[Bf-blender-cvs] [2783945b1b0] master: Eevee: Fix assert when displaying transparent film checker

[Clément Foucault]

Commit: 2783945b1b088260eeab1ff5e5a7ac8d3043f826
Author: Clément Foucault
Date:   Tue May 28 20:20:09 2019 +0200
Branches: master
https://developer.blender.org/rB2783945b1b088260eeab1ff5e5a7ac8d3043f826

Eevee: Fix assert when displaying transparent film checker

===================================================================

M	source/blender/draw/engines/eevee/eevee_effects.c
M	source/blender/draw/intern/draw_manager_data.c

===================================================================

diff --git a/source/blender/draw/engines/eevee/eevee_effects.c b/source/blender/draw/engines/eevee/eevee_effects.c
index cddef0c77d6..8e670da2ab7 100644
--- a/source/blender/draw/engines/eevee/eevee_effects.c
+++ b/source/blender/draw/engines/eevee/eevee_effects.c
@@ -352,12 +352,15 @@ void EEVEE_effects_cache_init(EEVEE_ViewLayerData *sldata, EEVEE_Data *vedata)
     DRW_shgroup_uniform_int_copy(grp, "size", 8);
     DRW_shgroup_call(grp, quad, NULL);
 
-    float mat[4][4];
-    unit_m4(mat);
+    float viewmat[4][4], winmat[4][4];
+    unit_m4(viewmat);
+    unit_m4(winmat);
+    /* Winmat must be negative. */
+    swap_v3_v3(winmat[0], winmat[1]);
 
     /* Using default view bypasses the culling. */
     const DRWView *default_view = DRW_view_default_get();
-    effects->checker_view = DRW_view_create_sub(default_view, mat, mat);
+    effects->checker_view = DRW_view_create_sub(default_view, viewmat, winmat);
   }
 }
 
diff --git a/source/blender/draw/intern/draw_manager_data.c b/source/blender/draw/intern/draw_manager_data.c
index 5674ebd3a60..24f2670dd2d 100644
--- a/source/blender/draw/intern/draw_manager_data.c
+++ b/source/blender/draw/intern/draw_manager_data.c
@@ -1292,8 +1292,11 @@ static void draw_view_matrix_state_update(DRWViewUboStorage *storage,
                                           const float winmat[4][4])
 {
   /* If only one the matrices is negative, then the
-   * polygon winding changes and we don't want that. */
-  BLI_assert(is_negative_m4(viewmat) != is_negative_m4(winmat));
+   * polygon winding changes and we don't want that.
+   * By convention, the winmat is negative because
+   * looking through the -Z axis. So this inverse the
+   * changes the test for the winmat. */
+  BLI_assert(is_negative_m4(viewmat) == !is_negative_m4(winmat));
 
   copy_m4_m4(storage->viewmat, viewmat);
   invert_m4_m4(storage->viewinv, storage->viewmat);