Shader:getBufferFormat

Edit

Returns the format of a buffer declared in shader code. The return type matches the same syntax used by lovr.graphics.newBuffer and Buffer:getFormat, so it can be used to quickly create a Buffer that matches a variable from a Shader.

format, length = Shader:getBufferFormat(name)

Notes

If the buffer only has a single array field, the format will be "unwrapped" to an array instead of a single-field struct with an array in it. Example:

shader = lovr.graphics.newShader([[
  buffer Numbers {
    uint numbers[64];
  };

  void lovrmain(){}
]])

shader:getBufferFormat('Numbers')
-- returns {{ name = 'numbers', type = 'u32' }}, 64
-- not     {{ name = 'numbers', type = 'u32', length = 64 }}, 1

Similarly, if the buffer only has a single struct field, the format will be "unwrapped" to the inner struct. This lets you use a struct for a Buffer's data without having to wrap everything in an extra namespace. Example:

shader = lovr.graphics.newShader([[
  struct HandParams {
    vec3 pos;
    float grip;
  };

  buffer Hand {
    HandParams params;
  };

  void lovrmain(){}
]])

shader:getBufferFormat('Hand')
-- returns {{ name = 'pos', type = 'vec3' }, { name = 'grip', type = 'float' }}, 1
-- not     {{ name = 'params', type = {...}}}, 1

Example

shader = lovr.graphics.newShader([[
  uniform Transforms {
    mat4 transforms[32];
  };

  vec4 lovrmain() {
    return Projection * View * transforms[InstanceIndex] * VertexPosition;
  }
]], 'unlit')

local format, length = shader:getBufferFormat('Transforms')
print(length) --> 32
print(format[1].name) --> 'transforms'
print(format[1].type) --> 'mat4'

-- Can pass the 2 results directly to newBuffer:
transforms = lovr.graphics.newBuffer(shader:getBufferFormat('Transforms'))

-- Or override the length with some initial data:
transforms = lovr.graphics.newBuffer(shader:getBufferFormat('Transforms'), objects)

See also

• lovr.graphics.newBuffer
• Buffer:getFormat
• Shader