Images: add mirror extension type

This adds a new mirror image extension type for shaders and
geometry nodes (next to the existing repeat, extend and clip
options).

See D16432 for a more detailed explanation of `wrap_mirror`.

This also adds a new sampler flag `GPU_SAMPLER_MIRROR_REPEAT`.
It acts as a modifier to `GPU_SAMPLER_REPEAT`, so any `REPEAT`
flag must be set for the `MIRROR` flag to have an effect.

Differential Revision: https://developer.blender.org/D16432

intern/cycles/device/cuda/device_impl.cpp

@@ -952,6 +952,9 @@ void CUDADevice::tex_alloc(device_texture &mem)
     case EXTENSION_CLIP:
       address_mode = CU_TR_ADDRESS_MODE_BORDER;
       break;
+    case EXTENSION_MIRROR:
+      address_mode = CU_TR_ADDRESS_MODE_MIRROR;
+      break;
     default:
       assert(0);
       break;

intern/cycles/device/hip/device_impl.cpp

@@ -909,6 +909,9 @@ void HIPDevice::tex_alloc(device_texture &mem)
        * because it's unsupported in HIP. */
       address_mode = hipAddressModeClamp;
       break;
+    case EXTENSION_MIRROR:
+      address_mode = hipAddressModeMirror;
+      break;
     default:
       assert(0);
       break;

intern/cycles/device/metal/device_impl.mm

@@ -856,7 +856,7 @@ void MetalDevice::tex_alloc(device_texture &mem)
   /* sampler_index maps into the GPU's constant 'metal_samplers' array */
   uint64_t sampler_index = mem.info.extension;
   if (mem.info.interpolation != INTERPOLATION_CLOSEST) {
-    sampler_index += 3;
+    sampler_index += 4;
   }
 
   /* Image Texture Storage */

intern/cycles/kernel/device/cpu/image.h

@@ -202,6 +202,14 @@ template<typename TexT, typename OutT = float4> struct TextureInterpolator {
     return clamp(x, 0, width - 1);
   }
 
+  static ccl_always_inline int wrap_mirror(int x, int width)
+  {
+    const int m = abs(x + (x < 0)) % (2 * width);
+    if (m >= width)
+      return 2 * width - m - 1;
+    return m;
+  }
+
   /* ********  2D interpolation ******** */
 
   static ccl_always_inline OutT interp_closest(const TextureInfo &info, float x, float y)
@@ -226,6 +234,10 @@ template<typename TexT, typename OutT = float4> struct TextureInterpolator {
         ix = wrap_clamp(ix, width);
         iy = wrap_clamp(iy, height);
         break;
+      case EXTENSION_MIRROR:
+        ix = wrap_mirror(ix, width);
+        iy = wrap_mirror(iy, height);
+        break;
       default:
         kernel_assert(0);
         return zero();
@@ -268,6 +280,12 @@ template<typename TexT, typename OutT = float4> struct TextureInterpolator {
         niy = wrap_clamp(iy + 1, height);
         iy = wrap_clamp(iy, height);
         break;
+      case EXTENSION_MIRROR:
+        nix = wrap_mirror(ix + 1, width);
+        ix = wrap_mirror(ix, width);
+        niy = wrap_mirror(iy + 1, height);
+        iy = wrap_mirror(iy, height);
+        break;
       default:
         kernel_assert(0);
         return zero();
@@ -331,6 +349,17 @@ template<typename TexT, typename OutT = float4> struct TextureInterpolator {
         nniy = wrap_clamp(iy + 2, height);
         iy = wrap_clamp(iy, height);
         break;
+      case EXTENSION_MIRROR:
+        pix = wrap_mirror(ix - 1, width);
+        nix = wrap_mirror(ix + 1, width);
+        nnix = wrap_mirror(ix + 2, width);
+        ix = wrap_mirror(ix, width);
+
+        piy = wrap_mirror(iy - 1, height);
+        niy = wrap_mirror(iy + 1, height);
+        nniy = wrap_mirror(iy + 2, height);
+        iy = wrap_mirror(iy, height);
+        break;
       default:
         kernel_assert(0);
         return zero();
@@ -403,6 +432,11 @@ template<typename TexT, typename OutT = float4> struct TextureInterpolator {
         iy = wrap_clamp(iy, height);
         iz = wrap_clamp(iz, depth);
         break;
+      case EXTENSION_MIRROR:
+        ix = wrap_mirror(ix, width);
+        iy = wrap_mirror(iy, height);
+        iz = wrap_mirror(iz, depth);
+        break;
       default:
         kernel_assert(0);
         return zero();
@@ -480,6 +514,16 @@ template<typename TexT, typename OutT = float4> struct TextureInterpolator {
         niz = wrap_clamp(iz + 1, depth);
         iz = wrap_clamp(iz, depth);
         break;
+      case EXTENSION_MIRROR:
+        nix = wrap_mirror(ix + 1, width);
+        ix = wrap_mirror(ix, width);
+
+        niy = wrap_mirror(iy + 1, height);
+        iy = wrap_mirror(iy, height);
+
+        niz = wrap_mirror(iz + 1, depth);
+        iz = wrap_mirror(iz, depth);
+        break;
       default:
         kernel_assert(0);
         return zero();
@@ -595,6 +639,22 @@ template<typename TexT, typename OutT = float4> struct TextureInterpolator {
         nniz = wrap_clamp(iz + 2, depth);
         iz = wrap_clamp(iz, depth);
         break;
+      case EXTENSION_MIRROR:
+        pix = wrap_mirror(ix - 1, width);
+        nix = wrap_mirror(ix + 1, width);
+        nnix = wrap_mirror(ix + 2, width);
+        ix = wrap_mirror(ix, width);
+
+        piy = wrap_mirror(iy - 1, height);
+        niy = wrap_mirror(iy + 1, height);
+        nniy = wrap_mirror(iy + 2, height);
+        iy = wrap_mirror(iy, height);
+
+        piz = wrap_mirror(iz - 1, depth);
+        niz = wrap_mirror(iz + 1, depth);
+        nniz = wrap_mirror(iz + 2, depth);
+        iz = wrap_mirror(iz, depth);
+        break;
       default:
         kernel_assert(0);
         return zero();

intern/cycles/kernel/device/metal/compat.h

@@ -301,10 +301,12 @@ enum SamplerType {
   SamplerFilterNearest_AddressRepeat,
   SamplerFilterNearest_AddressClampEdge,
   SamplerFilterNearest_AddressClampZero,
+  SamplerFilterNearest_AddressMirroredRepeat,
 
   SamplerFilterLinear_AddressRepeat,
   SamplerFilterLinear_AddressClampEdge,
   SamplerFilterLinear_AddressClampZero,
+  SamplerFilterLinear_AddressMirroredRepeat,
 
   SamplerCount
 };
@@ -313,7 +315,9 @@ constant constexpr array<sampler, SamplerCount> metal_samplers = {
     sampler(address::repeat, filter::nearest),
     sampler(address::clamp_to_edge, filter::nearest),
     sampler(address::clamp_to_zero, filter::nearest),
+    sampler(address::mirrored_repeat, filter::nearest),
     sampler(address::repeat, filter::linear),
     sampler(address::clamp_to_edge, filter::linear),
     sampler(address::clamp_to_zero, filter::linear),
+    sampler(address::mirrored_repeat, filter::linear),
 };

intern/cycles/kernel/device/metal/context_begin.h

@@ -47,9 +47,11 @@ class MetalKernelContext {
         case 0: return texture_array[tid].tex.sample(sampler(address::repeat, filter::nearest), coords);
         case 1: return texture_array[tid].tex.sample(sampler(address::clamp_to_edge, filter::nearest), coords);
         case 2: return texture_array[tid].tex.sample(sampler(address::clamp_to_zero, filter::nearest), coords);
-        case 3: return texture_array[tid].tex.sample(sampler(address::repeat, filter::linear), coords);
+        case 3: return texture_array[tid].tex.sample(sampler(address::mirrored_repeat, filter::nearest), coords);
-        case 4: return texture_array[tid].tex.sample(sampler(address::clamp_to_edge, filter::linear), coords);
+        case 4: return texture_array[tid].tex.sample(sampler(address::repeat, filter::linear), coords);
-        case 5: return texture_array[tid].tex.sample(sampler(address::clamp_to_zero, filter::linear), coords);
+        case 5: return texture_array[tid].tex.sample(sampler(address::clamp_to_edge, filter::linear), coords);
+        case 6: return texture_array[tid].tex.sample(sampler(address::clamp_to_zero, filter::linear), coords);
+        case 7: return texture_array[tid].tex.sample(sampler(address::mirrored_repeat, filter::linear), coords);
       }
     }
 #endif

intern/cycles/kernel/device/oneapi/image.h

@@ -24,6 +24,14 @@ ccl_device_inline int svm_image_texture_wrap_clamp(int x, int width)
   return clamp(x, 0, width - 1);
 }
 
+ccl_device_inline int svm_image_texture_wrap_mirror(int x, int width)
+{
+  const int m = abs(x + (x < 0)) % (2 * width);
+  if (m >= width)
+    return 2 * width - m - 1;
+  return m;
+}
+
 ccl_device_inline float4 svm_image_texture_read(const TextureInfo &info, int x, int y, int z)
 {
   const int data_offset = x + info.width * y + info.width * info.height * z;
@@ -85,6 +93,10 @@ ccl_device_inline float4 svm_image_texture_read_2d(int id, int x, int y)
     x = svm_image_texture_wrap_clamp(x, info.width);
     y = svm_image_texture_wrap_clamp(y, info.height);
   }
+  else if (info.extension == EXTENSION_MIRROR) {
+    x = svm_image_texture_wrap_mirror(x, info.width);
+    y = svm_image_texture_wrap_mirror(y, info.height);
+  }
   else {
     if (x < 0 || x >= info.width || y < 0 || y >= info.height) {
       return make_float4(0.0f, 0.0f, 0.0f, 0.0f);
@@ -109,6 +121,11 @@ ccl_device_inline float4 svm_image_texture_read_3d(int id, int x, int y, int z)
     y = svm_image_texture_wrap_clamp(y, info.height);
     z = svm_image_texture_wrap_clamp(z, info.depth);
   }
+  else if (info.extension == EXTENSION_MIRROR) {
+    x = svm_image_texture_wrap_mirror(x, info.width);
+    y = svm_image_texture_wrap_mirror(y, info.height);
+    z = svm_image_texture_wrap_mirror(z, info.depth);
+  }
   else {
     if (x < 0 || x >= info.width || y < 0 || y >= info.height || z < 0 || z >= info.depth) {
       return make_float4(0.0f, 0.0f, 0.0f, 0.0f);

intern/cycles/scene/shader_nodes.cpp

@@ -226,6 +226,7 @@ NODE_DEFINE(ImageTextureNode)
   extension_enum.insert("periodic", EXTENSION_REPEAT);
   extension_enum.insert("clamp", EXTENSION_EXTEND);
   extension_enum.insert("black", EXTENSION_CLIP);
+  extension_enum.insert("mirror", EXTENSION_MIRROR);
   SOCKET_ENUM(extension, "Extension", extension_enum, EXTENSION_REPEAT);
 
   static NodeEnum projection_enum;

intern/cycles/util/texture.h

@@ -65,6 +65,8 @@ typedef enum ExtensionType {
   EXTENSION_EXTEND = 1,
   /* Clip to image size and set exterior pixels as transparent. */
   EXTENSION_CLIP = 2,
+  /* Repeatedly flip the image horizontally and vertically. */
+  EXTENSION_MIRROR = 3,
 
   EXTENSION_NUM_TYPES,
 } ExtensionType;

source/blender/draw/engines/workbench/workbench_materials.cc

@@ -97,11 +97,13 @@ BLI_INLINE void workbench_material_get_image(
       case SH_NODE_TEX_IMAGE: {
         const NodeTexImage *storage = static_cast<NodeTexImage *>(node->storage);
         const bool use_filter = (storage->interpolation != SHD_INTERP_CLOSEST);
-        const bool use_repeat = (storage->extension == SHD_IMAGE_EXTENSION_REPEAT);
+        const bool use_mirror = (storage->extension == SHD_IMAGE_EXTENSION_MIRROR);
+        const bool use_repeat = use_mirror || (storage->extension == SHD_IMAGE_EXTENSION_REPEAT);
         const bool use_clip = (storage->extension == SHD_IMAGE_EXTENSION_CLIP);
         SET_FLAG_FROM_TEST(*r_sampler, use_filter, GPU_SAMPLER_FILTER);
         SET_FLAG_FROM_TEST(*r_sampler, use_repeat, GPU_SAMPLER_REPEAT);
         SET_FLAG_FROM_TEST(*r_sampler, use_clip, GPU_SAMPLER_CLAMP_BORDER);
+        SET_FLAG_FROM_TEST(*r_sampler, use_mirror, GPU_SAMPLER_MIRROR_REPEAT);
         break;
       }
       case SH_NODE_TEX_ENVIRONMENT: {

source/blender/gpu/GPU_texture.h

@@ -35,7 +35,8 @@ typedef enum eGPUSamplerState {
   GPU_SAMPLER_CLAMP_BORDER = (1 << 5), /* Clamp to border color instead of border texel. */
   GPU_SAMPLER_COMPARE = (1 << 6),
   GPU_SAMPLER_ANISO = (1 << 7),
-  GPU_SAMPLER_ICON = (1 << 8),
+  GPU_SAMPLER_MIRROR_REPEAT = (1 << 8), /* Requires any REPEAT flag to be set. */
+  GPU_SAMPLER_ICON = (1 << 9),
 
   GPU_SAMPLER_REPEAT = (GPU_SAMPLER_REPEAT_S | GPU_SAMPLER_REPEAT_T | GPU_SAMPLER_REPEAT_R),
 } eGPUSamplerState;

source/blender/gpu/metal/mtl_context.mm

@@ -1595,14 +1595,17 @@ id<MTLSamplerState> MTLContext::generate_sampler_from_state(MTLSamplerState samp
   MTLSamplerAddressMode clamp_type = (sampler_state.state & GPU_SAMPLER_CLAMP_BORDER) ?
                                          MTLSamplerAddressModeClampToBorderColor :
                                          MTLSamplerAddressModeClampToEdge;
+  MTLSamplerAddressMode repeat_type = (sampler_state.state & GPU_SAMPLER_MIRROR_REPEAT) ?
+                                         MTLSamplerAddressModeMirrorRepeat :
+                                         MTLSamplerAddressModeRepeat;
   descriptor.rAddressMode = (sampler_state.state & GPU_SAMPLER_REPEAT_R) ?
-                                MTLSamplerAddressModeRepeat :
+                                repeat_type :
                                 clamp_type;
   descriptor.sAddressMode = (sampler_state.state & GPU_SAMPLER_REPEAT_S) ?
-                                MTLSamplerAddressModeRepeat :
+                                repeat_type :
                                 clamp_type;
   descriptor.tAddressMode = (sampler_state.state & GPU_SAMPLER_REPEAT_T) ?
-                                MTLSamplerAddressModeRepeat :
+                                repeat_type :
                                 clamp_type;
   descriptor.borderColor = MTLSamplerBorderColorTransparentBlack;
   descriptor.minFilter = (sampler_state.state & GPU_SAMPLER_FILTER) ?

source/blender/gpu/opengl/gl_texture.cc

@@ -548,12 +548,13 @@ GLuint GLTexture::samplers_[GPU_SAMPLER_MAX] = {0};
 void GLTexture::samplers_init()
 {
   glGenSamplers(GPU_SAMPLER_MAX, samplers_);
-  for (int i = 0; i <= GPU_SAMPLER_ICON - 1; i++) {
+  for (int i = 0; i < GPU_SAMPLER_ICON; i++) {
     eGPUSamplerState state = static_cast<eGPUSamplerState>(i);
     GLenum clamp_type = (state & GPU_SAMPLER_CLAMP_BORDER) ? GL_CLAMP_TO_BORDER : GL_CLAMP_TO_EDGE;
-    GLenum wrap_s = (state & GPU_SAMPLER_REPEAT_S) ? GL_REPEAT : clamp_type;
+    GLenum repeat_type = (state & GPU_SAMPLER_MIRROR_REPEAT) ? GL_MIRRORED_REPEAT : GL_REPEAT;
-    GLenum wrap_t = (state & GPU_SAMPLER_REPEAT_T) ? GL_REPEAT : clamp_type;
+    GLenum wrap_s = (state & GPU_SAMPLER_REPEAT_S) ? repeat_type : clamp_type;
-    GLenum wrap_r = (state & GPU_SAMPLER_REPEAT_R) ? GL_REPEAT : clamp_type;
+    GLenum wrap_t = (state & GPU_SAMPLER_REPEAT_T) ? repeat_type : clamp_type;
+    GLenum wrap_r = (state & GPU_SAMPLER_REPEAT_R) ? repeat_type : clamp_type;
     GLenum mag_filter = (state & GPU_SAMPLER_FILTER) ? GL_LINEAR : GL_NEAREST;
     GLenum min_filter = (state & GPU_SAMPLER_FILTER) ?
                             ((state & GPU_SAMPLER_MIPMAP) ? GL_LINEAR_MIPMAP_LINEAR : GL_LINEAR) :
@@ -577,7 +578,7 @@ void GLTexture::samplers_init()
 
     char sampler_name[128] = "\0\0";
     SNPRINTF(sampler_name,
-             "%s%s%s%s%s%s%s%s%s%s",
+             "%s%s%s%s%s%s%s%s%s%s%s",
              (state == GPU_SAMPLER_DEFAULT) ? "_default" : "",
              (state & GPU_SAMPLER_FILTER) ? "_filter" : "",
              (state & GPU_SAMPLER_MIPMAP) ? "_mipmap" : "",
@@ -585,6 +586,7 @@ void GLTexture::samplers_init()
              (state & GPU_SAMPLER_REPEAT_S) ? "S" : "",
              (state & GPU_SAMPLER_REPEAT_T) ? "T" : "",
              (state & GPU_SAMPLER_REPEAT_R) ? "R" : "",
+             (state & GPU_SAMPLER_MIRROR_REPEAT) ? "-mirror" : "",
              (state & GPU_SAMPLER_CLAMP_BORDER) ? "_clamp_border" : "",
              (state & GPU_SAMPLER_COMPARE) ? "_compare" : "",
              (state & GPU_SAMPLER_ANISO) ? "_aniso" : "");
@@ -612,7 +614,7 @@ void GLTexture::samplers_update()
 
   float aniso_filter = min_ff(max_anisotropy, U.anisotropic_filter);
 
-  for (int i = 0; i <= GPU_SAMPLER_ICON - 1; i++) {
+  for (int i = 0; i < GPU_SAMPLER_ICON; i++) {
     eGPUSamplerState state = static_cast<eGPUSamplerState>(i);
     if ((state & GPU_SAMPLER_ANISO) && (state & GPU_SAMPLER_MIPMAP)) {
       glSamplerParameterf(samplers_[i], GL_TEXTURE_MAX_ANISOTROPY_EXT, aniso_filter);

source/blender/makesdna/DNA_node_types.h

@@ -1754,6 +1754,7 @@ enum {
 #define SHD_IMAGE_EXTENSION_REPEAT 0
 #define SHD_IMAGE_EXTENSION_EXTEND 1
 #define SHD_IMAGE_EXTENSION_CLIP 2
+#define SHD_IMAGE_EXTENSION_MIRROR 3
 
 /* image texture */
 #define SHD_PROJ_FLAT 0

source/blender/makesrna/intern/rna_nodetree.c

@@ -4690,6 +4690,30 @@ static const EnumPropertyItem node_subsurface_method_items[] = {
      "automatically adjusted to match color textures"},
     {0, NULL, 0, NULL, NULL}};
 
+static const EnumPropertyItem prop_image_extension[] = {
+    {SHD_IMAGE_EXTENSION_REPEAT,
+     "REPEAT",
+     0,
+     "Repeat",
+     "Cause the image to repeat horizontally and vertically"},
+    {SHD_IMAGE_EXTENSION_EXTEND,
+     "EXTEND",
+     0,
+     "Extend",
+     "Extend by repeating edge pixels of the image"},
+    {SHD_IMAGE_EXTENSION_CLIP,
+     "CLIP",
+     0,
+     "Clip",
+     "Clip to image size and set exterior pixels as transparent"},
+    {SHD_IMAGE_EXTENSION_MIRROR,
+     "MIRROR",
+     0,
+     "Mirror",
+     "Repeatedly flip the image horizontally and vertically"},
+    {0, NULL, 0, NULL, NULL},
+};
+
 /* -- Common nodes ---------------------------------------------------------- */
 
 static void def_group_input(StructRNA *UNUSED(srna))
@@ -5431,25 +5455,6 @@ static void def_sh_tex_image(StructRNA *srna)
       {0, NULL, 0, NULL, NULL},
   };
 
-  static const EnumPropertyItem prop_image_extension[] = {
-      {SHD_IMAGE_EXTENSION_REPEAT,
-       "REPEAT",
-       0,
-       "Repeat",
-       "Cause the image to repeat horizontally and vertically"},
-      {SHD_IMAGE_EXTENSION_EXTEND,
-       "EXTEND",
-       0,
-       "Extend",
-       "Extend by repeating edge pixels of the image"},
-      {SHD_IMAGE_EXTENSION_CLIP,
-       "CLIP",
-       0,
-       "Clip",
-       "Clip to image size and set exterior pixels as transparent"},
-      {0, NULL, 0, NULL, NULL},
-  };
-
   PropertyRNA *prop;
 
   prop = RNA_def_property(srna, "image", PROP_POINTER, PROP_NONE);
@@ -5516,25 +5521,6 @@ static void def_geo_image_texture(StructRNA *srna)
       {0, NULL, 0, NULL, NULL},
   };
 
-  static const EnumPropertyItem prop_image_extension[] = {
-      {SHD_IMAGE_EXTENSION_REPEAT,
-       "REPEAT",
-       0,
-       "Repeat",
-       "Cause the image to repeat horizontally and vertically"},
-      {SHD_IMAGE_EXTENSION_EXTEND,
-       "EXTEND",
-       0,
-       "Extend",
-       "Extend by repeating edge pixels of the image"},
-      {SHD_IMAGE_EXTENSION_CLIP,
-       "CLIP",
-       0,
-       "Clip",
-       "Clip to image size and set exterior pixels as transparent"},
-      {0, NULL, 0, NULL, NULL},
-  };
-
   PropertyRNA *prop;
 
   RNA_def_struct_sdna_from(srna, "NodeGeometryImageTexture", "storage");

source/blender/nodes/geometry/nodes/node_geo_image_texture.cc

@@ -114,6 +114,15 @@ class ImageFieldsFunction : public fn::MultiFunction {
     return std::clamp(x, 0, width - 1);
   }
 
+  static int wrap_mirror(const int x, const int width)
+  {
+    const int m = std::abs(x + (x < 0)) % (2 * width);
+    if (m >= width) {
+      return 2 * width - m - 1;
+    }
+    return m;
+  }
+
   static float4 image_pixel_lookup(const ImBuf &ibuf, const int px, const int py)
   {
     if (px < 0 || py < 0 || px >= ibuf.x || py >= ibuf.y) {
@@ -173,6 +182,17 @@ class ImageFieldsFunction : public fn::MultiFunction {
         piy = wrap_clamp(piy, height);
         break;
       }
+      case SHD_IMAGE_EXTENSION_MIRROR: {
+        ppix = wrap_mirror(pix - 1, width);
+        ppiy = wrap_mirror(piy - 1, height);
+        nix = wrap_mirror(pix + 1, width);
+        niy = wrap_mirror(piy + 1, height);
+        nnix = wrap_mirror(pix + 2, width);
+        nniy = wrap_mirror(piy + 2, height);
+        pix = wrap_mirror(pix, width);
+        piy = wrap_mirror(piy, height);
+        break;
+      }
       default:
         return float4(0.0f, 0.0f, 0.0f, 0.0f);
     }
@@ -233,6 +253,12 @@ class ImageFieldsFunction : public fn::MultiFunction {
         piy = wrap_clamp(piy, height);
         break;
       }
+      case SHD_IMAGE_EXTENSION_MIRROR:
+        nix = wrap_mirror(pix + 1, width);
+        niy = wrap_mirror(piy + 1, height);
+        pix = wrap_mirror(pix, width);
+        piy = wrap_mirror(piy, height);
+        break;
       default:
       case SHD_IMAGE_EXTENSION_REPEAT:
         pix = wrap_periodic(pix, width);
@@ -282,6 +308,11 @@ class ImageFieldsFunction : public fn::MultiFunction {
         iy = wrap_clamp(iy, height);
         return image_pixel_lookup(ibuf, ix, iy);
       }
+      case SHD_IMAGE_EXTENSION_MIRROR: {
+        ix = wrap_mirror(ix, width);
+        iy = wrap_mirror(iy, height);
+        return image_pixel_lookup(ibuf, ix, iy);
+      }
       default:
         return float4(0.0f, 0.0f, 0.0f, 0.0f);
     }

source/blender/nodes/shader/nodes/node_shader_tex_image.cc

@@ -61,6 +61,9 @@ static int node_shader_gpu_tex_image(GPUMaterial *mat,
     case SHD_IMAGE_EXTENSION_CLIP:
       sampler_state |= GPU_SAMPLER_CLAMP_BORDER;
       break;
+    case SHD_IMAGE_EXTENSION_MIRROR:
+      sampler_state |= GPU_SAMPLER_REPEAT | GPU_SAMPLER_MIRROR_REPEAT;
+      break;
     default:
       break;
   }