[Impeller] OpenGLES: Ensure frag/vert textures are bound with unique …

…texture units. (#47218) The fragment shader texture bindings will smash into the texture units used for the vertex shader bindings if the vertex and fragment shaders both have textures. Entities doesn't use any pipelines that tickle this case.
flutter · Nov 1, 2023 · 787f9ef · 787f9ef
1 parent c562fd7
commit 787f9ef
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Showing 2 changed files with 22 additions and 15 deletions.
diff --git a/impeller/renderer/backend/gles/buffer_bindings_gles.cc b/impeller/renderer/backend/gles/buffer_bindings_gles.cc
@@ -155,11 +155,15 @@ bool BufferBindingsGLES::BindUniformData(const ProcTableGLES& gl,
     }
   }
 
-  if (!BindTextures(gl, vertex_bindings, ShaderStage::kVertex)) {
+  std::optional<size_t> next_unit_index =
+      BindTextures(gl, vertex_bindings, ShaderStage::kVertex);
+  if (!next_unit_index.has_value()) {
     return false;
   }
 
-  if (!BindTextures(gl, fragment_bindings, ShaderStage::kFragment)) {
+  if (!BindTextures(gl, fragment_bindings, ShaderStage::kFragment,
+                    *next_unit_index)
+           .has_value()) {
     return false;
   }
 
@@ -334,20 +338,22 @@ bool BufferBindingsGLES::BindUniformBuffer(const ProcTableGLES& gl,
   return true;
 }
 
-bool BufferBindingsGLES::BindTextures(const ProcTableGLES& gl,
-                                      const Bindings& bindings,
-                                      ShaderStage stage) {
-  size_t active_index = 0;
+std::optional<size_t> BufferBindingsGLES::BindTextures(
+    const ProcTableGLES& gl,
+    const Bindings& bindings,
+    ShaderStage stage,
+    size_t unit_start_index) {
+  size_t active_index = unit_start_index;
   for (const auto& data : bindings.sampled_images) {
     const auto& texture_gles = TextureGLES::Cast(*data.second.texture.resource);
     if (data.second.texture.GetMetadata() == nullptr) {
       VALIDATION_LOG << "No metadata found for texture binding.";
-      return false;
+      return std::nullopt;
     }
 
     auto location = ComputeTextureLocation(data.second.texture.GetMetadata());
     if (location == -1) {
-      return false;
+      return std::nullopt;
     }
 
     //--------------------------------------------------------------------------
@@ -356,15 +362,15 @@ bool BufferBindingsGLES::BindTextures(const ProcTableGLES& gl,
     if (active_index >= gl.GetCapabilities()->GetMaxTextureUnits(stage)) {
       VALIDATION_LOG << "Texture units specified exceed the capabilities for "
                         "this shader stage.";
-      return false;
+      return std::nullopt;
     }
     gl.ActiveTexture(GL_TEXTURE0 + active_index);
 
     //--------------------------------------------------------------------------
     /// Bind the texture.
     ///
     if (!texture_gles.Bind()) {
-      return false;
+      return std::nullopt;
     }
 
     //--------------------------------------------------------------------------
@@ -373,7 +379,7 @@ bool BufferBindingsGLES::BindTextures(const ProcTableGLES& gl,
     ///
     const auto& sampler_gles = SamplerGLES::Cast(*data.second.sampler.resource);
     if (!sampler_gles.ConfigureBoundTexture(texture_gles, gl)) {
-      return false;
+      return std::nullopt;
     }
 
     //--------------------------------------------------------------------------
@@ -386,7 +392,7 @@ bool BufferBindingsGLES::BindTextures(const ProcTableGLES& gl,
     ///
     active_index++;
   }
-  return true;
+  return active_index;
 }
 
 }  // namespace impeller
diff --git a/impeller/renderer/backend/gles/buffer_bindings_gles.h b/impeller/renderer/backend/gles/buffer_bindings_gles.h
@@ -70,9 +70,10 @@ class BufferBindingsGLES {
                          Allocator& transients_allocator,
                          const BufferResource& buffer);
 
-  bool BindTextures(const ProcTableGLES& gl,
-                    const Bindings& bindings,
-                    ShaderStage stage);
+  std::optional<size_t> BindTextures(const ProcTableGLES& gl,
+                                     const Bindings& bindings,
+                                     ShaderStage stage,
+                                     size_t unit_start_index = 0);
 
   BufferBindingsGLES(const BufferBindingsGLES&) = delete;