export declare const hiZ_frag = "\nprecision highp float;\nprecision highp sampler2D;\n\nuniform sampler2D tPreviousLevel;\nuniform vec2 uInvSize;\nuniform vec2 uOffset;\n\nvoid main(void) {\n    vec2 position = gl_FragCoord.xy * uInvSize + uOffset;\n\n    float x = texture(tPreviousLevel, position).r;\n    float y = textureOffset(tPreviousLevel, position, ivec2(-1, 0)).r;\n    float z = textureOffset(tPreviousLevel, position, ivec2(-1, -1)).r;\n    float w = textureOffset(tPreviousLevel, position, ivec2(0, -1)).r;\n\n    gl_FragColor = vec4(max(max(x, y), max(z, w)));\n}\n";