Hi all… I’m trying to do a water ripple effect. I’m trying to use the Hugo Elias Algorithm http://freespace.virgin.net/hugo.elias/graphics/x-water.htm plus some examples in other languages… the program is not working, I really don’t know why… I’m relatve new to c++ I have been programming in python for many years…
I will paste the relevant code, any help would be appreciate
Thanks!
void testApp::setup(){
width = 640;
height = 480;
vidGrabber.setVerbose(true);
vidGrabber.setDeviceID(1);
vidGrabber.setUseTexture(true);
vidGrabber.initGrabber(width, height);
buffer1 = new int[width * height];
buffer2 = new int[width * height];
temp = new int[width * height];
testTex.allocate(width, height, GL_RGB);
colorImg.allocate(width,height);
diffs.allocate(width, height);
old.allocate(width, height);
bLearnBakground = true;
threshold = 30;
damping = 0.94;
}
void testApp::Step()
{
int i = 0;
int yw = 0;
for(int y = 1; y < height - 1; y++)
{
yw = y * width;
for(int x = 1; x < width -1; x++)
{
i = x + yw;
buffer2[i] = ((buffer1[i-1] + buffer1[i+1] + buffer1[i - width] + buffer1[i + width]) >>1 ) - buffer2[i];
buffer2[i] = (int)(buffer2[i]*damping);
}
}
}
/* this method should render the ripples */
void testApp::renderMap()
{
int i,xo,yo;
double shading;
xo = 0;
yo = 0;
shading = 0.0;
int yw = 0;
unsigned char *pix = colorImg.getPixels();
unsigned char* pixels = new unsigned char[width * height * 3];
i=0;
for(int y = 1; y < height - 1; y++)
{
yw = y * width;
for(int x = 1; x < width - 1; x++)
{
i = x + yw;
xo = buffer2[i-1] - buffer2[i+1];
yo = buffer2[i-width] - buffer2[i+width];
shading = (xo - yo)/2;
int xnew = x + xo;
if (xnew < 0) xnew = 0;
if (xnew >= width) xnew = width - 1;
int ynew = y + yo;
if (ynew < 0) ynew = 0;
if (ynew >= height) ynew = height - 1;
unsigned char tred = pix[((ynew-1)*width+(xnew-1)) + 1];
unsigned char tgreen = pix[((ynew-1)*width+(xnew-1)) + 1];
unsigned char tblue = pix[((ynew-1)*width+(xnew-1)) + 2];
if (shading < 0) shading = 0;
if (shading > 255) shading = 255;
tred = tred + shading;
tgreen = tgreen + shading;
tblue = tblue + shading;
pixels[((y-1)*width+(x-1))*3 + 0] = tred;
pixels[((y-1)*width+(x-1))*3 + 1] = tgreen;
pixels[((y-1)*width+(x-1))*3 + 2] = tblue;
}
}
temp = buffer1;
buffer1 = buffer2;
buffer2 = temp;
testTex.loadData(pixels, width, height, GL_RGB);
}
//--------------------------------------------------------------
void testApp::update(){
bool bNewFrame = false;
vidGrabber.grabFrame();
bNewFrame = vidGrabber.isFrameNew();
if (bNewFrame){
//colorImg.setFromPixels(vidGrabber.getPixels(), width, height);
//testApp::frameDiff(colorImg, old, diffs, threshold);
old = colorImg;
testApp::Step();
testApp::renderMap();
}
}
void testApp::draw(){
// draw the incoming, the grayscale, the bg and the thresholded difference
ofSetColor(0xffffff);
//colorImg.draw(0,0, width, height);
ofEnableAlphaBlending();
testTex.draw(0,0,width, height);
ofDisableAlphaBlending();
}
