fix shadow container overlap

Author: mike-ward

_shadow_test.v

@@ -0,0 +1,47 @@
+module gui
+
+import gg
+
+fn test_render_container_shadow_opacity() {
+	mut w := Window{
+		renderers: []Renderer{}
+	}
+	// Setup a shape with shadow alpha 128 (approx 0.5)
+	shadow_alpha := u8(128)
+	container_color := rgb(100, 100, 100)
+
+	mut s := Shape{
+		shape_type: .rectangle
+		x:          0
+		y:          0
+		width:      100
+		height:     100
+		color:      container_color
+		radius:     5
+		shadow:     &BoxShadow{
+			blur_radius: 10
+			color:       rgba(0, 0, 0, shadow_alpha)
+		}
+	}
+	clip := gg.Rect{0, 0, 200, 200}
+
+	render_container(mut s, color_transparent, clip, mut w)
+
+	assert w.renderers.len == 2
+	shadow_r := w.renderers[0]
+	container_r := w.renderers[1]
+
+	if shadow_r is DrawShadow {
+		assert shadow_r.color.a == shadow_alpha
+	} else {
+		assert false, 'Expected DrawShadow first'
+	}
+
+	if container_r is DrawRect {
+		// Crucial verification: Container color should be opaque (255)
+		assert container_r.color.a == 255
+		assert container_r.color.r == 100
+	} else {
+		assert false, 'Expected DrawRect second'
+	}
+}

render.v

@@ -805,6 +805,7 @@ pub fn draw_blur_rect(x f32, y f32, w f32, h f32, radius f32, blur f32, c gg.Col
 
 	draw_quad(sx, sy, sw, sh, z_val)
 	sgl.load_default_pipeline()
+	sgl.c4b(255, 255, 255, 255) // Reset color state
 
 	sgl.pop_matrix()
 	sgl.matrix_mode_modelview()
@@ -917,6 +918,7 @@ fn draw_gradient_rect(x f32, y f32, w f32, h f32, radius f32, gradient &Gradient
 	draw_quad(sx, sy, sw, sh, z_val)
 
 	sgl.load_default_pipeline()
+	sgl.c4b(255, 255, 255, 255) // Reset color state
 	sgl.pop_matrix()
 	sgl.matrix_mode_modelview()
 }

shaders.v

@@ -755,6 +755,7 @@ pub fn draw_shadow_rect(x f32, y f32, w f32, h f32, radius f32, blur f32, c gg.C
 
 	draw_quad(sx, sy, sw, sh, z_val)
 	sgl.load_default_pipeline()
+	sgl.c4b(255, 255, 255, 255) // Reset color state
 
 	sgl.pop_matrix()
 	sgl.matrix_mode_modelview()