class SAO

@:directlyUsed@:src({ @global var camera:{ var position : Vec3}; @range(4, 30) @const(127) var numSamples:Int; @range(1, 10) @const(16) var numSpiralTurns:Int; @const var useWorldUV:Bool; @const var USE_FADE:Bool = false; @ignore @param var depthTexture:Channel; @ignore @param var normalTexture:Channel3; @param var noiseTexture:Sampler2D; @param var noiseScale:Vec2; @range(0, 10) @param var sampleRadius:Float; @range(0, 10) @param var intensity:Float; @range(0, 0.2) @param var bias:Float; @ignore @param var cameraView:Mat3x4; @ignore @param var cameraInverseViewProj:Mat4; @ignore @param var screenRatio:Vec2; @ignore @param var fovTan:Float; @param var fadeStart:Float; @param var fadeEnd:Float; function sampleAO(uv:Vec2, position:Vec3, normal:Vec3, radiusSS:Float, tapIndex:Int, rotationAngle:Float):Float { var alpha = (float(tapIndex) + 0.5) * (1.0 / float(numSamples)); var angle = alpha * (float(numSpiralTurns) * 6.28) + rotationAngle; var unitOffset = vec2(cos(angle), sin(angle)); var targetUV = uv + radiusSS * alpha * unitOffset * screenRatio; var Q = getPosition(targetUV); var v = Q - position; var vv = dot(v, v); var vn = dot(v, normal) - (bias * sampleRadius); var radius2 = sampleRadius * sampleRadius; var f = max(radius2 - vv, 0.0) / radius2; var epsilon = 0.01; return f * f * f * max(vn / (epsilon + vv), 0.0); }; function getPosition(uv:Vec2):Vec3 { var depth = depthTexture.get(uv); var uv2 = uvToScreen(uv); var temp = vec4(uv2, depth, 1) * cameraInverseViewProj; var originWS = temp.xyz / temp.w; return originWS; }; function fragment() { var vUV = input.uv; var occlusion = 0.0; var origin = getPosition(vUV); var normal = normalTexture.get(vUV); var noiseUv:Vec2; if (useWorldUV) noiseUv = (origin.xy + origin.z) * noiseScale else noiseUv = vUV / screenRatio * noiseScale; var sampleNoise = noiseTexture.get(noiseUv).x; var randomPatternRotationAngle = 2.0 * PI * sampleNoise; var radiusSS = (sampleRadius * fovTan) / (origin * cameraView).z; for (i in 0 ... numSamples) occlusion += sampleAO(vUV, origin, normal, radiusSS, i, randomPatternRotationAngle); occlusion = 1.0 - occlusion / float(numSamples); occlusion = pow(occlusion, 1.0 + intensity).saturate(); if (USE_FADE) { var dist = distance(origin, camera.position); occlusion = mix(occlusion, 1.0, saturate((dist - fadeStart) / (fadeEnd - fadeStart))); }; output.color = vec4(occlusion.xxx, 1.); }; })@:build(hxsl.Macros.buildShader())@:autoBuild(hxsl.Macros.buildShader())

Screen space ambient occlusion. Uses "Scalable Ambient Obscurance" [McGuire12]