From 090f940f502c9ef0e9309e5f015629334a0120d8 Mon Sep 17 00:00:00 2001
From: Recep Aslantas <info@recp.me>
Date: Sat, 20 Jan 2018 18:38:26 +0300
Subject: [PATCH] swizzle support

---
 include/cglm/common.h |  3 +++
 include/cglm/vec3.h   | 27 +++++++++++++++++++++++++++
 include/cglm/vec4.h   | 29 +++++++++++++++++++++++++++++
 3 files changed, 59 insertions(+)

diff --git a/include/cglm/common.h b/include/cglm/common.h
index f0eb965..84a09b6 100644
--- a/include/cglm/common.h
+++ b/include/cglm/common.h
@@ -54,6 +54,9 @@
 
 #define glm__memzero(type, dest, size) glm__memset(type, dest, size, 0)
 
+#define GLM_SHUFFLE4(z, y, x, w) (((z) << 6) | ((y) << 4) | ((x) << 2) | (w))
+#define GLM_SHUFFLE3(z, y, x)    (((z) << 4) | ((y) << 2) | (x))
+
 #include "types.h"
 #include "simd/intrin.h"
 
diff --git a/include/cglm/vec3.h b/include/cglm/vec3.h
index ebcedcf..e5559e1 100644
--- a/include/cglm/vec3.h
+++ b/include/cglm/vec3.h
@@ -44,6 +44,7 @@
    CGLM_INLINE void  glm_vec_maxv(vec3 v1, vec3 v2, vec3 dest);
    CGLM_INLINE void  glm_vec_minv(vec3 v1, vec3 v2, vec3 dest);
    CGLM_INLINE void  glm_vec_ortho(vec3 v, vec3 dest);
+   CGLM_INLINE void  glm_vec_swizzle(vec3 v, int mask, vec3 dest);
 
  Convenient:
    CGLM_INLINE void  glm_cross(vec3 a, vec3 b, vec3 d);
@@ -69,6 +70,11 @@
 #define GLM_ZUP  (vec3){0.0f, 0.0f, 1.0f}
 #define GLM_XUP  (vec3){1.0f, 0.0f, 0.0f}
 
+#define GLM_XXX GLM_SHUFFLE3(0, 0, 0)
+#define GLM_YYY GLM_SHUFFLE3(1, 1, 1)
+#define GLM_ZZZ GLM_SHUFFLE3(2, 2, 2)
+#define GLM_ZYX GLM_SHUFFLE3(0, 1, 2)
+
 /*!
  * @brief init vec3 using vec4
  *
@@ -528,4 +534,25 @@ glm_normalize_to(vec3 v, vec3 dest) {
   glm_vec_normalize_to(v, dest);
 }
 
+/*!
+ * @brief swizzle vector components
+ *
+ * you can use existin masks e.g. GLM_XXX, GLM_ZYX
+ *
+ * @param[in]  v    source
+ * @param[in]  mask mask
+ * @param[out] dest destination
+ */
+CGLM_INLINE
+void
+glm_vec_swizzle(vec3 v, int mask, vec3 dest) {
+  vec3 t;
+
+  t[0] = v[(mask & (3 << 0))];
+  t[1] = v[(mask & (3 << 2)) >> 2];
+  t[2] = v[(mask & (3 << 4)) >> 4];
+
+  glm_vec_copy(t, dest);
+}
+
 #endif /* cglm_vec3_h */
diff --git a/include/cglm/vec4.h b/include/cglm/vec4.h
index e76bfac..a92758a 100644
--- a/include/cglm/vec4.h
+++ b/include/cglm/vec4.h
@@ -38,6 +38,7 @@
    CGLM_INLINE float glm_vec4_distance(vec4 v1, vec4 v2);
    CGLM_INLINE void  glm_vec4_maxv(vec4 v1, vec4 v2, vec4 dest);
    CGLM_INLINE void  glm_vec4_minv(vec4 v1, vec4 v2, vec4 dest);
+   CGLM_INLINE void  glm_vec4_swizzle(vec4 v, int mask, vec4 dest);
  */
 
 #ifndef cglm_vec4_h
@@ -57,6 +58,12 @@
 #define GLM_VEC4_ONE        (vec4)GLM_VEC4_ONE_INIT
 #define GLM_VEC4_BLACK      (vec4)GLM_VEC4_BLACK_INIT
 
+#define GLM_XXXX GLM_SHUFFLE4(0, 0, 0, 0)
+#define GLM_YYYY GLM_SHUFFLE4(1, 1, 1, 1)
+#define GLM_ZZZZ GLM_SHUFFLE4(2, 2, 2, 2)
+#define GLM_WWWW GLM_SHUFFLE4(3, 3, 3, 3)
+#define GLM_WZYX GLM_SHUFFLE4(0, 1, 2, 3)
+
 /*!
  * @brief init vec4 using vec3
  *
@@ -369,4 +376,26 @@ glm_vec4_minv(vec4 v1, vec4 v2, vec4 dest) {
   dest[3] = glm_min(v1[3], v2[3]);
 }
 
+/*!
+ * @brief swizzle vector components
+ *
+ * you can use existin masks e.g. GLM_XXXX, GLM_WZYX
+ *
+ * @param[in]  v    source
+ * @param[in]  mask mask
+ * @param[out] dest destination
+ */
+CGLM_INLINE
+void
+glm_vec4_swizzle(vec4 v, int mask, vec4 dest) {
+  vec4 t;
+
+  t[0] = v[(mask & (3 << 0))];
+  t[1] = v[(mask & (3 << 2)) >> 2];
+  t[2] = v[(mask & (3 << 4)) >> 4];
+  t[3] = v[(mask & (3 << 6)) >> 6];
+
+  glm_vec4_copy(t, dest);
+}
+
 #endif /* cglm_vec4_h */