Cycles: change perspective depth pass to be more standard

Now it matches Eevee, OpenGL and other renderers. Panoramic camera depth passes
are unchanged, and are still distance from the camera center.

2 files changed, 16 insertions, 2 deletions

diff --git a/intern/cycles/kernel/kernel_camera.h b/intern/cycles/kernel/kernel_camera.h
index 62ce04ba48f..445cf9eb44b 100644
--- a/intern/cycles/kernel/kernel_camera.h
+++ b/intern/cycles/kernel/kernel_camera.h
@@ -441,8 +441,22 @@ ccl_device_inline float camera_distance(KernelGlobals *kg, float3 P)
     float3 camD = make_float3(cameratoworld.x.z, cameratoworld.y.z, cameratoworld.z.z);
     return fabsf(dot((P - camP), camD));
   }
-  else
+  else {
     return len(P - camP);
+  }
+}
+
+ccl_device_inline float camera_z_depth(KernelGlobals *kg, float3 P)
+{
+  if (kernel_data.cam.type != CAMERA_PANORAMA) {
+    Transform worldtocamera = kernel_data.cam.worldtocamera;
+    return transform_point(&worldtocamera, P).z;
+  }
+  else {
+    Transform cameratoworld = kernel_data.cam.cameratoworld;
+    float3 camP = make_float3(cameratoworld.x.w, cameratoworld.y.w, cameratoworld.z.w);
+    return len(P - camP);
+  }
 }
 
 ccl_device_inline float3 camera_direction_from_point(KernelGlobals *kg, float3 P)
diff --git a/intern/cycles/kernel/kernel_passes.h b/intern/cycles/kernel/kernel_passes.h
index 7437e540a1f..753cf4561b2 100644
--- a/intern/cycles/kernel/kernel_passes.h
+++ b/intern/cycles/kernel/kernel_passes.h
@@ -194,7 +194,7 @@ ccl_device_inline void kernel_write_data_passes(KernelGlobals *kg,
         average(shader_bsdf_alpha(kg, sd)) >= kernel_data.film.pass_alpha_threshold) {
       if (state->sample == 0) {
         if (flag & PASSMASK(DEPTH)) {
-          float depth = camera_distance(kg, sd->P);
+          float depth = camera_z_depth(kg, sd->P);
           kernel_write_pass_float(buffer + kernel_data.film.pass_depth, depth);
         }
         if (flag & PASSMASK(OBJECT_ID)) {