Mad Max: Fix bloom/lens flare opacity being calculated from wrong spo…

…t on depth buffer

Calculating the opacity from the wrong spot on the depth buffer leads to
the bloom & lens flare appearing & disappearing when they should not,
being too pronounced, or not visible at all when it should be.

The pixel shader has the depth of the light source in Z buffer scale,
which we can use to correct this. Scale it out to world Z and use it to
offset the location of the depth buffer read to determine the opacity of
the bloom & lens flare.

Debugging is included to show where the depth buffer is being sampled.

Mad Max/ShaderFixes/cfe4a25b2677c39b-ps_replace.txt

@@ -1,3 +1,5 @@
+// Lens flare
+// VS e9849e745227d124
 
 cbuffer GlobalConstants : register(b0)
 {
@@ -33,21 +35,60 @@ void main(
   float4 fDest;
 
   r0.xy = saturate(InstanceConsts[0].xy);
+
+float4 stereo = StereoParams.Load(0);
+// Values from frame analysis of other shaders that sample depth buffer and
+// scale to world Z:
+float depth = 1 / (InstanceConsts[0].z * 9.9999752 + 0.000025);
+float correction = stereo.x * (depth - stereo.y) / depth / 2;
+
+
+//// Debugging, show original depth buffer sample location in red:
+//if (abs(v0.x/1920 - r0.x) < 0.01) {
+//	o0 = float4(1,0,0,1);
+//	return;
+//}
+
+r0.x += correction;
+
+//// Debugging, show adjusted depth buffer sample location in green:
+//if (abs(v0.x/1920 - r0.x) < 0.01) {
+//	o0 = float4(0,1,0,1);
+//	return;
+//}
+
+
   r0.x = DepthTexture.Sample(DepthTexture_s, r0.xy).x;
   r0.x = r0.x < InstanceConsts[0].z;
   r0.x = r0.x ? 0.500000 : 0;
   r1.xyzw = saturate(Globals[8].zwzw * float4(-3,3.5,3.5,6) + InstanceConsts[0].xyxy);
+
+r1.x += correction;
+r1.z += correction;
+
   r0.y = DepthTexture.Sample(DepthTexture_s, r1.xy).x;
   r0.z = DepthTexture.Sample(DepthTexture_s, r1.zw).x;
   r0.yz = r0.yz < InstanceConsts[0].zz;
-  r0.yz = r0.yz ? float2(1.04018739e+009,1.04018739e+009) : 0;
+
+// Decompiler bug misinterpreted 0x3e000000:
+  // r0.yz = r0.yz ? float2(1.04018739e+009,1.04018739e+009) : 0;
+  r0.yz = r0.yz ? float2(0.125, 0.125) : 0;
+
   r0.x = r0.x + r0.y;
   r0.x = r0.x + r0.z;
   r1.xyzw = saturate(Globals[8].zwzw * float4(-5,-3.5,3,-3) + InstanceConsts[0].xyxy);
+
+r1.x += correction;
+r1.z += correction;
+
   r0.y = DepthTexture.Sample(DepthTexture_s, r1.xy).x;
   r0.z = DepthTexture.Sample(DepthTexture_s, r1.zw).x;
   r0.yz = r0.yz < InstanceConsts[0].zz;
-  r0.yz = r0.yz ? float2(1.04018739e+009,1.04018739e+009) : 0;
+
+// Decompiler bug misinterpreted 0x3e000000:
+  // r0.yz = r0.yz ? float2(1.04018739e+009,1.04018739e+009) : 0;
+  r0.yz = r0.yz ? float2(0.125, 0.125) : 0;
+
   r0.x = r0.x + r0.y;
   r0.x = r0.x + r0.z;
   r0.y = SkyMaskB.Sample(SkyMaskB_s, InstanceConsts[1].xyz).y;

Mad Max/ShaderFixes/d6160e64bc5d9be7-ps_replace.txt

@@ -1,3 +1,5 @@
+// Bloom around lights
+// VS e9849e745227d124
 
 cbuffer GlobalConstants : register(b0)
 {
@@ -29,21 +31,59 @@ void main(
   float4 fDest;
 
   r0.xy = saturate(InstanceConsts[0].xy);
+
+float4 stereo = StereoParams.Load(0);
+// Values from frame analysis of other shaders that sample depth buffer and
+// scale to world Z:
+float depth = 1 / (InstanceConsts[0].z * 9.9999752 + 0.000025);
+float correction = stereo.x * (depth - stereo.y) / depth / 2;
+
+
+// // Debugging, show original depth buffer sample location in red:
+// if (abs(v0.x/1920 - r0.x) < 0.01) {
+// 	o0 = float4(1,0,0,1);
+// 	return;
+// }
+
+r0.x += correction;
+
+// // Debugging, show adjusted depth buffer sample location in green:
+// if (abs(v0.x/1920 - r0.x) < 0.01) {
+// 	o0 = float4(0,1,0,1);
+// 	return;
+// }
+
   r0.x = DepthTexture.Sample(DepthTexture_s, r0.xy).x;
   r0.x = r0.x < InstanceConsts[0].z;
   r0.x = r0.x ? 0.500000 : 0;
   r1.xyzw = saturate(Globals[8].zwzw * float4(-3,3.5,3.5,6) + InstanceConsts[0].xyxy);
+
+r1.x += correction;
+r1.z += correction;
+
   r0.y = DepthTexture.Sample(DepthTexture_s, r1.xy).x;
   r0.z = DepthTexture.Sample(DepthTexture_s, r1.zw).x;
   r0.yz = r0.yz < InstanceConsts[0].zz;
-  r0.yz = r0.yz ? float2(1.04018739e+009,1.04018739e+009) : 0;
+
+// Decompiler bug misinterpreted 0x3e000000:
+  //r0.yz = r0.yz ? float2(1.04018739e+009,1.04018739e+009) : 0;
+  r0.yz = r0.yz ? float2(0.125, 0.125) : 0;
+
   r0.x = r0.x + r0.y;
   r0.x = r0.x + r0.z;
   r1.xyzw = saturate(Globals[8].zwzw * float4(-5,-3.5,3,-3) + InstanceConsts[0].xyxy);
+
+r1.x += correction;
+r1.z += correction;
+
   r0.y = DepthTexture.Sample(DepthTexture_s, r1.xy).x;
   r0.z = DepthTexture.Sample(DepthTexture_s, r1.zw).x;
   r0.yz = r0.yz < InstanceConsts[0].zz;
-  r0.yz = r0.yz ? float2(1.04018739e+009,1.04018739e+009) : 0;
+
+// Decompiler bug misinterpreted 0x3e000000:
+  // r0.yz = r0.yz ? float2(1.04018739e+009,1.04018739e+009) : 0;
+  r0.yz = r0.yz ? float2(0.125, 0.125) : 0;
+
   r0.x = r0.x + r0.y;
   r0.x = r0.x + r0.z;
   r1.xyzw = DiffuseTexture.Sample(DiffuseTexture_s, v1.xy).xyzw;