It's a problem regarding the way shadows are handled for particles. This bug seems to happen a lot when doing quick modifications to shaders - I have no idea why.
They're even handled differently in the shader code:
// Apply lighting and fog.
vec4 fragColor = vec4(0.0f, 0.0f, 0.0f, 0.0f);
if(isParticle == 1)
{
vec4 texAlbedo = texture2D(tex, texCoord);
fragColor = texAlbedo * gl_Color;
fragColor.a = texAlbedo.a * gl_Color.a;
vec4 dirLightDirect = (dirLightColor * occlusionFactor) + (dirLightAmbient * occlusionFactor) + (dirShadowColor * (1.0f - occlusionFactor));
vec4 plt = accumulateParticlePointLights();
vec4 lightTotal = dirLightDirect + plt;
lightTotal.x = clamp(lightTotal.x, 0.0f, 1.2f);
lightTotal.y = clamp(lightTotal.y, 0.0f, 1.2f);
lightTotal.z = clamp(lightTotal.z, 0.0f, 1.2f);
fragColor = texAlbedo * gl_Color * lightTotal;
applyFog(fragColor);
fragColor.a = texAlbedo.a * gl_Color.a;
}
else
{
applyLighting(fragColor, albedo, occlusionFactor);
applyFog(fragColor);
}
