284 lines
No EOL
9.6 KiB
PostScript
284 lines
No EOL
9.6 KiB
PostScript
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#ifndef SSAO_QUALITY
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float4 calc_hbao(float z, float4 curN, float2 tc0)
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{
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return 1.0h;
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}
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#else // SSAO_QUALITY
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#define g_Resolution screen_res.xy
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#define g_InvResolution screen_res.zw
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static const float g_MaxFootprintUV=0.01f;
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static const float g_R = 0.400009334f;
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static const float g_sqr_R = 0.160007462f;
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static const float g_inv_R = 2.49994159f;
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// static const float g_Contrast = 1.5f;
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static const float g_Contrast = 0.8f;
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static const float g_AngleBias = 0.0f;
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#if SSAO_QUALITY == 3
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static const float g_NumDir = 6.0f;
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static const float g_NumSteps = 3.0f;
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#elif SSAO_QUALITY == 2
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static const float g_NumDir = 5.0f;
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static const float g_NumSteps = 3.0f;
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#elif SSAO_QUALITY == 1
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static const float g_NumDir = 4.0f;
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static const float g_NumSteps = 3.0f;
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#endif
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uniform sampler2D jitter4;
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#define M_PI 3.14159265f
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//----------------------------------------------------------------------------------
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float tangent(float3 P, float3 S)
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{
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return (P.z - S.z) / length(S.xy - P.xy);
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}
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//----------------------------------------------------------------------------------
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float3 fetch_eye_pos(float2 uv)
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{
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#ifdef SSAO_OPT_DATA
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float z = tex2Dlod(s_half_depth, float4(uv, 0, 0)).x;
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return uv_to_eye(uv, z);
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#else // SSAO_OPT_DATA
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return tex2Dlod (s_position, float4(uv, 0, 0));
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#endif // SSAO_OPT_DATA
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}
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float3 tangent_eye_pos(float2 uv, float4 tangentPlane)
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{
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// view vector going through the surface point at uv
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float3 V = fetch_eye_pos(uv);
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float NdotV = dot(tangentPlane.xyz, V);
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// intersect with tangent plane except for silhouette edges
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if (NdotV < 0.0) V *= (tangentPlane.w / NdotV);
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return V;
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}
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float length2(float3 v) { return dot(v, v); }
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//----------------------------------------------------------------------------------
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float3 min_diff(float3 P, float3 Pr, float3 Pl)
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{
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float3 V1 = Pr - P;
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float3 V2 = P - Pl;
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return (length2(V1) < length2(V2)) ? V1 : V2;
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}
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//----------------------------------------------------------------------------------
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float falloff(float r)
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{
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return 1.0f - r*r;
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}
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//----------------------------------------------------------------------------------
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float2 snap_uv_offset(float2 uv)
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{
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return round(uv * g_Resolution) * g_InvResolution;
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}
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//----------------------------------------------------------------------------------
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float tan_to_sin(float x)
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{
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return x / sqrt(1.0f + x*x);
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}
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//----------------------------------------------------------------------------------
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float3 tangent_vector(float2 deltaUV, float3 dPdu, float3 dPdv)
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{
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return deltaUV.x * dPdu + deltaUV.y * dPdv;
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}
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//----------------------------------------------------------------------------------
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void integrate_direction(inout float ao, float3 P, float2 uv, float2 deltaUV,
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float numSteps, float tanH, float sinH)
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{
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for (float j = 1; j <= numSteps; ++j) {
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uv += deltaUV;
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float3 S = fetch_eye_pos(uv);
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// Ignore any samples outside the radius of influence
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float d2 = length2(S - P);
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if (d2 < g_sqr_R) {
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float tanS = tangent(P, S);
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//[branch]
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if(tanS > tanH) {
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// Accumulate AO between the horizon and the sample
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float sinS = tanS / sqrt(1.0f + tanS*tanS);
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float r = sqrt(d2) * g_inv_R;
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ao += falloff(r) * (sinS - sinH);
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// Update the current horizon angle
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tanH = tanS;
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sinH = sinS;
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}
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}
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}
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}
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//----------------------------------------------------------------------------------
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float horizon_occlusion_integrateDirection(float2 deltaUV,
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float2 uv0,
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float3 P,
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float numSteps,
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float randstep)
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{
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// Randomize starting point within the first sample distance
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float2 uv = uv0 + snap_uv_offset( randstep * deltaUV );
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// Snap increments to pixels to avoid disparities between xy
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// and z sample locations and sample along a line
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deltaUV = snap_uv_offset( deltaUV );
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// Add a small bias in case (g_AngleBias == 0.0)
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float tanT = tan(-M_PI*0.5 + g_AngleBias + 1.e-5);
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float sinT = tan_to_sin(tanT);
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float ao = 0;
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integrate_direction(ao, P, uv, deltaUV, numSteps, tanT, sinT);
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// Integrate opposite directions together
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deltaUV = -deltaUV;
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uv = uv0 + snap_uv_offset( randstep * deltaUV );
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integrate_direction(ao, P, uv, deltaUV, numSteps, tanT, sinT);
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// Divide by 2 because we have integrated 2 directions together
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// Subtract 1 and clamp to remove the part below the surface
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return max(ao * 0.5 - 1.0, 0.0);
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}
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//----------------------------------------------------------------------------------
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float horizon_occlusion(float2 deltaUV,
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float2 uv0,
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float3 P,
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float numSteps,
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float randstep,
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float3 dPdu,
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float3 dPdv)
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{
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// Randomize starting point within the first sample distance
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float2 uv = uv0 + snap_uv_offset( randstep * deltaUV );
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// Snap increments to pixels to avoid disparities between xy
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// and z sample locations and sample along a line
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deltaUV = snap_uv_offset( deltaUV );
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// Compute tangent vector using the tangent plane
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float3 T = deltaUV.x * dPdu + deltaUV.y * dPdv;
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float phi = atan(-T.z / length(T.xy)) + 0.1f;//g_AngleBias;
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float tanH = tan(min(phi, M_PI*0.5));
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float sinH = tanH / sqrt(1.0f + tanH*tanH);
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float ao = 0;
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for(float j = 1; j <= numSteps; ++j) {
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uv += deltaUV;
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float3 S = fetch_eye_pos(uv);
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// Ignore any samples outside the radius of influence
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float d2 = length2(S - P);
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float tanS = tangent(P, S);
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if ((d2 < g_sqr_R) && (tanS > tanH)) {
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// Accumulate AO between the horizon and the sample
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float sinS = tanS / sqrt(1.0f + tanS*tanS);
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float r = sqrt(d2) * g_inv_R;
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ao += falloff(r) * (sinS - sinH);
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// Update the current horizon angle
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tanH = tanS;
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sinH = sinS;
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}
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}
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return ao;
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}
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float4 calc_hbao(float z, float4 curN, float2 tc0)
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{
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const float ssao_noise_tile_factor = ssao_params.x;
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const float ssao_kernel_size = ssao_params.y;
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float3 N = curN.xyz;
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float3 P = uv_to_eye(tc0, z);
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// Calculate the real number of steps based on Z distance, and
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// early out if geometry is too far away.
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float2 step_size = float2 (.5f / 1024.h, .5f / 768.h)*ssao_kernel_size/max(z,1.3);
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float numSteps = min ( g_NumSteps, min(step_size.x * g_Resolution.x, step_size.y * g_Resolution.y));
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float numDirs = min ( g_NumDir, min(step_size.x / 4 * g_Resolution.x, step_size.y / 4 * g_Resolution.y));
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// if( numSteps < 1.0 ) return 1.0;
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step_size = step_size / ( numSteps + 1 );
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// (cos(alpha),sin(alpha),jitter)
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#ifndef HBAO_WORLD_JITTER
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float3 rand_Dir = tex2D(jitter4, tc0 * g_Resolution /64.0f).rgb;
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#else
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float3 tc1 = mul( m_v2w, float4(P,1) );
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tc1 *= ssao_noise_tile_factor;
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tc1.xz += tc1.y;
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float3 rand_Dir = tex2D(jitter4, tc1.xz).xyz;
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#endif
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//rand_Dir = float3(1,0,0);
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// footprint optimization
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float maxNumSteps = g_MaxFootprintUV / step_size;
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if (maxNumSteps < numSteps)
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{
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numSteps = floor(maxNumSteps + rand_Dir.z);
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numSteps = max(numSteps, 1);
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step_size = g_MaxFootprintUV / numSteps;
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}
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float4 tangentPlane = float4(N, dot(P, N));
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// Nearest neighbor pixels on the tangent plane
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float3 Pr = tangent_eye_pos(tc0 + float2(g_InvResolution.x, 0), tangentPlane);
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float3 Pl = tangent_eye_pos(tc0 + float2(-g_InvResolution.x, 0), tangentPlane);
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float3 Pt = tangent_eye_pos(tc0 + float2(0, g_InvResolution.y), tangentPlane);
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float3 Pb = tangent_eye_pos(tc0 + float2(0, -g_InvResolution.y), tangentPlane);
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//float3 Pr, Pl, Pt, Pb;
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//Pr = fetch_eye_pos(IN.texUV + float2(g_InvResolution.x, 0));
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//Pl = fetch_eye_pos(IN.texUV + float2(-g_InvResolution.x, 0));
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//Pt = fetch_eye_pos(IN.texUV + float2(0, g_InvResolution.y));
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//Pb = fetch_eye_pos(IN.texUV + float2(0, -g_InvResolution.y));
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//float3 N = normalize(cross(Pr - Pl, Pt - Pb));
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//tangentPlane = float4(N, dot(P, N));
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// Screen-aligned basis for the tangent plane
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float3 dPdu = min_diff(P, Pr, Pl);
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float3 dPdv = min_diff(P, Pt, Pb) * (g_Resolution.y * g_InvResolution.x);
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// Loop over all directions
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float ao = 0;
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float delta = g_NumDir / numDirs;
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float alpha = 2.0f * M_PI / g_NumDir;
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for (float d = 0; d < g_NumDir; d+=delta) {
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float angle = alpha * d;
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float2 dir = float2(cos(angle), sin(angle));
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float2 deltaUV = float2(dir.x*rand_Dir.x - dir.y*rand_Dir.y,
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dir.x*rand_Dir.y + dir.y*rand_Dir.x)
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* step_size.xy;
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ao += horizon_occlusion(deltaUV, tc0, P, numSteps, rand_Dir.z, dPdu, dPdv);
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//ao += horizon_occlusion_integrateDirection(deltaUV, tc0, P, numSteps, rand_Dir.z);
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}
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// this saturate is not needed if the AO render target is UNORM
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return saturate(1.0 - ao / g_NumDir * g_Contrast);
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}
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#endif // SSAO_QUALITY |