v_yshearing: Make view and input behave more like Duke Nukem 3D ;)

[xonotic/darkplaces.git] / matrixlib.c

diff --git a/matrixlib.c b/matrixlib.c
index 78c859cfed39673b9e6f7f6628ca8dae90c91e50..a26b6f13d046644a36c49e59b32b121b77c70f87 100644 (file)
--- a/matrixlib.c
+++ b/matrixlib.c
@@ -890,6 +890,54 @@ void Matrix4x4_CreateFromQuakeEntity(matrix4x4_t *out, double x, double y, doubl
        }
 }
 
+void Matrix4x4_QuakeToDuke3D(const matrix4x4_t *in, matrix4x4_t *out)
+{
+       // Sorry - this isn't direct at all. We can't just use an alternative to
+       // Matrix4x4_CreateFromQuakeEntity as in some cases the input for
+       // generating the view matrix is generated externally.
+       vec3_t forward, left, up, angles;
+       double scaleforward, scaleleft, scaleup;
+#ifdef MATRIX4x4_OPENGLORIENTATION
+       VectorSet(forward, in->m[0][0], in->m[0][1], in->m[0][2]);
+       VectorSet(left, in->m[1][0], in->m[1][1], in->m[1][2]);
+       VectorSet(up, in->m[2][0], in->m[2][1], in->m[2][2]);
+#else
+       VectorSet(forward, in->m[0][0], in->m[1][0], in->m[2][0]);
+       VectorSet(left, in->m[0][1], in->m[1][1], in->m[2][1]);
+       VectorSet(up, in->m[0][2], in->m[1][2], in->m[2][2]);
+#endif
+       scaleforward = VectorNormalizeLength(forward);
+       scaleleft = VectorNormalizeLength(left);
+       scaleup = VectorNormalizeLength(up);
+       AnglesFromVectors(angles, forward, up, false);
+       AngleVectorsDuke3DFLU(angles, forward, left, up);
+       VectorScale(forward, scaleforward, forward);
+       VectorScale(left, scaleleft, left);
+       VectorScale(up, scaleup, up);
+       *out = *in;
+#ifdef MATRIX4x4_OPENGLORIENTATION
+       out->m[0][0] = forward[0];
+       out->m[1][0] = left[0];
+       out->m[2][0] = up[0];
+       out->m[0][1] = forward[1];
+       out->m[1][1] = left[1];
+       out->m[2][1] = up[1];
+       out->m[0][2] = forward[2];
+       out->m[1][2] = left[2];
+       out->m[2][2] = up[2];
+#else
+       out->m[0][0] = forward[0];
+       out->m[0][1] = left[0];
+       out->m[0][2] = up[0];
+       out->m[1][0] = forward[1];
+       out->m[1][1] = left[1];
+       out->m[1][2] = up[1];
+       out->m[2][0] = forward[2];
+       out->m[2][1] = left[2];
+       out->m[2][2] = up[2];
+#endif
+}
+
 void Matrix4x4_ToVectors(const matrix4x4_t *in, float vx[3], float vy[3], float vz[3], float t[3])
 {
 #ifdef MATRIX4x4_OPENGLORIENTATION