X-Git-Url: https://harrygodden.com/git/?a=blobdiff_plain;f=vg%2Fvg_m.h;h=0c4ba358593af4927a59f6e6335906a5cf0e653c;hb=c8165f11120b296045f670bbdd8e614e92b0c5e8;hp=27481ae995db9b3aca8694ffea139671e9f27438;hpb=b6c9cb0ad0f55deb891ea14fecfd80d3a73f2fe1;p=fishladder.git

diff --git a/vg/vg_m.h b/vg/vg_m.h
index 27481ae..0c4ba35 100644
--- a/vg/vg_m.h
+++ b/vg/vg_m.h
@@ -226,6 +226,40 @@ static inline void v4_zero( v4f a )
 	a[0] = 0.f; a[1] = 0.f; a[2] = 0.f; a[3] = 0.f;
 }
 
+// Matrix 2x2
+// ===========================================================================================================
+
+#define M2X2_INDENTIY 	{{1.0f, 0.0f, }, \
+							  	{ 0.0f, 1.0f, }}
+							  	
+#define M2X2_ZERO			{{0.0f, 0.0f, }, \
+								{ 0.0f, 0.0f, }}
+
+static inline void m2x2_copy( m2x2f a, m2x2f b )
+{
+	v2_copy( a[0], b[0] );
+	v2_copy( a[1], b[1] );
+}
+
+static inline void m2x2_identity( m2x2f a )
+{
+	m2x2f id = M2X2_INDENTIY;
+	m2x2_copy( id, a );
+}
+
+static inline void m2x2_create_rotation( m2x2f a, float theta )
+{
+	float s, c;
+	
+	s = sinf( theta );
+	c = cosf( theta );
+	
+	a[0][0] =  c;
+	a[0][1] = -s;
+	a[1][0] =  s;
+	a[1][1] =  c;
+}
+
 // Matrix 3x3
 //======================================================================================================