Shader Attribute Descriptors

From GiderosMobile

Available since: Gideros 2015.06.30
Class: Shader

Description

Each attribute descriptor entry is a Lua table with the following fields:

  • name: the name of the attribute/vertex data stream. Must match the name used in GLSL and HLSL code
  • type: data type used from the host point of view. One of Shader.DFLOAT, Shader.DBYTE, Shader.DUBYTE, Shader.DSHORT, Shader.DUSHORT or Shader.DINT
  • mult: number of components of the input vector
  • slot: index of the input slot (HLSL only)
  • offset: offset within the input slot (HLSL only, should be 0)

The first three attributes have fixed meaning. Those are, in order:

  • the vertex coordinate stream. Type must be Shader.DFLOAT and mult should be 3
  • the per-vertex color. Type must be Shader.DUBYTE and mult should be 4
  • the texture coordinates. Type must be Shader.DFLOAT and mult should be 2

If one of these fixed attributes is not used by the custom shader program, it should still be defined with a mult value of 0 to serve as a placeholder.

Examples

local shadergrey=Shader.new("openglshader/vShaderGrey","openglshader/fShaderGrey", 0,
	{
	{name="vMatrix", type=Shader.CMATRIX, sys=Shader.SYS_WVP, vertex=true},
	{name="fColor", type=Shader.CFLOAT4, sys=Shader.SYS_COLOR, vertex=false},
	{name="fTexture", type=Shader.CTEXTURE, vertex=false},
	},
	{
	{name="vVertex", type=Shader.DFLOAT, mult=3, slot=0, offset=0},
	{name="vColor", type=Shader.DUBYTE, mult=4, slot=1, offset=0},
	{name="vTexCoord", type=Shader.DFLOAT, mult=2, slot=2, offset=0},
	}
)
local shaderwave=Shader.new("openglshader/vShaderWave","openglshader/fShaderWave", 0,
{
	{name="g_MVPMatrix", type=Shader.CMATRIX, sys=Shader.SYS_WVP, vertex=true},
	{name="g_Color", type=Shader.CFLOAT4, mult=1, sys=Shader.SYS_COLOR},
	{name="g_Texture", type=Shader.CTEXTURE, mult=1, vertex=false},
	{name="time", type=Shader.CFLOAT, mult=1, vertex=false}
	},
	{
	{name="POSITION0", type=Shader.DFLOAT, mult=3, slot=0, offset=0},
	{name="vColor", type=Shader.DUBYTE, mult=0, slot=1, offset=0},
	{name="TEXCOORD0", type=Shader.DFLOAT, mult=2, slot=2, offset=0}
	}
)