more c30 work

1 files changed, 12 insertions, 7 deletions

diff --git a/math.cginc b/math.cginc
index f4e8f3a..c1e71fb 100644
--- a/math.cginc
+++ b/math.cginc
@@ -6,11 +6,13 @@
 #define PI 3.14159265358979323846264

 #define TAU (2 * PI)

 #define HALF_PI (PI * 0.5)

-#define PHI 1.618033989

-#define SQRT_2_RCP 0.707106781

+#define PHI             1.618033989f

+#define SQRT_2          1.414213562f

+#define SQRT_2_RCP      0.707106781f

+#define RCP_SQRT_2      0.707106781f

 #define TWO_OVER_THREE  0.6666666666666666f

 #define SQRT_3_OVER_2   0.8660254037844386f

-#define EULERS_CONSTANT 2.718281828

+#define EULERS_CONSTANT 2.718281828f

 

 

 float pow5(float x)

@@ -235,11 +237,11 @@ float4 qmul(float4 q1, float4 q2)
 }

 

 // Vector rotation with a quaternion

-// http://mathworld.wolfram.com/Quaternion.html

-float3 rotate_vector(float3 v, float4 r)

+// https://blog.molecular-matters.com/2013/05/24/a-faster-quaternion-vector-multiplication/

+float3 rotate_vector(float3 v, float4 q)

 {

-  float4 r_c = r * float4(-1, -1, -1, 1);

-  return qmul(r, qmul(float4(v, 0), r_c)).xyz;

+  float3 t = 2.0 * cross(q.xyz, v);

+  return v + q.w * t + cross(q.xyz, t);

 }

 

 float4 get_quaternion(float3 axis_normal, float theta) {

@@ -303,4 +305,7 @@ float2 hex_to_cart(float3 cart) {
       (cart[1] - cart[2]) * SQRT_3_OVER_2);

 }

 

+// Rotate 45 degrees.

+float2 rot45(float2 v) { return float2(v.x - v.y, v.x + v.y) * RCP_SQRT_2; }

+

 #endif  // __MATH_INC