Canvas: fix arc rendering on AMD GPUs

for some reason only using one discard statement makes the glitching go away
horizon-eda · Feb 18, 2024 · f197474 · f197474
1 parent 79704c7
commit f197474
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Showing 3 changed files with 10 additions and 14 deletions.
diff --git a/src/canvas/shaders/triangle-arc-fragment.glsl b/src/canvas/shaders/triangle-arc-fragment.glsl
@@ -14,8 +14,10 @@ vec2 p2r(float phi, float l) {
 }
 
 void main() {
+  bool disc = false;
+
   if(length(round_pos_to_fragment)>1)
-    discard;
+    disc = true;
 
   float my_alpha = alpha;
   if(layer_mode == LAYER_MODE_FILL_ONLY) { //force alpha for fill only mode
@@ -30,7 +32,6 @@ void main() {
   if(my_a0 < 0)
     my_a0 += 2*PI;
 
-  bool disc = false;
 
   float len = length(round_pos_to_fragment);
   if(((len < (1-line_width+border_width)) || (len > (1-border_width))) && layer_mode != LAYER_MODE_FILL_ONLY) {
@@ -43,7 +44,7 @@ void main() {
   }
 
   if(len < (1-line_width)) {
-    discard;
+    disc = true;
   }
 
   if(my_a0 > a1) { //outside of arc
@@ -66,7 +67,7 @@ void main() {
       }
     }
     else if (!e0 && !e1){
-      discard;
+      disc = true;
     }
   }
 

diff --git a/src/canvas/shaders/triangle-arc0-fragment.glsl b/src/canvas/shaders/triangle-arc0-fragment.glsl
@@ -9,9 +9,6 @@ flat in float a0;
 flat in float a1;
 
 void main() {
-  if(length(round_pos_to_fragment)>1)
-    discard;
-
   float my_alpha = 1;
   if(layer_mode == LAYER_MODE_FILL_ONLY) { //force alpha for stencil mode
     my_alpha = alpha;
@@ -25,11 +22,8 @@ void main() {
   if(my_a0 < 0)
     my_a0 += 2*PI;
 
-  if(my_a0 > a1)
+  if(my_a0 > a1 || length(round_pos_to_fragment)>1 || length(round_pos_to_fragment) < border_threshold)
    discard;
 
-  if(length(round_pos_to_fragment) < border_threshold) {
-    discard;
-  }
   outputColor = vec4(color_to_fragment, my_alpha);
 }
diff --git a/src/canvas/shaders/triangle-arc0-geometry.glsl b/src/canvas/shaders/triangle-arc0-geometry.glsl
@@ -32,17 +32,18 @@ void main() {
 
 	color_to_fragment = get_color(color_to_geom[0], color2_to_geom[0]);
 
-    a0 = p1.x;
-    a1 = p1.y;
+
 
 	float border_width = min_line_width;
 	float r = p2.x + border_width/scale/2;
 	float h = r*2;
 	float z = 2;
 
-	border_threshold = 1-border_width/(r*scale);
 
 	for(int i = 0; i<3; i++) {
+		a0 = p1.x;
+		a1 = p1.y;
+		border_threshold = 1-border_width/(r*scale);
 		float phi = PI*(2./3)*i;
 		gl_Position = t(p0+p2r(phi, h));
 		round_pos_to_fragment = p2r(phi,z);