Matteo Marson

once in a while, looking inside jitter shaders, I discover some new GL3 built-in uniforms never saw before. Sometimes, they provide the answer to problems I didn't know how to address before. I looked inside the jitter documetation, but I didn't find an exhaustive list of all the avaiables built-in uniforms. I know many of them can be found in the GLSL documentation out there, but i'd love to have a comprehensive list of what Max and GLSL can offer to let the users build their own shaders. Here there are the uniforms i met so far and what i understood about them:

type="mat4" state="MODELVIEW_PROJECTION_MATRIX" 

type="mat4" state="PREV_MODELVIEW_PROJECTION_MATRIX"

 == the previous frames modelview-projection matrix

type="mat4" state="VIEW_PROJECTION_MATRIX == 

type="mat4" state="CAM_PROJECTION_MATRIX"

gl3 only) Provides the current rendering cameras projection matrix; in most cases is equivalent to PROJECTION_MATRIX except in cases where a full-screen quad is rendering, e.g. in a jit.gl.slab/pix (or jit.gl.pass)

== Transforms normalized texture coordinates into rect coordinates

 == scene seen from the light position???

 == the spotlight cutoff in degrees (=spotlight angle)

 == exponent implied in the reflected light calculation

gives the values from the @mat_X attributes of the 3Dobj to which the shader is attached.

== (where "n" is an integer number) Nth custom vertex attribute

These are the built-in uniforms i know. I ignore the meaning of some entries in this list and I guess I'm still missing some of them. Could you please integrate the list with the uniforms you know? I will edit this first post adding the entries you provide, so to keep everything compact.

It would be very usefull if an analogue list were done with built-it variables.

Hope this could be usefull to you as much as it is to me. 

once in a while, looking inside jitter shaders, I discover some new GL3 built-in uniforms never saw before. Sometimes, they provide the answer to problems I didn't know how to address before. I looked inside the jitter documetation, but I didn't find an exhaustive list of all the avaiables built-in uniforms. I know many of them can be found in the GLSL  documentation out there, but i'd love to have a comprehensive list of what Max and GLSL can offer to let the users build their own shaders. Here there are the uniforms i met so far and what i understood about them:

MATRICES:
type="mat4" state="MODELVIEW_PROJECTION_MATRIX" == P * V * M
type="mat4" state="PREV_MODELVIEW_PROJECTION_MATRIX" == the previous frames modelview-projection matrix
type="mat4" state="VIEW_PROJECTION_MATRIX == P * V
type="mat4" state="MODELVIEW_MATRIX" == V * M
type="mat4" state="VIEW_MATRIX" == V
type="mat4" state="WORLD_MATRIX" == transforms into world coordinates
type="mat4" state="PROJECTION_MATRIX" == P
type="mat4" state="CAM_PROJECTION_MATRIX" == (gl3 only) Provides the current rendering cameras projection matrix; in most cases is equivalent to PROJECTION_MATRIX except in cases where a full-screen quad is rendering, e.g. in a jit.gl.slab/pix (or jit.gl.pass)
type="mat3" state="NORMAL_MATRIX" == it orients the normals in eye space
type="mat4" state="TEXTURE0_MATRIX" == Transforms normalized texture coordinates into rect coordinates

CAMERA:
type="float" state="FAR_CLIP" == Camera far clipping distance
type="float" state="NEAR_CLIP" == Camera near clipping distance
type="vec3" state="FAR_CORNER" == far corner of the view frustum
type="vec3" state="CAMERA_POSITION" == camera position in world space
type="vec3" state="CAMERA_DIRECTION" == camera direction in world space
type="vec2" state="VIEWPORT" ==  the pixel size of rendering window
type="vec2" state="INVERSE_VIEWPORT" == the inverse of the viewport dims

LIGHT:
type="mat4" state="LIGHT_VIEWPROJ_MATRIX0-7" == scene seen from the light position???
type="float" state="LIGHT_RANGE0-7 " == distance reached by the light
type="vec3" state="LIGHT0-7_POSITION" == position on the light
type="vec3" state="LIGHT0-7_DIRECTION" == direction of the light
type="vec4" state="LIGHT0-7_AMBIENT" == ambient light color
type="vec4" state="LIGHT0-7_DIFFUSE" == diffuse light color
type="vec4" state="LIGHT0-7_SPECULAR" == specular reflection color
type="float" state="LIGHT0-7_CUTOFF" ==  the spotlight cutoff in degrees (=spotlight angle)
type="float" state="LIGHT0-7_EXPONENT" == exponent implied in the reflected light calculation

MATERIAL:
type="vec4" state="DIFFUSE" == material diffuse color
type="vec4" state="AMBIENT" == material ambient color
type="vec4" state="SPECULAR" == material specular color
type="vec4" state="EMISSION" == mterial emission color
state="FRONT_MATERIAL" == gives the values from the @mat_X attributes of the 3Dobj to which the shader is attached.

VERTEX:
type="vec3" state="POSITION" == XYZ Position
type="vec4" state="COLOR" == RGBA Color
type="vec3" state="NORMAL" == Normal vectors
type="vec3" state="TANGENT" == Tangent vectors
type="vec3" state="BITANGENT" == Bitangent vectors
type="vec3" state="VERTEX_ATTR" == Custom vertex attribute
type="vec3" state="VERTEX_ATTRn" == (where "n" is an integer number) Nth custom vertex attribute
type="float" state="EDGEFLAG" == unused, ignore

TEXTURES:
type="vec2" state="TEXDIM0" == XY Dimension of texture 0 type="vec2" state="TEXCOORD" == XY texture coordinates

These are the built-in uniforms i know. I ignore the meaning of some entries in this list and I guess I'm still missing some of them. Could you please integrate the list with the uniforms you know? I will edit this first post adding the entries you provide, so to keep everything compact.

It would be very usefull if an analogue list were done with built-it variables.

Hope this could be usefull to you as much as it is to me. 
Thank you very much!

Hi everyone,
once in a while, looking inside jitter shaders, I discover some new GL3 built-in uniforms never saw before. Sometimes, they pro

exhausting-list-of-all-the-built-it-uniforms-avaiable-in-jitter-shaders

You are right, the MODEL_MATRIX doesn't exist. The Model Space is just the position of the vertices as they come from inside the model, in which usually the 0,0,0 is the center of the model itself. 

If you need the coordinates in WORLD SPACE you can use the WORLD_MATRIX built-in. 

FRONT_MATERIAL will give you the values from the @mat_X attributes of the 3Dobj to which the shader is attached. 

layout (std140) uniform FrontMaterialParameters {

                MaterialParameters frontMaterial;

Check the shader generated by the jit.gl.material object with the get_gl3_shader message to see how this works. 

You probably know this already but maybe can be useful for others: in the Max documentation "Appendix C: The JXS File Format" one can find all the built-in variables for the GLSL jxs shader format.

Thank you for this Matteo! 
You are right, the MODEL_MATRIX doesn't exist. The Model Space is just the position of the vertices as they come from inside the model, in which usually the 0,0,0 is the center of the model itself. 
If you need the coordinates in WORLD SPACE you can use the WORLD_MATRIX built-in.  

FRONT_MATERIAL will give you the values from the @mat_X attributes of the 3Dobj to which the shader is attached. 
layout (std140) uniform FrontMaterialParameters {
				MaterialParameters frontMaterial;
			};
Check the shader generated by the jit.gl.material object with the get_gl3_shader message to see how this works. 
You probably know this already but maybe can be useful for others: in the Max documentation "Appendix C: The JXS File Format" one can find all the built-in variables for the GLSL jxs shader format.  

I honestly missed that appendix...I added the missing entries in the original post, but some are still a bit obscure to me:

 == This one doesn't exist in the documentation, but i found it in mrt.ssao.render.gl3.jxs

Thank you very much Federico!
I honestly missed that appendix...I added the missing entries in the original post, but some are still a bit obscure to me:

type="mat4" state="PREV_MODELVIEW_PROJECTION_MATRIX" == ???
type="mat4" state="CAM_PROJECTION_MATRIX" == This one doesn't exist in the documentation, but i found it in mrt.ssao.render.gl3.jxs
type="vec3" state="FAR_CORNER" == far corner of the view frustum???
type="vec2" state="VIEWPORT" == ???
type="vec2" state="INVERSE_VIEWPORT" == ??? 
type="float" state="LIGHT0-7_CUTOFF" ==  spot light falloff???
type="float" state="EDGEFLAG" == ???

Ok so I think I can only add my contribution with VIEWPORT, which is simply the size in pixels of the rendering window. 

Keep it up Matteo! GLSL needs to be demystified

Ok so I think I can only add my contribution with VIEWPORT, which is simply the size in pixels of the rendering window. 
Keep it up Matteo! GLSL needs to be demystified

the previous frames modelview-projection matrix, used for velocity based effects (e.g. jit.gl.pass @fxname motionblur)

gl3 only, provides the current rendering cameras projection matrix, which in most cases is equivalent to PROJECTION_MATRIX except in cases where a full-screen quad is rendering, e.g. in a jit.gl.slab/pix (or jit.gl.pass). used in the gl3 engines ssao effect

yup. used for depth rebuilding i think, can't quite remember. ssao shader maybe?

as federico says above, the pixel size of rendering window

just as it sounds, the inverse of the viewport dims

the spotlight cutoff in degrees, another name for the spotlight angle

PREV_MODELVIEW_PROJECTION_MATRIX - the previous frames modelview-projection matrix, used for velocity based effects (e.g. jit.gl.pass @fxname motionblur)

CAM_PROJECTION_MATRIX - gl3 only, provides the current rendering cameras projection matrix, which in most cases is equivalent to PROJECTION_MATRIX except in cases where a full-screen quad is rendering, e.g. in a jit.gl.slab/pix (or jit.gl.pass). used in the gl3 engines ssao effect

FAR_CORNER == far corner of the view frustum??? - yup. used for depth rebuilding i think, can't quite remember. ssao shader maybe?

VIEWPORT - as federico says above, the pixel size of rendering window
INVERSE_VIEWPORT - just as it sounds, the inverse of the viewport dims

LIGHT0-7_CUTOFF - the spotlight cutoff in degrees, another name for the spotlight angle

I'll soon indicate for each built-it uniform a .jxs file in which it gets used, so that each variable can be seen in action in a reference patch.

so bad, and it was right under my nose...

Thank you so much, Federico and Rob!
I updated the list in the first post. 
I'll soon indicate for each built-it uniform a .jxs file in which it gets used, so that each variable can be seen in action in a reference patch.

btw, I wanted a "PREV_MODELVIEW_PROJECTION_MATRIX"-like variable so bad, and it was right under my nose...

cool, thanks much for taking the initiative here!

btw the PREV_MODELVIEW_PROJECTION_MATRIX is not yet implemented in gl3, but I hope to fix that sooner than later

cool, thanks much for taking the initiative here!

btw the PREV_MODELVIEW_PROJECTION_MATRIX is not yet implemented in gl3, but I hope to fix that sooner than later


Insane help here, and some example of code in action would indeed be of enormous value :o, I'm following you guys : )

Hi Riccardo, this tutorial I made today should be a fitting example of code in action:

Hi Riccardo, this tutorial I made today should be a fitting example of code in action:
https://youtu.be/gKIVuVCfBws 

Oww, I felt like being halfway to convert it and here you come. Thanks for the enlightening coding.

texture2D became texture... what about texture2DRect? If textureRect is the solution, this wasn't my real problem :o

I've been feeding a shader with two textures, the first for extrusion purpose, the second is the texture to be applied over the distorted shape. If i use "outColor = color" I can see my grey shape being distorted from the first texture, but when I'm trying to use my second texture, I'm getting this...

Schermata 2021-01-08 alle 17.31.07.png

Schermata 2021-01-08 alle 17.30.14.png

I'm hoping the problem lies here, if it is not, I can share the full code attached to a simple patcher as example.

Hi Riccardo, I think you get this error because you are using a vec4 as a second argument to the function "texture", which takes a vec2 as a second argument. 

I think you mixed up multiplying the texcoord by the texture matrix, for which you need a vec4, and using the texcoord to read the texture with the "texture" function.

Hi Riccardo, I think you get this error because you are using a vec4 as a second argument to the function "texture",  which takes a vec2 as a second argument. 
I think you mixed up multiplying the texcoord by the texture matrix, for which you need a vec4, and using the texcoord to read the texture with the "texture" function. 

It totally make sense. Still I'm playing with an invisible shape ohoh.

It totally make sense. Still I'm playing with an invisible shape ohoh.
I'll give it some more tries.

What is this? I guess it something related/opposite to FRONT_MATERIAL

I found another one:
state="BACK_MATERIAL"
What is this? I guess it something related/opposite to FRONT_MATERIAL

undocumented and unsupported at this time

I found this in one of the gl3 example patches

ah ok, thanks!
I found this in one of the gl3 example patches

quick note to say that as of 8.2 (and the bundled gl3), 

should now be functioning as expected in a gl3 context.

quick note to say that as of 8.2 (and the bundled gl3), PREV_MODELVIEW_PROJECTION_MATRIX should now be functioning as expected in a gl3 context.

Exhaustive list of all the built-it uniforms avaiable in Jitter shaders