help needed with raycasting

hii all,

i am struggling with raycasting algorithm for past few days … my program is showing output as attached in files…
my ray casting shader is as follows…

uniform sampler3D volumeData;
uniform sampler1D transferFunction;
varying vec3 texCoord;
uniform vec3 xCameraPosition;
uniform vec3 bboxMin;
uniform vec3 bboxMax;
uniform float step;
uniform int steps;
uniform vec3 bgColor;

void main(void) 
	vec3 rayOrigin = texCoord;
	vec3 rayDir = normalize(rayOrigin - xCameraPosition);
	vec3 position = rayOrigin;
	vec4 finalColor = vec4(0.0, 0.0, 0.0, 0.0);
	vec3 zarroVector = vec3(0, 0, 0);
	for (int i = 0; i < steps; ++i)
		position += step * rayDir;
		if (any(greaterThan(position, bboxMax)) || any(lessThan(position, bboxMin)))
		float density = texture3D(volumeData, position).r;
		vec4 color = texture1D(transferFunction, density);
		finalColor += vec4(color.rgb * (1.0 - color.a) * step, color.a);
		if (finalColor.a > .99)
    gl_FragColor = vec4(finalColor.rgb * finalColor.a + (1.0 - finalColor.a) * bgColor, 1.0);

i have checked my code many times and everything seems ok to me…can anyone please look at the output and suggest me what may be the problem is …?? i m really exhausted…its very important for my final year major project…plzz help…

thank you

edit: if u need any code from my c++ program please ask…nd i am using Ati radeon 5470 which supports opengl 3.2 and shader model 3

ok here my complete c++ source code…!!