Support double, groove, ridge borders in new border brush path.

webrender/res/clip_shared.glsl

@@ -98,13 +98,3 @@ ClipVertexInfo write_clip_tile_vertex(RectWithSize local_clip_rect,
 }
 
 #endif //WR_VERTEX_SHADER
-
-#ifdef WR_FRAGMENT_SHADER
-
-//Note: identical to prim_shared
-float distance_to_line(vec2 p0, vec2 perp_dir, vec2 p) {
-    vec2 dir_to_p0 = p0 - p;
-    return dot(normalize(perp_dir), dir_to_p0);
-}
-
-#endif //WR_FRAGMENT_SHADER

webrender/res/cs_border_segment.glsl

@@ -2,20 +2,58 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-#include shared,prim_shared,ellipse,shared_border
+#include shared,ellipse
 
-flat varying vec4 vColor0;
-flat varying vec4 vColor1;
+// For edges, the colors are the same. For corners, these
+// are the colors of each edge making up the corner.
+flat varying vec4 vColor0[2];
+flat varying vec4 vColor1[2];
+
+// A point + tangent defining the line where the edge
+// transition occurs. Used for corners only.
 flat varying vec4 vColorLine;
-flat varying int vFeatures;
-flat varying vec2 vClipCenter;
+
+// x = segment, y = styles, z = edge axes
+flat varying ivec3 vConfig;
+
+// xy = Local space position of the clip center.
+// zw = Scale the rect origin by this to get the outer
+// corner from the segment rectangle.
+flat varying vec4 vClipCenter_Sign;
+
+// An outer and inner elliptical radii for border
+// corner clipping.
 flat varying vec4 vClipRadii;
-flat varying vec2 vClipSign;
 
+// Reference point for determine edge clip lines.
+flat varying vec4 vEdgeReference;
+
+// Stores widths/2 and widths/3 to save doing this in FS.
+flat varying vec4 vPartialWidths;
+
+// Local space position
 varying vec2 vPos;
 
-#define CLIP_RADII      1
-#define MIX_COLOR       2
+#define SEGMENT_TOP_LEFT        0
+#define SEGMENT_TOP_RIGHT       1
+#define SEGMENT_BOTTOM_RIGHT    2
+#define SEGMENT_BOTTOM_LEFT     3
+#define SEGMENT_LEFT            4
+#define SEGMENT_TOP             5
+#define SEGMENT_RIGHT           6
+#define SEGMENT_BOTTOM          7
+
+// Border styles as defined in webrender_api/types.rs
+#define BORDER_STYLE_NONE         0
+#define BORDER_STYLE_SOLID        1
+#define BORDER_STYLE_DOUBLE       2
+#define BORDER_STYLE_DOTTED       3
+#define BORDER_STYLE_DASHED       4
+#define BORDER_STYLE_HIDDEN       5
+#define BORDER_STYLE_GROOVE       6
+#define BORDER_STYLE_RIDGE        7
+#define BORDER_STYLE_INSET        8
+#define BORDER_STYLE_OUTSET       9
 
 #ifdef WR_VERTEX_SHADER
 
@@ -27,15 +65,6 @@ in int aFlags;
 in vec2 aWidths;
 in vec2 aRadii;
 
-#define SEGMENT_TOP_LEFT        0
-#define SEGMENT_TOP_RIGHT       1
-#define SEGMENT_BOTTOM_RIGHT    2
-#define SEGMENT_BOTTOM_LEFT     3
-#define SEGMENT_LEFT            4
-#define SEGMENT_TOP             5
-#define SEGMENT_RIGHT           6
-#define SEGMENT_BOTTOM          7
-
 vec2 get_outer_corner_scale(int segment) {
     vec2 p;
 
@@ -61,67 +90,252 @@ vec2 get_outer_corner_scale(int segment) {
     return p;
 }
 
-void main(void) {
-    vec2 pos = aRect.xy + aRect.zw * aPosition.xy;
+vec4 mod_color(vec4 color, float f) {
+    return vec4(clamp(color.rgb * f, vec3(0.0), vec3(color.a)), color.a);
+}
+
+vec4[2] get_colors_for_side(vec4 color, int style) {
+    vec4 result[2];
+    const vec2 f = vec2(1.3, 0.7);
+
+    switch (style) {
+        case BORDER_STYLE_GROOVE:
+            result[0] = mod_color(color, f.x);
+            result[1] = mod_color(color, f.y);
+            break;
+        case BORDER_STYLE_RIDGE:
+            result[0] = mod_color(color, f.y);
+            result[1] = mod_color(color, f.x);
+            break;
+        default:
+            result[0] = color;
+            result[1] = color;
+            break;
+    }
+
+    return result;
+}
 
+void main(void) {
     int segment = aFlags & 0xff;
-    int style = (aFlags >> 8) & 0xff;
+    int style0 = (aFlags >> 8) & 0xff;
+    int style1 = (aFlags >> 16) & 0xff;
 
     vec2 outer_scale = get_outer_corner_scale(segment);
-    vec2 outer = aRect.xy + outer_scale * aRect.zw;
+    vec2 outer = outer_scale * aRect.zw;
     vec2 clip_sign = 1.0 - 2.0 * outer_scale;
 
-    vColor0 = aColor0;
-    vColor1 = aColor1;
-    vPos = pos;
-
-    vFeatures = 0;
-    vClipSign = clip_sign;
-    vClipCenter = outer + clip_sign * aRadii;
-    vClipRadii = vec4(aRadii, aRadii - aWidths);
-    vColorLine = vec4(0.0);
-
+    // Set some flags used by the FS to determine the
+    // orientation of the two edges in this corner.
+    ivec2 edge_axis;
+    // Derive the positions for the edge clips, which must be handled
+    // differently between corners and edges.
+    vec2 edge_reference;
     switch (segment) {
         case SEGMENT_TOP_LEFT:
+            edge_axis = ivec2(0, 1);
+            edge_reference = outer;
+            break;
         case SEGMENT_TOP_RIGHT:
+            edge_axis = ivec2(1, 0);
+            edge_reference = vec2(outer.x - aWidths.x, outer.y);
+            break;
         case SEGMENT_BOTTOM_RIGHT:
+            edge_axis = ivec2(0, 1);
+            edge_reference = outer - aWidths;
+            break;
         case SEGMENT_BOTTOM_LEFT:
-            vFeatures |= (CLIP_RADII | MIX_COLOR);
-            vColorLine = vec4(outer, aWidths.y * -clip_sign.y, aWidths.x * clip_sign.x);
+            edge_axis = ivec2(1, 0);
+            edge_reference = vec2(outer.x, outer.y - aWidths.y);
+            break;
+        case SEGMENT_TOP:
+        case SEGMENT_BOTTOM:
+            edge_axis = ivec2(1, 1);
+            edge_reference = vec2(0.0);
             break;
+        case SEGMENT_LEFT:
+        case SEGMENT_RIGHT:
         default:
+            edge_axis = ivec2(0, 0);
+            edge_reference = vec2(0.0);
             break;
     }
 
-    gl_Position = uTransform * vec4(aTaskOrigin + pos, 0.0, 1.0);
+    vConfig = ivec3(
+        segment,
+        style0 | (style1 << 16),
+        edge_axis.x | (edge_axis.y << 16)
+    );
+    vPartialWidths = vec4(aWidths / 3.0, aWidths / 2.0);
+    vPos = aRect.zw * aPosition.xy;
+
+    vColor0 = get_colors_for_side(aColor0, style0);
+    vColor1 = get_colors_for_side(aColor1, style1);
+    vClipCenter_Sign = vec4(outer + clip_sign * aRadii, clip_sign);
+    vClipRadii = vec4(aRadii, max(aRadii - aWidths, 0.0));
+    vColorLine = vec4(outer, aWidths.y * -clip_sign.y, aWidths.x * clip_sign.x);
+    vEdgeReference = vec4(edge_reference, edge_reference + aWidths);
+
+    gl_Position = uTransform * vec4(aTaskOrigin + aRect.xy + vPos, 0.0, 1.0);
 }
 #endif
 
 #ifdef WR_FRAGMENT_SHADER
+vec4 evaluate_color_for_style_in_corner(
+    vec2 clip_relative_pos,
+    int style,
+    vec4 color[2],
+    vec4 clip_radii,
+    float mix_factor,
+    int segment,
+    float aa_range
+) {
+    switch (style) {
+        case BORDER_STYLE_DOUBLE: {
+            // Get the distances from 0.33 of the radii, and
+            // also 0.67 of the radii. Use these to form a
+            // SDF subtraction which will clip out the inside
+            // third of the rounded edge.
+            float d_radii_a = distance_to_ellipse(
+                clip_relative_pos,
+                clip_radii.xy - vPartialWidths.xy,
+                aa_range
+            );
+            float d_radii_b = distance_to_ellipse(
+                clip_relative_pos,
+                clip_radii.xy - 2.0 * vPartialWidths.xy,
+                aa_range
+            );
+            float d = min(-d_radii_a, d_radii_b);
+            float alpha = distance_aa(aa_range, d);
+            return alpha * color[0];
+        }
+        case BORDER_STYLE_GROOVE:
+        case BORDER_STYLE_RIDGE: {
+            float d = distance_to_ellipse(
+                clip_relative_pos,
+                clip_radii.xy - vPartialWidths.zw,
+                aa_range
+            );
+            float alpha = distance_aa(aa_range, d);
+            float swizzled_factor;
+            switch (segment) {
+                case SEGMENT_TOP_LEFT: swizzled_factor = 0.0; break;
+                case SEGMENT_TOP_RIGHT: swizzled_factor = mix_factor; break;
+                case SEGMENT_BOTTOM_RIGHT: swizzled_factor = 1.0; break;
+                case SEGMENT_BOTTOM_LEFT: swizzled_factor = 1.0 - mix_factor; break;
+                default: swizzled_factor = 0.0; break;
+            };
+            vec4 c0 = mix(color[1], color[0], swizzled_factor);
+            vec4 c1 = mix(color[0], color[1], swizzled_factor);
+            return mix(c0, c1, alpha);
+        }
+        default:
+            break;
+    }
+
+    return color[0];
+}
+
+vec4 evaluate_color_for_style_in_edge(
+    vec2 pos,
+    int style,
+    vec4 color[2],
+    float aa_range,
+    int edge_axis
+) {
+    switch (style) {
+        case BORDER_STYLE_DOUBLE: {
+            float d0 = -1.0;
+            float d1 = -1.0;
+            if (vPartialWidths[edge_axis] > 1.0) {
+                vec2 ref = vec2(
+                    vEdgeReference[edge_axis] + vPartialWidths[edge_axis],
+                    vEdgeReference[edge_axis+2] - vPartialWidths[edge_axis]
+                );
+                d0 = pos[edge_axis] - ref.x;
+                d1 = ref.y - pos[edge_axis];
+            }
+            float d = min(d0, d1);
+            float alpha = distance_aa(aa_range, d);
+            return alpha * color[0];
+        }
+        case BORDER_STYLE_GROOVE:
+        case BORDER_STYLE_RIDGE: {
+            float ref = vEdgeReference[edge_axis] + vPartialWidths[edge_axis+2];
+            float d = pos[edge_axis] - ref;
+            float alpha = distance_aa(aa_range, d);
+            return mix(color[0], color[1], alpha);
+        }
+        default:
+            break;
+    }
+
+    return color[0];
+}
+
 void main(void) {
     float aa_range = compute_aa_range(vPos);
     float d = -1.0;
+    vec4 color0, color1;
+
+    int segment = vConfig.x;
+    ivec2 style = ivec2(vConfig.y & 0xffff, vConfig.y >> 16);
+    ivec2 edge_axis = ivec2(vConfig.z & 0xffff, vConfig.z >> 16);
 
-    // Apply color mix
     float mix_factor = 0.0;
-    if ((vFeatures & MIX_COLOR) != 0) {
+    if (edge_axis.x != edge_axis.y) {
         float d_line = distance_to_line(vColorLine.xy, vColorLine.zw, vPos);
         mix_factor = distance_aa(aa_range, -d_line);
     }
 
-    // Apply clip radii
-    if ((vFeatures & CLIP_RADII) != 0) {
-        vec2 p = vPos - vClipCenter;
-        if (vClipSign.x * p.x < 0.0 && vClipSign.y * p.y < 0.0) {
-            float d_radii_a = distance_to_ellipse(p, vClipRadii.xy, aa_range);
-            float d_radii_b = distance_to_ellipse(p, vClipRadii.zw, aa_range);
-            float d_radii = max(d_radii_a, -d_radii_b);
-            d = max(d, d_radii);
-        }
+    // Check if inside corner clip-region
+    vec2 clip_relative_pos = vPos - vClipCenter_Sign.xy;
+    bool in_clip_region = all(lessThan(vClipCenter_Sign.zw * clip_relative_pos, vec2(0.0)));
+
+    if (in_clip_region) {
+        float d_radii_a = distance_to_ellipse(clip_relative_pos, vClipRadii.xy, aa_range);
+        float d_radii_b = distance_to_ellipse(clip_relative_pos, vClipRadii.zw, aa_range);
+        float d_radii = max(d_radii_a, -d_radii_b);
+        d = max(d, d_radii);
+
+        color0 = evaluate_color_for_style_in_corner(
+            clip_relative_pos,
+            style.x,
+            vColor0,
+            vClipRadii,
+            mix_factor,
+            segment,
+            aa_range
+        );
+        color1 = evaluate_color_for_style_in_corner(
+            clip_relative_pos,
+            style.y,
+            vColor1,
+            vClipRadii,
+            mix_factor,
+            segment,
+            aa_range
+        );
+    } else {
+        color0 = evaluate_color_for_style_in_edge(
+            vPos,
+            style.x,
+            vColor0,
+            aa_range,
+            edge_axis.x
+        );
+        color1 = evaluate_color_for_style_in_edge(
+            vPos,
+            style.y,
+            vColor1,
+            aa_range,
+            edge_axis.y
+        );
     }
 
     float alpha = distance_aa(aa_range, d);
-    vec4 color = mix(vColor0, vColor1, mix_factor);
+    vec4 color = mix(color0, color1, mix_factor);
     oFragColor = color * alpha;
 }
 #endif

webrender/res/prim_shared.glsl

@@ -25,11 +25,6 @@ vec2 clamp_rect(vec2 pt, RectWithSize rect) {
     return clamp(pt, rect.p0, rect.p0 + rect.size);
 }
 
-float distance_to_line(vec2 p0, vec2 perp_dir, vec2 p) {
-    vec2 dir_to_p0 = p0 - p;
-    return dot(normalize(perp_dir), dir_to_p0);
-}
-
 // TODO: convert back to RectWithEndPoint if driver issues are resolved, if ever.
 flat varying vec4 vClipMaskUvBounds;
 varying vec3 vClipMaskUv;