[Impeller] Add debug ToString methods to render targets.

Also fixes and issue where SPrintF would only consider strings 64 bytes
or smaller.

Author: chinmaygarde

impeller/base/base_unittests.cc

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #include "flutter/testing/testing.h"
+#include "impeller/base/strings.h"
 #include "impeller/base/thread.h"
 
 namespace impeller {
@@ -68,5 +69,12 @@ TEST(ThreadTest, CanCreateRWMutexLock) {
   // f.mtx.UnlockReader(); <--- Static analysis error.
 }
 
+TEST(StringsTest, CanSPrintF) {
+  ASSERT_EQ(SPrintF("%sx%d", "Hello", 12), "Hellox12");
+  ASSERT_EQ(SPrintF(""), "");
+  ASSERT_EQ(SPrintF("Hello"), "Hello");
+  ASSERT_EQ(SPrintF("%sx%.2f", "Hello", 12.122222), "Hellox12.12");
+}
+
 }  // namespace testing
 }  // namespace impeller

impeller/base/strings.cc

@@ -10,12 +10,21 @@ namespace impeller {
 
 IMPELLER_PRINTF_FORMAT(1, 2)
 std::string SPrintF(const char* format, ...) {
+  std::string ret_val;
   va_list list;
+  va_list list2;
   va_start(list, format);
-  char buffer[64] = {0};
-  ::vsnprintf(buffer, sizeof(buffer), format, list);
+  va_copy(list2, list);
+  if (auto string_length = ::vsnprintf(nullptr, 0, format, list);
+      string_length >= 0) {
+    auto buffer = reinterpret_cast<char*>(::malloc(string_length + 1));
+    ::vsnprintf(buffer, string_length + 1, format, list2);
+    ret_val = std::string{buffer, static_cast<size_t>(string_length)};
+    ::free(buffer);
+  }
+  va_end(list2);
   va_end(list);
-  return buffer;
+  return ret_val;
 }
 
 bool HasPrefix(const std::string& string, const std::string& prefix) {

impeller/core/formats.cc

@@ -101,4 +101,44 @@ std::string TextureUsageMaskToString(TextureUsageMask mask) {
   return stream.str();
 }
 
+std::string AttachmentToString(const Attachment& attachment) {
+  std::stringstream stream;
+  if (attachment.texture) {
+    stream << "Texture=("
+           << TextureDescriptorToString(
+                  attachment.texture->GetTextureDescriptor())
+           << "),";
+  }
+  if (attachment.resolve_texture) {
+    stream << "ResolveTexture=("
+           << TextureDescriptorToString(
+                  attachment.resolve_texture->GetTextureDescriptor())
+           << "),";
+  }
+  stream << "LoadAction=" << LoadActionToString(attachment.load_action) << ",";
+  stream << "StoreAction=" << StoreActionToString(attachment.store_action);
+  return stream.str();
+}
+
+std::string ColorAttachmentToString(const ColorAttachment& color) {
+  std::stringstream stream;
+  stream << AttachmentToString(color) << ",";
+  stream << "ClearColor=(" << ColorToString(color.clear_color) << ")";
+  return stream.str();
+}
+
+std::string DepthAttachmentToString(const DepthAttachment& depth) {
+  std::stringstream stream;
+  stream << AttachmentToString(depth) << ",";
+  stream << "ClearDepth=" << SPrintF("%.2f", depth.clear_depth);
+  return stream.str();
+}
+
+std::string StencilAttachmentToString(const StencilAttachment& stencil) {
+  std::stringstream stream;
+  stream << AttachmentToString(stencil) << ",";
+  stream << "ClearStencil=" << stencil.clear_stencil;
+  return stream.str();
+}
+
 }  // namespace impeller

impeller/core/formats.h

@@ -110,6 +110,42 @@ enum class PixelFormat {
   kD32FloatS8UInt,
 };
 
+constexpr const char* PixelFormatToString(PixelFormat format) {
+  switch (format) {
+    case PixelFormat::kUnknown:
+      return "Unknown";
+    case PixelFormat::kA8UNormInt:
+      return "A8UNormInt";
+    case PixelFormat::kR8UNormInt:
+      return "R8UNormInt";
+    case PixelFormat::kR8G8UNormInt:
+      return "R8G8UNormInt";
+    case PixelFormat::kR8G8B8A8UNormInt:
+      return "R8G8B8A8UNormInt";
+    case PixelFormat::kR8G8B8A8UNormIntSRGB:
+      return "R8G8B8A8UNormIntSRGB";
+    case PixelFormat::kB8G8R8A8UNormInt:
+      return "B8G8R8A8UNormInt";
+    case PixelFormat::kB8G8R8A8UNormIntSRGB:
+      return "B8G8R8A8UNormIntSRGB";
+    case PixelFormat::kR32G32B32A32Float:
+      return "R32G32B32A32Float";
+    case PixelFormat::kR16G16B16A16Float:
+      return "R16G16B16A16Float";
+    case PixelFormat::kB10G10R10XR:
+      return "B10G10R10XR";
+    case PixelFormat::kB10G10R10XRSRGB:
+      return "B10G10R10XRSRGB";
+    case PixelFormat::kB10G10R10A10XR:
+      return "B10G10R10A10XR";
+    case PixelFormat::kS8UInt:
+      return "S8UInt";
+    case PixelFormat::kD32FloatS8UInt:
+      return "D32FloatS8UInt";
+  }
+  FML_UNREACHABLE();
+}
+
 enum class BlendFactor {
   kZero,
   kOne,
@@ -147,6 +183,30 @@ enum class StoreAction {
   kStoreAndMultisampleResolve,
 };
 
+constexpr const char* LoadActionToString(LoadAction action) {
+  switch (action) {
+    case LoadAction::kDontCare:
+      return "DontCare";
+    case LoadAction::kLoad:
+      return "Load";
+    case LoadAction::kClear:
+      return "Clear";
+  }
+}
+
+constexpr const char* StoreActionToString(StoreAction action) {
+  switch (action) {
+    case StoreAction::kDontCare:
+      return "DontCare";
+    case StoreAction::kStore:
+      return "Store";
+    case StoreAction::kMultisampleResolve:
+      return "MultisampleResolve";
+    case StoreAction::kStoreAndMultisampleResolve:
+      return "StoreAndMultisampleResolve";
+  }
+}
+
 constexpr bool CanClearAttachment(LoadAction action) {
   switch (action) {
     case LoadAction::kLoad:
@@ -530,6 +590,14 @@ struct StencilAttachment : public Attachment {
   uint32_t clear_stencil = 0;
 };
 
+std::string AttachmentToString(const Attachment& attachment);
+
+std::string ColorAttachmentToString(const ColorAttachment& color);
+
+std::string DepthAttachmentToString(const DepthAttachment& depth);
+
+std::string StencilAttachmentToString(const StencilAttachment& stencil);
+
 }  // namespace impeller
 
 namespace std {

impeller/core/texture_descriptor.cc

@@ -4,8 +4,20 @@
 
 #include "impeller/core/texture_descriptor.h"
 
+#include <sstream>
+
 namespace impeller {
 
-//
+std::string TextureDescriptorToString(const TextureDescriptor& desc) {
+  std::stringstream stream;
+  stream << "StorageMode=" << StorageModeToString(desc.storage_mode) << ",";
+  stream << "Type=" << TextureTypeToString(desc.type) << ",";
+  stream << "Format=" << PixelFormatToString(desc.format) << ",";
+  stream << "Size=" << desc.size << ",";
+  stream << "MipCount=" << desc.mip_count << ",";
+  stream << "SampleCount=" << static_cast<size_t>(desc.sample_count) << ",";
+  stream << "Compression=" << CompressionTypeToString(desc.compression_type);
+  return stream.str();
+}
 
 }  // namespace impeller

impeller/core/texture_descriptor.h

@@ -21,6 +21,17 @@ enum class CompressionType {
   kLossless,
   kLossy,
 };
+
+constexpr const char* CompressionTypeToString(CompressionType type) {
+  switch (type) {
+    case CompressionType::kLossless:
+      return "Lossless";
+    case CompressionType::kLossy:
+      return "Lossy";
+  }
+  FML_UNREACHABLE();
+}
+
 //------------------------------------------------------------------------------
 /// @brief      A lightweight object that describes the attributes of a texture
 ///             that can then used an allocator to create that texture.
@@ -63,4 +74,6 @@ struct TextureDescriptor {
   }
 };
 
+std::string TextureDescriptorToString(const TextureDescriptor& desc);
+
 }  // namespace impeller

impeller/geometry/color.cc

@@ -8,6 +8,7 @@
 #include <cmath>
 #include <sstream>
 
+#include "impeller/base/strings.h"
 #include "impeller/geometry/constants.h"
 #include "impeller/geometry/scalar.h"
 #include "impeller/geometry/vector.h"
@@ -360,4 +361,13 @@ Color Color::BlendColor(const Color& src,
   }
 }
 
+std::string ColorToString(const Color& color) {
+  return SPrintF("R=%.1f,G=%.1f,B=%.1f,A=%.1f",  //
+                 color.red,                      //
+                 color.green,                    //
+                 color.blue,                     //
+                 color.alpha                     //
+  );
+}
+
 }  // namespace impeller

impeller/geometry/color.h

@@ -797,6 +797,8 @@ struct Color {
   constexpr bool IsOpaque() const { return alpha == 1.0f; }
 };
 
+std::string ColorToString(const Color& color);
+
 /**
  *  Represents a color by its constituent hue, saturation, brightness and alpha
  */

impeller/renderer/render_target.cc

@@ -4,6 +4,8 @@
 
 #include "impeller/renderer/render_target.h"
 
+#include <sstream>
+
 #include "impeller/base/strings.h"
 #include "impeller/base/validation.h"
 #include "impeller/core/allocator.h"
@@ -59,21 +61,27 @@ bool RenderTarget::IsValid() const {
 
       if (texture_type != attachment.texture->GetTextureDescriptor().type) {
         passes_type_validation = false;
+        VALIDATION_LOG << "Render target has incompatible texture types: "
+                       << TextureTypeToString(texture_type.value()) << " != "
+                       << TextureTypeToString(
+                              attachment.texture->GetTextureDescriptor().type)
+                       << " on target " << ToString();
         return false;
       }
 
       if (sample_count !=
           attachment.texture->GetTextureDescriptor().sample_count) {
         passes_type_validation = false;
+        VALIDATION_LOG << "Render target (" << ToString()
+                       << ") has incompatible sample counts.";
+
         return false;
       }
 
       return true;
     };
     IterateAllAttachments(iterator);
     if (!passes_type_validation) {
-      VALIDATION_LOG << "Render target texture types are not of the same type "
-                        "and sample count.";
       return false;
     }
   }
@@ -370,4 +378,24 @@ size_t RenderTarget::GetTotalAttachmentCount() const {
   return count;
 }
 
+std::string RenderTarget::ToString() const {
+  std::stringstream stream;
+
+  for (const auto& [index, color] : colors_) {
+    stream << SPrintF("Color[%zu]=(%s)", index,
+                      ColorAttachmentToString(color).c_str());
+  }
+  if (depth_) {
+    stream << ",";
+    stream << SPrintF("Depth=(%s)",
+                      DepthAttachmentToString(depth_.value()).c_str());
+  }
+  if (stencil_) {
+    stream << ",";
+    stream << SPrintF("Stencil=(%s)",
+                      StencilAttachmentToString(stencil_.value()).c_str());
+  }
+  return stream.str();
+}
+
 }  // namespace impeller

impeller/renderer/render_target.h

@@ -109,6 +109,8 @@ class RenderTarget final {
   void IterateAllAttachments(
       const std::function<bool(const Attachment& attachment)>& iterator) const;
 
+  std::string ToString() const;
+
  private:
   std::map<size_t, ColorAttachment> colors_;
   std::optional<DepthAttachment> depth_;