/*
 * SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
 * Copyright (C) 1991-2000 Silicon Graphics, Inc. All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice including the dates of first publication and
 * either this permission notice or a reference to
 * http://oss.sgi.com/projects/FreeB/
 * shall be included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * SILICON GRAPHICS, INC. BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
 * OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 * Except as contained in this notice, the name of Silicon Graphics, Inc.
 * shall not be used in advertising or otherwise to promote the sale, use or
 * other dealings in this Software without prior written authorization from
 * Silicon Graphics, Inc.
 *
 * OpenGL ES 1.0 CM port of part of GLU by Mike Gorchak <mike@malva.ua>
 */

#include <math.h>
#include "glues_project.h"

/*
** Make m an identity matrix
*/

static void __gluMakeIdentityf(GLfloat m[16])
{
    m[0+4*0] = 1; m[0+4*1] = 0; m[0+4*2] = 0; m[0+4*3] = 0;
    m[1+4*0] = 0; m[1+4*1] = 1; m[1+4*2] = 0; m[1+4*3] = 0;
    m[2+4*0] = 0; m[2+4*1] = 0; m[2+4*2] = 1; m[2+4*3] = 0;
    m[3+4*0] = 0; m[3+4*1] = 0; m[3+4*2] = 0; m[3+4*3] = 1;
}

GLAPI void APIENTRY
gluOrtho2D(GLfloat left, GLfloat right, GLfloat bottom, GLfloat top)
{
    glOrthof(left, right, bottom, top, -1, 1);
}

#define __glPi 3.14159265358979323846

GLAPI void APIENTRY
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]);
}

static void normalize(GLfloat v[3])
{
    GLfloat r;

    r=(GLfloat)sqrt(v[0]*v[0] + v[1]*v[1] + v[2]*v[2]);
    if (r==0.0f)
    {
        return;
    }

    v[0]/=r;
    v[1]/=r;
    v[2]/=r;
}

static void cross(GLfloat v1[3], GLfloat v2[3], GLfloat result[3])
{
    result[0] = v1[1]*v2[2] - v1[2]*v2[1];
    result[1] = v1[2]*v2[0] - v1[0]*v2[2];
    result[2] = v1[0]*v2[1] - v1[1]*v2[0];
}

GLAPI void APIENTRY
gluLookAt(GLfloat eyex, GLfloat eyey, GLfloat eyez, GLfloat centerx,
          GLfloat centery, GLfloat centerz, GLfloat upx, GLfloat upy,
          GLfloat upz)
{
    GLfloat forward[3], side[3], up[3];
    GLfloat m[4][4];

    forward[0] = centerx - eyex;
    forward[1] = centery - eyey;
    forward[2] = centerz - eyez;

    up[0] = upx;
    up[1] = upy;
    up[2] = upz;

    normalize(forward);

    /* Side = forward x up */
    cross(forward, up, side);
    normalize(side);

    /* Recompute up as: up = side x forward */
    cross(side, forward, up);

    __gluMakeIdentityf(&m[0][0]);
    m[0][0] = side[0];
    m[1][0] = side[1];
    m[2][0] = side[2];

    m[0][1] = up[0];
    m[1][1] = up[1];
    m[2][1] = up[2];

    m[0][2] = -forward[0];
    m[1][2] = -forward[1];
    m[2][2] = -forward[2];

    glMultMatrixf(&m[0][0]);
    glTranslatef(-eyex, -eyey, -eyez);
}

static void __gluMultMatrixVecf(const GLfloat matrix[16], const GLfloat in[4],
                                GLfloat out[4])
{
    int i;

    for (i=0; i<4; i++)
    {
        out[i] = in[0] * matrix[0*4+i] +
                 in[1] * matrix[1*4+i] +
                 in[2] * matrix[2*4+i] +
                 in[3] * matrix[3*4+i];
    }
}

/*
** Invert 4x4 matrix.
** Contributed by David Moore (See Mesa bug #6748)
*/
static int __gluInvertMatrixf(const GLfloat m[16], GLfloat invOut[16])
{
    GLfloat inv[16], det;
    int i;

    inv[0] =   m[5]*m[10]*m[15] - m[5]*m[11]*m[14] - m[9]*m[6]*m[15]
             + m[9]*m[7]*m[14] + m[13]*m[6]*m[11] - m[13]*m[7]*m[10];
    inv[4] =  -m[4]*m[10]*m[15] + m[4]*m[11]*m[14] + m[8]*m[6]*m[15]
             - m[8]*m[7]*m[14] - m[12]*m[6]*m[11] + m[12]*m[7]*m[10];
    inv[8] =   m[4]*m[9]*m[15] - m[4]*m[11]*m[13] - m[8]*m[5]*m[15]
             + m[8]*m[7]*m[13] + m[12]*m[5]*m[11] - m[12]*m[7]*m[9];
    inv[12] = -m[4]*m[9]*m[14] + m[4]*m[10]*m[13] + m[8]*m[5]*m[14]
             - m[8]*m[6]*m[13] - m[12]*m[5]*m[10] + m[12]*m[6]*m[9];
    inv[1] =  -m[1]*m[10]*m[15] + m[1]*m[11]*m[14] + m[9]*m[2]*m[15]
             - m[9]*m[3]*m[14] - m[13]*m[2]*m[11] + m[13]*m[3]*m[10];
    inv[5] =   m[0]*m[10]*m[15] - m[0]*m[11]*m[14] - m[8]*m[2]*m[15]
             + m[8]*m[3]*m[14] + m[12]*m[2]*m[11] - m[12]*m[3]*m[10];
    inv[9] =  -m[0]*m[9]*m[15] + m[0]*m[11]*m[13] + m[8]*m[1]*m[15]
             - m[8]*m[3]*m[13] - m[12]*m[1]*m[11] + m[12]*m[3]*m[9];
    inv[13] =  m[0]*m[9]*m[14] - m[0]*m[10]*m[13] - m[8]*m[1]*m[14]
             + m[8]*m[2]*m[13] + m[12]*m[1]*m[10] - m[12]*m[2]*m[9];
    inv[2] =   m[1]*m[6]*m[15] - m[1]*m[7]*m[14] - m[5]*m[2]*m[15]
             + m[5]*m[3]*m[14] + m[13]*m[2]*m[7] - m[13]*m[3]*m[6];
    inv[6] =  -m[0]*m[6]*m[15] + m[0]*m[7]*m[14] + m[4]*m[2]*m[15]
             - m[4]*m[3]*m[14] - m[12]*m[2]*m[7] + m[12]*m[3]*m[6];
    inv[10] =  m[0]*m[5]*m[15] - m[0]*m[7]*m[13] - m[4]*m[1]*m[15]
             + m[4]*m[3]*m[13] + m[12]*m[1]*m[7] - m[12]*m[3]*m[5];
    inv[14] = -m[0]*m[5]*m[14] + m[0]*m[6]*m[13] + m[4]*m[1]*m[14]
             - m[4]*m[2]*m[13] - m[12]*m[1]*m[6] + m[12]*m[2]*m[5];
    inv[3] =  -m[1]*m[6]*m[11] + m[1]*m[7]*m[10] + m[5]*m[2]*m[11]
             - m[5]*m[3]*m[10] - m[9]*m[2]*m[7] + m[9]*m[3]*m[6];
    inv[7] =   m[0]*m[6]*m[11] - m[0]*m[7]*m[10] - m[4]*m[2]*m[11]
             + m[4]*m[3]*m[10] + m[8]*m[2]*m[7] - m[8]*m[3]*m[6];
    inv[11] = -m[0]*m[5]*m[11] + m[0]*m[7]*m[9] + m[4]*m[1]*m[11]
             - m[4]*m[3]*m[9] - m[8]*m[1]*m[7] + m[8]*m[3]*m[5];
    inv[15] =  m[0]*m[5]*m[10] - m[0]*m[6]*m[9] - m[4]*m[1]*m[10]
             + m[4]*m[2]*m[9] + m[8]*m[1]*m[6] - m[8]*m[2]*m[5];

    det = m[0]*inv[0] + m[1]*inv[4] + m[2]*inv[8] + m[3]*inv[12];
    if (det == 0)
        return GL_FALSE;

    det=1.0f/det;

    for (i = 0; i < 16; i++)
        invOut[i] = inv[i] * det;

    return GL_TRUE;
}

static void __gluMultMatricesf(const GLfloat a[16], const GLfloat b[16],
                               GLfloat r[16])
{
    int i, j;

    for (i = 0; i < 4; i++)
    {
        for (j = 0; j < 4; j++)
        {
            r[i*4+j] = a[i*4+0]*b[0*4+j] +
                       a[i*4+1]*b[1*4+j] +
                       a[i*4+2]*b[2*4+j] +
                       a[i*4+3]*b[3*4+j];
        }
    }
}

GLAPI GLint APIENTRY
gluProject(GLfloat objx, GLfloat objy, GLfloat objz, 
           const GLfloat modelMatrix[16], 
           const GLfloat projMatrix[16],
           const GLint viewport[4],
           GLfloat* winx, GLfloat* winy, GLfloat* winz)
{
    GLfloat in[4];
    GLfloat out[4];

    in[0]=objx;
    in[1]=objy;
    in[2]=objz;
    in[3]=1.0;
    __gluMultMatrixVecf(modelMatrix, in, out);
    __gluMultMatrixVecf(projMatrix, out, in);
    if (in[3] == 0.0)
    {
        return(GL_FALSE);
    }

    in[0]/=in[3];
    in[1]/=in[3];
    in[2]/=in[3];
    /* Map x, y and z to range 0-1 */
    in[0]=in[0]*0.5f+0.5f;
    in[1]=in[1]*0.5f+0.5f;
    in[2]=in[2]*0.5f+0.5f;

    /* Map x,y to viewport */
    in[0]=in[0] * viewport[2] + viewport[0];
    in[1]=in[1] * viewport[3] + viewport[1];

    *winx=in[0];
    *winy=in[1];
    *winz=in[2];

    return(GL_TRUE);
}

GLAPI GLint APIENTRY
gluUnProject(GLfloat winx, GLfloat winy, GLfloat winz,
             const GLfloat modelMatrix[16], 
             const GLfloat projMatrix[16],
             const GLint viewport[4],
             GLfloat* objx, GLfloat* objy, GLfloat* objz)
{
    GLfloat finalMatrix[16];
    GLfloat in[4];
    GLfloat out[4];

    __gluMultMatricesf(modelMatrix, projMatrix, finalMatrix);
    if (!__gluInvertMatrixf(finalMatrix, finalMatrix))
    {
        return(GL_FALSE);
    }

    in[0]=winx;
    in[1]=winy;
    in[2]=winz;
    in[3]=1.0;

    /* Map x and y from window coordinates */
    in[0] = (in[0] - viewport[0]) / viewport[2];
    in[1] = (in[1] - viewport[1]) / viewport[3];

    /* Map to range -1 to 1 */
    in[0] = in[0] * 2 - 1;
    in[1] = in[1] * 2 - 1;
    in[2] = in[2] * 2 - 1;

    __gluMultMatrixVecf(finalMatrix, in, out);
    if (out[3] == 0.0)
    {
        return(GL_FALSE);
    }

    out[0] /= out[3];
    out[1] /= out[3];
    out[2] /= out[3];
    *objx = out[0];
    *objy = out[1];
    *objz = out[2];

    return(GL_TRUE);
}

GLAPI GLint APIENTRY
gluUnProject4(GLfloat winx, GLfloat winy, GLfloat winz, GLfloat clipw,
              const GLfloat modelMatrix[16],
              const GLfloat projMatrix[16],
              const GLint viewport[4],
              GLclampf nearVal, GLclampf farVal,
              GLfloat *objx, GLfloat *objy, GLfloat *objz,
              GLfloat *objw)
{
    GLfloat finalMatrix[16];
    GLfloat in[4];
    GLfloat out[4];

    __gluMultMatricesf(modelMatrix, projMatrix, finalMatrix);
    if (!__gluInvertMatrixf(finalMatrix, finalMatrix))
    {
        return(GL_FALSE);
    }

    in[0]=winx;
    in[1]=winy;
    in[2]=winz;
    in[3]=clipw;

    /* Map x and y from window coordinates */
    in[0] = (in[0] - viewport[0]) / viewport[2];
    in[1] = (in[1] - viewport[1]) / viewport[3];
    in[2] = (in[2] - nearVal) / (farVal - nearVal);

    /* Map to range -1 to 1 */
    in[0] = in[0] * 2 - 1;
    in[1] = in[1] * 2 - 1;
    in[2] = in[2] * 2 - 1;

    __gluMultMatrixVecf(finalMatrix, in, out);
    if (out[3] == 0.0)
    {
        return(GL_FALSE);
    }

    *objx = out[0];
    *objy = out[1];
    *objz = out[2];
    *objw = out[3];

    return(GL_TRUE);
}

GLAPI void APIENTRY
gluPickMatrix(GLfloat x, GLfloat y, GLfloat deltax, GLfloat deltay,
              GLint viewport[4])
{
    if (deltax <= 0 || deltay <= 0)
    {
        return;
    }

    /* Translate and scale the picked region to the entire window */
    glTranslatef((viewport[2] - 2 * (x - viewport[0])) / deltax,
                 (viewport[3] - 2 * (y - viewport[1])) / deltay, 0);
    glScalef(viewport[2] / deltax, viewport[3] / deltay, 1.0);
}

#define PI_OVER_180 0.017453292519943295769236907684886f

GLAPI void APIENTRY
glPerspective(GLfloat fovy, GLfloat aspect, GLfloat zNear, GLfloat zFar)
{
	GLfloat halfHeight = zNear * tanf(fovy * 0.5f * PI_OVER_180);
	GLfloat halfWidth = halfHeight * aspect;
	glFrustumf(-halfWidth, halfWidth, -halfHeight, halfHeight, zNear, zFar);
}
