forked from Mirrors/openclonk
70 lines
2.7 KiB
C++
70 lines
2.7 KiB
C++
/*
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* OpenClonk, http://www.openclonk.org
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*
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* Copyright (c) 1998-2000, Matthes Bender
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* Copyright (c) 2001-2009, RedWolf Design GmbH, http://www.clonk.de/
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* Copyright (c) 2009-2016, The OpenClonk Team and contributors
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*
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* Distributed under the terms of the ISC license; see accompanying file
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* "COPYING" for details.
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*
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* "Clonk" is a registered trademark of Matthes Bender, used with permission.
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* See accompanying file "TRADEMARK" for details.
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*
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* To redistribute this file separately, substitute the full license texts
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* for the above references.
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*/
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#include "C4Include.h"
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#include "graphics/C4BltTransform.h"
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void C4BltTransform::SetRotate(float iAngle, float fOffX, float fOffY) // set by angle and rotation offset
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{
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// iAngle is in degrees (cycling from 0 to 360)
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// determine sine and cos of reversed angle in radians
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// fAngle = -iAngle * pi/180 = iAngle * -pi/180
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float fAngle = iAngle * -0.0174532925f;
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float fsin = sinf(fAngle); float fcos = cosf(fAngle);
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// set matrix values
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mat[0] = +fcos; mat[1] = +fsin; mat[2] = (1-fcos)*fOffX - fsin*fOffY;
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mat[3] = -fsin; mat[4] = +fcos; mat[5] = (1-fcos)*fOffY + fsin*fOffX;
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mat[6] = 0; mat[7] = 0; mat[8] = 1;
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/* calculation of rotation matrix:
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x2 = fcos*(x1-fOffX) + fsin*(y1-fOffY) + fOffX
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= fcos*x1 - fcos*fOffX + fsin*y1 - fsin*fOffY + fOffX
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= x1*fcos + y1*fsin + (1-fcos)*fOffX - fsin*fOffY
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y2 = -fsin*(x1-fOffX) + fcos*(y1-fOffY) + fOffY
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= x1*-fsin + fsin*fOffX + y1*fcos - fcos*fOffY + fOffY
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= x1*-fsin + y1*fcos + fsin*fOffX + (1-fcos)*fOffY */
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}
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bool C4BltTransform::SetAsInv(C4BltTransform &r)
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{
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// calc inverse of matrix
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float det = r.mat[0]*r.mat[4]*r.mat[8] + r.mat[1]*r.mat[5]*r.mat[6]
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+ r.mat[2]*r.mat[3]*r.mat[7] - r.mat[2]*r.mat[4]*r.mat[6]
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- r.mat[0]*r.mat[5]*r.mat[7] - r.mat[1]*r.mat[3]*r.mat[8];
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if (!det) { Set(1,0,0,0,1,0,0,0,1); return false; }
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mat[0] = (r.mat[4] * r.mat[8] - r.mat[5] * r.mat[7]) / det;
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mat[1] = (r.mat[2] * r.mat[7] - r.mat[1] * r.mat[8]) / det;
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mat[2] = (r.mat[1] * r.mat[5] - r.mat[2] * r.mat[4]) / det;
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mat[3] = (r.mat[5] * r.mat[6] - r.mat[3] * r.mat[8]) / det;
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mat[4] = (r.mat[0] * r.mat[8] - r.mat[2] * r.mat[6]) / det;
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mat[5] = (r.mat[2] * r.mat[3] - r.mat[0] * r.mat[5]) / det;
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mat[6] = (r.mat[3] * r.mat[7] - r.mat[4] * r.mat[6]) / det;
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mat[7] = (r.mat[1] * r.mat[6] - r.mat[0] * r.mat[7]) / det;
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mat[8] = (r.mat[0] * r.mat[4] - r.mat[1] * r.mat[3]) / det;
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return true;
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}
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void C4BltTransform::TransformPoint(float &rX, float &rY) const
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{
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// apply matrix
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float fW = mat[6] * rX + mat[7] * rY + mat[8];
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// store in temp, so original rX is used for calculation of rY
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float fX = (mat[0] * rX + mat[1] * rY + mat[2]) / fW;
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rY = (mat[3] * rX + mat[4] * rY + mat[5]) / fW;
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rX = fX; // apply temp
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}
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