fix linear scaling

1 files changed, 5 insertions, 4 deletions

diff --git a/render/fx_renderer/gles2/shaders/quad_grad.frag b/render/fx_renderer/gles2/shaders/quad_grad.frag
index a73975b..6f611ca 100644
--- a/render/fx_renderer/gles2/shaders/quad_grad.frag
+++ b/render/fx_renderer/gles2/shaders/quad_grad.frag
@@ -25,11 +25,12 @@ vec4 gradient(){
 	float rad = radians(degree);
 
 	if(linear){
-		float angle = rad + atan(uv.x, uv.y);
+		uv *= vec2(1.0)/vec2(abs(cos(rad)) + abs(sin(rad)));
 
-		float len = length(uv);
-		uv = vec2(cos(angle) * len, sin(angle) * len) + origin;
-		step = uv.x;
+		vec2 rotated = vec2(uv.x * cos(rad) - uv.y * sin(rad) + origin.x,
+						uv.x * sin(rad) + uv.y * cos(rad) + origin.y);
+
+		step = rotated.x;
 	} else {
 		vec2 uv = normal - origin;
 		uv = vec2(uv.x * cos(rad) - uv.y * sin(rad),