Const raymarch_write_depth_fragment
raymarch_write_depth_fragment: "vec4 clipPos = mvpMatrix * vec4(position, 1.0);gl_FragDepthEXT = (clipPos.z / clipPos.w) * 0.5 + 0.5;" = `vec4 clipPos = mvpMatrix * vec4(position, 1.0);gl_FragDepthEXT = (clipPos.z / clipPos.w) * 0.5 + 0.5;`