1 files changed, 99 insertions, 0 deletions
diff --git a/include/cglm/clipspace/view_lh.h b/include/cglm/clipspace/view_lh.h
new file mode 100644
index 0000000..5667694
--- /dev/null
+++ b/include/cglm/clipspace/view_lh.h
@@ -0,0 +1,99 @@
+/*
+ * Copyright (c), Recep Aslantas.
+ *
+ * MIT License (MIT), http://opensource.org/licenses/MIT
+ * Full license can be found in the LICENSE file
+ */
+
+/*
+ Functions:
+   CGLM_INLINE void glm_lookat_lh(vec3 eye, vec3 center, vec3 up, mat4 dest)
+   CGLM_INLINE void glm_look_lh(vec3 eye, vec3 dir, vec3 up, mat4 dest)
+   CGLM_INLINE void glm_look_anyup_lh(vec3 eye, vec3 dir, mat4 dest)
+ */
+
+#ifndef cglm_view_lh_h
+#define cglm_view_lh_h
+
+#include "../common.h"
+#include "../plane.h"
+
+/*!
+ * @brief set up view matrix (LH)
+ *
+ * NOTE: The UP vector must not be parallel to the line of sight from
+ *       the eye point to the reference point
+ *
+ * @param[in]  eye    eye vector
+ * @param[in]  center center vector
+ * @param[in]  up     up vector
+ * @param[out] dest   result matrix
+ */
+CGLM_INLINE
+void
+glm_lookat_lh(vec3 eye, vec3 center, vec3 up, mat4 dest) {
+  CGLM_ALIGN(8) vec3 f, u, s;
+
+  glm_vec3_sub(center, eye, f);
+  glm_vec3_normalize(f);
+
+  glm_vec3_crossn(up, f, s);
+  glm_vec3_cross(f, s, u);
+
+  dest[0][0] = s[0];
+  dest[0][1] = u[0];
+  dest[0][2] = f[0];
+  dest[1][0] = s[1];
+  dest[1][1] = u[1];
+  dest[1][2] = f[1];
+  dest[2][0] = s[2];
+  dest[2][1] = u[2];
+  dest[2][2] = f[2];
+  dest[3][0] =-glm_vec3_dot(s, eye);
+  dest[3][1] =-glm_vec3_dot(u, eye);
+  dest[3][2] =-glm_vec3_dot(f, eye);
+  dest[0][3] = dest[1][3] = dest[2][3] = 0.0f;
+  dest[3][3] = 1.0f;
+}
+
+/*!
+ * @brief set up view matrix with left handed coordinate system
+ *
+ * convenient wrapper for lookat: if you only have direction not target self
+ * then this might be useful. Because you need to get target from direction.
+ *
+ * NOTE: The UP vector must not be parallel to the line of sight from
+ *       the eye point to the reference point
+ *
+ * @param[in]  eye    eye vector
+ * @param[in]  dir    direction vector
+ * @param[in]  up     up vector
+ * @param[out] dest   result matrix
+ */
+CGLM_INLINE
+void
+glm_look_lh(vec3 eye, vec3 dir, vec3 up, mat4 dest) {
+  CGLM_ALIGN(8) vec3 target;
+  glm_vec3_add(eye, dir, target);
+  glm_lookat_lh(eye, target, up, dest);
+}
+
+/*!
+ * @brief set up view matrix with left handed coordinate system
+ *
+ * convenient wrapper for look: if you only have direction and if you don't
+ * care what UP vector is then this might be useful to create view matrix
+ *
+ * @param[in]  eye    eye vector
+ * @param[in]  dir    direction vector
+ * @param[out] dest   result matrix
+ */
+CGLM_INLINE
+void
+glm_look_anyup_lh(vec3 eye, vec3 dir, mat4 dest) {
+  CGLM_ALIGN(8) vec3 up;
+  glm_vec3_ortho(dir, up);
+  glm_look_lh(eye, dir, up, dest);
+}
+
+#endif /*cglm_view_lh_h*/