Add ultrafast semi-accurate trig functions and update Cylone to use them. (#547)

src/common/tpt-math.cpp

@@ -0,0 +1,110 @@
+#include <cmath>
+#include "TrigTables.h"
+
+float orig_atan(float val)
+{
+	return atan(val);
+}
+
+namespace tpt
+{
+
+float sin(float angle)
+{
+	angle *= 81.4873;
+	int i = (int)angle % 512;
+
+	if (i < 0)
+	{
+		i += 512;
+	}
+
+	return sineLookupTable[i];
+}
+
+
+float cos(float angle)
+{
+	angle *= 81.4873;
+	int i = (int)angle % 512;
+
+	if (i < 0)
+	{
+		i += 512;
+	}
+
+	return cosineLookupTable[i];
+}
+
+float tan(float angle)
+{
+	angle *= 81.4873;
+	int i = (int)angle % 512;
+	if (i < 0)
+	{
+		i += 512;
+	}
+
+	return tanLookupTable[i];
+}
+
+float asin(float angle)
+{
+	angle *= 81.4873;
+	if (angle > 256 || angle < 0)
+	{
+		return 0.0;
+	}
+
+	return asinLookupTable[(int)(angle + 256)];
+}
+
+float acos(float angle)
+{
+	angle *= 81.4873;
+	if (angle > 256 || angle < 0)
+	{
+		return 0.0;
+	}
+
+	return acosLookupTable[(int)(angle + 256)];
+}
+
+float atan(float ratio)
+{
+	if (ratio > 20)
+	{
+		return orig_atan(ratio);
+	}
+	if (ratio < -20)
+	{
+		return orig_atan(ratio);
+	}
+	return atanLookupTable[(int)(ratio * 100) + 2000];
+}
+
+
+float atan2(float y, float x)
+{
+	if (x > 0)
+	{
+		return tpt::atan(y / x);
+	}
+	else if (x < 0)
+	{
+		if (y >= 0)
+		{
+			return tpt::atan(y / x) + M_PI;
+		}
+
+		return tpt::atan(y / x) - M_PI;
+	}
+	else if (y > 0)
+		return M_PI_2;
+	else if (y < 0)
+		return M_PI_2;
+	else
+		return 0.0f;
+}
+
+}

src/common/tpt-math.h

@@ -0,0 +1,21 @@
+#ifndef TPT_MATH_
+#define TPT_MATH_
+
+namespace tpt
+{
+	float sin(float angle);
+
+	float cos(float angle);
+
+	float tan(float angle);
+
+	float asin(float angle);
+
+	float acos(float angle);
+
+	float atan(float ratio);
+
+	float atan2(float y, float x);
+
+}
+#endif /* TPT_MATH_ */

src/simulation/simtools/Cyclone.cpp

@@ -1,5 +1,8 @@
 #include "ToolClasses.h"
 #include "simulation/Air.h"
+#include "common/tpt-math.h"
+
+
 //#TPT-Directive ToolClass Tool_Cycl TOOL_CYCL 7
 Tool_Cycl::Tool_Cycl()
 {
@@ -16,16 +19,16 @@ int Tool_Cycl::Perform(Simulation * sim, Particle * cpart, int x, int y, int bru
 		Air velocity X = cosine of cell angle
 		Angle of cell is calculated via cells X/Y relation to the brush center and arctangent
 		Angle has 1.57 radians added to it (90 degrees) in order to make the velocity be at 90 degrees to the centerpoint.
-		Ditto for X, except X uses sine
+		Ditto for Y, except Y uses sine
 	*/
 	// only trigger once per cell (less laggy)
 	if ((x%CELL) == 0 && (y%CELL) == 0)
 	{
-		float *vx = &sim->air->vx[y/CELL][x/CELL];
-		float *vy = &sim->air->vy[y/CELL][x/CELL];
+		float *vx = &sim->air->vx[y / CELL][x / CELL];
+		float *vy = &sim->air->vy[y / CELL][x / CELL];
 
-		*vx -= (strength / 16) * (cos(1.57f + (atan2(brushY - y, brushX - x))));
-		*vy -= (strength / 16) * (sin(1.57f + (atan2(brushY - y, brushX - x))));
+		*vx -= (strength / 16) * (tpt::cos(1.57f + (tpt::atan2(brushY - y, brushX - x))));
+		*vy -= (strength / 16) * (tpt::sin(1.57f + (tpt::atan2(brushY - y, brushX - x))));
 
 		// Clamp velocities
 		if (*vx > 256.0f)