source/blender/draw/engines/image/image_drawing_mode.hh

@@ -11,6 +11,8 @@
 
 #include "IMB_imbuf_types.h"
 
+#include "GPU_capabilities.h"
+
 #include "BLI_math_matrix_types.hh"
 #include "BLI_math_vector_types.hh"
 
@@ -509,7 +511,9 @@ template<typename TextureMethod> class ScreenSpaceDrawingMode : public AbstractD
             offset++;
           }
         }
-        IMB_gpu_clamp_half_float(&extracted_buffer);
+        if (!GPU_texture_clamp_to_half()) {
+          IMB_gpu_clamp_half_float(tile_buffer);
+        }
 
         GPU_texture_update_sub(texture,
                                GPU_DATA_FLOAT,
@@ -562,7 +566,9 @@ template<typename TextureMethod> class ScreenSpaceDrawingMode : public AbstractD
       }
       BKE_image_release_ibuf(image, tile_buffer, lock);
     }
-    IMB_gpu_clamp_half_float(&texture_buffer);
+    if (!GPU_texture_clamp_to_half()) {
+      IMB_gpu_clamp_half_float(&texture_buffer);
+    }
     GPU_texture_update(info.texture, GPU_DATA_FLOAT, texture_buffer.float_buffer.data);
     imb_freerectImbuf_all(&texture_buffer);
   }

source/blender/gpu/GPU_capabilities.h

@@ -55,6 +55,9 @@ bool GPU_shader_draw_parameters_support(void);
 bool GPU_mem_stats_supported(void);
 void GPU_mem_stats_get(int *totalmem, int *freemem);
 
+/* Check if the active GPU backend automatically clamp values to fit in 16F. */
+bool GPU_texture_clamp_to_half(void);
+
 /**
  * Return support for the active context + window.
  */

source/blender/gpu/intern/gpu_capabilities.cc

@@ -201,6 +201,11 @@ bool GPU_transform_feedback_support(void)
   return GCaps.transform_feedback_support;
 }
 
+bool GPU_texture_clamp_to_half(void)
+{
+  return GCaps.texture_clamp_to_half;
+}
+
 /** \} */
 
 /* -------------------------------------------------------------------- */

source/blender/gpu/intern/gpu_capabilities_private.hh

@@ -56,6 +56,7 @@ struct GPUCapabilities {
   bool use_hq_normals_workaround = false;
   bool clear_viewport_workaround = false;
   /* Vulkan related workarounds. */
+  bool texture_clamp_to_half = false;
 
   /* Metal related workarounds. */
   /* Minimum per-vertex stride in bytes (For a vertex buffer). */

source/blender/gpu/vulkan/vk_backend.cc

@@ -193,6 +193,7 @@ void VKBackend::capabilities_init(VKDevice &device)
   GCaps.compute_shader_support = true;
   GCaps.shader_storage_buffer_objects_support = true;
   GCaps.shader_image_load_store_support = true;
+  GCaps.texture_clamp_to_half = true;
 
   GCaps.max_texture_size = max_ii(limits.maxImageDimension1D, limits.maxImageDimension2D);
   GCaps.max_texture_3d_size = limits.maxImageDimension3D;