#include "gles.h"
#include <cmath>
#include <cstdio>

static const float __glPi = 3.14159265358979323846f;

static void __gluMakeIdentityf(GLfloat m[16]);


void gluPerspective(GLfloat fovy, GLfloat aspect, GLfloat zNear, GLfloat zFar) {
    GLfloat m[4][4];
    GLfloat sine, cotangent, deltaZ;
    GLfloat radians=(GLfloat)(fovy/2.0f*__glPi/180.0f);

    deltaZ=zFar-zNear;
    sine=(GLfloat)sin(radians);
    if ((deltaZ==0.0f) || (sine==0.0f) || (aspect==0.0f))
    {
        return;
    }
    cotangent=(GLfloat)(cos(radians)/sine);

    __gluMakeIdentityf(&m[0][0]);
    m[0][0] = cotangent / aspect;
    m[1][1] = cotangent;
    m[2][2] = -(zFar + zNear) / deltaZ;
    m[2][3] = -1.0f;
    m[3][2] = -2.0f * zNear * zFar / deltaZ;
    m[3][3] = 0;
    glMultMatrixf(&m[0][0]);
}

void __gluMakeIdentityf(GLfloat m[16]) {
    m[0] = 1;  m[4] = 0;  m[8]  = 0;  m[12] = 0;
    m[1] = 0;  m[5] = 1;  m[9]  = 0;  m[13] = 0;
    m[2] = 0;  m[6] = 0;  m[10] = 1;  m[14] = 0;
    m[3] = 0;  m[7] = 0;  m[11] = 0;  m[15] = 1;
}

void glInit()
{
#ifndef OPENGL_ES
	
	GLenum err = glewInit();
	printf("Err: %d\n", err);
#endif
}

void anGenBuffers(GLsizei n, GLuint* buffers) {
#ifdef __EMSCRIPTEN__
    glGenBuffers(n, buffers);
#else
    static GLuint k = 1;
    for (int i = 0; i < n; ++i)
        buffers[i] = ++k;
#endif
}

#ifdef USE_VBO
void drawArrayVT(int bufferId, int vertices, int vertexSize /* = 24 */, unsigned int mode /* = GL_TRIANGLES */) {
	//if (Options::debugGl) LOGI("drawArray\n");
	glBindBuffer2(GL_ARRAY_BUFFER, bufferId);
	glTexCoordPointer2(2, GL_FLOAT, vertexSize, (GLvoid*) (3 * 4));
	glEnableClientState2(GL_TEXTURE_COORD_ARRAY);
	glVertexPointer2(3, GL_FLOAT, vertexSize, 0);
	glEnableClientState2(GL_VERTEX_ARRAY);
	glDrawArrays2(mode, 0, vertices);
	glDisableClientState2(GL_VERTEX_ARRAY);
	glDisableClientState2(GL_TEXTURE_COORD_ARRAY);
}

#ifndef drawArrayVT_NoState
void drawArrayVT_NoState(int bufferId, int vertices, int vertexSize /* = 24 */) {
	//if (Options::debugGl) LOGI("drawArray\n");
	glBindBuffer2(GL_ARRAY_BUFFER, bufferId);
	glTexCoordPointer2(2, GL_FLOAT, vertexSize, (GLvoid*) (3 * 4));
	//glEnableClientState2(GL_TEXTURE_COORD_ARRAY);
	glVertexPointer2(3, GL_FLOAT, vertexSize, 0);
	//glEnableClientState2(GL_VERTEX_ARRAY);
	glDrawArrays2(GL_TRIANGLES, 0, vertices);
	//glDisableClientState2(GL_VERTEX_ARRAY);
	//glDisableClientState2(GL_TEXTURE_COORD_ARRAY);
}
#endif

void drawArrayVTC(int bufferId, int vertices, int vertexSize /* = 24 */) {
	//if (Options::debugGl) LOGI("drawArray\n");
	//LOGI("draw-vtc: %d, %d, %d\n", bufferId, vertices, vertexSize);
	glEnableClientState2(GL_VERTEX_ARRAY);
	glEnableClientState2(GL_TEXTURE_COORD_ARRAY);
	glEnableClientState2(GL_COLOR_ARRAY);

	glBindBuffer2(GL_ARRAY_BUFFER, bufferId);

	glVertexPointer2(  3, GL_FLOAT, vertexSize, 0);
	glTexCoordPointer2(2, GL_FLOAT, vertexSize, (GLvoid*) (3 * 4));
	glColorPointer2(4, GL_UNSIGNED_BYTE, vertexSize, (GLvoid*) (5*4));

	glDrawArrays2(GL_TRIANGLES, 0, vertices);

	glDisableClientState2(GL_VERTEX_ARRAY);
	glDisableClientState2(GL_TEXTURE_COORD_ARRAY);
	glDisableClientState2(GL_COLOR_ARRAY); 
}

#ifndef drawArrayVTC_NoState
void drawArrayVTC_NoState(int bufferId, int vertices, int vertexSize /* = 24 */) {
	glBindBuffer2(GL_ARRAY_BUFFER, bufferId);

	glVertexPointer2(  3, GL_FLOAT, vertexSize, 0);
	glTexCoordPointer2(2, GL_FLOAT, vertexSize, (GLvoid*) (3 * 4));
	glColorPointer2(4, GL_UNSIGNED_BYTE, vertexSize, (GLvoid*) (5*4));

	glDrawArrays2(GL_TRIANGLES, 0, vertices);
}
#endif

#endif


//
// Code borrowed from OpenGL.org
// http://www.opengl.org/wiki/GluProject_and_gluUnProject_code
// The gluUnProject code in Android seems to be broken
//

void MultiplyMatrices4by4OpenGL_FLOAT(float *result, float *matrix1, float *matrix2)
{
	result[0]=matrix1[0]*matrix2[0]+
		matrix1[4]*matrix2[1]+
		matrix1[8]*matrix2[2]+
		matrix1[12]*matrix2[3];
	result[4]=matrix1[0]*matrix2[4]+
		matrix1[4]*matrix2[5]+
		matrix1[8]*matrix2[6]+
		matrix1[12]*matrix2[7];
	result[8]=matrix1[0]*matrix2[8]+
		matrix1[4]*matrix2[9]+
		matrix1[8]*matrix2[10]+
		matrix1[12]*matrix2[11];
	result[12]=matrix1[0]*matrix2[12]+
		matrix1[4]*matrix2[13]+
		matrix1[8]*matrix2[14]+
		matrix1[12]*matrix2[15];
	result[1]=matrix1[1]*matrix2[0]+
		matrix1[5]*matrix2[1]+
		matrix1[9]*matrix2[2]+
		matrix1[13]*matrix2[3];
	result[5]=matrix1[1]*matrix2[4]+
		matrix1[5]*matrix2[5]+
		matrix1[9]*matrix2[6]+
		matrix1[13]*matrix2[7];
	result[9]=matrix1[1]*matrix2[8]+
		matrix1[5]*matrix2[9]+
		matrix1[9]*matrix2[10]+
		matrix1[13]*matrix2[11];
	result[13]=matrix1[1]*matrix2[12]+
		matrix1[5]*matrix2[13]+
		matrix1[9]*matrix2[14]+
		matrix1[13]*matrix2[15];
	result[2]=matrix1[2]*matrix2[0]+
		matrix1[6]*matrix2[1]+
		matrix1[10]*matrix2[2]+
		matrix1[14]*matrix2[3];
	result[6]=matrix1[2]*matrix2[4]+
		matrix1[6]*matrix2[5]+
		matrix1[10]*matrix2[6]+
		matrix1[14]*matrix2[7];
	result[10]=matrix1[2]*matrix2[8]+
		matrix1[6]*matrix2[9]+
		matrix1[10]*matrix2[10]+
		matrix1[14]*matrix2[11];
	result[14]=matrix1[2]*matrix2[12]+
		matrix1[6]*matrix2[13]+
		matrix1[10]*matrix2[14]+
		matrix1[14]*matrix2[15];
	result[3]=matrix1[3]*matrix2[0]+
		matrix1[7]*matrix2[1]+
		matrix1[11]*matrix2[2]+
		matrix1[15]*matrix2[3];
	result[7]=matrix1[3]*matrix2[4]+
		matrix1[7]*matrix2[5]+
		matrix1[11]*matrix2[6]+
		matrix1[15]*matrix2[7];
	result[11]=matrix1[3]*matrix2[8]+
		matrix1[7]*matrix2[9]+
		matrix1[11]*matrix2[10]+
		matrix1[15]*matrix2[11];
	result[15]=matrix1[3]*matrix2[12]+
		matrix1[7]*matrix2[13]+
		matrix1[11]*matrix2[14]+
		matrix1[15]*matrix2[15];
}

void MultiplyMatrixByVector4by4OpenGL_FLOAT(float *resultvector, const float *matrix, const float *pvector)
{
	resultvector[0]=matrix[0]*pvector[0]+matrix[4]*pvector[1]+matrix[8]*pvector[2]+matrix[12]*pvector[3];
	resultvector[1]=matrix[1]*pvector[0]+matrix[5]*pvector[1]+matrix[9]*pvector[2]+matrix[13]*pvector[3];
	resultvector[2]=matrix[2]*pvector[0]+matrix[6]*pvector[1]+matrix[10]*pvector[2]+matrix[14]*pvector[3];
	resultvector[3]=matrix[3]*pvector[0]+matrix[7]*pvector[1]+matrix[11]*pvector[2]+matrix[15]*pvector[3];
}

#define SWAP_ROWS_DOUBLE(a, b) { double *_tmp = a; (a)=(b); (b)=_tmp; }
#define SWAP_ROWS_FLOAT(a, b) { float *_tmp = a; (a)=(b); (b)=_tmp; }
#define MAT(m,r,c) (m)[(c)*4+(r)]

//This code comes directly from GLU except that it is for float
int glhInvertMatrixf2(float *m, float *out)
{
	float wtmp[4][8];
	float m0, m1, m2, m3, s;
	float *r0, *r1, *r2, *r3;
	r0 = wtmp[0], r1 = wtmp[1], r2 = wtmp[2], r3 = wtmp[3];
	r0[0] = MAT(m, 0, 0), r0[1] = MAT(m, 0, 1),
		r0[2] = MAT(m, 0, 2), r0[3] = MAT(m, 0, 3),
		r0[4] = 1.0f, r0[5] = r0[6] = r0[7] = 0.0f,
		r1[0] = MAT(m, 1, 0), r1[1] = MAT(m, 1, 1),
		r1[2] = MAT(m, 1, 2), r1[3] = MAT(m, 1, 3),
		r1[5] = 1.0f, r1[4] = r1[6] = r1[7] = 0.0f,
		r2[0] = MAT(m, 2, 0), r2[1] = MAT(m, 2, 1),
		r2[2] = MAT(m, 2, 2), r2[3] = MAT(m, 2, 3),
		r2[6] = 1.0f, r2[4] = r2[5] = r2[7] = 0.0f,
		r3[0] = MAT(m, 3, 0), r3[1] = MAT(m, 3, 1),
		r3[2] = MAT(m, 3, 2), r3[3] = MAT(m, 3, 3),
		r3[7] = 1.0f, r3[4] = r3[5] = r3[6] = 0.0f;
	/* choose pivot - or die */
	if (fabsf(r3[0]) > fabsf(r2[0]))
		SWAP_ROWS_FLOAT(r3, r2);
	if (fabsf(r2[0]) > fabsf(r1[0]))
		SWAP_ROWS_FLOAT(r2, r1);
	if (fabsf(r1[0]) > fabsf(r0[0]))
		SWAP_ROWS_FLOAT(r1, r0);
	if (0.0f == r0[0])
		return 0;
	/* eliminate first variable     */
	m1 = r1[0] / r0[0];
	m2 = r2[0] / r0[0];
	m3 = r3[0] / r0[0];
	s = r0[1];
	r1[1] -= m1 * s;
	r2[1] -= m2 * s;
	r3[1] -= m3 * s;
	s = r0[2];
	r1[2] -= m1 * s;
	r2[2] -= m2 * s;
	r3[2] -= m3 * s;
	s = r0[3];
	r1[3] -= m1 * s;
	r2[3] -= m2 * s;
	r3[3] -= m3 * s;
	s = r0[4];
	if (s != 0.0f) {
		r1[4] -= m1 * s;
		r2[4] -= m2 * s;
		r3[4] -= m3 * s;
	}
	s = r0[5];
	if (s != 0.0f) {
		r1[5] -= m1 * s;
		r2[5] -= m2 * s;
		r3[5] -= m3 * s;
	}
	s = r0[6];
	if (s != 0.0f) {
		r1[6] -= m1 * s;
		r2[6] -= m2 * s;
		r3[6] -= m3 * s;
	}
	s = r0[7];
	if (s != 0.0f) {
		r1[7] -= m1 * s;
		r2[7] -= m2 * s;
		r3[7] -= m3 * s;
	}
	/* choose pivot - or die */
	if (fabsf(r3[1]) > fabsf(r2[1]))
		SWAP_ROWS_FLOAT(r3, r2);
	if (fabsf(r2[1]) > fabsf(r1[1]))
		SWAP_ROWS_FLOAT(r2, r1);
	if (0.0f == r1[1])
		return 0;
	/* eliminate second variable */
	m2 = r2[1] / r1[1];
	m3 = r3[1] / r1[1];
	r2[2] -= m2 * r1[2];
	r3[2] -= m3 * r1[2];
	r2[3] -= m2 * r1[3];
	r3[3] -= m3 * r1[3];
	s = r1[4];
	if (0.0f != s) {
		r2[4] -= m2 * s;
		r3[4] -= m3 * s;
	}
	s = r1[5];
	if (0.0f != s) {
		r2[5] -= m2 * s;
		r3[5] -= m3 * s;
	}
	s = r1[6];
	if (0.0f != s) {
		r2[6] -= m2 * s;
		r3[6] -= m3 * s;
	}
	s = r1[7];
	if (0.0f != s) {
		r2[7] -= m2 * s;
		r3[7] -= m3 * s;
	}
	/* choose pivot - or die */
	if (fabsf(r3[2]) > fabsf(r2[2]))
		SWAP_ROWS_FLOAT(r3, r2);
	if (0.0f == r2[2])
		return 0;
	/* eliminate third variable */
	m3 = r3[2] / r2[2];
	r3[3] -= m3 * r2[3], r3[4] -= m3 * r2[4],
		r3[5] -= m3 * r2[5], r3[6] -= m3 * r2[6], r3[7] -= m3 * r2[7];
	/* last check */
	if (0.0f == r3[3])
		return 0;
	s = 1.0f / r3[3];		/* now back substitute row 3 */
	r3[4] *= s;
	r3[5] *= s;
	r3[6] *= s;
	r3[7] *= s;
	m2 = r2[3];			/* now back substitute row 2 */
	s = 1.0f / r2[2];
	r2[4] = s * (r2[4] - r3[4] * m2), r2[5] = s * (r2[5] - r3[5] * m2),
		r2[6] = s * (r2[6] - r3[6] * m2), r2[7] = s * (r2[7] - r3[7] * m2);
	m1 = r1[3];
	r1[4] -= r3[4] * m1, r1[5] -= r3[5] * m1,
		r1[6] -= r3[6] * m1, r1[7] -= r3[7] * m1;
	m0 = r0[3];
	r0[4] -= r3[4] * m0, r0[5] -= r3[5] * m0,
		r0[6] -= r3[6] * m0, r0[7] -= r3[7] * m0;
	m1 = r1[2];			/* now back substitute row 1 */
	s = 1.0f / r1[1];
	r1[4] = s * (r1[4] - r2[4] * m1), r1[5] = s * (r1[5] - r2[5] * m1),
		r1[6] = s * (r1[6] - r2[6] * m1), r1[7] = s * (r1[7] - r2[7] * m1);
	m0 = r0[2];
	r0[4] -= r2[4] * m0, r0[5] -= r2[5] * m0,
		r0[6] -= r2[6] * m0, r0[7] -= r2[7] * m0;
	m0 = r0[1];			/* now back substitute row 0 */
	s = 1.0f / r0[0];
	r0[4] = s * (r0[4] - r1[4] * m0), r0[5] = s * (r0[5] - r1[5] * m0),
		r0[6] = s * (r0[6] - r1[6] * m0), r0[7] = s * (r0[7] - r1[7] * m0);
	MAT(out, 0, 0) = r0[4];
	MAT(out, 0, 1) = r0[5], MAT(out, 0, 2) = r0[6];
	MAT(out, 0, 3) = r0[7], MAT(out, 1, 0) = r1[4];
	MAT(out, 1, 1) = r1[5], MAT(out, 1, 2) = r1[6];
	MAT(out, 1, 3) = r1[7], MAT(out, 2, 0) = r2[4];
	MAT(out, 2, 1) = r2[5], MAT(out, 2, 2) = r2[6];
	MAT(out, 2, 3) = r2[7], MAT(out, 3, 0) = r3[4];
	MAT(out, 3, 1) = r3[5], MAT(out, 3, 2) = r3[6];
	MAT(out, 3, 3) = r3[7];
	return 1;
}

int glhUnProjectf(	float winx, float winy, float winz,
					float *modelview, float *projection,
					int *viewport, float *objectCoordinate)
{
	//Transformation matrices
	float m[16], A[16];
	float in[4], out[4];
	//Calculation for inverting a matrix, compute projection x modelview
	//and store in A[16]
	MultiplyMatrices4by4OpenGL_FLOAT(A, projection, modelview);
	//Now compute the inverse of matrix A
	if(glhInvertMatrixf2(A, m)==0)
		return 0;
	//Transformation of normalized coordinates between -1 and 1
	in[0]=(winx-(float)viewport[0])/(float)viewport[2]*2.0f-1.0f;
	in[1]=(winy-(float)viewport[1])/(float)viewport[3]*2.0f-1.0f;
	in[2]=2.0f*winz-1.0f;
	in[3]=1.0f;
	//Objects coordinates
	MultiplyMatrixByVector4by4OpenGL_FLOAT(out, m, in);
	if(out[3]==0.0f)
		return 0;
	out[3]=1.0f/out[3];
	objectCoordinate[0]=out[0]*out[3];
	objectCoordinate[1]=out[1]*out[3];
	objectCoordinate[2]=out[2]*out[3];
	return 1;
}