rcam_20200608_01.diff

diff --git a/release/scripts/startup/bl_ui/properties_data_camera.py b/release/scripts/startup/bl_ui/properties_data_camera.py
index 62dffa3b6ba..370d8a1ca32 100644
--- a/release/scripts/startup/bl_ui/properties_data_camera.py
+++ b/release/scripts/startup/bl_ui/properties_data_camera.py
@@ -90,6 +90,7 @@ class DATA_PT_lens(CameraButtonsPanel, Panel):
             elif cam.lens_unit == 'FOV':
                 col.prop(cam, "angle")
             col.prop(cam, "lens_unit")
+            col.prop(cam, "cam_reverse")
 
         elif cam.type == 'ORTHO':
             col.prop(cam, "ortho_scale")
diff --git a/source/blender/blenkernel/BKE_camera.h b/source/blender/blenkernel/BKE_camera.h
index f93003dc423..09a87e69d1d 100644
--- a/source/blender/blenkernel/BKE_camera.h
+++ b/source/blender/blenkernel/BKE_camera.h
@@ -61,6 +61,8 @@ typedef struct CameraParams {
   float lens;
   float ortho_scale;
   float zoom;
+  /* SUNGREEN */
+  bool cam_reverse;
 
   float shiftx;
   float shifty;
diff --git a/source/blender/blenkernel/intern/camera.c b/source/blender/blenkernel/intern/camera.c
index 5ec4c84c013..5f6fba61836 100644
--- a/source/blender/blenkernel/intern/camera.c
+++ b/source/blender/blenkernel/intern/camera.c
@@ -221,6 +221,8 @@ void BKE_camera_params_from_object(CameraParams *params, const Object *ob)
     }
     params->lens = cam->lens;
     params->ortho_scale = cam->ortho_scale;
+    /* SUNGREEN */
+    params->cam_reverse = cam->cam_reverse;
 
     params->shiftx = cam->shiftx;
     params->shifty = cam->shifty;
@@ -370,13 +372,12 @@ void BKE_camera_params_compute_matrix(CameraParams *params)
                     params->clip_end);
   }
   else {
-    perspective_m4(params->winmat,
-                   viewplane.xmin,
-                   viewplane.xmax,
-                   viewplane.ymin,
-                   viewplane.ymax,
-                   params->clip_start,
-                   params->clip_end);
+    /* SUNGREEN for EEVEE */
+    if(params->cam_reverse){
+        perspective_m4(params->winmat, viewplane.xmin, viewplane.xmax, viewplane.ymin, viewplane.ymax, params->clip_end, params->clip_start);
+    } else {
+        perspective_m4(params->winmat, viewplane.xmin, viewplane.xmax, viewplane.ymin, viewplane.ymax, params->clip_start, params->clip_end);
+    }
   }
 }
 
diff --git a/source/blender/blenlib/BLI_math_matrix.h b/source/blender/blenlib/BLI_math_matrix.h
index 2d11797bc34..29c7a767d2c 100644
--- a/source/blender/blenlib/BLI_math_matrix.h
+++ b/source/blender/blenlib/BLI_math_matrix.h
@@ -367,6 +367,8 @@ bool is_zero_m4(const float mat[4][4]);
 bool equals_m3m3(const float mat1[3][3], const float mat2[3][3]);
 bool equals_m4m4(const float mat1[4][4], const float mat2[4][4]);
 
+/*SUNGREEN*/ bool reverse_perspective(float m[4][4], const float left, const float right, const float bottom, const float top, const float near, const float far);
+
 /* SpaceTransform helper */
 typedef struct SpaceTransform {
   float local2target[4][4];
diff --git a/source/blender/blenlib/intern/math_geom.c b/source/blender/blenlib/intern/math_geom.c
index e7c1fc8c2d9..70b53209860 100644
--- a/source/blender/blenlib/intern/math_geom.c
+++ b/source/blender/blenlib/intern/math_geom.c
@@ -4718,6 +4718,10 @@ void perspective_m4(float mat[4][4],
                     const float nearClip,
                     const float farClip)
 {
+    /*SUNGREEN*/ if(nearClip>farClip){
+        reverse_perspective(mat,left,right,bottom,top,farClip,nearClip);
+        return;
+    }
   const float Xdelta = right - left;
   const float Ydelta = top - bottom;
   const float Zdelta = farClip - nearClip;
@@ -4733,7 +4737,7 @@ void perspective_m4(float mat[4][4],
   mat[2][3] = -1.0f;
   mat[3][2] = (-2.0f * nearClip * farClip) / Zdelta;
   mat[0][1] = mat[0][2] = mat[0][3] = mat[1][0] = mat[1][2] = mat[1][3] = mat[3][0] = mat[3][1] =
-      mat[3][3] = 0.0f;
+  mat[3][3] = 0.0f;
 }
 
 void perspective_m4_fov(float mat[4][4],
diff --git a/source/blender/blenlib/intern/math_matrix.c b/source/blender/blenlib/intern/math_matrix.c
index 9e398239bc7..f7672d7379e 100644
--- a/source/blender/blenlib/intern/math_matrix.c
+++ b/source/blender/blenlib/intern/math_matrix.c
@@ -3102,6 +3102,41 @@ void invert_m4_m4_safe(float Ainv[4][4], const float A[4][4])
   }
 }
 
+/* SUNGREEN WN WF*/
+bool reverse_perspective(float m[4][4], const float left, const float right, const float bottom, const float top, const float near, const float far)
+{
+    float A, B, C, D, Q, WN, WF;
+    WN = 1.0f;
+    WF = (near+far)/far/far;
+
+    C = (WF-WN)/(near-far);
+    D = WF+C*far;
+    A = (WF+WN)/(near-far);
+    B = WF+A*far;
+    Q = 1/(far*near);
+
+    m[0][0] = 2*Q * near / (right - left);
+    m[1][0] = 0.0f;
+    m[2][0] = (right + left) / (right - left);
+    m[3][0] = 0.0f;
+
+    m[0][1] = 0.0f;
+    m[1][1] = 2*Q * near / (top - bottom);
+    m[2][1] = (top + bottom) / (top - bottom);
+    m[3][1] = 0.0f;
+
+    m[0][2] = 0.0f;
+    m[1][2] = 0.0f;
+    m[2][2] = A;
+    m[3][2] = B;
+
+    m[0][3] = 0.0f;
+    m[1][3] = 0.0f;
+    m[2][3] = C;
+    m[3][3] = D;
+    return true;
+}
+
 /**
  * #SpaceTransform struct encapsulates all needed data to convert between two coordinate spaces
  * (where conversion can be represented by a matrix multiplication).
diff --git a/source/blender/editors/gpencil/gpencil_fill.c b/source/blender/editors/gpencil/gpencil_fill.c
index d23a914fc49..0d3a4a0fb95 100644
--- a/source/blender/editors/gpencil/gpencil_fill.c
+++ b/source/blender/editors/gpencil/gpencil_fill.c
@@ -321,7 +321,8 @@ static void gp_draw_datablock(tGPDfill *tgpf, const float ink[4])
 /* draw strokes in offscreen buffer */
 static bool gp_render_offscreen(tGPDfill *tgpf)
 {
-  bool is_ortho = false;
+  bool is_ortho;
+  bool is_reverse;
   float winmat[4][4];
 
   if (!tgpf->gpd) {
@@ -365,8 +366,10 @@ static bool gp_render_offscreen(tGPDfill *tgpf)
 
   rctf viewplane;
   float clip_start, clip_end;
+  /*SUNGREEN*/
 
-  is_ortho = ED_view3d_viewplane_get(tgpf->depsgraph,
+
+  ED_view3d_viewplane_get(tgpf->depsgraph,
                                      tgpf->v3d,
                                      tgpf->rv3d,
                                      tgpf->sizex,
@@ -374,7 +377,9 @@ static bool gp_render_offscreen(tGPDfill *tgpf)
                                      &viewplane,
                                      &clip_start,
                                      &clip_end,
-                                     NULL);
+                                     NULL,
+                                     &is_ortho,
+                                     &is_reverse);
   if (is_ortho) {
     orthographic_m4(winmat,
                     viewplane.xmin,
@@ -385,13 +390,23 @@ static bool gp_render_offscreen(tGPDfill *tgpf)
                     clip_end);
   }
   else {
-    perspective_m4(winmat,
+      if(!is_reverse){
+        perspective_m4(winmat,
                    viewplane.xmin,
                    viewplane.xmax,
                    viewplane.ymin,
                    viewplane.ymax,
                    clip_start,
                    clip_end);
+      } else {
+          perspective_m4(winmat,
+                     viewplane.xmin,
+                     viewplane.xmax,
+                     viewplane.ymin,
+                     viewplane.ymax,
+                     clip_end,
+                     clip_start);
+      }
   }
 
   GPU_matrix_push_projection();
diff --git a/source/blender/editors/include/ED_view3d.h b/source/blender/editors/include/ED_view3d.h
index beca517f0a6..555aa156d3e 100644
--- a/source/blender/editors/include/ED_view3d.h
+++ b/source/blender/editors/include/ED_view3d.h
@@ -421,7 +421,7 @@ bool ED_view3d_clip_range_get(struct Depsgraph *depsgraph,
                               float *r_clipsta,
                               float *r_clipend,
                               const bool use_ortho_factor);
-bool ED_view3d_viewplane_get(struct Depsgraph *depsgraph,
+void ED_view3d_viewplane_get(struct Depsgraph *depsgraph,
                              const struct View3D *v3d,
                              const struct RegionView3D *rv3d,
                              int winxi,
@@ -429,7 +429,9 @@ bool ED_view3d_viewplane_get(struct Depsgraph *depsgraph,
                              struct rctf *r_viewplane,
                              float *r_clipsta,
                              float *r_clipend,
-                             float *r_pixsize);
+                             float *r_pixsize,
+                             bool *is_ortho,
+                             bool *is_reverse);
 
 void ED_view3d_polygon_offset(const struct RegionView3D *rv3d, const float dist);
 
diff --git a/source/blender/editors/space_view3d/view3d_draw.c b/source/blender/editors/space_view3d/view3d_draw.c
index fac378ae104..72a0647a544 100644
--- a/source/blender/editors/space_view3d/view3d_draw.c
+++ b/source/blender/editors/space_view3d/view3d_draw.c
@@ -1870,6 +1870,7 @@ ImBuf *ED_view3d_draw_offscreen_imbuf(Depsgraph *depsgraph,
 
   /* view state */
   bool is_ortho = false;
+  bool is_reverse = false;
   float winmat[4][4];
 
   if (ofs && ((GPU_offscreen_width(ofs) != sizex) || (GPU_offscreen_height(ofs) != sizey))) {
@@ -1922,8 +1923,9 @@ ImBuf *ED_view3d_draw_offscreen_imbuf(Depsgraph *depsgraph,
     rctf viewplane;
     float clip_start, clipend;
 
-    is_ortho = ED_view3d_viewplane_get(
-        depsgraph, v3d, rv3d, sizex, sizey, &viewplane, &clip_start, &clipend, NULL);
+    /* SUNGREEN ED_view3d_viewplane_get ??? */
+    ED_view3d_viewplane_get(
+        depsgraph, v3d, rv3d, sizex, sizey, &viewplane, &clip_start, &clipend, NULL, &is_ortho, &is_reverse);
     if (is_ortho) {
       orthographic_m4(winmat,
                       viewplane.xmin,
@@ -1934,13 +1936,23 @@ ImBuf *ED_view3d_draw_offscreen_imbuf(Depsgraph *depsgraph,
                       clipend);
     }
     else {
-      perspective_m4(winmat,
+        if(!is_reverse){
+            perspective_m4(winmat,
                      viewplane.xmin,
                      viewplane.xmax,
                      viewplane.ymin,
                      viewplane.ymax,
                      clip_start,
                      clipend);
+        } else {
+            perspective_m4(winmat,
+                 viewplane.xmin,
+                 viewplane.xmax,
+                 viewplane.ymin,
+                 viewplane.ymax,
+                 clipend,
+                 clip_start);
+        }
     }
   }
 
diff --git a/source/blender/editors/space_view3d/view3d_utils.c b/source/blender/editors/space_view3d/view3d_utils.c
index 377e8c58ba3..d5f2c33d546 100644
--- a/source/blender/editors/space_view3d/view3d_utils.c
+++ b/source/blender/editors/space_view3d/view3d_utils.c
@@ -155,7 +155,7 @@ bool ED_view3d_clip_range_get(Depsgraph *depsgraph,
   return params.is_ortho;
 }
 
-bool ED_view3d_viewplane_get(Depsgraph *depsgraph,
+void ED_view3d_viewplane_get(Depsgraph *depsgraph,
                              const View3D *v3d,
                              const RegionView3D *rv3d,
                              int winx,
@@ -163,10 +163,12 @@ bool ED_view3d_viewplane_get(Depsgraph *depsgraph,
                              rctf *r_viewplane,
                              float *r_clip_start,
                              float *r_clip_end,
-                             float *r_pixsize)
+                             float *r_pixsize,
+                             bool *is_ortho,
+                             bool *is_reverse)
 {
   CameraParams params;
-
+  /* SUNGREEN ED_view3d_viewplane_get*/
   BKE_camera_params_init(&params);
   BKE_camera_params_from_view3d(&params, depsgraph, v3d, rv3d);
   BKE_camera_params_compute_viewplane(&params, winx, winy, 1.0f, 1.0f);
@@ -183,8 +185,8 @@ bool ED_view3d_viewplane_get(Depsgraph *depsgraph,
   if (r_pixsize) {
     *r_pixsize = params.viewdx;
   }
-
-  return params.is_ortho;
+  *is_ortho = params.is_ortho;
+  *is_reverse = params.cam_reverse;
 }
 
 /** \} */
diff --git a/source/blender/editors/space_view3d/view3d_view.c b/source/blender/editors/space_view3d/view3d_view.c
index fe77ca05a04..a538917ebfd 100644
--- a/source/blender/editors/space_view3d/view3d_view.c
+++ b/source/blender/editors/space_view3d/view3d_view.c
@@ -743,9 +743,10 @@ void view3d_winmatrix_set(Depsgraph *depsgraph,
   rctf viewplane;
   float clipsta, clipend;
   bool is_ortho;
+  bool is_reverse;
 
-  is_ortho = ED_view3d_viewplane_get(
-      depsgraph, v3d, rv3d, region->winx, region->winy, &viewplane, &clipsta, &clipend, NULL);
+  ED_view3d_viewplane_get(
+      depsgraph, v3d, rv3d, region->winx, region->winy, &viewplane, &clipsta, &clipend, NULL, &is_ortho, &is_reverse);
   rv3d->is_persp = !is_ortho;
 
 #if 0
@@ -775,8 +776,12 @@ void view3d_winmatrix_set(Depsgraph *depsgraph,
         viewplane.xmin, viewplane.xmax, viewplane.ymin, viewplane.ymax, clipsta, clipend);
   }
   else {
-    GPU_matrix_frustum_set(
-        viewplane.xmin, viewplane.xmax, viewplane.ymin, viewplane.ymax, clipsta, clipend);
+    /*SUNGREEN FRUSTUM SET*/
+    if(is_reverse){
+        GPU_matrix_frustum_set(viewplane.xmin, viewplane.xmax, viewplane.ymin, viewplane.ymax, clipend, clipsta);
+    } else {
+        GPU_matrix_frustum_set(viewplane.xmin, viewplane.xmax, viewplane.ymin, viewplane.ymax, clipsta, clipend);
+    }
   }
 
   /* update matrix in 3d view region */
diff --git a/source/blender/gpu/intern/gpu_matrix.c b/source/blender/gpu/intern/gpu_matrix.c
index 8260e1496ff..9042b6f2cbf 100644
--- a/source/blender/gpu/intern/gpu_matrix.c
+++ b/source/blender/gpu/intern/gpu_matrix.c
@@ -326,6 +326,9 @@ static void mat4_ortho_set(
 static void mat4_frustum_set(
     float m[4][4], float left, float right, float bottom, float top, float near, float far)
 {
+  /*SUNGREEN*/if(near>far){
+        reverse_perspective(m,left,right,bottom,top,far,near);
+    } else {
   m[0][0] = 2.0f * near / (right - left);
   m[1][0] = 0.0f;
   m[2][0] = (right + left) / (right - left);
@@ -345,7 +348,7 @@ static void mat4_frustum_set(
   m[1][3] = 0.0f;
   m[2][3] = -1.0f;
   m[3][3] = 0.0f;
-
+}
   gpu_matrix_state_active_set_dirty(true);
 }
 
diff --git a/source/blender/makesdna/DNA_camera_types.h b/source/blender/makesdna/DNA_camera_types.h
index b12d25d74e0..8145ead0cc7 100644
--- a/source/blender/makesdna/DNA_camera_types.h
+++ b/source/blender/makesdna/DNA_camera_types.h
@@ -98,6 +98,9 @@ typedef struct Camera {
   char type;
   /** Draw type extra. */
   char dtx;
+  /* SUNGREEN */
+  char cam_reverse;
+  char cam_reverses[7];
   short flag;
   float passepartalpha;
   float clip_start, clip_end;
diff --git a/source/blender/makesrna/intern/rna_camera.c b/source/blender/makesrna/intern/rna_camera.c
index 47a09233769..5e85193923c 100644
--- a/source/blender/makesrna/intern/rna_camera.c
+++ b/source/blender/makesrna/intern/rna_camera.c
@@ -620,6 +620,12 @@ void RNA_def_camera(BlenderRNA *brna)
   RNA_def_property_ui_text(prop, "Stereo", "");
 
   /* flag */
+  /* SUNGREEN */
+  prop = RNA_def_property(srna, "cam_reverse", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, NULL, "cam_reverse", 1);
+  RNA_def_property_ui_text(prop, "Reverse perspective", "Reverse perspective camera");
+  RNA_def_property_update(prop, NC_OBJECT | ND_DRAW, NULL);
+
   prop = RNA_def_property(srna, "show_limits", PROP_BOOLEAN, PROP_NONE);
   RNA_def_property_boolean_sdna(prop, NULL, "flag", CAM_SHOWLIMITS);
   RNA_def_property_ui_text(
diff --git a/source/blender/render/intern/include/render_types.h b/source/blender/render/intern/include/render_types.h
index 3ae4b9c0b90..51bfc6d8174 100644
--- a/source/blender/render/intern/include/render_types.h
+++ b/source/blender/render/intern/include/render_types.h
@@ -104,6 +104,9 @@ struct Render {
   float clip_start;
   float clip_end;
 
+  /* SUNGREEN */
+  char cam_reverse;
+
   /* main, scene, and its full copy of renderdata and world */
   struct Main *main;
   Scene *scene;
diff --git a/source/blender/render/intern/source/initrender.c b/source/blender/render/intern/source/initrender.c
index 138d95af055..f9355e0cd40 100644
--- a/source/blender/render/intern/source/initrender.c
+++ b/source/blender/render/intern/source/initrender.c
@@ -180,6 +180,8 @@ static void re_camera_params_get(Render *re, CameraParams *params)
   re->clip_end = params->clip_end;
 
   re->viewplane = params->viewplane;
+  /* SUNGREEN */
+  re->cam_reverse = params->cam_reverse;
 }
 
 void RE_SetOverrideCamera(Render *re, Object *camera)
@@ -221,7 +223,10 @@ void RE_GetCameraWindow(struct Render *re, struct Object *camera, float mat[4][4
 void RE_GetCameraWindowWithOverscan(struct Render *re, float mat[4][4], float overscan)
 {
   CameraParams params;
-  params.is_ortho = re->winmat[3][3] != 0.0f;
+  /* SUNGREEN */
+  params.cam_reverse = re->cam_reverse;
+  params.is_ortho = (re->winmat[2][3]== 0.0f && re->winmat[3][3] != 0.0f);
+
   params.clip_start = re->clip_start;
   params.clip_end = re->clip_end;
   params.viewplane = re->viewplane;