vulkan: Rewrite AA shaders to respect scale

The border and color shaders - the ones that do AA - now multiply their
coordinates by the scale factor, which gives them better rounding
capabilities.

This in particular improves the case where they are used in fractional
scaling situations, where the scale is defined at the root element.

gsk/vulkan/resources/border.frag

@@ -5,20 +5,18 @@
 
 layout(location = 0) in vec2 inPos;
 layout(location = 1) in vec4 inColor;
-layout(location = 2) in vec4 inRect;
-layout(location = 3) in vec4 inCornerWidths;
-layout(location = 4) in vec4 inCornerHeights;
+layout(location = 2) in RoundedRect inRect;
 layout(location = 5) in vec4 inBorderWidths;
 
 layout(location = 0) out vec4 color;
 
 void main()
 {
-  RoundedRect routside = RoundedRect (vec4(inRect.xy, inRect.xy + inRect.zw), inCornerWidths, inCornerHeights);
+  RoundedRect routside = inRect;
   RoundedRect rinside = rounded_rect_shrink (routside, inBorderWidths);
   
   float alpha = clamp (rounded_rect_coverage (routside, inPos) -
                        rounded_rect_coverage (rinside, inPos),
                        0.0, 1.0);
-  color = clip (inPos, vec4(inColor.rgb * inColor.a, inColor.a) * alpha);
+  color = clip_scaled (inPos, vec4(inColor.rgb * inColor.a, inColor.a) * alpha);
 }

gsk/vulkan/resources/border.vert

@@ -1,6 +1,7 @@
 #version 420 core
 
 #include "clip.vert.glsl"
+#include "rounded-rect.glsl"
 
 layout(location = 0) in vec4 inRect;
 layout(location = 1) in vec4 inCornerWidths;
@@ -10,9 +11,7 @@ layout(location = 4) in mat4 inBorderColors;
 
 layout(location = 0) out vec2 outPos;
 layout(location = 1) out flat vec4 outColor;
-layout(location = 2) out flat vec4 outRect;
-layout(location = 3) out flat vec4 outCornerWidths;
-layout(location = 4) out flat vec4 outCornerHeights;
+layout(location = 2) out flat RoundedRect outRect;
 layout(location = 5) out flat vec4 outBorderWidths;
 
 vec2 offsets[6] = { vec2(0.0, 0.0),
@@ -97,11 +96,10 @@ void main() {
     pos = mix (rect.bounds.xy, rect.bounds.zw, offsets[vert_index]);
   else
     pos = mix (rect.bounds.zy, rect.bounds.xw, offsets[vert_index]);
-  gl_Position = push.mvp * vec4 (push.scale * pos, 0.0, 1.0);
+  gl_Position = push.mvp * vec4 (pos, 0.0, 1.0);
   outColor = inBorderColors[((gl_VertexIndex / 3 + 15) / 4) % 4];
   outPos = pos;
-  outRect = inRect;
-  outCornerWidths = inCornerWidths;
-  outCornerHeights = inCornerHeights;
-  outBorderWidths = inBorderWidths;
+  outRect = RoundedRect(inRect.xyxy + vec4(0,0,inRect.zw), inCornerWidths, inCornerHeights);
+  outRect = rounded_rect_scale (outRect, push.scale);
+  outBorderWidths = inBorderWidths * push.scale.yxyx;
 }

gsk/vulkan/resources/clip.frag.glsl

@@ -5,25 +5,41 @@
 #define _CLIP_
 
 #ifdef CLIP_ROUNDED_RECT
-vec4 clip(vec2 pos, vec4 color)
+
+vec4
+clip_scaled (vec2 pos, vec4 color)
 {
   RoundedRect r = RoundedRect(vec4(push.clip_bounds.xy, push.clip_bounds.xy + push.clip_bounds.zw), push.clip_widths, push.clip_heights);
 
+  r = rounded_rect_scale (r, push.scale);
+
   return color * rounded_rect_coverage (r, pos);
 }
+
 #elif defined(CLIP_RECT)
-vec4 clip(vec2 pos, vec4 color)
+
+vec4
+clip_scaled (vec2 pos, vec4 color)
 {
-  /* clipped in vertex shader already */
   return color;
 }
+
 #elif defined(CLIP_NONE)
-vec4 clip(vec2 pos, vec4 color)
+
+vec4
+clip_scaled (vec2 pos, vec4 color)
 {
   return color;
 }
+
 #else
 #error "No clipping define given. Need CLIP_NONE, CLIP_RECT or CLIP_ROUNDED_RECT"
 #endif
 
+vec4
+clip (vec2 pos, vec4 color)
+{
+  return clip_scaled (pos * push.scale, color);
+}
+
 #endif

gsk/vulkan/resources/color.frag

@@ -12,5 +12,5 @@ layout(location = 0) out vec4 color;
 void main()
 {
   float alpha = inColor.a * rect_coverage (inRect, inPos);
-  color = clip (inPos, vec4(inColor.rgb, 1) * alpha);
+  color = clip_scaled (inPos, vec4(inColor.rgb, 1) * alpha);
 }

gsk/vulkan/resources/color.vert

@@ -21,7 +21,7 @@ void main() {
   Rect rect = rect_round_larger (clip_rect (rect_from_gsk (inRect)));
 
   vec2 pos = mix (rect.bounds.xy, rect.bounds.zw, offsets[gl_VertexIndex]);
-  gl_Position = push.mvp * vec4 (push.scale * pos, 0.0, 1.0);
+  gl_Position = push.mvp * vec4 (pos, 0.0, 1.0);
   outPos = pos;
   outRect = rect_from_gsk (inRect);
   outColor = inColor;

gsk/vulkan/resources/rect.glsl

@@ -11,7 +11,7 @@ struct Rect
 Rect
 rect_from_gsk (vec4 xywh)
 {
-  return Rect(xywh.xyxy + vec4(0,0,xywh.zw));
+  return Rect((xywh.xyxy + vec4(0,0,xywh.zw)) * push.scale.xyxy);
 }
 
 float

gsk/vulkan/resources/rounded-rect.glsl

@@ -42,6 +42,16 @@ rounded_rect_distance (RoundedRect r, vec2 p)
   return max (max2.x, max2.y);
 }
 
+RoundedRect
+rounded_rect_scale (RoundedRect r, vec2 scale)
+{
+  r.bounds *= scale.xyxy;
+  r.corner_widths *= scale.xxxx;
+  r.corner_heights *= scale.yyyy;
+
+  return r;
+}
+
 RoundedRect
 rounded_rect_shrink (RoundedRect r, vec4 amount)
 {