add unproject function

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
 }

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 */
+
+

include/cglm/cglm.h

@@ -23,5 +23,6 @@
 #include "color.h"
 #include "util.h"
 #include "io.h"
+#include "project.h"
 
 #endif /* cglm_h */

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 */

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);
+}

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" />

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>