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fazekaim

OpenGL problem around ATI light scattering

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Hello! I tried to implements this paper in opengl: http://www.ati.com/developer/dx9/ATI-LightScattering.pdf Triple is just a vec3-like class writen in Java... My scattering computation in a static initializing block:
        // scattering computation
        sunColorValue = new Triple( 1.0f, 1.0f, 1.0f );

        Triple lambda = new Triple( 1.0f / 650e-9f, 1.0f / 570e-9f, 1.0f / 475e-9f );
        Triple lambda2 = new Triple();
        Triple lambda4 = new Triple();
        lambda2.x = lambda.x * lambda.x;
        lambda2.y = lambda.y * lambda.y;
        lambda2.z = lambda.z * lambda.z;
        lambda4.x = lambda2.x * lambda2.x;
        lambda4.y = lambda2.y * lambda2.y;
        lambda4.z = lambda2.z * lambda2.z;

        float n = 1.003f;
        float N = 2.545e25f;
        float pn = 0.035f;
        float T = 2.0f;
        float c = (6.544f * T - 6.51f) * 1e-17f;
        float tempRay = (float)(Math.PI * Math.PI * (n * n - 1.0) * (n * n - 1.0) * (6.0 + 3.0 * pn) / (6.0 - 7.0 * pn) / N);
        betaRayValue = lambda4.scale( (float)(8.0 * tempRay * Math.PI / 3.0) );
        float tempMie = (float)(0.434 * c * Math.PI * (2 * Math.PI) * (2 * Math.PI) * 0.5);
        betaMieValue = new Triple( lambda2.x * 0.685f, lambda2.y * 0.679f, lambda2.z * 0.67f).scale( tempMie );
        betaRayDValue = betaRayValue.scale( (float)(3.0/16.0/Math.PI) );
        betaMieDValue = betaMieValue.scale( (float)(1.0/4.0/Math.PI) );
        cameraValue = new Triple( 1.0f, 1.0f, 1.0f );
        sunDirValue =
            new Triple(
                (float)(Math.sin(85 / 10.0)*4096),
                (float)(Math.cos(85 / 10.0) * 4096),
                (float)(0.1 + Math.abs(Math.sin(85 / 30.0)) * 4096)
            );
        float g = 0.8f * 1.5f;
        greensteinValue = new Triple( (1.0f-g)*(1.0f-g), (1.0f+g)*(1.0f+g), 2.0f*g );
        skySizeValue = 4096;

My GLSL vertex shader code::
uniform vec3 sunColor;
            uniform vec3 betaRay;
            uniform vec3 betaMie;
            uniform vec3 betaRayD;
            uniform vec3 betaMieD;
            uniform vec3 camera;
            uniform vec3 sunDir;
            uniform vec3 greenstein;
            uniform float skySize;

            varying vec4 skyColor;
           // e = 2,7182818284590452353602874713527
            void main(void)
            {
              gl_Position = ftransform();
              vec3 wDir = normalize( gl_Vertex.xyz - camera );
              float cosTheta = dot( sunDir, wDir );
              vec3 betaSumm = betaRay + betaMie;
              float dist = distance( camera, sunDir ) / skySize;
              vec3 Fex = pow( vec3( 2.7182818284590452353602874713527,2.7182818284590452353602874713527,2.7182818284590452353602874713527), -(betaSumm) * dist);
              vec3 betaR = betaRayD * ( 1.0 + cosTheta * cosTheta);
              vec3 betaM = betaMieD * ( greenstein.x ) / pow(greenstein.y - greenstein.z * cosTheta, 3.0 / 2.0 );
              vec3 Lin = (betaR + betaM) * sunColor * (1.0-Fex) / (betaSumm);
              vec4 LsT =  vec4(sunColor * Fex + Lin, 1.0);
              skyColor = LsT;
            }

My GLSL fragment shader code::
varying vec4 skyColor;
void main(void)
{
  gl_FragColor = skyColor;
}

And my shader calling code::
gl.glUseProgramObjectARB( skyShaderObject[0] );
            gl.glUniform3fARB( sunColor[0], sunColorValue.x, sunColorValue.y, sunColorValue.z );
            gl.glUniform3fARB( betaRay[0], betaRayValue.x, betaRayValue.y, betaRayValue.z );
            gl.glUniform3fARB( betaMie[0], betaMieValue.x, betaMieValue.y, betaMieValue.z );
            gl.glUniform3fARB( betaRayD[0], betaRayDValue.x, betaRayDValue.y, betaRayDValue.z );
            gl.glUniform3fARB( betaMieD[0], betaMieDValue.x, betaMieDValue.y, betaMieDValue.z );
            gl.glUniform3fARB( camera[0], cameraValue.x, cameraValue.y, cameraValue.z );
            gl.glUniform3fARB( sunDir[0], sunDirValue.x, sunDirValue.y, sunDirValue.z );
            gl.glUniform3fARB( greenstein[0], greensteinValue.x, greensteinValue.y, greensteinValue.z );
            gl.glUniform1fARB( skySize[0], skySizeValue );

            gl.glBegin( GL.GL_TRIANGLE_STRIP );
                for (int i=0; i<sky.length; ++i) {
                    Triple triple = sky;
                    float[] tex = skyTextureCoordinates;
                    gl.glTexCoord3f( tex[0], tex[1], 0 );
                    gl.glVertex3f( triple.x, triple.y, triple.z );
                }
            gl.glEnd();

        gl.glUseProgramObjectARB( 0 );

When I run the code, the shader compile very well, but my skydome is filled white. I checked the paper, and it seems to be ok. The paper is ok, so the code has some error, that i couldn't not found (around coefficients,skysize, skycolor). Can anyone help me? Thanks.

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