18 lines
706 B
C
18 lines
706 B
C
#include <c3d/maths.h>
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void Mtx_Persp(C3D_Mtx* mtx, float fovy, float aspect, float near, float far, bool isLeftHanded)
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{
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float fovy_tan = tanf(fovy/2.0f);
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Mtx_Zeros(mtx);
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// Standard perspective projection matrix, with a fixed depth range of [-1,0] (required by PICA)
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// http://www.wolframalpha.com/input/?i=%7B%7B1,0,0,0%7D,%7B0,1,0,0%7D,%7B0,0,0.5,-0.5%7D,%7B0,0,0,1%7D%7D%7B%7B1%2F(a*tan(v)),0,0,0%7D,%7B0,1%2Ftan(v),0,0%7D,%7B0,0,(n%2Bf)%2F(n-f),(2fn)%2F(n-f)%7D,%7B0,0,-1,0%7D%7D
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mtx->r[0].x = 1.0f / (aspect * fovy_tan);
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mtx->r[1].y = 1.0f / fovy_tan;
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mtx->r[2].w = far*near / (near - far);
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mtx->r[3].z = isLeftHanded ? 1.0f : -1.0f;
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mtx->r[2].z = -mtx->r[3].z * near / (near - far);
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}
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