colors[4]);
	glPushMatrix();
	glRotatef(90., 0., 0., 1.);
	glRotatef(270., 0., 1., 0.);
	glTranslatef(0., 0, 1.);
	cuadrado_unitario();
	glPopMatrix();

	//cara6
	glColor3fv(colors[5]);
	glPushMatrix();
	glRotatef(-90., 0., 0., 1.);
	glRotatef(270., 0., 1., 0.);
	glTranslatef(0., 0, 1.);
	cuadrado_unitario();
	glPopMatrix();

	glPopMatrix();
}


void colorcube_sincolor(void)
{
	/* map vertices to faces */
	glPushMatrix();
	glScalef(10., 10., 10.);
	//cara1
	//glColor3fv(colors[0]);
	glPushMatrix();
	glTranslatef(0., 0, 1.);
	cuadrado_con_textura();	//cuadrado_unitario();
	glPopMatrix();
	//cara2
	//glColor3fv(colors[1]);
	glPushMatrix();
	glRotatef(90., 0., 1., 0.);
	glTranslatef(0., 0, 1.);
	cuadrado_unitario();
	glPopMatrix();
	//cara3
	//glColor3fv(colors[2]);
	glPushMatrix();
	glRotatef(180., 0., 1., 0.);
	glTranslatef(0., 0, 1.);
	cuadrado_unitario();
	glPopMatrix();

	//cara4
	//glColor3fv(colors[3]);
	glPushMatrix();
	glRotatef(270., 0., 1., 0.);
	glTranslatef(0., 0, 1.);
	cuadrado_unitario();
	glPopMatrix();

	//cara5
	//glColor3fv(colors[4]);
	glPushMatrix();
	glRotatef(90., 0., 0., 1.);
	glRotatef(270., 0., 1., 0.);
	glTranslatef(0., 0, 1.);
	cuadrado_unitario();
	glPopMatrix();

	//cara6
	//glColor3fv(colors[5]);
	glPushMatrix();
	glRotatef(-90., 0., 0., 1.);
	glRotatef(270., 0., 1., 0.);
	glTranslatef(0., 0, 1.);
	cuadrado_unitario();
	glPopMatrix();

	glPopMatrix();
}


void SombradeMiMundo(GLfloat datosdeLuz[], GLfloat datosdePlano[]) {
	glColor4f(0.4, 0.4, 0.4, ALFA);
	glPushMatrix();
	//void gltMakeShadowMatrix(GLfloat vPlaneEquation[],
	//                      GLfloat vLightPos[], GLfloat destMat[])
	gltMakeShadowMatrix(datosdePlano, datosdeLuz, MatrizSombra);
	glMultMatrixf(MatrizSombra);
	colorcube_sincolor();/*Objetos_de_MiMundo();*/
	glPopMatrix();
}


// Called to draw scene
void piso() {

	glPushMatrix();
	glTranslatef(0., -datos_piso[3] /*-50.*/, 0.);
	glRotatef(-90., 1., 0, 0);
	glScalef(50., 50., 50.);
	glColor4f(0.7, 0.7, 0.7, ALFA);
	cuadrado_unitario();
	lineas();
	glPopMatrix();
}


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();//DrawFloor(0,0,0);

		   // 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);
}


void foquito() {
	glColor3f(1., 1., 0);
	glPushMatrix();
	glTranslatef(datos_luz[0], datos_luz[1], datos_luz[2]/*, 15., 55., 0.*/);
	glutSolidSphere(1.5, 20, 20);
	glPopMatrix();
}



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);

	// 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);
	/*inicia reflejo*/
	glEnable(GL_BLEND);
	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);


	glFrontFace(GL_CCW);
	glPushMatrix();
	glTranslatef(0.0f,/*+ o - ?*/-datos_piso[3], 0.0f);
	glScalef(1.0f, -1.0f, 1.0f);
	glTranslatef(0.0f, datos_piso[3], 0.0f);

	/*stencil para reflejo*/
	glEnable(GL_STENCIL_TEST);
	Stencil_Config();
	foquito();
	colorcube2();
	glDisable(GL_STENCIL_TEST);
	glPopMatrix();
	glFrontFace(GL_CW);
	/*fin reflejo*/

	/*objetos del mundo normal*/
	foquito();
	piso();
	colorcube2();
	glDisable(GL_BLEND);
	/*fin objetos del mundo normal*/

	/*stencil para sombra*/
	glEnable(GL_STENCIL_TEST);
	Stencil_Config();
	glEnable(GL_BLEND);
	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

	glDisable(GL_DEPTH_TEST);
	SombradeMiMundo(datos_luz, datos_piso);
	if (bDepth)  glEnable(GL_DEPTH_TEST);

	glDisable(GL_STENCIL_TEST);
	glDisable(GL_BLEND);
	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, 500.0);
	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_F5)datos_luz[1] *= (1.0f + deltaR);
	if (key == GLUT_KEY_F6)datos_luz[1] *= (1.0f - deltaR);
	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_STENCIL);
	glutInitWindowSize(200, 200);
	glutInitWindowPosition(100, 100);
	glutCreateWindow(argv[0]);
	glutDisplayFunc(RenderScene);
	glutReshapeFunc(ChangeSize);
	glutSpecialFunc(SpecialKeys);

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