[Bf-blender-cvs] [153e1dc31a5] master: Fix T103513: Images lose their alpha channel when OSL is enabled for GPU Compute

[Patrick Mours]

Commit: 153e1dc31a518fc307c7d87bb5bd700688e438f9
Author: Patrick Mours
Date:   Mon Jan 2 13:52:59 2023 +0100
Branches: master
https://developer.blender.org/rB153e1dc31a518fc307c7d87bb5bd700688e438f9

Fix T103513: Images lose their alpha channel when OSL is enabled for GPU Compute

The "osl_texture" intrinsic was not implemented correctly. It should handle alpha
separately from color, the number of channels input parameter only counts color
channels.

===================================================================

M	intern/cycles/kernel/osl/services_gpu.h

===================================================================

diff --git a/intern/cycles/kernel/osl/services_gpu.h b/intern/cycles/kernel/osl/services_gpu.h
index 744c7103b28..b9ffd959f1a 100644
--- a/intern/cycles/kernel/osl/services_gpu.h
+++ b/intern/cycles/kernel/osl/services_gpu.h
@@ -1532,7 +1532,7 @@ ccl_device_extern void osl_texture_set_missingcolor_alpha(ccl_private OSLTexture
 ccl_device_extern bool osl_texture(ccl_private ShaderGlobals *sg,
                                    DeviceString filename,
                                    ccl_private void *texture_handle,
-                                   OSLTextureOptions *opt,
+                                   ccl_private OSLTextureOptions *opt,
                                    float s,
                                    float t,
                                    float dsdx,
@@ -1557,13 +1557,14 @@ ccl_device_extern bool osl_texture(ccl_private ShaderGlobals *sg,
 
   const float4 rgba = kernel_tex_image_interp(nullptr, id, s, 1.0f - t);
 
-  result[0] = rgba.x;
+  if (nchannels > 0)
+    result[0] = rgba.x;
   if (nchannels > 1)
     result[1] = rgba.y;
   if (nchannels > 2)
     result[2] = rgba.z;
-  if (nchannels > 3)
-    result[3] = rgba.w;
+  if (alpha)
+    *alpha = rgba.w;
 
   return true;
 }
@@ -1571,7 +1572,7 @@ ccl_device_extern bool osl_texture(ccl_private ShaderGlobals *sg,
 ccl_device_extern bool osl_texture3d(ccl_private ShaderGlobals *sg,
                                      DeviceString filename,
                                      ccl_private void *texture_handle,
-                                     OSLTextureOptions *opt,
+                                     ccl_private OSLTextureOptions *opt,
                                      ccl_private const float3 *P,
                                      ccl_private const float3 *dPdx,
                                      ccl_private const float3 *dPdy,
@@ -1594,13 +1595,14 @@ ccl_device_extern bool osl_texture3d(ccl_private ShaderGlobals *sg,
 
   const float4 rgba = kernel_tex_image_interp_3d(nullptr, id, *P, INTERPOLATION_NONE);
 
-  result[0] = rgba.x;
+  if (nchannels > 0)
+    result[0] = rgba.x;
   if (nchannels > 1)
     result[1] = rgba.y;
   if (nchannels > 2)
     result[2] = rgba.z;
-  if (nchannels > 3)
-    result[3] = rgba.w;
+  if (alpha)
+    *alpha = rgba.w;
 
   return true;
 }
@@ -1608,7 +1610,7 @@ ccl_device_extern bool osl_texture3d(ccl_private ShaderGlobals *sg,
 ccl_device_extern bool osl_environment(ccl_private ShaderGlobals *sg,
                                        DeviceString filename,
                                        ccl_private void *texture_handle,
-                                       OSLTextureOptions *opt,
+                                       ccl_private OSLTextureOptions *opt,
                                        ccl_private const float3 *R,
                                        ccl_private const float3 *dRdx,
                                        ccl_private const float3 *dRdy,
@@ -1621,13 +1623,14 @@ ccl_device_extern bool osl_environment(ccl_private ShaderGlobals *sg,
                                        ccl_private float *dalphay,
                                        ccl_private void *errormessage)
 {
-  result[0] = 1.0f;
+  if (nchannels > 0)
+    result[0] = 1.0f;
   if (nchannels > 1)
     result[1] = 0.0f;
   if (nchannels > 2)
     result[2] = 1.0f;
-  if (nchannels > 3)
-    result[3] = 1.0f;
+  if (alpha)
+    *alpha = 1.0f;
 
   return false;
 }