OpenCL image distortion

ripple.opencl

/**
	QueryFormat example : query image format dynamically inside the kernel
	Written by Olivier Chafik, no right reserved :-) */	

// See http://www.khronos.org/registry/cl/sdk/1.0/docs/man/xhtml/sampler_t.html
const sampler_t sampler = CLK_NORMALIZED_COORDS_FALSE | CLK_FILTER_NEAREST | CLK_ADDRESS_CLAMP_TO_EDGE;

int2 ripple(float x, float y, float a, float w) {
	float m = sqrt(x*x + y*y);

	float s = sin(w*m);
	float x1 = a*y*m*s;
	float y1 = -a*x*m*s;

	return (int2)(x1, y1);
}

int2 displacement(int xi, int yi, int width, int height) {
	float aspect = ((float) height) / ((float) width);
	float x = ((float) xi) / ((float) width), y = ((float) yi) / ((float) height);
	return ripple(x - 0.5, aspect*(y - 0.5 + 0.35), 50, 800)
             - ripple(x - 0.5, aspect*(y - 0.5 - 0.35), 50, 800)
             + ripple(x - 0.5, aspect*(y), 2, 5000);
}

__kernel void test(
	read_only image2d_t inputImage,
	write_only image2d_t outputImage)
{
   // See http://www.khronos.org/registry/cl/sdk/1.0/docs/man/xhtml/get_image_dim.html
   int2 dimensions = get_image_dim(inputImage);
   int width = dimensions.x, height = dimensions.y;
   
   // See http://www.khronos.org/registry/cl/sdk/1.0/docs/man/xhtml/get_image_channel_data_type.html
   int channelDataType = get_image_channel_data_type(inputImage);
   
   // See http://www.khronos.org/registry/cl/sdk/1.0/docs/man/xhtml/get_image_channel_order.html
   int channelOrder = get_image_channel_order(inputImage);
   
   int x = get_global_id(0), y = get_global_id(1);
   int2 coordinates = (int2)(x, y);
   int2 disp = displacement(x, y, width, height);
   int2 fromCoordinates = coordinates + disp;

   // See http://www.khronos.org/registry/cl/sdk/1.0/docs/man/xhtml/read_imagef2d.html
   //float4 pixel = read_imagef(inputImage, sampler, coordinates);
   float4 pixel = read_imagef(inputImage, sampler, fromCoordinates);
   float4 transformedPixel = pixel;
   //float4 transformedPixel = (float4)(0);//pixel;
   
   // See http://www.khronos.org/registry/cl/sdk/1.0/docs/man/xhtml/write_image.html
   write_imagef(outputImage, coordinates, transformedPixel);
}