It look like the problem appear when I try to pass loop counter to function
for example
struct ST_LightParameter{
vec4 position;
vec4 diffuse;
vec4 specular;
float radius;
};
uniform ST_LightParameter stLightSource[2];
uniform sampler2D baseTexture;
uniform sampler2D cellShadeTexture;
uniform vec4 globalAmbient;
varying vec3 intLightVec[2];
varying vec3 intEye;
varying vec4 debugColor;
varying vec3 intNorm;
vec4 diffuseTerm = vec4(0.0,0.0,0.0,1.0);
vec4 diffuseCellShadeTerm = vec4(0.0,0.0,0.0,1.0);
vec4 specularTerm = vec4(0.0,0.0,0.0,1.0);
void diffuseHemiSphere(vec4 diffuse,vec3 normal,vec3 lightVec,float attenuation){
vec4 GroundColor = vec4(0.2,0.2,0.2,1.0);
float costheta = dot(normal, lightVec);
float a = 0.5 + 0.5 * costheta;
diffuseTerm += (a*diffuse + (1.0-a)*GroundColor)*gl_FrontMaterial.diffuse*attenuation;
}
void diffuseCellShadeTexture(vec4 diffuse,vec3 normal,vec3 lightVec,float attenuation){
float ln = dot(normal, lightVec);
ln = (ln+1.0)/2.0;
if(ln > 0.99){
ln = 0.99;
}
vec4 cellColor = texture2D(cellShadeTexture,vec2(ln,0.5).st);
cellColor[3] = 1.0;
diffuseCellShadeTerm += cellColor;
}
void specular(vec4 specular,vec3 normal,vec3 lightVec,vec3 eye,float attenuation){
vec3 halfVector = normalize(lightVec + eye);
float nDotVP = max(0.0, dot(normal, lightVec));
float nDotHV = max(0.0, dot(normal, halfVector));
float pf;
if (nDotVP == 0.0)
pf = 0.0;
else
pf = pow(nDotHV, gl_FrontMaterial.shininess);
specularTerm += specular*gl_FrontMaterial.specular*pf*attenuation;
}
float getAttenuationRadiusBased(float radius,vec3 ulVec){
vec3 aUL = ulVec/radius;
float atten = max(0.0, 1.0 - dot(aUL,aUL));
return atten;
}
void pointLightByRadiusCellShade(int i,vec3 norNorm,vec3 eyeNorm){
float attenuation = getAttenuationRadiusBased(stLightSource[i].radius,intLightVec[i]);
vec3 lightVec = normalize(intLightVec[i]);
diffuseCellShadeTexture(stLightSource[i].diffuse,norNorm,lightVec,attenuation);
diffuseHemiSphere(stLightSource[i].diffuse,norNorm,lightVec,attenuation);
specular(stLightSource[i].specular,norNorm,lightVec,eyeNorm,attenuation);
}
void main()
{
vec3 eyeNorm = normalize(intEye);
vec3 norNorm = normalize(intNorm);
for(int i=0;i<2;i++){
pointLightByRadiusCellShade(i,norNorm,eyeNorm);
}
vec4 texColor = texture2D(baseTexture,gl_TexCoord[0].st);
vec4 finalColor = (diffuseTerm*diffuseCellShadeTerm + specularTerm + globalAmbient*gl_FrontMaterial.ambient)*texColor;
gl_FragData[0] = finalColor;
gl_FragData[1] = vec4(norNorm,1.0);
}
will give an error result (only diffuse value appear to be correct on both i =0 & i=1 , the position value will alway be of i=0 )
but if i remove the function and do something like this instead.
for(int i=0;i<2;i++){
float attenuation = getAttenuationRadiusBased(stLightSource[i].radius,intLightVec[i]);
vec3 lightVec = normalize(intLightVec[i]);
diffuseCellShadeTexture(stLightSource[i].diffuse,norNorm,lightVec,attenuation);
diffuseHemiSphere(stLightSource[i].diffuse,norNorm,lightVec,attenuation);
specular(stLightSource[i].specular,norNorm,lightVec,eyeNorm,attenuation);
}
the result are correct as expected.
Is this a bug or GLSL limited ?, since both code doesn’t report any compilation error.
