Java-Gaming.org Hi !
 Featured games (90) games approved by the League of Dukes Games in Showcase (683) Games in Android Showcase (196) games submitted by our members Games in WIP (751) games currently in development
 News: Read the Java Gaming Resources, or peek at the official Java tutorials
Pages: [1]
 ignore  |  Print
 Drawing IZOLINES of temperature  (Read 2820 times) 0 Members and 1 Guest are viewing this topic.
poonury

Junior Newbie

 « Posted 2012-10-29 20:19:22 »

Hello everybody!

I stuck with my problem.

PROBLEM:
- very slow algorithm
- no idea how to improve it
- any existing algorithm in Java/ JOGL?

HOW I DO:
I use shader to calculate izolines of temperature and i obtain for example this:

http://imageshack.us/photo/my-images/26/izoline.png

now i must to draw in JOGL black lines on color edges. I read all pixels from GL buffer.

 1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20  21 `public BufferedImage toImage(GL gl, int w, int h)     {        gl.glReadBuffer(GL.GL_FRONT); // or GL.GL_BACK        ByteBuffer glBB = ByteBuffer.allocate(3 * w * h);         gl.glReadPixels(0, 0, w, h, GL.GL_BGR, GL.GL_BYTE, glBB);        BufferedImage bi = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);        int[] bd = ((DataBufferInt) bi.getRaster().getDataBuffer()).getData();                for (int y = 0; y < h; y++) {            for (int x = 0; x < w; x++) {                int b = 2 * glBB.get();                int g = 2 * glBB.get();                int r = 2 * glBB.get();                bd[(h - y - 1) * w + x] = (r << 16) | (g << 8) | b | 0xFF000000;            }        }        return bi;    }`

But trying find edge pixel by pixel is soooo long in time. Like this:

 1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20 `BufferedImage bi = toImage(m_gl, Resources.dCanvasWidth, Resources.dCanvasHeight);            for(int i=0; i< 20; ++i)            {                System.out.println( i );                for(int i1=0; i1< bi.getData().getHeight()-1; ++i1)                {                    int[] buff1;                    int[] buff2;                                        buff1 = bi.getData().getPixel(i, i1, (int[]) null );                    buff2 = bi.getData().getPixel(i, i1, (int[]) null );                                        if( !Arrays.equals(buff1, buff2) )                    {                        m_gl.glDrawPixels(i, i1,GL.GL_RGB, GL.GL_INT, blackPixel);                        m_gl.glFlush();                                           }                                    } `

Can somebody help me solve this problem?
gouessej
 « Reply #1 - Posted 2012-10-29 20:29:55 »

Hi

Maybe you can compute iso-contours in the fragment shader too.

poonury

Junior Newbie

 « Reply #2 - Posted 2012-10-29 20:39:17 »

I tried but i havent neighbour pixels.

When I calculate it without neigbours but by function calculating my color. I tried obtain izo by 10 degrees it doted or all black, or line is to width.
theagentd

« JGO Bitwise Duke »

Medals: 807
Projects: 4
Exp: 8 years

 « Reply #3 - Posted 2012-10-29 20:41:03 »

Do it in two passes and you'll have access to neighboring pixels in the second pass. You can't have each pixel depend on what's being put into neighboring pixels or you'll get a paradox. =S

Myomyomyo.
poonury

Junior Newbie

 « Reply #4 - Posted 2012-10-29 20:45:36 »

Hmm i agree with you but how i can write somthing like that?

 1  2  3  4  5  6  7  8  9 `gl.glVertexAttrib1f(vs_fTempAtribute, (float) t1.getValueInNode( Resources.mesh.getFace( Resources.mesh.getArea(dAreaCounter).getFaceNr(dFaceCounter) ).m_dwVertex[0]));gl.glVertex2d(  Resources.mesh.getVertex( Resources.mesh.getFace( Resources.mesh.getArea(dAreaCounter).getFaceNr(dFaceCounter) ).m_dwVertex[0] ).m_position.x,                Resources.mesh.getVertex( Resources.mesh.getFace( Resources.mesh.getArea(dAreaCounter).getFaceNr(dFaceCounter) ).m_dwVertex[0] ).m_position.y);gl.glVertexAttrib1f(vs_fTempAtribute, (float) t1.getValueInNode( Resources.mesh.getFace( Resources.mesh.getArea(dAreaCounter).getFaceNr(dFaceCounter) ).m_dwVertex[1]));gl.glVertex2d(  Resources.mesh.getVertex( Resources.mesh.getFace( Resources.mesh.getArea(dAreaCounter).getFaceNr(dFaceCounter) ).m_dwVertex[1] ).m_position.x,                Resources.mesh.getVertex( Resources.mesh.getFace( Resources.mesh.getArea(dAreaCounter).getFaceNr(dFaceCounter) ).m_dwVertex[1] ).m_position.y);gl.glVertexAttrib1f(vs_fTempAtribute, (float) t1.getValueInNode( Resources.mesh.getFace( Resources.mesh.getArea(dAreaCounter).getFaceNr(dFaceCounter) ).m_dwVertex[2]));gl.glVertex2d(  Resources.mesh.getVertex( Resources.mesh.getFace( Resources.mesh.getArea(dAreaCounter).getFaceNr(dFaceCounter) ).m_dwVertex[2] ).m_position.x,               Resources.mesh.getVertex( Resources.mesh.getFace( Resources.mesh.getArea(dAreaCounter).getFaceNr(dFaceCounter) ).m_dwVertex[2] ).m_position.y);`

First i put in shader a temperature and it calculate color. Where put second step? On this same vertices? I do not imagine that
theagentd

« JGO Bitwise Duke »

Medals: 807
Projects: 4
Exp: 8 years

 « Reply #5 - Posted 2012-10-29 21:23:45 »

Render what you're currently doing directly to a texture using a framebuffer object (FBO). That way you'll have the data easily accessible later. Then render (using just a single fullscreen quad) this texture to the screen (back buffer) using a different shader that finds your edges or whatever and adds them to the screen. This is called post-processing a rendered image and is pretty much what you're doing on the CPU right now, am I right?

Myomyomyo.
poonury

Junior Newbie

 « Reply #6 - Posted 2012-10-29 21:34:43 »

In the code is not as easy as in theory ;( I can't imagine how ... I need to sleep mayby tomorrow will be better.
gouessej
 « Reply #7 - Posted 2012-10-29 23:56:42 »

You can use FBObject to implement theagentd's suggestion.

Pages: [1]
 ignore  |  Print

You cannot reply to this message, because it is very, very old.

 orrenravid (210 views) 2016-07-16 03:57:23 theagentd (281 views) 2016-07-11 14:28:54 Hydroque (366 views) 2016-07-06 05:56:57 Hydroque (519 views) 2016-07-03 08:52:54 GrandCastle (392 views) 2016-07-01 09:13:47 GrandCastle (385 views) 2016-07-01 09:09:45 CopyableCougar4 (437 views) 2016-06-25 16:56:52 Hydroque (413 views) 2016-06-22 02:17:53 SwampChicken (379 views) 2016-06-20 13:22:57 SwampChicken (303 views) 2016-06-20 13:22:49
 Archive 30x Brynn 23x Slyth2727 23x TritonDreyja 22x EgonOlsen 22x orangepascal 22x orange451 20x DavidBVal 19x Spasi 18x KaiHH 12x LiquidNitrogen 11x Phased 11x Opiop 11x princec 11x Longor1996 10x theagentd 10x
 Making a Dynamic Plugin Systemby Hydroque2016-06-25 00:13:25Java Data structures2016-06-13 21:22:09Java Data structures2016-06-13 21:20:42FPS Camera Tutorialby Hydroque2016-05-22 05:40:58Website offering 3D Models specifically for games for freeby vusman2016-05-18 17:23:09Website offering 3D Models specifically for games for freeby vusman2016-05-09 08:50:56Website offering 3D Models specifically for games for freeby vusman2016-05-06 11:10:21Website offering 3D Models specifically for games for freeby vusman2016-04-29 12:56:17
 java-gaming.org is not responsible for the content posted by its members, including references to external websites, and other references that may or may not have a relation with our primarily gaming and game production oriented community. inquiries and complaints can be sent via email to the info‑account of the company managing the website of java‑gaming.org