GPU: Add Texture::debug_clear

Clear uninitialized textures to NaN/debug values.
Enabled for `--debug-gpu` only.

Pull Request: https://projects.blender.org/blender/blender/pulls/113781

source/blender/draw/intern/DRW_gpu_wrapper.hh

@@ -64,6 +64,8 @@
 #include "draw_manager.h"
 #include "draw_texture_pool.h"
 
+#include "BKE_global.h"
+
 #include "BLI_math_vector_types.hh"
 #include "BLI_span.hh"
 #include "BLI_utildefines.h"
@@ -858,6 +860,25 @@ class Texture : NonCopyable {
     GPU_texture_clear(tx_, GPU_DATA_INT, &values[0]);
   }
 
+  /**
+   * Clear the texture to NaN for floats, or a to debug value for ints.
+   * (For debugging unitialized data issues)
+   */
+  void debug_clear()
+  {
+    if (GPU_texture_has_float_format(this->tx_) || GPU_texture_has_normalized_format(this->tx_)) {
+      this->clear(float4(NAN_FLT));
+    }
+    else if (GPU_texture_has_integer_format(this->tx_)) {
+      if (GPU_texture_has_signed_format(this->tx_)) {
+        this->clear(int4(0xF0F0F0F0));
+      }
+      else {
+        this->clear(uint4(0xF0F0F0F0));
+      }
+    }
+  }
+
   /**
    * Returns a buffer containing the texture data for the specified miplvl.
    * The memory block needs to be manually freed by MEM_freeN().
@@ -923,6 +944,9 @@ class Texture : NonCopyable {
     }
     if (tx_ == nullptr) {
       tx_ = create(w, h, d, mip_len, format, usage, data, layered, cubemap);
+      if (data == nullptr && (G.debug & G_DEBUG_GPU)) {
+        debug_clear();
+      }
       return true;
     }
     return false;
@@ -981,6 +1005,10 @@ class TextureFromPool : public Texture, NonMovable {
 
     this->tx_ = DRW_texture_pool_texture_acquire(
         DST.vmempool->texture_pool, UNPACK2(extent), format, usage);
+
+    if (G.debug & G_DEBUG_GPU) {
+      debug_clear();
+    }
   }
 
   void release()

source/blender/gpu/GPU_texture.h

@@ -990,6 +990,21 @@ bool GPU_texture_has_stencil_format(const GPUTexture *texture);
  */
 bool GPU_texture_has_integer_format(const GPUTexture *texture);
 
+/**
+ * Return true if the texture format is a float type.
+ */
+bool GPU_texture_has_float_format(const GPUTexture *tex);
+
+/**
+ * Return true if the texture format is an integer normalized type.
+ */
+bool GPU_texture_has_normalized_format(const GPUTexture *tex);
+
+/**
+ * Return true if the texture format is a signed type.
+ */
+bool GPU_texture_has_signed_format(const GPUTexture *tex);
+
 /**
  * Returns the pixel dimensions of a texture's mip-map level.
  * \a size is expected to be a pointer to a vector of dimension matching the texture's dimension

source/blender/gpu/intern/gpu_texture.cc

@@ -920,6 +920,22 @@ bool GPU_texture_has_integer_format(const GPUTexture *tex)
   return (reinterpret_cast<const Texture *>(tex)->format_flag_get() & GPU_FORMAT_INTEGER) != 0;
 }
 
+bool GPU_texture_has_float_format(const GPUTexture *tex)
+{
+  return (reinterpret_cast<const Texture *>(tex)->format_flag_get() & GPU_FORMAT_FLOAT) != 0;
+}
+
+bool GPU_texture_has_normalized_format(const GPUTexture *tex)
+{
+  return (reinterpret_cast<const Texture *>(tex)->format_flag_get() &
+          GPU_FORMAT_NORMALIZED_INTEGER) != 0;
+}
+
+bool GPU_texture_has_signed_format(const GPUTexture *tex)
+{
+  return (reinterpret_cast<const Texture *>(tex)->format_flag_get() & GPU_FORMAT_SIGNED) != 0;
+}
+
 bool GPU_texture_is_cube(const GPUTexture *tex)
 {
   return (reinterpret_cast<const Texture *>(tex)->type_get() & GPU_TEXTURE_CUBE) != 0;