Raspberry(PI 2) EGL SDC canvas

[alexfish]

Hi All

For those with a Raspberry PI 2 ,

BaCon EGL canvas (Beta Testing), this will form the base for an EGL GL canvas

There are for archives , download and extract into one folder , the file to Convert is Test_SDC.bac

Requirement GTK2 libs dev , also check the VC folder in the /opt/ . should see /opt/vc from the File Manager

the test program , as some know the EGL frame buffer has no means to be resized or moved
this lib resolves those bits via a gtk window , all positioning an clipping happens relative to where and size of the gtk window

this also resolves the issue of print though to the desk top area when using the Alpha Channel .
the test program next post

Update as dated @ Edit reasons

Added Font see below .. also method to free the contexts , call with

DeInit()

See Text Examples next Post::


BR
Alex

Attachments:

cube_texture_and_coords.h.bz2 (1.05 KB)

SDC.bac.bz2 (5.69 KB)

eglinc.h.bz2 (326 B)

[alexfish]

Added Font libs.
Edit >> now updated the myfont.bac as FUNCTION , returns width of text line .. see example 3 , as a button with text.
Required myfont.h and myfont.bac

Example of usage ,

INCLUDE SDC.bac
INCLUDE myfont.bac


' ***********************************************************
SUB QUIT()
   DeInit()
PRINT "BYE"
SLEEP 500
END
END SUB

' ***********************************************************
win = WINDOW("Text-Demo",600,400)

CALLBACK(win,"delete_event",QUIT)

CLS(win)
ORTHO
INK(255,0,0,255)
TEXT("This is a line of text",100,100)
' All done : Swap Buffers
SYNC

REM loop for ever static draw , on static drawing must use loop with a call to DoEvents
WHILE 1 DO
REM must call DOEVENTS within main loop
DOEVENTS
WEND

version , keep all bits together , + ROTATED text

INCLUDE SDC.bac
INCLUDE myfont.bac


' ***********************************************************
SUB QUIT()
   DeInit()
PRINT "BYE"
SLEEP 500
END
END SUB

' ***********************************************************
win = WINDOW("Text-Demo",600,400)

CALLBACK(win,"delete_event",QUIT)

WHILE 1 DO
CLS(win)
ORTHO
INK(255,0,0,255)
ROTATE(20,0,0,1)
TEXT("This is a line of text",150,50)
' All done : Swap Buffers
SYNC
WEND

Did a render test of 10 lines of text containing 50 chars.
500 chars , Frame rate still averages 50 frames a second

Example 3 . using the udated myfont.bac , render a button with text , the TEXT returns width of text line.


INCLUDE SDC.bac
INCLUDE myfont.bac

' ***********************************************************
SUB QUIT()
   DeInit()
PRINT "BYE"
SLEEP 500
END
END SUB

' ***********************************************************

LOCAL text_width TYPE float

win = WINDOW("Text-Demo",600,400)
CALLBACK(win,"delete_event",QUIT)

text_width=TEXT("Button_1",10,50)
WHILE 1 DO
CLS(win)
ORTHO
TRANSLATE((text_width/2)-4,50,0)
INK(255,100,0,200)
Gbutton((text_width/2)+2,25,1)

ORTHO
INK(255,0,0,200)
text_width=TEXT("Button_1",10,50)

' All done : Swap Buffers
SYNC
WEND

' ***********************************************************

Alex

Attachments:

myfont.h.bz2 (2.83 KB)

myfont.bac.bz2 (543 B)

[vovchik]

Dear Alex,

I am PI-less at the moment, so I can't test, but the code looks fine very unbloated. I hope we get some feedback from some PI users soon.

With kind regards,
vovchik

[alexfish]

Hi Vovchik

Plenty of time , now going through some bits. all in the main , Just pleased to get EGL to use glColor and not have to
use or program the shaders ..

but as can be see by the data , everything is a Cube and everything is a Triangle , but should be able to replicate in the likes of glut

So how in EGL and a 3d World can we draw a line or a square .

Here using the triangular vertexes ,

first code draws a square as in a line square IE not filled

/* Draw a Square 20 units back 20 units right of center */
 WHILE 1 DO
DoEvents()
  ALIGN()
glLoadIdentity();
/* move back to see results */
glTranslatef(0.0, 0.f,-20);

glColor4ub(255,0,0,190)

glEnableClientState( GL_VERTEX_ARRAY );

glClear ( GL_COLOR_BUFFER_BIT );

glTranslatef(0.0, 0.f,-80);
glTranslatef(20.00, 0.f,0.0);
glVertexAttribPointer ( 0, 2, GL_FLOAT, GL_FALSE,0,vVertices )

glEnableVertexAttribArray ( 0 )
glDrawArrays (GL_LINES, 0, 2 )

glRotatef(90,0,0,1)
glDrawArrays (GL_LINES, 0, 2 )

glRotatef(90,0,0,1)
glDrawArrays (GL_LINES, 0, 2 )

glRotatef(90,0,0,1)
glDrawArrays (GL_LINES, 0, 2 )
eglSwapBuffers(Display, Surface)

WEND

here draw a filled Square

 WHILE 1 DO
 DoEvents()
 ALIGN()
glLoadIdentity();
glTranslatef(0.0, 0.f,-20);
glColor4ub(255,0,0,190)

glEnableClientState( GL_VERTEX_ARRAY );
glClear ( GL_COLOR_BUFFER_BIT );

glTranslatef(0.0, 0.f,-80);
glTranslatef(20.80, 0.f,0.0);
glVertexAttribPointer ( 0, 3, GL_FLOAT, GL_FALSE,0,vVertices )
glEnableVertexAttribArray ( 0 )
glDrawArrays (GL_TRIANGLES, 0, 3 )
glRotatef(180,0,0,1)
glDrawArrays (GL_TRIANGLES, 0, 3 )
eglSwapBuffers(Display, Surface)

WEND

BR
Alex

[vovchik]

Dear Alex,

Thanks...I will study the code. If you have time, have a look at my SVG/TTF button demo. It crashes after a few mouse clicks and I cannot figure out why. You are good at finding all sorts of bugs.

http://basic-converter.proboards.com/attachment/download/1505

With kind regards,
vovchik

[alexfish]

Jan 30, 2016 16:23:48 GMT 1 vovchik said:

Dear Alex,

Thanks...I will study the code. If you have time, have a look at my SVG/TTF button demo. It crashes after a few mouse clicks and I cannot figure out why. You are good at finding all sorts of bugs.

http://basic-converter.proboards.com/attachment/download/1505

With kind regards,
vovchik

Hi Vovchik

have not downloaded the demo , yet can see what the problem is ,

will look at it , then post back

BR
Alex

[alexfish]

Now , what about rotation using 2d

here we go , use same draw routine to init , then here is the WHILE LOOP
also combined the two code bits as above, solid sq and a line sq.

LOCAL t TYPE float=0

 WHILE 1 DO
DoEvents()
  ALIGN()
glLoadIdentity();
glTranslatef(0.0, 0.f,-100);

glColor4ub(255,0,0,190)

glEnableClientState( GL_VERTEX_ARRAY );

glClear ( GL_COLOR_BUFFER_BIT );
glVertexAttribPointer ( 0, 3, GL_FLOAT, GL_FALSE,0,vVertices )
glEnableVertexAttribArray ( 0 )
glDrawArrays (GL_TRIANGLES, 0, 3 )
glRotatef(180,0,0,1)
glDrawArrays (GL_TRIANGLES, 0, 3 )

/* rotate sq in 2d coords */
glLoadIdentity();

glTranslatef(0.0, 0.f,-100);

glColor4ub(0,255,0,190)

glEnableClientState( GL_VERTEX_ARRAY );

glTranslatef(30.00, 0.f,0.0);

glRotatef(t,0,0,1)
glVertexAttribPointer ( 0, 2, GL_FLOAT, GL_FALSE,0,vVertices )

glEnableVertexAttribArray ( 0 )
glDrawArrays (GL_LINES, 0, 2 )

glRotatef(90,0,0,1)
glDrawArrays (GL_LINES, 0, 2 )

glRotatef(90,0,0,1)
glDrawArrays (GL_LINES, 0, 2 )

glRotatef(90,0,0,1)
glDrawArrays (GL_LINES, 0, 2 )
eglSwapBuffers(Display, Surface)
INCR t

WEND

[vovchik]

Dear Alex,

I commented out all the TTEXT calls in the SVG/TTF button demo, and it does not crash. So, you have a hunch about where the problem is.

With kind regards,
vovchik

[alexfish]

Here , have update the draw function to re-calc the fustrum

this keeps eveyrthing in perspective , can now Resize or Max the window at will .

the bit


/* CALCULATE THE FUSTRUM*/
glGetIntegerv(GL_VIEWPORT, viewport)
hht = nearp * (float)tan(45.0 / 2.0 / 180.0 * M_PI);
hwd = hht * (float)viewport[2] / (float)viewport[3];
glFrustumf(-hwd, hwd, -hht, hht, nearp, farp);

/***************************************************/

now the draw code // can now place the bits x & y relative and draw in 2d + Rotate , here is Rotating solid square + wire square

SUB draw_square()
 
ESContext esContext;
esInitContext ( &esContext );
esCreateWindow ( &esContext, 600, 400,ES_WINDOW_RGB    )


glEnable(GL_BLEND)
glEnable(GL_CULL_FACE)
  glHint( GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST )
  glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)

glVertexPointer( 3, GL_BYTE, 0, quadx );

glMatrixMode(GL_PROJECTION)

glLoadIdentity();

glClearColor(1.0f, 1.0f, 1.0f, 0.0f)

GLfloat vVertices[] = {  0.0f,  0.5f, 0.0f, \
                          -0.5f, -0.5f, 0.0f, \
                           0.5f, -0.5f, 0.0f };

glMatrixMode(GL_MODELVIEW);

ALIGN()

 
/* BeginMode
GL_POINTS
GL_LINES
GL_LINE_LOOP
GL_LINE_STRIP
GL_TRIANGLES
GL_TRIANGLE_STRIP
GL_TRIANGLE_FAN

*/
LOCAL nearp = 1.0f TYPE float
LOCAL farp = 500.0f TYPE float
LOCAL hht = 1.0f TYPE float
LOCAL hwd = 1.0f TYPE float
LOCAL viewport[4] TYPE int
LOCAL t =0 TYPE float

 WHILE 1 DO
DoEvents()
  ALIGN()

/* CALCULATE THE FUSTRUM*/
glGetIntegerv(GL_VIEWPORT, viewport)
hht = nearp * (float)tan(45.0 / 2.0 / 180.0 * M_PI);
hwd = hht * (float)viewport[2] / (float)viewport[3];
/***************************************************/
glFrustumf(-hwd, hwd, -hht, hht, nearp, farp);
' *******************************************************
glLoadIdentity();
glFrustumf(-hwd, hwd, -hht, hht, nearp, farp);

/* move back to see results */
glTranslatef(0.0, 0.f,-100);
glRotatef(-t,0,0,1)
glColor4ub(255,0,0,255)

glEnableClientState( GL_VERTEX_ARRAY );

glClear ( GL_COLOR_BUFFER_BIT );
glVertexAttribPointer ( 0, 3, GL_FLOAT, GL_FALSE,0,vVertices )
glEnableVertexAttribArray ( 0 )
glDrawArrays (GL_TRIANGLES, 0, 3 )
glRotatef(-180,0,0,1)
glDrawArrays (GL_TRIANGLES, 0, 3 )


glLoadIdentity();
glFrustumf(-hwd, hwd, -hht, hht, nearp, farp);

glTranslatef(0.0, 0.f,-100);

glColor4ub(0,255,0,255)

glEnableClientState( GL_VERTEX_ARRAY );

glTranslatef(28.30, 0.f,0.0);

glRotatef(t,0,0,1)
glVertexAttribPointer ( 0, 2, GL_FLOAT, GL_FALSE,0,vVertices )

glEnableVertexAttribArray ( 0 )
glDrawArrays (GL_LINES, 0, 2 )

glRotatef(90,0,0,1)
glDrawArrays (GL_LINES, 0, 2 )

glRotatef(90,0,0,1)
glDrawArrays (GL_LINES, 0, 2 )

glRotatef(90,0,0,1)
glDrawArrays (GL_LINES, 0, 2 )
eglSwapBuffers(Display, Surface)
INCR t , 2

WEND

END SUB
BR
Alex

[alexfish]

Do the bits stay together

here replace the while loop with the below

here placing the solid Square and wire Square on x & y + rotating one on Y+Z & one on the X+Z , all bits connect and the solid square will cull when behind 'the scene'

BR
Alex

 WHILE 1 DO
DoEvents()
  ALIGN()

/* CALCULATE THE FUSTRUM*/
glGetIntegerv(GL_VIEWPORT, viewport)
hht = nearp * (float)tan(45.0 / 2.0 / 180.0 * M_PI)
hwd = hht * (float)viewport[2] / (float)viewport[3]
glLineWidth(1)
glFrustumf(-hwd, hwd, -hht, hht, nearp, farp);


glLoadIdentity();
glFrustumf(-hwd, hwd, -hht, hht, nearp, farp);

/* move back to see results */
glTranslatef(-20.0,-15.0,-75);
glRotatef(-t,0,0,1)
glRotatef(t/2,0,1,0)
glColor4ub(255,0,0,255)

glEnableClientState( GL_VERTEX_ARRAY );
glLineWidth(3)
glClear ( GL_COLOR_BUFFER_BIT );
glVertexAttribPointer ( 0, 3, GL_FLOAT, GL_FALSE,0,vVertices )
glEnableVertexAttribArray ( 0 )
glDrawArrays (GL_TRIANGLES, 0, 3 )
glRotatef(-180,0,0,1)
glDrawArrays (GL_TRIANGLES, 0, 3 )


glLoadIdentity();
glFrustumf(-hwd, hwd, -hht, hht, nearp, farp);

glTranslatef(0.0, 0.f,-75);

glColor4ub(0,255,0,255)

glEnableClientState( GL_VERTEX_ARRAY );

glTranslatef(20.0, 15.0,0.0);

glRotatef(t,0,0,1)
glRotatef(t/2,1,0,0)
glVertexAttribPointer ( 0, 2, GL_FLOAT, GL_FALSE,0,vVertices )

glEnableVertexAttribArray ( 0 )
glDrawArrays (GL_LINES, 0, 2 )

glRotatef(90,0,0,1)
glDrawArrays (GL_LINES, 0, 2 )

glRotatef(90,0,0,1)
glDrawArrays (GL_LINES, 0, 2 )

glRotatef(90,0,0,1)
glDrawArrays (GL_LINES, 0, 2 )
eglSwapBuffers(Display, Surface)
INCR t , 2

WEND


[vovchik]

Dear Alex,

Your code looks very good. I really will have to get a PI soon.

With kind regards,
vovchik

[alexfish]

Hi Vovchik

although the Raspberry is a low power device , programming the EGL , gpu direct is best.

decided to take this route since the likes of Windowed GL surfaces are not good in terms of speed ,

so here , on the raspberry can draw a square at the full size of the screen , and rotate it at 50 frames a second , only then can appreciate .

BR
Alex

[alexfish]

Circle

Not Ideal under this scheme , yet can work in quad POINTS from the same triangle vertex data

here we go
LOCAL lp TYPE int

glClear ( GL_COLOR_BUFFER_BIT );
/* CALCULATE THE FUSTRUM*/
glGetIntegerv(GL_VIEWPORT, viewport)
hht = nearp * (float)tan(45.0 / 2.0 / 180.0 * M_PI)
hwd = hht * (float)viewport[2] / (float)viewport[3]

glLoadIdentity();
glFrustumf(-hwd, hwd, -hht, hht, nearp, farp);
glEnableClientState( GL_VERTEX_ARRAY );


/* move back to see results */
glTranslatef(0,0,-75);

glColor4ub(255,0,0,255)

glEnableClientState( GL_VERTEX_ARRAY );

glPointSize(1.0)
glVertexAttribPointer ( 0,3, GL_FLOAT, GL_TRUE,0,vVertices )
glEnableVertexAttribArray ( 0 )
FOR lp = 0 TO 90
glDrawArrays (GL_POINTS, 0, 4)
glRotatef(1,0,0,1)
NEXT



ADDED : ortho type layout as high performance canvas can be ahieved like so

Where 0,0 is top left

glFrustumf(0, hwd*2, hht*2, 0, nearp, farp)

+ fill CIRCLE / this can be refined see the two bits of code

FOR lp = 0 TO 91
glDrawArrays (GL_TRIANGLE_STRIP, 0, 4)
glRotatef(1,0,0,1)
NEXT
Note that the glRotate angle Must Match the STEP .. here = ' 0.5 '
FOR lp = 0 TO 91 STEP 0.5
glDrawArrays (GL_TRIANGLE_STRIP, 0, 4)
glRotatef(0.5,0,0,1)
NEXT

under present scheme .. need to get back to PIXEL size , try different combinations of the draw , to get would be thinking fastest draw method
then try , scale factor . this gets pixel size in all directions

glScalef(0.01,0.01,0.01)

can also use scaling 'up from 1' eg scale in the X

glScalef(2,1,1)

scale in Y

glScalef(1,2,1)

scale in Z

glScalef(1,1,2)

happy coding
BR
Alex

[alexfish]

Well

this one was an amazing find , Quick Draw Wire cube using the original triangle vertex data

No maths involved , no coords to update.. this is the Wire Cube rotating data , looking at this then a solid cube about the same.


BR
Alex
the data


/* draw line Cube */
glLoadIdentity();
glFrustumf(-hwd, hwd, -hht, hht, nearp, farp);
glEnableClientState( GL_VERTEX_ARRAY )
/* color green */
glColor4ub(0,255,0,255)
/* set back to see */
glTranslatef(0.0, 0.f,-75);
/* set to the right and up to get clear pic of the pespective */
glTranslatef(20.0, 15.0,0.0);
/* can rotate the cube using increment float 't ' */
glRotatef(t,0,0,1)
glRotatef(t/2,1,0,0)

glVertexAttribPointer ( 0, 8, GL_FLOAT, GL_FALSE,0,vVertices )

glEnableVertexAttribArray ( 0 )
glDrawArrays (GL_LINES, 0, 8)

glRotatef(90,0,0,1)
glDrawArrays (GL_LINES, 0,8)

glRotatef(90,0,1,0)
glDrawArrays (GL_LINES, 0, 8)

glRotatef(180,0,1,0)
glDrawArrays (GL_LINES, 0, 8)


If U'r asking does this make sense , No , something tells me I am accessing an out of bounds array,
yet there be no errors , worth looking into.

Update : now found the reason , this happens on the init stage of glVertexPointer()
the array is defined "static const GLbyte quadx[6*4*3]" , weird Shit this EGL..
Yet now looking here , looks like have Isolated the necessary vertexes & pointers , + arrays ,
As a side note during this ?? have managed to draw a line from the 0.0 to anywhere on x y.,

YES A LINE , a Single solitary LINE . from 0.0

here is a simple line 0,0 to 1,0
static const GLbyte line[] = {

0, 0, 1,0

};

Looks like can now set up some basic geometric functions much like in Peters Canvases .
from these bits can convert to what ever by changing the data in the likes of say the line

Looks like this will be the last update on this post . Now looking to update the lib with the new features

[alexfish]

Hi All

Last update , then will the base core lib will be updated ,

Here have completed bounds testing , using the Frustum data as in previous posts

tested here to outer bounds with say Zdepth_ptr = 5 then placement x max is hwd*5 and y max is hht *5
/* back -5 right max & top max */
glTranslatef(hwd*Zdepth_ptr,hht*Zdepth_ptr,-Zdepth_ptr);
test bottom left cords would be
glTranslatef(-hwd*Zdepth_ptr,-hht*Zdepth_ptr,-Zdepth_ptr);

ADDED suppose the only diff between the freeglut geometry section is that they be in float,
wonder what would happen if re-write into Bytes . mm! food for thought. looking further , some of that data be in bytes..

update : now got the float arrays working with glcolor , never thought I would see the day ::

BR
Alex