GPencil: Implement Stroke Hardeness

Still pending the aspect ratio

4 files changed, 28 insertions, 5 deletions

diff --git a/source/blender/draw/engines/gpencil/shaders/gpencil_common_lib.glsl b/source/blender/draw/engines/gpencil/shaders/gpencil_common_lib.glsl
index 17986db54f7..80e3df699f8 100644
--- a/source/blender/draw/engines/gpencil/shaders/gpencil_common_lib.glsl
+++ b/source/blender/draw/engines/gpencil/shaders/gpencil_common_lib.glsl
@@ -151,10 +151,13 @@ flat IN_OUT vec2 strokePt1;
 flat IN_OUT vec2 strokePt2;
 flat IN_OUT int matFlag;
 flat IN_OUT float depth;
+noperspective IN_OUT float strokeHardeness;
 
 #ifdef GPU_FRAGMENT_SHADER
 
-float stroke_round_cap_mask(vec2 p1, vec2 p2, float thickness)
+#  define linearstep(p0, p1, v) (clamp(((v) - (p0)) / abs((p1) - (p0)), 0.0, 1.0))
+
+float stroke_round_cap_mask(vec2 p1, vec2 p2, float thickness, float hardfac)
 {
   /* We create our own uv space to avoid issues with triangulation and linear
    * interpolation artifacts. */
@@ -171,7 +174,11 @@ float stroke_round_cap_mask(vec2 p1, vec2 p2, float thickness)
   /* Divide by stroke radius. */
   uv_end /= thickness;
 
-  return (dot(uv_end, uv_end) > 0.25) ? 0.0 : 1.0;
+  float dist = clamp(1.0 - length(uv_end) * 2.0, 0.0, 1.0);
+  /* Modulate the falloff profile */
+  float hardness = 1.0 - hardfac;
+  dist = pow(dist, mix(0.1, 10.0, hardness));
+  return smoothstep(0.0, 1.0, dist);
 }
 
 #endif
@@ -221,6 +228,11 @@ in vec4 col2;
 
 in vec4 fcol1;
 
+in vec2 hard;
+in vec2 hard1;
+in vec2 hard2;
+in vec2 hard3;
+
 void discard_vert()
 {
   /* We set the vertex at the camera origin to generate 0 fragments. */
@@ -372,6 +384,7 @@ void stroke_vertex()
   thickness = stroke_thickness_modulate(thickness);
 
   finalUvs = vec2(x, y) * 0.5 + 0.5;
+  strokeHardeness = (use_curr) ? hard1.y : hard2.y;
 
   if (is_dot) {
 #  ifdef GP_MATERIAL_BUFFER_LEN
diff --git a/source/blender/draw/engines/gpencil/shaders/gpencil_frag.glsl b/source/blender/draw/engines/gpencil/shaders/gpencil_frag.glsl
index bca922ec018..43a9286f7d5 100644
--- a/source/blender/draw/engines/gpencil/shaders/gpencil_frag.glsl
+++ b/source/blender/draw/engines/gpencil/shaders/gpencil_frag.glsl
@@ -85,7 +85,7 @@ void main()
 
   fragColor.rgb *= gpencil_lighting();
 
-  fragColor *= stroke_round_cap_mask(strokePt1, strokePt2, strokeThickness);
+  fragColor *= stroke_round_cap_mask(strokePt1, strokePt2, strokeThickness, strokeHardeness);
 
   /* For compatibility with colored alpha buffer.
    * Note that we are limited to mono-chromatic alpha blending here
diff --git a/source/blender/draw/engines/overlay/shaders/outline_prepass_frag.glsl b/source/blender/draw/engines/overlay/shaders/outline_prepass_frag.glsl
index fdbce27b38d..c8a0a9ac4b6 100644
--- a/source/blender/draw/engines/overlay/shaders/outline_prepass_frag.glsl
+++ b/source/blender/draw/engines/overlay/shaders/outline_prepass_frag.glsl
@@ -18,7 +18,7 @@ vec3 ray_plane_intersection(vec3 ray_ori, vec3 ray_dir, vec4 plane)
 void main()
 {
 #ifdef USE_GPENCIL
-  if (stroke_round_cap_mask(strokePt1, strokePt2, strokeThickness) < 0.001) {
+  if (stroke_round_cap_mask(strokePt1, strokePt2, strokeThickness, strokeHardeness) < 0.001) {
     discard;
   }
 
diff --git a/source/blender/draw/intern/draw_cache_impl_gpencil.c b/source/blender/draw/intern/draw_cache_impl_gpencil.c
index e77026e850a..0c7c426f81e 100644
--- a/source/blender/draw/intern/draw_cache_impl_gpencil.c
+++ b/source/blender/draw/intern/draw_cache_impl_gpencil.c
@@ -182,6 +182,8 @@ typedef struct gpStrokeVert {
   /** Position and thickness packed in the same attribute. */
   float pos[3], thickness;
   float uv_fill[2], u_stroke, v_rot;
+  /** Aspect ratio and hardnes. */
+  float aspect_ratio, hardness;
 } gpStrokeVert;
 
 static GPUVertFormat *gpencil_stroke_format(void)
@@ -191,6 +193,7 @@ static GPUVertFormat *gpencil_stroke_format(void)
     GPU_vertformat_attr_add(&format, "ma", GPU_COMP_F32, 4, GPU_FETCH_FLOAT);
     GPU_vertformat_attr_add(&format, "pos", GPU_COMP_F32, 4, GPU_FETCH_FLOAT);
     GPU_vertformat_attr_add(&format, "uv", GPU_COMP_F32, 4, GPU_FETCH_FLOAT);
+    GPU_vertformat_attr_add(&format, "hard", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
     /* IMPORTANT: This means having only 4 attributes to fit into GPU module limit of 16 attrib. */
     GPU_vertformat_multiload_enable(&format, 4);
   }
@@ -289,6 +292,9 @@ static void gpencil_buffer_add_point(gpStrokeVert *verts,
   vert->thickness = max_ff(0.0f, gps->thickness * pt->pressure) * (round_cap1 ? 1.0 : -1.0);
   /* Tag endpoint material to -1 so they get discarded by vertex shader. */
   vert->mat = (is_endpoint) ? -1 : (gps->mat_nr % GP_MATERIAL_BUFFER_LEN);
+
+  vert->aspect_ratio = gps->gradient_s[0] / max_ff(gps->gradient_s[1], 1e-8);
+  vert->hardness = gps->gradient_f;
 }
 
 static void gpencil_buffer_add_stroke(gpStrokeVert *verts,
@@ -483,13 +489,17 @@ GPUBatch *DRW_cache_gpencil_face_wireframe_get(Object *ob)
 bGPDstroke *DRW_cache_gpencil_sbuffer_stroke_data_get(Object *ob)
 {
   bGPdata *gpd = (bGPdata *)ob->data;
+  Brush *brush = gpd->runtime.sbuffer_brush;
   /* Convert the sbuffer to a bGPDstroke. */
   if (gpd->runtime.sbuffer_gps == NULL) {
     bGPDstroke *gps = MEM_callocN(sizeof(*gps), "bGPDstroke sbuffer");
     gps->totpoints = gpd->runtime.sbuffer_used;
     gps->mat_nr = max_ii(0, gpd->runtime.matid - 1);
     gps->flag = gpd->runtime.sbuffer_sflag;
-    gps->thickness = gpd->runtime.brush_size;
+    gps->thickness = brush->size;
+    gps->gradient_f = brush->gpencil_settings->gradient_f;
+    copy_v2_v2(gps->gradient_s, brush->gpencil_settings->gradient_s);
+
     /* Reduce slightly the opacity of fill to make easy fill areas while drawing. */
     gps->fill_opacity_fac = 0.8f;