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CanvasItem shaders

Les shaders de type CanvasItem sont utilisés pour dessiner tous les éléments 2D dans Godot. Ceux-ci incluent tous les nœuds qui héritent de CanvasItems, et tous les éléments d'interface graphique.

CanvasItem shaders contain fewer built-in variables and functionality than Spatial shaders, but they maintain the same basic structure with vertex, fragment, and light processor functions.

Mode de rendu

Mode de rendu	Description
blend_mix	Mode de fusion par mélange (alpha est la transparence), par défaut.
blend_add	Mode de fusion additif.
blend_sub	Mode de fusion substractif.
blend_mul	Mode de fusion multiplicatif.
blend_premul_alpha	Mode de mélange alpha pré-multiplié.
blend_disabled	Désactive le mélange, les valeurs (y compris l'alpha) sont écrites telles quelles.
unshaded	Le résultat est juste l'albedo. Pas d'éclairage/d'ombres n'a lieu dans le matériau.
light_only	Only draw in the light pass.
skip_vertex_transform	`VERTEX` needs to be transformed manually in the `vertex()` function.
world_vertex_coords	`VERTEX` is modified in world coordinates instead of local.

Variables intégrées

Values marked as in are read-only. Values marked as out can optionally be written to and will not necessarily contain sensible values. Values marked as inout provide a sensible default value, and can optionally be written to. Samplers cannot be written to so they are not marked.

Not all built-ins are available in all processing functions. To access a vertex built-in from the fragment() function, you can use a varying. The same applies for accessing fragment built-ins from the light() function.

Variables intégrées Globales

Les modules intégrés globaux sont disponibles partout, y compris dans les fonctions personnalisées.

Intégré	Description
in float TIME	Global time since the engine has started, in seconds. It repeats after every `3,600` seconds (which can be changed with the rollover setting). It's affected by time_scale but not by pausing. If you need a `TIME` variable that is not affected by time scale, add your own global shader uniform and update it each frame.
in float PI	A `PI` constant (`3.141592`). The ratio of a circle's circumference to its diameter and the number of radians in a half turn.
in float TAU	A `TAU` constant (`6.283185`). Equivalent to `PI * 2` and the number of radians in a full turn.
in float E	An `E` constant (`2.718281`). Euler's number, the base of the natural logarithm.

Variables intégrées de sommet

Vertex data (VERTEX) is presented in local space (pixel coordinates, relative to the Node2D's origin). If not written to, these values will not be modified and be passed through as they came.

The user can disable the built-in model to world transform (world to screen and projection will still happen later) and do it manually with the following code:

shader_type canvas_item;
render_mode skip_vertex_transform;

void vertex() {

    VERTEX = (MODEL_MATRIX * vec4(VERTEX, 0.0, 1.0)).xy;
}

Other built-ins, such as UV and COLOR, are also passed through to the fragment() function if not modified.

For instancing, the INSTANCE_CUSTOM variable contains the instance custom data. When using particles, this information is usually:

x : Angle de rotation en radians.
y: Phase during lifetime (0.0 to 1.0).
z : Trame d'animation.

Intégré	Description
in mat4 MODEL_MATRIX	Local space to world space transform. World space is the coordinates you normally use in the editor.
in mat4 CANVAS_MATRIX	World space to canvas space transform. In canvas space the origin is the upper-left corner of the screen and coordinates range from `(0.0, 0.0)` to viewport size.
in mat4 SCREEN_MATRIX	Canvas space to clip space transform. In clip space coordinates range from `(-1.0, -1.0)` to `(1.0, 1.0).`
in int INSTANCE_ID	Identifiant de l'instance pour l'instanciation.
in vec4 INSTANCE_CUSTOM	Données personnalisées de l'instance.
in bool AT_LIGHT_PASS	Toujours `false`.
in vec2 TEXTURE_PIXEL_SIZE	Normalized pixel size of the default 2D texture. For a Sprite2D with a texture of size 64×32 pixels, `TEXTURE_PIXEL_SIZE` = `vec2(1.0 / 64.0, 1.0 / 32.0)`.
inout vec2 VERTEX	Vertex position, in local space.
in int VERTEX_ID	L'index du sommet actuel dans le buffer des sommets.
inout vec2 UV	Normalized texture coordinates. Range from `0.0` to `1.0`.
inout vec4 COLOR	Color from vertex primitive multiplied by the CanvasItem's modulate multiplied by CanvasItem's self_modulate.
inout float POINT_SIZE	Taille des points pour le dessin de point.
in vec4 CUSTOM0	Custom value from vertex primitive.
in vec4 CUSTOM1	Custom value from vertex primitive.

Variables intégrées de fragment

COLOR et TEXTURE

The built-in variable COLOR is used for a few things:

In the vertex() function, COLOR contains the color from the vertex primitive multiplied by the CanvasItem's modulate multiplied by the CanvasItem's self_modulate.

In the fragment() function, the input value COLOR is that same value multiplied by the color from the default TEXTURE (if present).

In the fragment() function, COLOR is also the final output.

Certain nodes (for example, Sprite2D) display a texture by default, for example texture. When using a custom fragment() function, you have a few options on how to sample this texture.

To read only the contents of the default texture, ignoring the vertex COLOR:

void fragment() {
  COLOR = texture(TEXTURE, UV);
}

To read the contents of the default texture multiplied by vertex COLOR:

void fragment() {
  // Equivalent to an empty fragment() function, since COLOR is also the output variable.
  COLOR = COLOR;
}

To read only the vertex COLOR in fragment(), ignoring the main texture, you must pass COLOR as a varying, then read it in fragment():

varying vec4 vertex_color;
void vertex() {
  vertex_color = COLOR;
}
void fragment() {
  COLOR = vertex_color;
}

NORMAL

Similarly, if a normal map is used in the CanvasTexture, Godot uses it by default and assigns its value to the built-in NORMAL variable. If you are using a normal map meant for use in 3D, it will appear inverted. In order to use it in your shader, you must assign it to the NORMAL_MAP property. Godot will handle converting it for use in 2D and overwriting NORMAL.

NORMAL_MAP = texture(NORMAL_TEXTURE, UV).rgb;

Intégré	Description
in vec4 FRAGCOORD	Coordinate of pixel center. In screen space. `xy` specifies position in viewport. Upper-left of the viewport is the origin, `(0.0, 0.0)`. Bottom-right of the viewport is `(1.0, 1.0)`.
in vec2 SCREEN_PIXEL_SIZE	Size of individual pixels. Equal to the inverse of resolution.
in vec4 REGION_RECT	Visible area of the sprite region in format `(x, y, width, height)`. Varies according to Sprite2D's `region_enabled` property. Values are normalized; for example, a 600×400 region on a 1000×800 texture with a 100×100 offset would be `vec4(0.1, 0.125, 0.6, 0.5)`. Values may exceed the 0.0 to 1.0 range if the X/Y offset is negative, or if the size exceeds the texture's size.
in vec2 POINT_COORD	Coordinate for drawing points in the 0.0 to 1.0 range.
sampler2D TEXTURE	Texture 2D par défault.
in vec2 TEXTURE_PIXEL_SIZE	Normalized pixel size of the default 2D texture. For a Sprite2D with a texture of size 64×32 pixels, `TEXTURE_PIXEL_SIZE` = `vec2(1.0 / 64.0, 1.0 / 32.0)`.
in bool AT_LIGHT_PASS	Toujours `false`.
sampler2D SPECULAR_SHININESS_TEXTURE	Texture de brillance spéculaire pour cet objet.
in vec4 SPECULAR_SHININESS	Specular shininess color, as sampled from the texture.
in vec2 UV	UV from the `vertex()` function. For a Sprite2D with region enabled, this will sample the entire texture. Use `REGION_RECT` instead to sample only the region defined in the Sprite2D's properties.
in vec2 SCREEN_UV	Screen UV coordinate for the current pixel.
sampler2D SCREEN_TEXTURE	Removed in Godot 4. Use a `sampler2D` with `hint_screen_texture` instead.
inout vec3 NORMAL	Normal read from `NORMAL_TEXTURE`. Writable.
sampler2D NORMAL_TEXTURE	Texture 2D des normales par défaut.
out vec3 NORMAL_MAP	Configures normal maps meant for 3D for use in 2D. If used, overrides `NORMAL`.
out float NORMAL_MAP_DEPTH	Normal map depth for scaling.
inout vec2 VERTEX	Pixel position in screen space.
inout vec2 SHADOW_VERTEX	Same as `VERTEX` but can be written to alter shadows.
inout vec3 LIGHT_VERTEX	Same as `VERTEX` but can be written to alter lighting. Z component represents height.
inout vec4 COLOR	`COLOR` from the `vertex()` function multiplied by the `TEXTURE` color. Also output color value.

Variables intégrées de lumière

Light processor functions work differently in Godot 4.x than they did in Godot 3.x. In Godot 4.x all lighting is done during the regular draw pass. In other words, Godot no longer draws the object again for each light.

Use the unshaded render mode if you do not want the light() function to run. Use the light_only render mode if you only want to see the impact of lighting on an object; this can be useful when you only want the object visible where it is covered by light.

If you define a light() function it will replace the built-in light function, even if your light function is empty.

Below is an example of a light shader that takes a CanvasItem's normal map into account:

void light() {
  float cNdotL = max(0.0, dot(NORMAL, LIGHT_DIRECTION));
  LIGHT = vec4(LIGHT_COLOR.rgb * COLOR.rgb * LIGHT_ENERGY * cNdotL, LIGHT_COLOR.a);
}

Intégré	Description
in vec4 FRAGCOORD	Coordinate of pixel center. In screen space. `xy` specifies position in viewport. Upper-left of the viewport is the origin, `(0.0, 0.0)`. Bottom-right of the viewport is `(1.0, 1.0)`.
in vec3 NORMAL	Input normal.
in vec4 COLOR	Input color. This is the output of the `fragment()` function.
in vec2 UV	UV from the `vertex()` function, equivalent to the UV in the `fragment()` function.
sampler2D TEXTURE	Current texture in use for the CanvasItem.
in vec2 TEXTURE_PIXEL_SIZE	Normalized pixel size of `TEXTURE`. For a Sprite2D with a `TEXTURE` of size 64×32 pixels, `TEXTURE_PIXEL_SIZE` = `vec2(1.0 / 64.0, 1.0 / 32.0)`.
in vec2 SCREEN_UV	Screen UV coordinate for the current pixel.
in vec2 POINT_COORD	UV pour Point Sprite.
in vec4 LIGHT_COLOR	Color of the Light2D. If the light is a PointLight2D, multiplied by the light's texture.
in float LIGHT_ENERGY	Energy multiplier of the Light2D.
in vec3 LIGHT_POSITION	Position of the Light2D in screen space. If using a DirectionalLight2D this is always `(0.0, 0.0, 0.0)`.
in vec3 LIGHT_DIRECTION	Direction de la Light2D dans le repère de l'écran.
in bool LIGHT_IS_DIRECTIONAL	`true` s'il cette passe est une DirectionalLight2D.
in vec3 LIGHT_VERTEX	Pixel position, in screen space as modified in the `fragment()` function.
inout vec4 LIGHT	Couleur de sortie pour cette Light2D.
in vec4 SPECULAR_SHININESS	Specular shininess, as set in the object's texture.
out vec4 SHADOW_MODULATE	Multiply shadows cast at this point by this color.

Fonctions CDS

There are a few additional functions implemented to sample an automatically generated Signed Distance Field texture. These functions are available in the fragment() and light() functions of CanvasItem shaders. Custom functions may also use them as long as they are called from supported functions.

The signed distance field is generated from LightOccluder2D nodes present in the scene with the SDF Collision property enabled (which is the default). See the 2D lights and shadows documentation for more information.

Fonction	Description
float texture_sdf (vec2 sdf_pos)	Effectue une recherche de texture SDF.
vec2 texture_sdf_normal (vec2 sdf_pos)	Calculates a normal from the SDF texture.
vec2 sdf_to_screen_uv (vec2 sdf_pos)	Converts an SDF to screen UV.
vec2 screen_uv_to_sdf (vec2 uv)	Converts screen UV to an SDF.