/*
Copyright (C) 1996-2001 Id Software, Inc.
Copyright (C) 2002-2009 John Fitzgibbons and others
Copyright (C) 2007-2008 Kristian Duske
Copyright (C) 2009-2014 Baker and others

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/
// q_mathlib.c -- math primitives

#include "quakedef.h"
#include "q_mathlib.h" // Courtesy


///////////////////////////////////////////////////////////////////////////////
//  BoxOnPlaneSide
///////////////////////////////////////////////////////////////////////////////


/*
==================
BOPS_Error

Split out like this for ASM to call.
==================
*/
void BOPS_Error (void) __core_attribute__((__noreturn__));
void BOPS_Error (void)  /* qasm */
{
	System_Error ("BoxOnPlaneSide:  Bad signbits");
}

#if !id386

/*
==================
BoxOnPlaneSide

Returns 1, 2, or 1 + 2
==================
*/
int BoxOnPlaneSide (vec3_t emins, vec3_t emaxs, mplane_t *p) // C version of asm function
{
	float	dist1, dist2;
	int		sides;

#if 0	// this is done by the BOX_ON_PLANE_SIDE macro before calling this
		// function
// fast axial cases
	if (p->type < 3)
	{
		if (p->dist <= emins[p->type])
			return 1;
		if (p->dist >= emaxs[p->type])
			return 2;
		return 3;
	}
#endif

// general case
	switch (p->signbits)
	{
	case 0:
		dist1 = p->normal[0]*emaxs[0] + p->normal[1]*emaxs[1] + p->normal[2]*emaxs[2];
		dist2 = p->normal[0]*emins[0] + p->normal[1]*emins[1] + p->normal[2]*emins[2];
		break;
	case 1:
		dist1 = p->normal[0]*emins[0] + p->normal[1]*emaxs[1] + p->normal[2]*emaxs[2];
		dist2 = p->normal[0]*emaxs[0] + p->normal[1]*emins[1] + p->normal[2]*emins[2];
		break;
	case 2:
		dist1 = p->normal[0]*emaxs[0] + p->normal[1]*emins[1] + p->normal[2]*emaxs[2];
		dist2 = p->normal[0]*emins[0] + p->normal[1]*emaxs[1] + p->normal[2]*emins[2];
		break;
	case 3:
		dist1 = p->normal[0]*emins[0] + p->normal[1]*emins[1] + p->normal[2]*emaxs[2];
		dist2 = p->normal[0]*emaxs[0] + p->normal[1]*emaxs[1] + p->normal[2]*emins[2];
		break;
	case 4:
		dist1 = p->normal[0]*emaxs[0] + p->normal[1]*emaxs[1] + p->normal[2]*emins[2];
		dist2 = p->normal[0]*emins[0] + p->normal[1]*emins[1] + p->normal[2]*emaxs[2];
		break;
	case 5:
		dist1 = p->normal[0]*emins[0] + p->normal[1]*emaxs[1] + p->normal[2]*emins[2];
		dist2 = p->normal[0]*emaxs[0] + p->normal[1]*emins[1] + p->normal[2]*emaxs[2];
		break;
	case 6:
		dist1 = p->normal[0]*emaxs[0] + p->normal[1]*emins[1] + p->normal[2]*emins[2];
		dist2 = p->normal[0]*emins[0] + p->normal[1]*emaxs[1] + p->normal[2]*emaxs[2];
		break;
	case 7:
		dist1 = p->normal[0]*emins[0] + p->normal[1]*emins[1] + p->normal[2]*emins[2];
		dist2 = p->normal[0]*emaxs[0] + p->normal[1]*emaxs[1] + p->normal[2]*emaxs[2];
		break;
	default:
		dist1 = dist2 = 0;		// shut up compiler
		BOPS_Error ();
		break;
	}

#if 0
	int		i;
	vec3_t	corners[2];

	for (i=0 ; i<3 ; i++)
	{
		if (plane->normal[i] < 0)
		{
			corners[0][i] = emins[i];
			corners[1][i] = emaxs[i];
		}
		else
		{
			corners[1][i] = emins[i];
			corners[0][i] = emaxs[i];
		}
	}
	dist = DotProduct (plane->normal, corners[0]) - plane->dist;
	dist2 = DotProduct (plane->normal, corners[1]) - plane->dist;
	sides = 0;
	if (dist1 >= 0)
		sides = 1;
	if (dist2 < 0)
		sides |= 2;

#endif // 0

	sides = 0;
	if (dist1 >= p->dist)
		sides = 1;
	if (dist2 < p->dist)
		sides |= 2;

#ifdef PARANOID
	if (sides == 0)
		System_Error ("BoxOnPlaneSide: sides == 0");
#endif // PARANOID

	return sides;
}

#endif // !id386


///////////////////////////////////////////////////////////////////////////////
//  Software Render exclusives
///////////////////////////////////////////////////////////////////////////////


int GreatestCommonDivisor (int i1, int i2)
{
	if (i1 > i2)
	{
		if (i2 == 0)
			return (i1);
		return GreatestCommonDivisor (i2, i1 % i2);
	}
	else
	{
		if (i1 == 0)
			return (i2);
		return GreatestCommonDivisor (i1, i2 % i1);
	}
}


/*
===================
FloorDivMod

Returns mathematically correct (floor-based) quotient and remainder for
numer and denom, both of which should contain no fractional part. The
quotient must fit in 32 bits.
====================
*/

void FloorDivMod (double numer, double denom, int *quotient, int *rem)
{
	int		q, r;
	double	x;

#ifndef PARANOID
	if (denom <= 0.0)
		System_Error ("FloorDivMod: bad denominator %f", denom);

//	if ((floor(numer) != numer) || (floor(denom) != denom))
//		System_Error ("FloorDivMod: non-integer numer or denom %f %f",
//				numer, denom);
#endif

	if (numer >= 0.0)
	{

		x = floor(numer / denom);
		q = (int)x;
		r = (int)floor(numer - (x * denom));
	}
	else
	{
	//
	// perform operations with positive values, and fix mod to make floor-based
	//
		x = floor(-numer / denom);
		q = -(int)x;
		r = (int)floor(-numer - (x * denom));
		if (r != 0)
		{
			q--;
			r = (int)denom - r;
		}
	}

	*quotient = q;
	*rem = r;
}


/*
================
R_ConcatRotations
================
*/
void R_ConcatRotations (float in1[3][3], float in2[3][3], float out[3][3])
{
	out[0][0] = in1[0][0] * in2[0][0] + in1[0][1] * in2[1][0] +
				in1[0][2] * in2[2][0];
	out[0][1] = in1[0][0] * in2[0][1] + in1[0][1] * in2[1][1] +
				in1[0][2] * in2[2][1];
	out[0][2] = in1[0][0] * in2[0][2] + in1[0][1] * in2[1][2] +
				in1[0][2] * in2[2][2];
	out[1][0] = in1[1][0] * in2[0][0] + in1[1][1] * in2[1][0] +
				in1[1][2] * in2[2][0];
	out[1][1] = in1[1][0] * in2[0][1] + in1[1][1] * in2[1][1] +
				in1[1][2] * in2[2][1];
	out[1][2] = in1[1][0] * in2[0][2] + in1[1][1] * in2[1][2] +
				in1[1][2] * in2[2][2];
	out[2][0] = in1[2][0] * in2[0][0] + in1[2][1] * in2[1][0] +
				in1[2][2] * in2[2][0];
	out[2][1] = in1[2][0] * in2[0][1] + in1[2][1] * in2[1][1] +
				in1[2][2] * in2[2][1];
	out[2][2] = in1[2][0] * in2[0][2] + in1[2][1] * in2[1][2] +
				in1[2][2] * in2[2][2];
}


/*
================
R_ConcatTransforms
================
*/
void R_ConcatTransforms (float in1[3][4], float in2[3][4], float out[3][4])
{
	out[0][0] = in1[0][0] * in2[0][0] + in1[0][1] * in2[1][0] +
				in1[0][2] * in2[2][0];
	out[0][1] = in1[0][0] * in2[0][1] + in1[0][1] * in2[1][1] +
				in1[0][2] * in2[2][1];
	out[0][2] = in1[0][0] * in2[0][2] + in1[0][1] * in2[1][2] +
				in1[0][2] * in2[2][2];
	out[0][3] = in1[0][0] * in2[0][3] + in1[0][1] * in2[1][3] +
				in1[0][2] * in2[2][3] + in1[0][3];
	out[1][0] = in1[1][0] * in2[0][0] + in1[1][1] * in2[1][0] +
				in1[1][2] * in2[2][0];
	out[1][1] = in1[1][0] * in2[0][1] + in1[1][1] * in2[1][1] +
				in1[1][2] * in2[2][1];
	out[1][2] = in1[1][0] * in2[0][2] + in1[1][1] * in2[1][2] +
				in1[1][2] * in2[2][2];
	out[1][3] = in1[1][0] * in2[0][3] + in1[1][1] * in2[1][3] +
				in1[1][2] * in2[2][3] + in1[1][3];
	out[2][0] = in1[2][0] * in2[0][0] + in1[2][1] * in2[1][0] +
				in1[2][2] * in2[2][0];
	out[2][1] = in1[2][0] * in2[0][1] + in1[2][1] * in2[1][1] +
				in1[2][2] * in2[2][1];
	out[2][2] = in1[2][0] * in2[0][2] + in1[2][1] * in2[1][2] +
				in1[2][2] * in2[2][2];
	out[2][3] = in1[2][0] * in2[0][3] + in1[2][1] * in2[1][3] +
				in1[2][2] * in2[2][3] + in1[2][3];
}

/*
===================
Invert24To16

Inverts an 8.24 value to a 16.16 value
====================
*/
/* Baker: Not called in C version, otherwise it uses the assembly version.  Keep so we have the C version for reference
fixed16_t Invert24To16(fixed16_t val)
{
	if (val < 256)
		return (0xFFFFFFFF);

	return (fixed16_t)
			(((double)0x10000 * (double)0x1000000 / (double)val) + 0.5);
}
*/


///////////////////////////////////////////////////////////////////////////////
//  NaN, origin
///////////////////////////////////////////////////////////////////////////////

const vec3_t vec3_origin = {0,0,0};
int nanmask = 255<<23;


///////////////////////////////////////////////////////////////////////////////
//  Misc
///////////////////////////////////////////////////////////////////////////////


float anglemod (float a) // called several places (input, sv_move, pr_cmds, ...)
{
#if 0
	if (a >= 0)
		a -= 360*(int)(a/360);
	else
		a += 360*( 1 + (int)(-a/360) );
#endif
	a = (360.0/65536) * ((int)(a*(65536/360.0)) & 65535);
	return a;
}


int ParseFloats (const char *s, float *f, int *f_size) // Used by view.c->View_Custom_CShift
{
	int i, argc;

	if (!s || !f || !f_size)
		System_Error("ParseFloats() wrong params");

	if (f_size[0] <= 0)
		return (f_size[0] = 0); // array have no size, unusual but no crime
	else
	{
		lparse_t *line = Line_Parse_Alloc (s, false);

		argc = c_min (line->count, f_size[0]);

		for(i = 0; i < argc; i++)
				f[i] = atof(line->args[i]);
	
		for( ; i < f_size[0]; i++)
			f[i] = 0; // zeroing unused elements
	
		Line_Parse_Free (line);
		return (f_size[0] = argc);
	}
}



/*
===============
Math_CalcRoll

Used by view and sv_user
===============
*/

// Baker: This was living in view.c but used by sv_user.c too and used client variables, corrected and moved to here.
float Math_CalcRoll (vec3_t angles, vec3_t velocity, float rollangle, float rollspeed)
{
	vec3_t	forward, right, up;
	float	sign;
	float	side;
	float	value;

	AngleVectors (angles, forward, right, up);
	side = DotProduct (velocity, right);
	sign = side < 0 ? -1 : 1;
	side = fabs(side);

	value = rollangle;
//	if (cl.inwater)
//		value *= 6;

	if (side < cl_rollspeed.value)
		side = side * value / rollspeed;
	else
		side = value;

	return side*sign;

}

// Baker: Wow this requires tons of information
void QGetPitchYaw (reply float *pitch_delta_out, reply float *yaw_delta_out, 
	int mouse_x, int mouse_y, required const int *viewport, const glmatrix *m_projection3d, 
	const glmatrix *m_modelview, const vec3_t qcamera_angles, int screenheight, int winy, float znear, float zfar)
{
	position3d		pfar, pnear;

	// This is if we want center of pixel.
	// m.view has the camera rolled into it, so I think it's ok.
	//	gg.inps.raw_x = gg.client_canvas.width / 2 + 0.5;
	//	gg.inps.raw_y = gg.client_canvas.height / 2 + 0.5;

	// Make sure height isn't stale?
	Mat4_UnProject_Smart (mouse_x, mouse_y,  /* near */ 0, m_modelview, m_projection3d, viewport, clheight, &pnear.x, &pnear.y, &pnear.z);
	Mat4_UnProject_Smart (mouse_x, mouse_y,  /* far */  1, m_modelview, m_projection3d, viewport, clheight, &pfar.x,  &pfar.y,  &pfar.z );

	{
		vec3_t	slope;
		
		slope[0] /*pitch*/ = pfar.x - pnear.x; // far - near
		slope[1] /*roll*/  = pfar.y - pnear.y; // far - near
		slope[2] /*yaw*/   = pfar.z - pnear.z; // far - near

		{
			float raylength = VectorLength(slope); // normalize the length to distance where sum of all = 1.
			vec3_t	slope_normalized;

			// I disagree with this because it pitch/roll/raw should be degrees, right?  But we are a true vector here.
			slope_normalized[0]	= slope[0] / raylength;  // Pitch
			slope_normalized[1]	= slope[1] / raylength;  // Roll
			slope_normalized[2]	= slope[2] / raylength;  // Yaw
			
			//slope_normalized[2] = 0; // For Quake this is roll.  We don't want it.
			{
#if 1
				vec3_t	degrees;  VectorToAngles (slope_normalized, degrees);; //

#else
				vec3_t	degrees;  //QVector_To_Angles_Rollless (slope_normalized, degrees);; // We need to get the roll out of the pitch
				c_swapf (&slope_normalized[1], &slope_normalized[2]);
				QVector_To_Angles_Rollless (slope_normalized, degrees); // <--- I don't trust
				//son of a bitch!  IT IS A SPHERE!  We are in a sphere.  The yaw and pitch do change
				//We want the literal yaw and pitch on the screen
#endif
//				degrees[0] = angledelta_maybe_wrap (degrees[0] - qcamera_angles[PITCH /*0*/], NULL);  // Pitch is fine.
//				degrees[2] = angledelta_maybe_wrap (degrees[2] - qcamera_angles[YAW   /*2*/], NULL);  // OpenGL yaw and Quake yaw and different index.
				// It's giving me 315 to 40

				NOT_MISSING_ASSIGN (pitch_delta_out, angledelta_maybe_wrap(-degrees[0], NULL));
				NOT_MISSING_ASSIGN (yaw_delta_out,   angledelta_maybe_wrap(degrees[1], NULL));
			}
		}
	}
}

