Eevee: Implement Overscan option

This option make the internal render size larger than the output size in
order to minimize screenspace effects disapearing at the render edges.

The overscan size added around the render is the maximum dimension
multiplied by the overscan percentage.

2 files changed, 20 insertions, 0 deletions

diff --git a/source/blender/render/extern/include/RE_pipeline.h b/source/blender/render/extern/include/RE_pipeline.h
index cc2bd01718a..614a1735f44 100644
--- a/source/blender/render/extern/include/RE_pipeline.h
+++ b/source/blender/render/extern/include/RE_pipeline.h
@@ -335,6 +335,7 @@ struct RenderPass *RE_pass_find_by_type(volatile struct RenderLayer *rl, int pas
 #define RE_BAKE_AO					2
 
 void RE_GetCameraWindow(struct Render *re, struct Object *camera, int frame, float mat[4][4]);
+void RE_GetCameraWindowWithOverscan(struct Render *re, float mat[4][4], float overscan);
 void RE_GetCameraModelMatrix(struct Render *re, struct Object *camera, float r_mat[4][4]);
 struct Scene *RE_GetScene(struct Render *re);
 void RE_SetScene(struct Render *re, struct Scene *sce);
diff --git a/source/blender/render/intern/source/initrender.c b/source/blender/render/intern/source/initrender.c
index 828d626f9a7..1420b8feef7 100644
--- a/source/blender/render/intern/source/initrender.c
+++ b/source/blender/render/intern/source/initrender.c
@@ -195,6 +195,25 @@ void RE_GetCameraWindow(struct Render *re, struct Object *camera, int frame, flo
 	copy_m4_m4(mat, re->winmat);
 }
 
+/* Must be called after RE_GetCameraWindow(), does not change re->winmat. */
+void RE_GetCameraWindowWithOverscan(struct Render *re, float mat[4][4], float overscan)
+{
+	CameraParams params;
+	params.is_ortho = re->winmat[3][3] != 0.0f;
+	params.clipsta = re->clipsta;
+	params.clipend = re->clipend;
+	params.viewplane = re->viewplane;
+
+	overscan *= max_ff(BLI_rctf_size_x(&params.viewplane), BLI_rctf_size_y(&params.viewplane));
+
+	params.viewplane.xmin -= overscan;
+	params.viewplane.xmax += overscan;
+	params.viewplane.ymin -= overscan;
+	params.viewplane.ymax += overscan;
+	BKE_camera_params_compute_matrix(&params);
+	copy_m4_m4(mat, params.winmat);
+}
+
 void RE_GetCameraModelMatrix(Render *re, struct Object *camera, float r_mat[4][4])
 {
 	BKE_camera_multiview_model_matrix(&re->r, camera, re->viewname, r_mat);