Shader

Supported platforms:
Available since: Gideros 2015.06.30
Inherits from: Object

Description

Gideros internally uses five distinct shaders:

• the ‘Basic’ shader handles shapes with a constant color
• the ‘Color’ shader handles shapes with per-vertex colors (mostly used by Mesh sprite)
• the ‘Texture’ shader handles textured shapes (Bitmaps)
• the ‘TextureColor’ shader handles textured and per-vertex colored shapes
• and the ‘Particle’ shader deals with Box2D particle systems

The shader API allows replacing the default shader used by Gideros with a custom one, on a sprite per sprite basis. As with most of Gideros API’s this one is straightforward: you create a Shader object and assign it to one or several sprites.

That said, since Gideros will use your shader as if it was the standard one, you will have to make sure that your custom shader is compatible with the standard one, which essentially means that it takes the same input parameters.

You can also write your shader code in Lua, it will then be automatically translated to the relevant shader language for the platform you are using, eg GLSL, HLSL or MTL. This is the recommended way.

Example

A blur shader

--Shaders are in vShader.glsl and fShader.glsl files
local shader = Shader.new("vShader", "fShader", 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="fTexelSize", type=Shader.CFLOAT4, vertex=false},
		{name="fRad", type=Shader.CINT, 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},
	}
);

shader:setConstant("fRad", Shader.CINT, 1, 0) -- initial blur level
shader:setConstant("fTexelSize", Shader.CFLOAT4, 1, {1/texw, 1/texh, 0, 0}) -- initial texel size

sprite:setShader(shader)

Methods Shader.new creates a new shader Shader.getEngineVersion gets the shader engine version Shader.getProperties gets the graphics engine properties Shader.getShaderLanguage gets the shader language Shader:isValid check if this shader was compiled successfully Shader:setConstant changes the value of a uniform

Events Constants Shader.CFLOAT a float value Shader.CFLOAT2 a vector of two floats Shader.CFLOAT3 a vector of three floats Shader.CFLOAT4 a vector of four floats Shader.CINT an integer value Shader.CMATRIX a 4x4 float matrix Shader.CTEXTURE a texture Shader.DBYTE Shader.DFLOAT Shader.DINT Shader.DSHORT Shader.DUBYTE Shader.DUSHORT Shader.FLAG_FROM_CODE Shader.FLAG_NONE Shader.FLAG_NO_DEFAULT_HEADER Shader.SYS_COLOR The current color (CFLOAT4) Shader.SYS_NONE Not filled by Gideros Shader.SYS_PARTICLESIZE The particle size Shader.SYS_PROJECTION The projection matrix (CMATRIX) Shader.SYS_TEXTUREINFO Real extent and texel size of the texture (CFLOAT4) Shader.SYS_TIMER Current time (CFLOAT) Shader.SYS_VIEW The view matrix (CMATRIX) Shader.SYS_VP Combined view/projection matrix (CMATRIX) Shader.SYS_WIT The World Inverse Transpose matrix (CMATRIX) Shader.SYS_WIT3 3x3 World Inverse Transpose matrix Shader.SYS_WORLD The world or matrix (CMATRIX) Shader.SYS_WVP The combined world/view/projection matrix (CMATRIX)

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