Shader:send

Available since LÖVE 0.9.0

It has been renamed from PixelEffect:send.

Sends one or more values to a special (uniform) variable inside the shader. Uniform variables have to be marked using the uniform or extern keyword, e.g.

uniform float time;  // "float" is the typical number type used in GLSL shaders.
uniform float vars[2];
uniform vec2 light_pos;
uniform vec4 colors[4];

The corresponding send calls would be

shader:send("time", t)
shader:send("vars",a,b)
shader:send("light_pos", {light_x, light_y})
shader:send("colors", {r1, g1, b1, a1},  {r2, g2, b2, a2},  {r3, g3, b3, a3},  {r4, g4, b4, a4})

Uniform / extern variables are read-only in the shader code and remain constant until modified by a Shader:send call. Uniform variables can be accessed in both the Vertex and Pixel components of a shader, as long as the variable is declared in each.

There is a bug in version 0.10.2 which causes Shader:send to ignore the last argument when sending arrays. A simple workaround is to add an extra dummy argument when sending multiple values to a uniform array.

Function

Synopsis

Shader:send( name, number, ... )

Arguments

string name

Name of the number to send to the shader.

number number

Number to send to store in the uniform variable.

number ...

Additional numbers to send if the uniform variable is an array.

Returns

Nothing.

Notes

Because all numbers in Lua are floating point, in versions prior to 0.10.2 you must use the function Shader:sendInt to send values to uniform int variables in the shader's code.

Function

Synopsis

Shader:send( name, vector, ... )

Arguments

string name

Name of the vector to send to the shader.

table vector

Numbers to send to the uniform variable as a vector. The number of elements in the table determines the type of the vector (e.g. two numbers -> vec2). At least two and at most four numbers can be used.

table ...

Additional vectors to send if the uniform variable is an array. All vectors need to be of the same size (e.g. only vec3's).

Returns

Nothing.

Function

Synopsis

Shader:send( name, matrix, ... )

Arguments

string name

Name of the matrix to send to the shader.

table matrix

2x2, 3x3, or 4x4 matrix to send to the uniform variable. Using table form: {{a,b,c,d}, {e,f,g,h}, ... } or (since version 0.10.2) {a,b,c,d, e,f,g,h, ...}. The order in 0.10.2 is column-major; starting in 11.0 it's row-major instead.

table ...

Additional matrices of the same type as matrix to store in a uniform array.

Returns

Nothing.

Function

Synopsis

Shader:send( name, texture )

Arguments

string name

Name of the Texture to send to the shader.

Texture texture

Texture (Image or Canvas) to send to the uniform variable.

Returns

Nothing.

Function

Synopsis

Shader:send( name, boolean, ... )

Arguments

string name

Name of the boolean to send to the shader.

boolean boolean

Boolean to send to store in the uniform variable.

boolean ...

Additional booleans to send if the uniform variable is an array.

Returns

Nothing.

Function

Available since LÖVE 0.11.0

This variant is not supported in earlier versions.

Sends uniform values to the Shader sourced from the contents of a Data object. This directly copies the bytes of the data.

Synopsis

Shader:send( name, data, offset, size )

Arguments

string name

Name of the uniform to send to the shader.

Data data

Data object containing the values to send.

number offset (0)

Offset in bytes from the start of the Data object.

number size (all)

Size in bytes of the data to send. If nil, as many bytes as the specified uniform uses will be copied.

Returns

Nothing.

Function

Available since LÖVE 0.11.0

This variant is not supported in earlier versions.

Sends uniform matrices to the Shader sourced from the contents of a Data object. This directly copies the bytes of the data.

Synopsis

Shader:send( name, data, matrixlayout, offset, size )

Arguments

string name

Name of the uniform matrix to send to the shader.

Data data

Data object containing the values to send.

MatrixLayout matrixlayout

The layout (row- or column-major) of the matrix in memory.

number offset (0)

Offset in bytes from the start of the Data object.

number size (all)

Size in bytes of the data to send. If nil, as many bytes as the specified uniform uses will be copied.

Returns

Nothing.

See Also

• Shader

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