[Bf-blender-cvs] [319e769ea37] greasepencil-object: GPencil: Support XRay mode in solid and fix occlusion in wireframe mode

[Clément Foucault]

Commit: 319e769ea37ec91d24af9c16ebac41fac20f8cb6
Author: Clément Foucault
Date:   Thu Feb 13 00:35:32 2020 +0100
Branches: greasepencil-object
https://developer.blender.org/rB319e769ea37ec91d24af9c16ebac41fac20f8cb6

GPencil: Support XRay mode in solid and fix occlusion in wireframe mode

This add basic alpha support in xray mode. However the wireframe mode
only support occlusion if xray is dissabled (i.e: there is no support for
partial occlusion).

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

M	source/blender/draw/engines/gpencil/gpencil_engine.c
M	source/blender/draw/engines/gpencil/gpencil_engine.h
M	source/blender/draw/engines/gpencil/shaders/gpencil_composite_frag.glsl

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

diff --git a/source/blender/draw/engines/gpencil/gpencil_engine.c b/source/blender/draw/engines/gpencil/gpencil_engine.c
index f576c9fbd00..4f735e92d30 100644
--- a/source/blender/draw/engines/gpencil/gpencil_engine.c
+++ b/source/blender/draw/engines/gpencil/gpencil_engine.c
@@ -99,7 +99,8 @@ void GPENCIL_engine_init(void *ved)
   stl->pd->sbuffer_tobjects.first = NULL;
   stl->pd->sbuffer_tobjects.last = NULL;
   stl->pd->dummy_tx = txl->dummy_texture;
-  stl->pd->draw_depth_only = !DRW_state_is_fbo() || (v3d && v3d->shading.type == OB_WIRE);
+  stl->pd->draw_depth_only = !DRW_state_is_fbo();
+  stl->pd->draw_wireframe = (v3d && v3d->shading.type == OB_WIRE) && !stl->pd->draw_depth_only;
   stl->pd->scene_depth_tx = stl->pd->draw_depth_only ? txl->dummy_texture : dtxl->depth;
   stl->pd->scene_fb = dfbl->default_fb;
   stl->pd->is_render = txl->render_depth_tx || (v3d && v3d->shading.type == OB_RENDER);
@@ -130,11 +131,15 @@ void GPENCIL_engine_init(void *ved)
     const bool overlays_on = (v3d->flag2 & V3D_HIDE_OVERLAYS) == 0;
     stl->pd->use_multiedit_lines_only = !overlays_on ||
                                         (v3d->gp_flag & V3D_GP_SHOW_MULTIEDIT_LINES) != 0;
+
+    const bool shmode_xray_support = v3d->shading.type <= OB_SOLID;
+    stl->pd->xray_alpha = (shmode_xray_support && XRAY_ENABLED(v3d)) ? XRAY_ALPHA(v3d) : 1.0f;
   }
   else if (stl->pd->is_render) {
     use_scene_lights = true;
     use_scene_world = true;
     stl->pd->use_multiedit_lines_only = false;
+    stl->pd->xray_alpha = 1.0f;
   }
 
   stl->pd->use_lighting = (v3d && v3d->shading.type > OB_SOLID) || stl->pd->is_render;
@@ -275,6 +280,7 @@ void GPENCIL_cache_init(void *ved)
     grp = DRW_shgroup_create(sh, psl->composite_ps);
     DRW_shgroup_uniform_texture_ref(grp, "colorBuf", &pd->color_tx);
     DRW_shgroup_uniform_texture_ref(grp, "revealBuf", &pd->reveal_tx);
+    DRW_shgroup_uniform_bool_copy(grp, "onlyAlpha", pd->draw_wireframe);
     DRW_shgroup_call_procedural_triangles(grp, NULL, 1);
   }
   {
@@ -508,6 +514,7 @@ static void gp_layer_cache_populate(bGPDlayer *gpl,
     float onion_alpha = use_onion_fade ? (1.0f / abs(gpf->runtime.onion_id)) : 0.5f;
     onion_alpha += (gpd->onion_factor * 2.0f - 1.0f);
     onion_alpha = clamp_f(onion_alpha, 0.01f, 1.0f);
+    onion_alpha *= iter->pd->xray_alpha;
 
     DRW_shgroup_uniform_vec4_copy(iter->grp, "layerTint", onion_col);
     DRW_shgroup_uniform_float_copy(iter->grp, "layerOpacity", onion_alpha);
@@ -516,7 +523,7 @@ static void gp_layer_cache_populate(bGPDlayer *gpl,
     float alpha = GPENCIL_SIMPLIFY_TINT(scene) ? 0.0f : gpl->tintcolor[3];
     float tintcolor[4] = {gpl->tintcolor[0], gpl->tintcolor[1], gpl->tintcolor[2], alpha};
     DRW_shgroup_uniform_vec4_copy(iter->grp, "layerTint", tintcolor);
-    DRW_shgroup_uniform_float_copy(iter->grp, "layerOpacity", 1.0f);
+    DRW_shgroup_uniform_float_copy(iter->grp, "layerOpacity", iter->pd->xray_alpha);
   }
 }
 
diff --git a/source/blender/draw/engines/gpencil/gpencil_engine.h b/source/blender/draw/engines/gpencil/gpencil_engine.h
index b234a65093d..9a2f73f20fa 100644
--- a/source/blender/draw/engines/gpencil/gpencil_engine.h
+++ b/source/blender/draw/engines/gpencil/gpencil_engine.h
@@ -291,6 +291,8 @@ typedef struct GPENCIL_PrivateData {
   bool is_render;
   /* True in selection and auto_depth drawing */
   bool draw_depth_only;
+  /* Is shading set to wireframe. */
+  bool draw_wireframe;
   /* Used by the depth merge step. */
   int is_stroke_order_3d;
   float object_bound_mat[4][4];
@@ -347,6 +349,8 @@ typedef struct GPENCIL_PrivateData {
   float fade_3d_object_opacity;
   /* Mask opacity uniform. */
   float mask_opacity;
+  /* Xray transparency in solid mode. */
+  float xray_alpha;
   /* Mask invert uniform. */
   int mask_invert;
 } GPENCIL_PrivateData;
diff --git a/source/blender/draw/engines/gpencil/shaders/gpencil_composite_frag.glsl b/source/blender/draw/engines/gpencil/shaders/gpencil_composite_frag.glsl
index 7ac992e046d..097e7b5b762 100644
--- a/source/blender/draw/engines/gpencil/shaders/gpencil_composite_frag.glsl
+++ b/source/blender/draw/engines/gpencil/shaders/gpencil_composite_frag.glsl
@@ -1,6 +1,7 @@
 
 uniform sampler2D colorBuf;
 uniform sampler2D revealBuf;
+uniform bool onlyAlpha;
 
 in vec4 uvcoordsvar;
 
@@ -18,4 +19,10 @@ void main()
   fragColor.rgb = textureLod(colorBuf, uvcoordsvar.xy, 0.0).rgb;
   /* Add the alpha. */
   fragColor.a = 1.0 - fragRevealage.a;
+
+  if (onlyAlpha) {
+    /* Special case in wireframe xray mode. */
+    fragColor.rgba = vec4(0.0);
+    fragRevealage.rgb = fragRevealage.aaa;
+  }
 }