At first I thought I would have to. But after doing some searching on shaders
and OpenGL it turns out that if you don’t mind using the same shader, you can
just send multiple objects in and different model-views into the original
kernel (the GLSL code you are referring to).
It gets a little crazy because the cube drawing program has similar names for
things that are represented in different worlds so to speak.
The kernel:
#version 120
#define lowp
#define mediump
#define highp
attribute highp vec3 vertex;
attribute lowp vec3 color;
varying lowp vec4 v_color;
uniform mat4 mvp;
void main(void)
{
gl_Position = mvp * vec4(vertex,1.0);
v_color = vec4(color,1.0);
}
So the cube program in a_g_initialize does the following to associate top level
J variables with the GPU variables defined in GLSL:
vertexAttr=: >@{. glGetAttribLocation program;'vertex'
assert. _1~: vertexAttr
colorAttr=: >@{. glGetAttribLocation program;'color'
assert. _1~: colorAttr
mvpUni=: >@{. glGetUniformLocation program;’mvp'
‘Vertex’, ‘color’, and ‘mop’ on the right above refer to Kernel GLSL code
locations.
Those are mapped into my J nouns on the left with slightly adjusted names.
Now looking at the code more closely I don’t need what I thought was connecting
a second object:
NB. Second duplicate object as above
vertexAttr1=: >@{. glGetAttribLocation program;'vertex'
assert. _1~: vertexAttr1
colorAttr1=: >@{. glGetAttribLocation program;'color'
assert. _1~: colorAttr1
These are just the same pointers named differently from the original code and
therefore superfluous.
The big binding of data from J to the kernel space takes place next and is
centered around the vbo array. I see now that you have focused me on this that
vbo is just an array of pointers that get bound by openGL calls.
glGenBuffers 2;vbo=: 4#_1
glBindBuffer GL_ARRAY_BUFFER; 0{vbo
glBufferData GL_ARRAY_BUFFER; (#vertexData); (symdat <'vertexData');
GL_STATIC_DRAW
glBindBuffer GL_ARRAY_BUFFER; 1{vbo
glBufferData GL_ARRAY_BUFFER; (#colorData); (symdat <'colorData');
GL_STATIC_DRAW
glBindBuffer GL_ARRAY_BUFFER; 2{vbo
glBufferData GL_ARRAY_BUFFER; (#vertexData); (symdat <'vertexData');
GL_STATIC_DRAW
glBindBuffer GL_ARRAY_BUFFER; 3{vbo
glBufferData GL_ARRAY_BUFFER; (#colorData); (symdat <'colorData');
GL_STATIC_DRAW
glBindBuffer GL_ARRAY_BUFFER; 0
Where I just reuse the vertexData and colorData to represent a second object to
draw.
Now in a_g_paint:
glUniformMatrix4fv mvpUni; 1; GL_FALSE; mvp
glBindBuffer GL_ARRAY_BUFFER; 0{vbo
glEnableVertexAttribArray vertexAttr
glVertexAttribPointer vertexAttr; 3; GL_FLOAT; 0; 0; 0
glBindBuffer GL_ARRAY_BUFFER; 1{vbo
glEnableVertexAttribArray colorAttr
glVertexAttribPointer colorAttr; 3; GL_FLOAT; 0; 0; 0
glDrawArrays GL_TRIANGLES; 0; 36
Sends the data to be drawn. That data was associated with the first 2 locations
of vbo and point back to vertexData and colorData.
If I repeat the same code with a different mvp matrix to translate the cube to
the left on the x axis:
NB. Draw object 2
glUniformMatrix4fv mvpUni; 1; GL_FALSE; mvp1
glBindBuffer GL_ARRAY_BUFFER; 2{vbo
glEnableVertexAttribArray vertexAttr
glVertexAttribPointer vertexAttr; 3; GL_FLOAT; 0; 0; 0
glBindBuffer GL_ARRAY_BUFFER; 3{vbo
glEnableVertexAttribArray colorAttr
glVertexAttribPointer colorAttr; 3; GL_FLOAT; 0; 0; 0
glDrawArrays GL_TRIANGLES; 0; 36
I get 2 duplicate color shaded cubes going through their rotations together.
All I had to do was use different vbo buffer locations and a new map variable
(mvp1).
I assume the calls send that down to the kernel shader code variables vertex,
color, map and openGL takes care of the rest.
Tom McGuire
> On Feb 28, 2020, at 2:42 AM, bill lam <bbill....@gmail.com> wrote:
>
> Kernel means the program running inside GPU, which is
> the c source stored inside nouns vsrc and fsrc.
>
> Fri, 28 Feb 2020, Thomas McGuire написал(а):
>> Not sure I know what you mean but I’m using 807 on a MacBook Pro with just
>> the full Jqt install.
>>
>>> On Feb 27, 2020, at 9:28 PM, bill lam <bbill....@gmail.com> wrote:
>>>
>>> Did kernels need any modification?
>>>
>>> Thu, 27 Feb 2020, Thomas McGuire написал(а):
>>>> It took me a while to understand this a little bit. But the shader can
>>>> render any number of objects you just need to set up the data and tell the
>>>> shader to paint the object. To create 2 cubes I had to modify the
>>>> a_g_initialize function and the a_g_paint function. I have placed comments
>>>> in the code trying to show with my limited understanding of OpenGL what is
>>>> being done. To just create 2 duplicate cubes this code could be
>>>> simplified. But if 2 different types of objects needed to be rendered
>>>> everything would likely stay the same with a second set of vertex and
>>>> color data being added for the new object (right now I reuse vertexData
>>>> and colorData).
>>>>
>>>>
>>>> a_g_initialize=: 3 : 0
>>>> if. p=. >@{. glGetString GL_VERSION do. smoutput 'GL_VERSION: ', memr 0 _1
>>>> 2,~ p end.
>>>> if. 0=p do. smoutput 'cannot retrieve GL_VERSION' return. end.
>>>> if. p=. >@{. glGetString GL_VENDOR do. smoutput 'GL_VENDOR: ', memr 0 _1
>>>> 2,~ p end.
>>>> if. p=. >@{. glGetString GL_RENDERER do. smoutput 'GL_RENDERER: ', memr 0
>>>> _1 2,~ p end.
>>>> if. p=. >@{. glGetString GL_SHADING_LANGUAGE_VERSION do. smoutput
>>>> 'GL_SHADING_LANGUAGE_VERSION: ', memr 0 _1 2,~ p end.
>>>> GLSL=: wglGLSL''
>>>>
>>>> wglPROC''
>>>> sprog=: 0
>>>> if. GLSL>120 do.
>>>> vsrc=. vsrc2
>>>> fsrc=. fsrc2
>>>> else.
>>>> vsrc=. vsrc1
>>>> fsrc=. fsrc1
>>>> if. 0=GLES_VERSION_jgles_ do.
>>>> vsrc=. vsrc,~ '#define lowp', LF, '#define mediump', LF, '#define highp',
>>>> LF
>>>> fsrc=. fsrc,~ '#define lowp', LF, '#define mediump', LF, '#define highp',
>>>> LF
>>>> end.
>>>> end.
>>>> vsrc=. '#version ',(":GLSL),((GLSL>:300)#(*GLES_VERSION){::' core';'
>>>> es'),LF,vsrc
>>>> fsrc=. '#version ',(":GLSL),((GLSL>:300)#(*GLES_VERSION){::' core';'
>>>> es'),LF,fsrc
>>>> if.(GLSL>:300)*.0~:GLES_VERSION_jgles_ do.
>>>> fsrc=. ('void main';'out vec4 gl_FragColor;',LF,'void main') stringreplace
>>>> fsrc
>>>> end.
>>>> smoutput vsrc
>>>> smoutput fsrc
>>>> 'err program'=. gl_makeprogram vsrc;fsrc
>>>> if. #err do. smoutput err return. end.
>>>>
>>>> NB. original cube data and the model-view-projection matrix
>>>> vertexAttr=: >@{. glGetAttribLocation program;'vertex'
>>>> assert. _1~: vertexAttr
>>>> colorAttr=: >@{. glGetAttribLocation program;'color'
>>>> assert. _1~: colorAttr
>>>> mvpUni=: >@{. glGetUniformLocation program;'mvp'
>>>> assert. _1~: mvpUni
>>>>
>>>> NB. Second duplicate object as above
>>>> vertexAttr1=: >@{. glGetAttribLocation program;'vertex'
>>>> assert. _1~: vertexAttr1
>>>> colorAttr1=: >@{. glGetAttribLocation program;'color'
>>>> assert. _1~: colorAttr1
>>>>
>>>> NB. Here is where my shape is defined. this provides the hooks
>>>> NB. between J data and openGL
>>>> NB. Here I increase the buffer vbo to 4 locations and reuse the
>>>> NB. object vertexData and colorData that make the colorful cube
>>>> glGenBuffers 2;vbo=: 4#_1
>>>> glBindBuffer GL_ARRAY_BUFFER; 0{vbo
>>>> glBufferData GL_ARRAY_BUFFER; (#vertexData); (symdat <'vertexData');
>>>> GL_STATIC_DRAW
>>>> glBindBuffer GL_ARRAY_BUFFER; 1{vbo
>>>> glBufferData GL_ARRAY_BUFFER; (#colorData); (symdat <'colorData');
>>>> GL_STATIC_DRAW
>>>> glBindBuffer GL_ARRAY_BUFFER; 2{vbo
>>>> glBufferData GL_ARRAY_BUFFER; (#vertexData); (symdat <'vertexData');
>>>> GL_STATIC_DRAW
>>>> glBindBuffer GL_ARRAY_BUFFER; 3{vbo
>>>> glBufferData GL_ARRAY_BUFFER; (#colorData); (symdat <'colorData');
>>>> GL_STATIC_DRAW
>>>> glBindBuffer GL_ARRAY_BUFFER; 0
>>>>
>>>> sprog=: program
>>>>
>>>> glClearColor 0; 0; 1; 0
>>>> )
>>>>
>>>>
>>>> a_g_paint=: 3 : 0
>>>> if. 0=sprog do. return. end.
>>>>
>>>> wh=. gl_qwh''
>>>> glClearColor 0 0 0 0
>>>> glClear GL_COLOR_BUFFER_BIT + GL_DEPTH_BUFFER_BIT
>>>>
>>>> glUseProgram sprog
>>>> glEnable GL_DEPTH_TEST
>>>> glEnable GL_CULL_FACE
>>>>
>>>> NB. matrix convention: current matrix on the left
>>>> NB. note pre-multiplication
>>>>
>>>> NB. model-view
>>>> NB. I created a new model: mvp1 so it will translate the cube
>>>> NB. so there will be 2 cubes side by side
>>>> mvp=: (gl_Rotate (0{R), 1 0 0 ) mp (gl_Rotate (1{R), 0 1 0) mp (gl_Rotate
>>>> (2{R), 0 0 1) mp (gl_Scale STEPS%100) mp (gl_Translate 0.6 0 _8) mp
>>>> glu_LookAt EYE,LR,UD,IO,UP
>>>> mvp1=: (gl_Rotate (0{R), 1 0 0 ) mp (gl_Rotate (1{R), 0 1 0) mp (gl_Rotate
>>>> (2{R), 0 0 1) mp (gl_Scale STEPS%100) mp (gl_Translate _1.2 0 _8) mp
>>>> glu_LookAt EYE,LR,UD,IO,UP
>>>>
>>>> NB. projection
>>>> mvp=: mvp mp gl_Perspective 30, (%/wh),1 10
>>>> mvp1=: mvp1 mp gl_Perspective 30, (%/wh),1 10
>>>>
>>>> NB. note GL_FALSE, no transpose
>>>> NB. Draw Object 1
>>>> glUniformMatrix4fv mvpUni; 1; GL_FALSE; mvp
>>>>
>>>> glBindBuffer GL_ARRAY_BUFFER; 0{vbo
>>>> glEnableVertexAttribArray vertexAttr
>>>> glVertexAttribPointer vertexAttr; 3; GL_FLOAT; 0; 0; 0
>>>>
>>>> glBindBuffer GL_ARRAY_BUFFER; 1{vbo
>>>> glEnableVertexAttribArray colorAttr
>>>> glVertexAttribPointer colorAttr; 3; GL_FLOAT; 0; 0; 0
>>>>
>>>> glDrawArrays GL_TRIANGLES; 0; 36
>>>>
>>>> NB. Draw object 2
>>>> glUniformMatrix4fv mvpUni; 1; GL_FALSE; mvp1
>>>>
>>>> glBindBuffer GL_ARRAY_BUFFER; 2{vbo
>>>> glEnableVertexAttribArray vertexAttr1
>>>> glVertexAttribPointer vertexAttr1; 3; GL_FLOAT; 0; 0; 0
>>>>
>>>> glBindBuffer GL_ARRAY_BUFFER; 3{vbo
>>>> glEnableVertexAttribArray colorAttr1
>>>> glVertexAttribPointer colorAttr1; 3; GL_FLOAT; 0; 0; 0
>>>>
>>>> glDrawArrays GL_TRIANGLES; 0; 36
>>>>
>>>> NB. Objects drawn perform glDisableVertexAttribArray
>>>> NB. what ever that is for
>>>> glBindBuffer GL_ARRAY_BUFFER; 0
>>>> glDisableVertexAttribArray colorAttr
>>>> glDisableVertexAttribArray vertexAttr
>>>> glDisableVertexAttribArray colorAttr1
>>>> glDisableVertexAttribArray vertexAttr1
>>>>
>>>> glDisable GL_DEPTH_TEST
>>>> glDisable GL_CULL_FACE
>>>>
>>>> glUseProgram 0
>>>>
>>>> gl_clear ''
>>>> gl_rgb 0 255 0
>>>> gl_textcolor ''
>>>> gl_textxy 10 30
>>>> gl_text 'keys: x y z a s l r F10'
>>>> gl_textxy 10 50
>>>> gl_text 'scale: ',":STEPS%100
>>>> gl_textxy 10 70
>>>> gl_text 'angle: ',":R
>>>> gl_textxy 10 90
>>>> if. 0=sprog do. return. end.
>>>> gl_text 'matrix:'
>>>> for_i. i.4 do.
>>>> gl_textxy 10, 105+i*15
>>>> gl_text 6j2": i{mvp
>>>> end.
>>>> )
>>>>
>>>>
>>>>> On Feb 14, 2020, at 4:14 PM, Brian Schott <schott.br...@gmail.com> wrote:
>>>>>
>>>>> Bill,
>>>>>
>>>>> Thank you very much.
>>>>>
>>>>> Mostly I want to get n turtles, not cubes, that are not rotating to time
>>>>> but behave like "Logo" turtles and react to commands in the Terminal
>>>>> window
>>>>> like Forward 3 and Right 90. So I want to start with 2 separate turtles
>>>>> and
>>>>> I guess I am all wrong in my idea that the long mvp commands are moving
>>>>> the
>>>>> eye, but moving the cube/turtle. So my next experiment will be to copy and
>>>>> edit the code beginning at the following line of code.
>>>>>
>>>>> glGenBuffers 2;vbo=: 2#_1
>>>>>
>>>>> So for example to make another cube/turtle I'm thinking that that line
>>>>> could be changed so that _2 replaces the _1. Does that make any sense?
>>>>>
>>>>> *****************below I react to your code
>>>>> revisions***********************
>>>>> I had to change your f8 and f9 to f6 and f7 because on my Mac f8 is
>>>>> clipboard and f9 is run project.
>>>>> Now, at least when I put an smoutput into a_f6_fkey and a_f7_fkey I see
>>>>> they are being executed, but I do not see the cube, (and this happens
>>>>> without changing the focus to the Terminal window, which is needed below).
>>>>> After intially loading and running the shader.ijs script in the project
>>>>> window, I get a blank "a" window and each time I press F10 I get a new
>>>>> fresh, blank "a" window. But if I click on the Terminal window and then
>>>>> click on the "a" window and THEN press F10, I get the moving cube.
>>>>> Subsequent F6 and F7 presses produce the smoutput results in the Terminal
>>>>> window but BLANK the active "a" window.
>>>>> *****************above I react to your code
>>>>> revisions***********************
>>>>>
>>>>> But the previous paragraph is mostly a distraction except that you code
>>>>> revision shows me a little about how the "handle" is important for finding
>>>>> the parent from the child and vice versa. And about repainting.
>>>>>
>>>>> I am mostly interested in how commands in the Terminal window can be sent
>>>>> to the Cube in the "a" window. Any pointers?
>>>>>
>>>>>
>>>>> On Fri, Feb 14, 2020 at 1:58 AM bill lam <bbill....@gmail.com> wrote:
>>>>>
>>>>>> I tried to incoporate your change into shader.ijs
>>>>>> with f8/f9 to change value for gl_translate.
>>>>>> The changes lines are marked by NB. <<<<<
>>>>>> pressing f8/f9 can trigger repaint and the matrix
>>>>>> display also updated, but I can't see the cube at all.
>>>>>> Pressing F10 to start original code, the cube came back.
>>>>>> I did not pursue further but hope this is enough to
>>>>>> answer your question about how to repaint.
>>>>>>
>>>>>>
>>>>> ----------------------------------------------------------------------
>>>>> For information about J forums see http://www.jsoftware.com/forums.htm
>>>>
>>>> ----------------------------------------------------------------------
>>>> For information about J forums see http://www.jsoftware.com/forums.htm
>>>
>>> --
>>> regards,
>>> ====================================================
>>> GPG key 1024D/4434BAB3 2008-08-24
>>> gpg --keyserver subkeys.pgp.net --armor --export 4434BAB3
>>> ----------------------------------------------------------------------
>>> For information about J forums see http://www.jsoftware.com/forums.htm
>>
>> ----------------------------------------------------------------------
>> For information about J forums see http://www.jsoftware.com/forums.htm
>
> --
> regards,
> ====================================================
> GPG key 1024D/4434BAB3 2008-08-24
> gpg --keyserver subkeys.pgp.net --armor --export 4434BAB3
> ----------------------------------------------------------------------
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