Merge "Support in_opacity in SIMPLEX_SIMPLE_SHADER" into main

                // Compute turbulence effect with the uv distorted with simplex noise.

                vec3 noisePos = vec3(uv + in_noiseMove.xy, in_noiseMove.z) * in_gridNum;

                float mixFactor = simplex3d(noisePos) * 0.5 + 0.5;

                return mix(in_color, in_screenColor, mixFactor);

                vec4 mixedColor = mix(in_screenColor * in_screenColor.a, in_color * in_color.a, mixFactor);

                return mixedColor * in_opacity;

            }

        """