[Bf-blender-cvs] [230b9eac69c] master: Fix T70193 Overlay: Grid floor disappears for orthographic camera

[Clément Foucault]

Commit: 230b9eac69c4ba42f8a6934e4032d09ba10b5715
Author: Clément Foucault
Date:   Thu Jun 25 18:01:35 2020 +0200
Branches: master
https://developer.blender.org/rB230b9eac69c4ba42f8a6934e4032d09ba10b5715

Fix T70193 Overlay: Grid floor disappears for orthographic camera

The fix is to disable the fading for in the +Z direction in this case.

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

M	source/blender/draw/engines/overlay/overlay_grid.c
M	source/blender/draw/engines/overlay/shaders/grid_frag.glsl

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

diff --git a/source/blender/draw/engines/overlay/overlay_grid.c b/source/blender/draw/engines/overlay/overlay_grid.c
index 5ed32de6d93..e3079870d8f 100644
--- a/source/blender/draw/engines/overlay/overlay_grid.c
+++ b/source/blender/draw/engines/overlay/overlay_grid.c
@@ -41,6 +41,7 @@ enum {
   CLIP_ZPOS = (1 << 7),
   CLIP_ZNEG = (1 << 8),
   GRID_BACK = (1 << 9),
+  GRID_CAMERA = (1 << 10),
 };
 
 void OVERLAY_grid_init(OVERLAY_Data *vedata)
@@ -145,6 +146,9 @@ void OVERLAY_grid_init(OVERLAY_Data *vedata)
   if (rv3d->persp == RV3D_CAMOB && v3d->camera && v3d->camera->type == OB_CAMERA) {
     Object *camera_object = DEG_get_evaluated_object(draw_ctx->depsgraph, v3d->camera);
     dist = ((Camera *)(camera_object->data))->clip_end;
+    shd->grid_flag |= GRID_CAMERA;
+    shd->zneg_flag |= GRID_CAMERA;
+    shd->zpos_flag |= GRID_CAMERA;
   }
   else {
     dist = v3d->clip_end;
diff --git a/source/blender/draw/engines/overlay/shaders/grid_frag.glsl b/source/blender/draw/engines/overlay/shaders/grid_frag.glsl
index 9743f918ce3..317e9fe0447 100644
--- a/source/blender/draw/engines/overlay/shaders/grid_frag.glsl
+++ b/source/blender/draw/engines/overlay/shaders/grid_frag.glsl
@@ -28,7 +28,8 @@ uniform float gridSteps[STEPS_LEN] = float[](0.001, 0.01, 0.1, 1.0, 10.0, 100.0,
 #define PLANE_XY (1 << 4)
 #define PLANE_XZ (1 << 5)
 #define PLANE_YZ (1 << 6)
-#define GRID_BACK (1 << 9) /* grid is behind objects */
+#define GRID_BACK (1 << 9)    /* grid is behind objects */
+#define GRID_CAMERA (1 << 10) /* In camera view */
 
 #define M_1_SQRTPI 0.5641895835477563 /* 1/sqrt(pi) */
 
@@ -104,7 +105,9 @@ void main()
     fade *= 1.0 - smoothstep(0.0, gridDistance, dist - gridDistance);
   }
   else {
-    dist = abs(gl_FragCoord.z * 2.0 - 1.0);
+    dist = gl_FragCoord.z * 2.0 - 1.0;
+    /* Avoid fading in +Z direction in camera view (see T70193). */
+    dist = ((gridFlag & GRID_CAMERA) != 0) ? clamp(dist, 0.0, 1.0) : abs(dist);
     fade = 1.0 - smoothstep(0.0, 0.5, dist - 0.5);
     dist = 1.0; /* avoid branch after */