From 29996d0bddea84c6ba80b5e5e0ce9f6b2e75af02 Mon Sep 17 00:00:00 2001
From: Recep Aslantas <info@recp.me>
Date: Thu, 8 Mar 2018 13:02:33 +0300
Subject: [PATCH 01/12] add unproject function

---
 include/cglm/call.h         |  1 +
 include/cglm/call/project.h | 29 +++++++++++++
 include/cglm/cglm.h         |  1 +
 include/cglm/project.h      | 84 +++++++++++++++++++++++++++++++++++++
 src/project.c               | 21 ++++++++++
 win/cglm.vcxproj            |  3 ++
 win/cglm.vcxproj.filters    |  9 ++++
 7 files changed, 148 insertions(+)
 create mode 100644 include/cglm/call/project.h
 create mode 100644 include/cglm/project.h
 create mode 100644 src/project.c

diff --git a/include/cglm/call.h b/include/cglm/call.h
index 3f7bf14..ce08b78 100644
--- a/include/cglm/call.h
+++ b/include/cglm/call.h
@@ -24,6 +24,7 @@ extern "C" {
 #include "call/frustum.h"
 #include "call/box.h"
 #include "call/io.h"
+#include "call/project.h"
 
 #ifdef __cplusplus
 }
diff --git a/include/cglm/call/project.h b/include/cglm/call/project.h
new file mode 100644
index 0000000..1120b21
--- /dev/null
+++ b/include/cglm/call/project.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright (c), Recep Aslantas.
+ *
+ * MIT License (MIT), http://opensource.org/licenses/MIT
+ * Full license can be found in the LICENSE file
+ */
+
+#ifndef cglmc_project_h
+#define cglmc_project_h
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "../cglm.h"
+
+CGLM_EXPORT
+void
+glmc_unprojecti(mat4 invMat, vec4 vp, vec3 coord, vec3 dest);
+
+CGLM_EXPORT
+void
+glmc_unproject(mat4 m, vec2 vp, vec3 coord, vec3 dest);
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* cglmc_project_h */
+
+
diff --git a/include/cglm/cglm.h b/include/cglm/cglm.h
index e99bb09..52c7e97 100644
--- a/include/cglm/cglm.h
+++ b/include/cglm/cglm.h
@@ -23,5 +23,6 @@
 #include "color.h"
 #include "util.h"
 #include "io.h"
+#include "project.h"
 
 #endif /* cglm_h */
diff --git a/include/cglm/project.h b/include/cglm/project.h
new file mode 100644
index 0000000..27cb42a
--- /dev/null
+++ b/include/cglm/project.h
@@ -0,0 +1,84 @@
+/*
+ * Copyright (c), Recep Aslantas.
+ *
+ * MIT License (MIT), http://opensource.org/licenses/MIT
+ * Full license can be found in the LICENSE file
+ */
+
+#ifndef cglm_project_h
+#define cglm_project_h
+
+#include "mat4.h"
+
+/*!
+ * @brief maps the specified viewport coordinates into specified space [1]
+ *        the matrix should contain projection matrix.
+ *
+ * if you don't have ( and don't want to have ) an inverse matrix then use
+ * glm_unproject version. You may use existing inverse of matrix in somewhere
+ * else, this is why glm_unprojecti exists to save save inversion cost
+ *
+ * [1] space:
+ *  1- if m = invProj:     View Space
+ *  2- if m = invViewProj: World Space
+ *  3- if m = invMVP:      Object Space
+ *
+ * You probably want to map the coordinates into object space
+ * so use invMVP as m
+ *
+ * Computing viewProj:
+ *   glm_mat4_mul(proj, view, viewProj);
+ *   glm_mat4_mul(viewProj, model, MVP);
+ *   glm_mat4_inv(viewProj, invMVP);
+ *
+ * @param[in]  invMat   matrix (see brief)
+ * @param[in]  vp       viewport as [x, y, width, height]
+ * @param[in]  coord    viewport coordinates
+ * @param[out] dest     unprojected coordinates
+ */
+CGLM_INLINE
+void
+glm_unprojecti(mat4 invMat, vec4 vp, vec3 coord, vec4 dest) {
+  vec4 v;
+
+  v[0] = 2.0f * (coord[0] - vp[0]) / vp[2] - 1.0f;
+  v[1] = 2.0f * (coord[1] - vp[1]) / vp[3] - 1.0f;
+  v[2] = 2.0f *  coord[2]                  - 1.0f;
+  v[3] = 1.0f;
+
+  glm_mat4_mulv(invMat, v, dest);
+}
+
+/*!
+ * @brief maps the specified viewport coordinates into specified space [1]
+ *        the matrix should contain projection matrix.
+ *
+ * this is same as glm_unprojecti except this function get inverse matrix for
+ * you.
+ *
+ * [1] space:
+ *  1- if m = proj:     View Space
+ *  2- if m = viewProj: World Space
+ *  3- if m = MVP:      Object Space
+ *
+ * You probably want to map the coordinates into object space
+ * so use MVP as m
+ *
+ * Computing viewProj:
+ *   glm_mat4_mul(proj, view, viewProj);
+ *   glm_mat4_mul(viewProj, model, MVP);
+ *
+ * @param[in]  m        matrix (see brief)
+ * @param[in]  vp       viewport as [x, y, width, height]
+ * @param[in]  coord    viewport coordinates
+ * @param[out] dest     unprojected coordinates
+ */
+CGLM_INLINE
+void
+glm_unproject(mat4 m, vec2 vp, vec3 coord, vec3 dest) {
+  mat4 inv;
+  glm_mat4_inv(m, inv);
+  glm_unprojecti(inv, vp, coord, dest);
+}
+
+#endif /* cglm_project_h */
diff --git a/src/project.c b/src/project.c
new file mode 100644
index 0000000..80e0b44
--- /dev/null
+++ b/src/project.c
@@ -0,0 +1,21 @@
+/*
+ * Copyright (c), Recep Aslantas.
+ *
+ * MIT License (MIT), http://opensource.org/licenses/MIT
+ * Full license can be found in the LICENSE file
+ */
+
+#include "../include/cglm/cglm.h"
+#include "../include/cglm/call.h"
+
+CGLM_EXPORT
+void
+glmc_unprojecti(mat4 invMat, vec4 vp, vec3 coord, vec3 dest) {
+  glm_unprojecti(invMat, vp, coord, dest);
+}
+
+CGLM_EXPORT
+void
+glmc_unproject(mat4 m, vec2 vp, vec3 coord, vec3 dest) {
+  glm_unproject(m, vp, coord, dest);
+}
diff --git a/win/cglm.vcxproj b/win/cglm.vcxproj
index 4a0463d..415a87d 100644
--- a/win/cglm.vcxproj
+++ b/win/cglm.vcxproj
@@ -29,6 +29,7 @@
     <ClCompile Include="..\src\mat3.c" />
     <ClCompile Include="..\src\mat4.c" />
     <ClCompile Include="..\src\plane.c" />
+    <ClCompile Include="..\src\project.c" />
     <ClCompile Include="..\src\quat.c" />
     <ClCompile Include="..\src\vec3.c" />
     <ClCompile Include="..\src\vec4.c" />
@@ -47,6 +48,7 @@
     <ClInclude Include="..\include\cglm\call\mat3.h" />
     <ClInclude Include="..\include\cglm\call\mat4.h" />
     <ClInclude Include="..\include\cglm\call\plane.h" />
+    <ClInclude Include="..\include\cglm\call\project.h" />
     <ClInclude Include="..\include\cglm\call\quat.h" />
     <ClInclude Include="..\include\cglm\call\vec3.h" />
     <ClInclude Include="..\include\cglm\call\vec4.h" />
@@ -60,6 +62,7 @@
     <ClInclude Include="..\include\cglm\mat3.h" />
     <ClInclude Include="..\include\cglm\mat4.h" />
     <ClInclude Include="..\include\cglm\plane.h" />
+    <ClInclude Include="..\include\cglm\project.h" />
     <ClInclude Include="..\include\cglm\quat.h" />
     <ClInclude Include="..\include\cglm\simd\avx\affine.h" />
     <ClInclude Include="..\include\cglm\simd\avx\mat4.h" />
diff --git a/win/cglm.vcxproj.filters b/win/cglm.vcxproj.filters
index 506f3d8..3090d72 100644
--- a/win/cglm.vcxproj.filters
+++ b/win/cglm.vcxproj.filters
@@ -75,6 +75,9 @@
     <ClCompile Include="..\src\box.c">
       <Filter>src</Filter>
     </ClCompile>
+    <ClCompile Include="..\src\project.c">
+      <Filter>src</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="..\src\config.h">
@@ -206,5 +209,11 @@
     <ClInclude Include="..\include\cglm\color.h">
       <Filter>include\cglm</Filter>
     </ClInclude>
+    <ClInclude Include="..\include\cglm\project.h">
+      <Filter>include\cglm</Filter>
+    </ClInclude>
+    <ClInclude Include="..\include\cglm\call\project.h">
+      <Filter>include\cglm\call</Filter>
+    </ClInclude>
   </ItemGroup>
 </Project>
\ No newline at end of file

From c148eacdc25a82c0fdca3552fe3115856c88486c Mon Sep 17 00:00:00 2001
From: Recep Aslantas <info@recp.me>
Date: Thu, 8 Mar 2018 13:12:08 +0300
Subject: [PATCH 02/12] fix unproject's parameters

---
 include/cglm/project.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/cglm/project.h b/include/cglm/project.h
index 27cb42a..911a69b 100644
--- a/include/cglm/project.h
+++ b/include/cglm/project.h
@@ -75,7 +75,7 @@ glm_unprojecti(mat4 invMat, vec4 vp, vec3 coord, vec4 dest) {
  */
 CGLM_INLINE
 void
-glm_unproject(mat4 m, vec2 vp, vec3 coord, vec3 dest) {
+glm_unproject(mat4 m, vec4 vp, vec3 coord, vec4 dest) {
   mat4 inv;
   glm_mat4_inv(m, inv);
   glm_unprojecti(inv, vp, coord, dest);

From 780179ff0d5796690a3ae84c2160e4cd5e4de22c Mon Sep 17 00:00:00 2001
From: Recep Aslantas <info@recp.me>
Date: Thu, 8 Mar 2018 22:29:10 +0300
Subject: [PATCH 03/12] fix unproject

---
 include/cglm/call/project.h | 2 +-
 include/cglm/project.h      | 5 ++++-
 src/project.c               | 2 +-
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/include/cglm/call/project.h b/include/cglm/call/project.h
index 1120b21..c60b9b3 100644
--- a/include/cglm/call/project.h
+++ b/include/cglm/call/project.h
@@ -19,7 +19,7 @@ glmc_unprojecti(mat4 invMat, vec4 vp, vec3 coord, vec3 dest);
 
 CGLM_EXPORT
 void
-glmc_unproject(mat4 m, vec2 vp, vec3 coord, vec3 dest);
+glmc_unproject(mat4 m, vec4 vp, vec3 coord, vec3 dest);
 
 #ifdef __cplusplus
 }
diff --git a/include/cglm/project.h b/include/cglm/project.h
index 911a69b..8a53577 100644
--- a/include/cglm/project.h
+++ b/include/cglm/project.h
@@ -9,6 +9,8 @@
 #define cglm_project_h
 
 #include "mat4.h"
+#include "vec3.h"
+#include "vec4.h"
 
 /*!
  * @brief maps the specified viewport coordinates into specified space [1]
@@ -46,7 +48,8 @@ glm_unprojecti(mat4 invMat, vec4 vp, vec3 coord, vec4 dest) {
   v[2] = 2.0f *  coord[2]                  - 1.0f;
   v[3] = 1.0f;
 
-  glm_mat4_mulv(invMat, v, dest);
+  glm_mat4_mulv(invMat, v, v);
+  glm_vec4_scale(v, 1.0f / v[3], dest);
 }
 
 /*!
diff --git a/src/project.c b/src/project.c
index 80e0b44..16209e7 100644
--- a/src/project.c
+++ b/src/project.c
@@ -16,6 +16,6 @@ glmc_unprojecti(mat4 invMat, vec4 vp, vec3 coord, vec3 dest) {
 
 CGLM_EXPORT
 void
-glmc_unproject(mat4 m, vec2 vp, vec3 coord, vec3 dest) {
+glmc_unproject(mat4 m, vec4 vp, vec3 coord, vec3 dest) {
   glm_unproject(m, vp, coord, dest);
 }

From 3399595dc261c937f883b982d4eb8dd792077e46 Mon Sep 17 00:00:00 2001
From: Recep Aslantas <info@recp.me>
Date: Tue, 3 Apr 2018 10:46:46 +0300
Subject: [PATCH 04/12] add vec2 type

---
 include/cglm/types.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/cglm/types.h b/include/cglm/types.h
index a4170c4..c411d8b 100644
--- a/include/cglm/types.h
+++ b/include/cglm/types.h
@@ -14,6 +14,7 @@
 #  define CGLM_ALIGN(X) __attribute((aligned(X)))
 #endif
 
+typedef float vec2[2];
 typedef float vec3[3];
 typedef int  ivec3[3];
 typedef CGLM_ALIGN(16) float vec4[4];

From 9f389ab8ec6ef846801f202c3b3faedeaf2629d5 Mon Sep 17 00:00:00 2001
From: Recep Aslantas <info@recp.me>
Date: Tue, 3 Apr 2018 11:09:13 +0300
Subject: [PATCH 05/12] project function

---
 include/cglm/project.h | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/include/cglm/project.h b/include/cglm/project.h
index 8a53577..fec21b0 100644
--- a/include/cglm/project.h
+++ b/include/cglm/project.h
@@ -84,4 +84,27 @@ glm_unproject(mat4 m, vec4 vp, vec3 coord, vec4 dest) {
   glm_unprojecti(inv, vp, coord, dest);
 }
 
+/*!
+ * @brief map object coordinates to window coordinates
+ *
+ * @param[in]  pos      object coordinates
+ * @param[in]  m        MVP matrix
+ * @param[in]  vp       viewport as [x, y, width, height]
+ * @param[out] dest     projected coordinates
+ */
+CGLM_INLINE
+void
+glm_project(vec3 pos, mat4 m, vec4 vp, vec3 dest) {
+  vec4 pos4;
+
+  glm_vec4(pos, 1.0f, pos4);
+
+  glm_mat4_mulv(m, pos4, pos4);
+  glm_vec4_scale(pos4, 1.0f / pos4[3], pos4); /* pos = pos / pos.w */
+
+  dest[0] = (pos4[0] + 1.0f) * 0.5f * vp[2] + vp[0];
+  dest[1] = (pos4[1] + 1.0f) * 0.5f * vp[3] + vp[1];
+  dest[2] = (pos4[2] + 1.0f) * 0.5f;
+}
+
 #endif /* cglm_project_h */

From eb527e39b45d6f29322c34cff830a4d90244651e Mon Sep 17 00:00:00 2001
From: Recep Aslantas <info@recp.me>
Date: Tue, 3 Apr 2018 11:25:33 +0300
Subject: [PATCH 06/12] optimize project

---
 include/cglm/project.h | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/include/cglm/project.h b/include/cglm/project.h
index fec21b0..fdb0cf9 100644
--- a/include/cglm/project.h
+++ b/include/cglm/project.h
@@ -67,7 +67,7 @@ glm_unprojecti(mat4 invMat, vec4 vp, vec3 coord, vec4 dest) {
  * You probably want to map the coordinates into object space
  * so use MVP as m
  *
- * Computing viewProj:
+ * Computing viewProj and MVP:
  *   glm_mat4_mul(proj, view, viewProj);
  *   glm_mat4_mul(viewProj, model, MVP);
  *
@@ -87,6 +87,10 @@ glm_unproject(mat4 m, vec4 vp, vec3 coord, vec4 dest) {
 /*!
  * @brief map object coordinates to window coordinates
  *
+ * Computing MVP:
+ *   glm_mat4_mul(proj, view, viewProj);
+ *   glm_mat4_mul(viewProj, model, MVP);
+ *
  * @param[in]  pos      object coordinates
  * @param[in]  m        MVP matrix
  * @param[in]  vp       viewport as [x, y, width, height]
@@ -95,16 +99,18 @@ glm_unproject(mat4 m, vec4 vp, vec3 coord, vec4 dest) {
 CGLM_INLINE
 void
 glm_project(vec3 pos, mat4 m, vec4 vp, vec3 dest) {
-  vec4 pos4;
+  vec4 pos4, vone = GLM_VEC4_ONE_INIT;
 
   glm_vec4(pos, 1.0f, pos4);
 
   glm_mat4_mulv(m, pos4, pos4);
   glm_vec4_scale(pos4, 1.0f / pos4[3], pos4); /* pos = pos / pos.w */
+  glm_vec4_add(pos4, vone, pos4);
+  glm_vec4_scale(pos4, 0.5f, pos4);
 
-  dest[0] = (pos4[0] + 1.0f) * 0.5f * vp[2] + vp[0];
-  dest[1] = (pos4[1] + 1.0f) * 0.5f * vp[3] + vp[1];
-  dest[2] = (pos4[2] + 1.0f) * 0.5f;
+  dest[0] = pos4[0] * vp[2] + vp[0];
+  dest[1] = pos4[1] * vp[3] + vp[1];
+  dest[2] = pos4[2];
 }
 
 #endif /* cglm_project_h */

From 63acfd681e815dc0a4937d0786e2eeded845c24c Mon Sep 17 00:00:00 2001
From: Recep Aslantas <info@recp.me>
Date: Tue, 3 Apr 2018 12:27:20 +0300
Subject: [PATCH 07/12] fix unproject, add tests to project/unproject

---
 include/cglm/call/project.h |  8 ++++++--
 include/cglm/project.h      | 19 ++++++++++---------
 src/project.c               | 14 ++++++++++----
 test/src/test_main.c        |  3 +++
 test/src/test_project.c     | 31 +++++++++++++++++++++++++++++++
 test/src/test_tests.h       |  3 +++
 6 files changed, 63 insertions(+), 15 deletions(-)
 create mode 100644 test/src/test_project.c

diff --git a/include/cglm/call/project.h b/include/cglm/call/project.h
index c60b9b3..35ac087 100644
--- a/include/cglm/call/project.h
+++ b/include/cglm/call/project.h
@@ -15,11 +15,15 @@ extern "C" {
 
 CGLM_EXPORT
 void
-glmc_unprojecti(mat4 invMat, vec4 vp, vec3 coord, vec3 dest);
+glmc_unprojecti(vec3 pos, mat4 invMat, vec4 vp, vec3 dest);
 
 CGLM_EXPORT
 void
-glmc_unproject(mat4 m, vec4 vp, vec3 coord, vec3 dest);
+glmc_unproject(vec3 pos, mat4 m, vec4 vp, vec3 dest);
+
+CGLM_EXPORT
+void
+glmc_project(vec3 pos, mat4 m, vec4 vp, vec3 dest);
 
 #ifdef __cplusplus
 }
diff --git a/include/cglm/project.h b/include/cglm/project.h
index fdb0cf9..a0b306b 100644
--- a/include/cglm/project.h
+++ b/include/cglm/project.h
@@ -33,23 +33,24 @@
  *   glm_mat4_mul(viewProj, model, MVP);
  *   glm_mat4_inv(viewProj, invMVP);
  *
+ * @param[in]  pos    viewport coordinates
  * @param[in]  invMat   matrix (see brief)
  * @param[in]  vp       viewport as [x, y, width, height]
- * @param[in]  coord    viewport coordinates
  * @param[out] dest     unprojected coordinates
  */
 CGLM_INLINE
 void
-glm_unprojecti(mat4 invMat, vec4 vp, vec3 coord, vec4 dest) {
+glm_unprojecti(vec3 pos, mat4 invMat, vec4 vp, vec3 dest) {
   vec4 v;
 
-  v[0] = 2.0f * (coord[0] - vp[0]) / vp[2] - 1.0f;
-  v[1] = 2.0f * (coord[1] - vp[1]) / vp[3] - 1.0f;
-  v[2] = 2.0f *  coord[2]                  - 1.0f;
+  v[0] = 2.0f * (pos[0] - vp[0]) / vp[2] - 1.0f;
+  v[1] = 2.0f * (pos[1] - vp[1]) / vp[3] - 1.0f;
+  v[2] = 2.0f *  pos[2]                  - 1.0f;
   v[3] = 1.0f;
 
   glm_mat4_mulv(invMat, v, v);
-  glm_vec4_scale(v, 1.0f / v[3], dest);
+  glm_vec4_scale(v, 1.0f / v[3], v);
+  glm_vec3(v, dest);
 }
 
 /*!
@@ -71,17 +72,17 @@ glm_unprojecti(mat4 invMat, vec4 vp, vec3 coord, vec4 dest) {
  *   glm_mat4_mul(proj, view, viewProj);
  *   glm_mat4_mul(viewProj, model, MVP);
  *
+ * @param[in]  pos      viewport coordinates
  * @param[in]  m        matrix (see brief)
  * @param[in]  vp       viewport as [x, y, width, height]
- * @param[in]  coord    viewport coordinates
  * @param[out] dest     unprojected coordinates
  */
 CGLM_INLINE
 void
-glm_unproject(mat4 m, vec4 vp, vec3 coord, vec4 dest) {
+glm_unproject(vec3 pos, mat4 m, vec4 vp, vec3 dest) {
   mat4 inv;
   glm_mat4_inv(m, inv);
-  glm_unprojecti(inv, vp, coord, dest);
+  glm_unprojecti(pos, inv, vp, dest);
 }
 
 /*!
diff --git a/src/project.c b/src/project.c
index 16209e7..91c7128 100644
--- a/src/project.c
+++ b/src/project.c
@@ -10,12 +10,18 @@
 
 CGLM_EXPORT
 void
-glmc_unprojecti(mat4 invMat, vec4 vp, vec3 coord, vec3 dest) {
-  glm_unprojecti(invMat, vp, coord, dest);
+glmc_unprojecti(vec3 pos, mat4 invMat, vec4 vp, vec3 dest) {
+  glm_unprojecti(pos, invMat, vp, dest);
 }
 
 CGLM_EXPORT
 void
-glmc_unproject(mat4 m, vec4 vp, vec3 coord, vec3 dest) {
-  glm_unproject(m, vp, coord, dest);
+glmc_unproject(vec3 pos, mat4 m, vec4 vp, vec3 dest) {
+  glm_unproject(pos, m, vp, dest);
+}
+
+CGLM_EXPORT
+void
+glmc_project(vec3 pos, mat4 m, vec4 vp, vec3 dest) {
+  glm_project(pos, m, vp, dest);
 }
diff --git a/test/src/test_main.c b/test/src/test_main.c
index 5d59cfd..61fa7d5 100644
--- a/test/src/test_main.c
+++ b/test/src/test_main.c
@@ -15,6 +15,9 @@ main(int argc, const char * argv[]) {
     /* camera */
     cmocka_unit_test(test_camera_lookat),
     cmocka_unit_test(test_camera_decomp)
+
+    /* project */
+    cmocka_unit_test(test_project)
   };
 
   return cmocka_run_group_tests(tests, NULL, NULL);
diff --git a/test/src/test_project.c b/test/src/test_project.c
new file mode 100644
index 0000000..4cdac9e
--- /dev/null
+++ b/test/src/test_project.c
@@ -0,0 +1,31 @@
+/*
+ * Copyright (c), Recep Aslantas.
+ *
+ * MIT License (MIT), http://opensource.org/licenses/MIT
+ * Full license can be found in the LICENSE file
+ */
+
+#include "test_common.h"
+
+void
+test_project(void **state) {
+  mat4 model, view, proj, mvp;
+  vec4 viewport = {0.0f, 0.0f, 800.0f, 600.0f};
+  vec3 pos      = {13.0f, 45.0f, 0.74f};
+  vec3 projected, unprojected;
+
+  glm_translate_make(model, (vec3){0.0f, 0.0f, -10.0f});
+  glm_lookat((vec3){0.0f, 0.0f, 0.0f}, pos, GLM_YUP, view);
+
+  glm_perspective_default(0.5f, proj);
+  glm_mat4_mulN((mat4 *[]){&proj, &view, &model}, 3, mvp);
+
+  glmc_project(pos, mvp, viewport, projected);
+  glmc_unproject(projected, mvp, viewport, unprojected);
+
+  /* unprojected of projected vector must be same as original one */
+  /* we used 0.01 because of projection floating point errors */
+  assert_true(fabsf(pos[0] - unprojected[0]) < 0.01);
+  assert_true(fabsf(pos[1] - unprojected[1]) < 0.01);
+  assert_true(fabsf(pos[2] - unprojected[2]) < 0.01);
+}
diff --git a/test/src/test_tests.h b/test/src/test_tests.h
index a4e5adb..26eb91d 100644
--- a/test/src/test_tests.h
+++ b/test/src/test_tests.h
@@ -16,4 +16,7 @@ test_camera_lookat(void **state);
 void
 test_camera_decomp(void **state);
 
+void
+test_project(void **state);
+
 #endif /* test_tests_h */

From be81d738950979ec5856f2cc4ca43966660a8b3e Mon Sep 17 00:00:00 2001
From: Recep Aslantas <m@recp.me>
Date: Tue, 3 Apr 2018 12:32:21 +0300
Subject: [PATCH 08/12] Update test_main.c

---
 test/src/test_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/src/test_main.c b/test/src/test_main.c
index dad20f9..f1dfc9b 100644
--- a/test/src/test_main.c
+++ b/test/src/test_main.c
@@ -17,7 +17,7 @@ main(int argc, const char * argv[]) {
     cmocka_unit_test(test_camera_decomp)
 
     /* project */
-    cmocka_unit_test(test_project)
+    cmocka_unit_test(test_project),
 
     /* vector */
     cmocka_unit_test(test_clamp),

From e8615ea14c1fa11e3dafcd07fb9fa071401289bd Mon Sep 17 00:00:00 2001
From: Recep Aslantas <info@recp.me>
Date: Tue, 3 Apr 2018 12:35:30 +0300
Subject: [PATCH 09/12] fix tests list

---
 test/src/test_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/src/test_main.c b/test/src/test_main.c
index f1dfc9b..5c1a647 100644
--- a/test/src/test_main.c
+++ b/test/src/test_main.c
@@ -14,7 +14,7 @@ main(int argc, const char * argv[]) {
 
     /* camera */
     cmocka_unit_test(test_camera_lookat),
-    cmocka_unit_test(test_camera_decomp)
+    cmocka_unit_test(test_camera_decomp),
 
     /* project */
     cmocka_unit_test(test_project),

From 024412f00ec05e1c931f604ce5261d2b30c32108 Mon Sep 17 00:00:00 2001
From: Recep Aslantas <info@recp.me>
Date: Tue, 3 Apr 2018 16:41:13 +0300
Subject: [PATCH 10/12] add docs for project/unproject

---
 docs/source/api.rst     |   1 +
 docs/source/project.rst | 102 ++++++++++++++++++++++++++++++++++++++++
 include/cglm/project.h  |   4 +-
 3 files changed, 105 insertions(+), 2 deletions(-)
 create mode 100644 docs/source/project.rst

diff --git a/docs/source/api.rst b/docs/source/api.rst
index e2c03d4..c61365b 100644
--- a/docs/source/api.rst
+++ b/docs/source/api.rst
@@ -41,6 +41,7 @@ Follow the :doc:`build` documentation for this
    vec4-ext
    color
    plane
+   project
    util
    io
    call
diff --git a/docs/source/project.rst b/docs/source/project.rst
new file mode 100644
index 0000000..b31a86a
--- /dev/null
+++ b/docs/source/project.rst
@@ -0,0 +1,102 @@
+.. default-domain:: C
+
+Project / UnProject
+================================================================================
+
+Header: cglm/project.h
+
+Viewport is required as *vec4* **[X, Y, Width, Height]** but this doesn't mean
+that you should store it as **vec4**. You can convert your data representation
+to vec4 before passing it to related functions.
+
+Table of contents (click to go):
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Functions:
+
+1. :c:func:`glm_unprojecti`
+#. :c:func:`glm_unproject`
+#. :c:func:`glm_project`
+
+Functions documentation
+~~~~~~~~~~~~~~~~~~~~~~~
+
+.. c:function:: void  glm_unprojecti(vec3 pos, mat4 invMat, vec4 vp, vec3 dest)
+
+    | maps the specified viewport coordinates into specified space [1]
+      the matrix should contain projection matrix.
+
+    if you don't have ( and don't want to have ) an inverse matrix then use
+    glm_unproject version. You may use existing inverse of matrix in somewhere
+    else, this is why glm_unprojecti exists to save save inversion cost
+
+    [1] space:
+      - if m = invProj:     View Space
+      - if m = invViewProj: World Space
+      - if m = invMVP:      Object Space
+
+    You probably want to map the coordinates into object space
+    so use invMVP as m
+
+    Computing viewProj:
+
+    .. code-block:: c
+
+       glm_mat4_mul(proj, view, viewProj);
+       glm_mat4_mul(viewProj, model, MVP);
+       glm_mat4_inv(viewProj, invMVP);
+
+    Parameters:
+      | *[in]*  **pos**     point/position in viewport coordinates
+      | *[in]*  **invMat**  matrix (see brief)
+      | *[in]*  **vp**      viewport as [x, y, width, height]
+      | *[out]* **dest**    unprojected coordinates
+
+.. c:function:: void  glm_unproject(vec3 pos, mat4 m, vec4 vp, vec3 dest)
+
+    | maps the specified viewport coordinates into specified space [1]
+      the matrix should contain projection matrix.
+
+    this is same as glm_unprojecti except this function get inverse matrix for
+    you.
+
+    [1] space:
+      - if m = proj:     View Space
+      - if m = viewProj: World Space
+      - if m = MVP:      Object Space
+
+    You probably want to map the coordinates into object space so use MVP as m
+
+    Computing viewProj and MVP:
+
+    .. code-block:: c
+
+       glm_mat4_mul(proj, view, viewProj);
+       glm_mat4_mul(viewProj, model, MVP);
+
+    Parameters:
+      | *[in]*  **pos**  point/position in viewport coordinates
+      | *[in]*  **m**    matrix (see brief)
+      | *[in]*  **vp**   viewport as [x, y, width, height]
+      | *[out]* **dest** unprojected coordinates
+
+.. c:function:: void  glm_project(vec3 pos, mat4 m, vec4 vp, vec3 dest)
+
+    | map object coordinates to window coordinates
+
+    Computing MVP:
+
+    .. code-block:: c
+
+       glm_mat4_mul(proj, view, viewProj);
+       glm_mat4_mul(viewProj, model, MVP);
+
+    this could be useful for gettng a bbox which fits with view frustum and
+    object bounding boxes. In this case you crop view frustum box with objects
+    box
+
+    Parameters:
+      | *[in]*  **pos**      object coordinates
+      | *[in]*  **m**        MVP matrix
+      | *[in]*  **vp**       viewport as [x, y, width, height]
+      | *[out]* **dest**     projected coordinates
diff --git a/include/cglm/project.h b/include/cglm/project.h
index a0b306b..fea44b0 100644
--- a/include/cglm/project.h
+++ b/include/cglm/project.h
@@ -33,7 +33,7 @@
  *   glm_mat4_mul(viewProj, model, MVP);
  *   glm_mat4_inv(viewProj, invMVP);
  *
- * @param[in]  pos    viewport coordinates
+ * @param[in]  pos      point/position in viewport coordinates
  * @param[in]  invMat   matrix (see brief)
  * @param[in]  vp       viewport as [x, y, width, height]
  * @param[out] dest     unprojected coordinates
@@ -72,7 +72,7 @@ glm_unprojecti(vec3 pos, mat4 invMat, vec4 vp, vec3 dest) {
  *   glm_mat4_mul(proj, view, viewProj);
  *   glm_mat4_mul(viewProj, model, MVP);
  *
- * @param[in]  pos      viewport coordinates
+ * @param[in]  pos      point/position in viewport coordinates
  * @param[in]  m        matrix (see brief)
  * @param[in]  vp       viewport as [x, y, width, height]
  * @param[out] dest     unprojected coordinates

From 429fdfd5c53442c37e9264465fb071c3d728890e Mon Sep 17 00:00:00 2001
From: Recep Aslantas <info@recp.me>
Date: Tue, 3 Apr 2018 16:47:51 +0300
Subject: [PATCH 11/12] update build scripts

---
 makefile.am | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/makefile.am b/makefile.am
index a81bdd5..217fff3 100644
--- a/makefile.am
+++ b/makefile.am
@@ -98,13 +98,15 @@ libcglm_la_SOURCES=\
     src/mat4.c \
     src/plane.c \
     src/frustum.c \
-    src/box.c
+    src/box.c \
+    src/project.c
 
 test_tests_SOURCES=\
     test/src/test_common.c \
     test/src/test_main.c \
     test/src/test_mat4.c \
     test/src/test_cam.c \
+    test/src/test_project.c \
     test/src/test_clamp.c \
     test/src/test_euler.c
 

From ea0a10ade9a76830c71ea3a2b528dcce7849f34a Mon Sep 17 00:00:00 2001
From: Recep Aslantas <info@recp.me>
Date: Tue, 3 Apr 2018 16:47:59 +0300
Subject: [PATCH 12/12] suppress warnings

---
 include/cglm/util.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/cglm/util.h b/include/cglm/util.h
index 2a9ece7..85fc789 100644
--- a/include/cglm/util.h
+++ b/include/cglm/util.h
@@ -43,7 +43,7 @@ glm_sign(int val) {
 CGLM_INLINE
 float
 glm_signf(float val) {
-  return (val > 0.0f) - (val < 0.0f);
+  return (float)((val > 0.0f) - (val < 0.0f));
 }
 
 /*!