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CanvasGroup

繼承： Node2D < CanvasItem < Node < Object

將若干 2D 節點合併至單次繪製操作。

說明

Child CanvasItem nodes of a CanvasGroup are drawn as a single object. It allows to e.g. draw overlapping translucent 2D nodes without causing the overlapping sections to be more opaque than intended (set the CanvasItem.self_modulate property on the CanvasGroup to achieve this effect).

Note: The CanvasGroup uses a custom shader to read from the backbuffer to draw its children. Assigning a Material to the CanvasGroup overrides the built-in shader. To duplicate the behavior of the built-in shader in a custom Shader, use the following:

shader_type canvas_item;
render_mode unshaded;

uniform sampler2D screen_texture : hint_screen_texture, repeat_disable, filter_nearest;

void fragment() {
    vec4 c = textureLod(screen_texture, SCREEN_UV, 0.0);

    if (c.a > 0.0001) {
        c.rgb /= c.a;
    }

    COLOR *= c;
}

Note: Since CanvasGroup and CanvasItem.clip_children both utilize the backbuffer, children of a CanvasGroup who have their CanvasItem.clip_children set to anything other than CanvasItem.CLIP_CHILDREN_DISABLED will not function correctly.

屬性

float	clear_margin	10.0
float	fit_margin	10.0
bool	use_mipmaps	false

---

屬性說明

float clear_margin = 10.0 🔗

• void set_clear_margin(value: float)

• float get_clear_margin()

設定用於擴充該 CanvasGroup 清除矩形的邊距大小。會對該 CanvasGroup 所使用的後臺緩衝的區域進行擴充。邊距較小時可以減少後臺緩衝的區域大小，從而提升性能，但如果啟用了 use_mipmaps，較小的邊距可能在該 CanvasGroup 邊緣造成 mipmap 錯誤。因此，這個值應該儘量調小，但是如果畫布組的邊緣出現問題，就應該將其調大。

---

float fit_margin = 10.0 🔗

• void set_fit_margin(value: float)

• float get_fit_margin()

設定用於擴充該 CanvasGroup 繪圖矩形的邊距大小。確定該 CanvasGroup 大小的方法是：首先框定子節點的矩形區域，然後將該矩形按照 fit_margin 進行擴展。會增大該 CanvasGroup 所使用的後臺緩衝的區域，也會增大該 CanvasGroup 所覆蓋的面積，兩者都會降低性能。這個值應該儘量調小，僅在需要時調大（例如自定義著色器效果）。

---

bool use_mipmaps = false 🔗

• void set_use_mipmaps(value: bool)

• bool is_using_mipmaps()

如果為 true，則會在繪製該 CanvasGroup 之前為其後臺緩衝計算 mipmap，附加到該 CanvasGroup 的自訂 ShaderMaterial 就可以使用 mipmap。Mipmap 的生成會造成性能消耗，所以應在必要時才啟用。