Godot Shader笔记:2D着色器(二)
2019-06-18 本文已影响0人
吃烧烤的老王
原文地址:Docs » Shading » Shading reference » CanvasItem shaders
内置片元属性(Fragment built-ins)
一些节点(例如:Sprite)，会显示一个默认的纹理。然而当给这些节点添加了自定义片元函数以后，纹理的查找则需要手动来完成。在内置属性COLOR中，Godot并没有提供纹理的颜色。如果想在这些节点中读取纹理颜色，需要如下方法:
COLOR = texture(TEXTURE, UV);
这和法线贴图有所不同，如果一个节点添加了法线贴图，则Godot可以默认使用它并且把它赋值给内置的NORMAL属性。如果你使用了一个本用于3D的法线贴图，它将呈现为翻转状态。如果你想在自己的Shader中使用它你需要把它赋值给NORMALMAP属性，Godot会把它转换成2D模式并重写NORMAL属性
NORMALMAP = texture(NORMAL_TEXTURE, UV).rgb;
| 内置片元属性 | 描述 |
|---|---|
| in vec4 FRAGCOORD | Fragment coordinate, pixel adjusted. |
| inout vec3 NORMAL | Normal read from NORMAL_TEXTURE. Writable. |
| out vec3 NORMALMAP | Configures normal maps meant for 3D for use in 2D. If used, overwrites NORMAL. |
| inout float NORMALMAP_DEPTH | Normalmap depth for scaling. |
| in vec2 UV | UV from vertex function. |
| inout vec4 COLOR | Color from vertex function and output fragment color. If unused, will be set to TEXTURE color. |
| in sampler2D TEXTURE | Default 2D texture. |
| in sampler2D NORMAL_TEXTURE | Default 2D normal texture. |
| in vec2 TEXTURE_PIXEL_SIZE | Normalized pixel size of default 2D texture. For a Sprite with a texture of size 64x32px, TEXTURE_PIXEL_SIZE = vec2(1/64, 1/32)
|
| in vec2 SCREEN_UV | Screen UV for use with SCREEN_TEXTURE. |
| in vec2 SCREEN_PIXEL_SIZE | Size of individual pixels. Equal to inverse of resolution. |
| in vec2 POINT_COORD | Coordinate for drawing points. |
| in float TIME | Global time in seconds. |
| in bool AT_LIGHT_PASS | True if this is a light pass. |
| in sampler2D SCREEN_TEXTURE | Screen texture, mipmaps contain gaussian blurred versions. |
