CSE2-tweaks/src/Triangle.cpp

131 lines
1.7 KiB
C++

// THIS IS DECOMPILED PROPRIETARY CODE - USE AT YOUR OWN RISK.
//
// The original code belongs to Daisuke "Pixel" Amaya.
//
// Modifications and custom code are under the MIT licence.
// See LICENCE.txt for details.
#include "Triangle.h"
#include <math.h>
int gSin[0x100];
short gTan[0x21];
void InitTriangleTable(void)
{
int i;
// Sine
for (i = 0; i < 0x100; ++i)
gSin[i] = (int)(sin(i * 6.2831998 / 256.0) * 512.0);
float a, b;
// Tangent
for (i = 0; i < 0x21; ++i)
{
a = (float)(i * 6.2831855f / 256.0f);
b = (float)sin(a) / (float)cos(a);
gTan[i] = (short)(b * 8192.0f);
}
}
int GetSin(unsigned char deg)
{
return gSin[deg];
}
int GetCos(unsigned char deg)
{
deg += 0x40;
return gSin[deg];
}
unsigned char GetArktan(int x, int y)
{
short k;
unsigned char a;
x *= -1;
y *= -1;
a = 0;
if (x > 0)
{
if (y > 0)
{
if (x > y)
{
k = (y * 0x2000) / x;
while (k > gTan[a])
++a;
}
else
{
k = (x * 0x2000) / y;
while (k > gTan[a])
++a;
a = 0x40 - a;
}
}
else
{
if (x > -y)
{
k = (-y * 0x2000) / x;
while (k > gTan[a])
++a;
a = 0x100 - a;
}
else
{
k = (x * 0x2000) / -y;
while (k > gTan[a])
++a;
a = 0x100 - 0x40 + a;
}
}
}
else
{
if (y > 0)
{
if (-x > y)
{
k = (y * 0x2000) / -x;
while (k > gTan[a])
++a;
a = 0x80 - a;
}
else
{
k = (-x * 0x2000) / y;
while (k > gTan[a])
++a;
a = 0x40 + a;
}
}
else
{
if (-x > -y)
{
k = (-y * 0x2000) / -x;
while (k > gTan[a])
++a;
a = 0x80 + a;
}
else
{
k = (-x * 0x2000) / -y;
while (k > gTan[a])
++a;
a = 0x100 - 0x40 - a;
}
}
}
return a;
}