123 lines
1.5 KiB
C++
123 lines
1.5 KiB
C++
#include "Triangle.h"
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#include <math.h>
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int gSin[0x100];
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short gTan[0x21];
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void InitTriangleTable(void)
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{
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int i;
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// Sine
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for (i = 0; i < 0x100; ++i)
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gSin[i] = (int)(sin(i * 6.2831998 / 256.0) * 512.0);
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float a, b;
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// Tangent
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for (i = 0; i < 0x21; ++i)
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{
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a = (float)(i * 6.2831855f / 256.0f);
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b = (float)sin(a) / (float)cos(a);
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gTan[i] = (short)(b * 8192.0f);
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}
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}
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int GetSin(unsigned char deg)
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{
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return gSin[deg];
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}
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int GetCos(unsigned char deg)
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{
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deg += 0x40;
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return gSin[deg];
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}
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unsigned char GetArktan(int x, int y)
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{
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short k;
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unsigned char a;
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x *= -1;
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y *= -1;
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a = 0;
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if (x > 0)
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{
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if (y > 0)
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{
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if (x > y)
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{
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k = (y * 0x2000) / x;
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while (k > gTan[a])
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++a;
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}
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else
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{
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k = (x * 0x2000) / y;
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while (k > gTan[a])
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++a;
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a = 0x40 - a;
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}
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}
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else
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{
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if (x > -y)
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{
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k = (-y * 0x2000) / x;
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while (k > gTan[a])
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++a;
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a = 0x100 - a;
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}
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else
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{
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k = (x * 0x2000) / -y;
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while (k > gTan[a])
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++a;
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a = 0x100 - 0x40 + a;
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}
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}
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}
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else
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{
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if (y > 0)
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{
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if (-x > y)
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{
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k = (y * 0x2000) / -x;
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while (k > gTan[a])
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++a;
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a = 0x80 - a;
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}
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else
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{
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k = (-x * 0x2000) / y;
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while (k > gTan[a])
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++a;
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a = 0x40 + a;
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}
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}
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else
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{
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if (-x > -y)
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{
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k = (-y * 0x2000) / -x;
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while (k > gTan[a])
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++a;
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a = 0x80 + a;
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}
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else
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{
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k = (-x * 0x2000) / -y;
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while (k > gTan[a])
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++a;
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a = 0x100 - 0x40 - a;
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}
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}
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}
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return a;
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}
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