Exposed support for dynamically enabling extensions in command buffer...

gpu/command_buffer/service/feature_info.cc

Index: gpu/command_buffer/service/feature_info.cc
===================================================================
--- gpu/command_buffer/service/feature_info.cc	(revision 68245)
+++ gpu/command_buffer/service/feature_info.cc	(working copy)
@@ -12,7 +12,7 @@
 namespace gpu {
 namespace gles2 {
 
-FeatureInfo::FeatureInfo() {
+FeatureInfo::FeatureInfo() : requestable_extensions_dirty_(false) {
 }
 
 // Helps query for extensions.
@@ -89,8 +89,6 @@
       reinterpret_cast<const char*>(glGetString(GL_EXTENSIONS)),
       desired_features);
 
-  bool npot_ok = false;
-
   AddExtensionString("GL_CHROMIUM_map_sub");
   AddExtensionString("GL_CHROMIUM_copy_texture_to_parent_texture");
   AddExtensionString("GL_CHROMIUM_resource_safe");
@@ -101,6 +99,8 @@
   if (desired_features && ext.Desire("GL_CHROMIUM_webglsl")) {
     AddExtensionString("GL_CHROMIUM_webglsl");
     feature_flags_.chromium_webglsl = true;
+  } else {
+    AddRequestableExtensionString("GL_CHROMIUM_webglsl");
   }
 
   // Check if we should allow GL_EXT_texture_compression_dxt1 and
@@ -108,13 +108,12 @@
   bool enable_dxt1 = false;
   bool enable_s3tc = false;
 
-  if (ext.HaveAndDesire("GL_EXT_texture_compression_dxt1")) {
+  DoSimpleTestForEnablingExtension(
+      &ext, "GL_EXT_texture_compression_dxt1", &enable_dxt1);
+  DoSimpleTestForEnablingExtension(
+      &ext, "GL_EXT_texture_compression_s3tc", &enable_s3tc);
+  if (enable_s3tc)
     enable_dxt1 = true;
-  }
-  if (ext.HaveAndDesire("GL_EXT_texture_compression_s3tc")) {
-    enable_dxt1 = true;
-    enable_s3tc = true;
-  }
 
   if (enable_dxt1) {
     AddExtensionString("GL_EXT_texture_compression_dxt1");
@@ -133,7 +132,10 @@
   }
 
   // Check if we should enable GL_EXT_texture_filter_anisotropic.
-  if (ext.HaveAndDesire("GL_EXT_texture_filter_anisotropic")) {
+  bool enable_anisotropic = false;
+  DoSimpleTestForEnablingExtension(
+      &ext, "GL_EXT_texture_filter_anisotropic", &enable_anisotropic);
+  if (enable_anisotropic) {
     AddExtensionString("GL_EXT_texture_filter_anisotropic");
     validators_.texture_parameter.AddValue(
         GL_TEXTURE_MAX_ANISOTROPY_EXT);
@@ -148,21 +150,26 @@
   // GL_OES_packed_depth_stencil does not provide. Therefore we made up
   // GL_GOOGLE_depth_texture.
   bool enable_depth_texture = false;
-  if (ext.Desire("GL_GOOGLE_depth_texture") &&
-      (ext.Have("GL_ARB_depth_texture") ||
-       ext.Have("GL_OES_depth_texture"))) {
-    enable_depth_texture = true;
-    AddExtensionString("GL_GOOGLE_depth_texture");
-    validators_.texture_internal_format.AddValue(GL_DEPTH_COMPONENT);
-    validators_.texture_format.AddValue(GL_DEPTH_COMPONENT);
-    validators_.pixel_type.AddValue(GL_UNSIGNED_SHORT);
-    validators_.pixel_type.AddValue(GL_UNSIGNED_INT);
+  if (ext.Have("GL_ARB_depth_texture") ||
+      ext.Have("GL_OES_depth_texture")) {
+    if (ext.Desire("GL_GOOGLE_depth_texture")) {
+      enable_depth_texture = true;
+      AddExtensionString("GL_GOOGLE_depth_texture");
+      validators_.texture_internal_format.AddValue(GL_DEPTH_COMPONENT);
+      validators_.texture_format.AddValue(GL_DEPTH_COMPONENT);
+      validators_.pixel_type.AddValue(GL_UNSIGNED_SHORT);
+      validators_.pixel_type.AddValue(GL_UNSIGNED_INT);
+    } else {
+      AddRequestableExtensionString("GL_GOOGLE_depth_texture");
+    }
   }
+
   // TODO(gman): Add depth types fo ElementsPerGroup and BytesPerElement
-
-  if (ext.Desire("GL_OES_packed_depth_stencil") &&
-      (ext.Have("GL_EXT_packed_depth_stencil") ||
-       ext.Have("GL_OES_packed_depth_stencil"))) {
+  bool enable_packed_depth_stencil = false;
+  DoSimpleTestForEnablingExtension(
+      &ext, "GL_OES_packed_depth_stencil", "GL_EXT_packed_depth_stencil",
+      &enable_packed_depth_stencil);
+  if (enable_packed_depth_stencil) {
     AddExtensionString("GL_OES_packed_depth_stencil");
     if (enable_depth_texture) {
       validators_.texture_internal_format.AddValue(GL_DEPTH_STENCIL);
@@ -175,18 +182,22 @@
   bool enable_texture_format_bgra8888 = false;
   bool enable_read_format_bgra = false;
   // Check if we should allow GL_EXT_texture_format_BGRA8888
-  if (ext.Desire("GL_EXT_texture_format_BGRA8888") &&
-      (ext.Have("GL_EXT_texture_format_BGRA8888") ||
-       ext.Have("GL_APPLE_texture_format_BGRA8888"))) {
-    enable_texture_format_bgra8888 = true;
-  }
+  DoSimpleTestForEnablingExtension(
+      &ext,
+      "GL_EXT_texture_format_BGRA8888",
+      "GL_APPLE_texture_format_BGRA8888",
+      &enable_texture_format_bgra8888);
 
-  if (ext.HaveAndDesire("GL_EXT_bgra")) {
+  bool temp_bgra_variable = false;
+  DoSimpleTestForEnablingExtension(&ext, "GL_EXT_bgra", &temp_bgra_variable);
+  if (temp_bgra_variable) {
     enable_texture_format_bgra8888 = true;
     enable_read_format_bgra = true;
   }
 
-  if (ext.HaveAndDesire("GL_EXT_read_format_bgra")) {
+  DoSimpleTestForEnablingExtension(
+      &ext, "GL_EXT_read_format_bgra", &temp_bgra_variable);
+  if (temp_bgra_variable) {
     enable_read_format_bgra = true;
   }
 
@@ -202,11 +213,13 @@
   }
 
   // Check if we should allow GL_OES_texture_npot
-  if (ext.Desire("GL_OES_texture_npot") &&
-      (ext.Have("GL_ARB_texture_non_power_of_two") ||
-       ext.Have("GL_OES_texture_npot"))) {
+  bool npot_ok = false;
+
+  DoSimpleTestForEnablingExtension(
+      &ext, "GL_OES_texture_npot", "GL_ARB_texture_non_power_of_two",
+      &npot_ok);
+  if (npot_ok) {
     AddExtensionString("GL_OES_texture_npot");
-    npot_ok = true;
   }
 
   // Check if we should allow GL_OES_texture_float, GL_OES_texture_half_float,
@@ -215,26 +228,23 @@
   bool enable_texture_float_linear = false;
   bool enable_texture_half_float = false;
   bool enable_texture_half_float_linear = false;
-  if (ext.HaveAndDesire("GL_ARB_texture_float")) {
-    enable_texture_float = true;
-    enable_texture_float_linear = true;
-    enable_texture_half_float = true;
-    enable_texture_half_float_linear = true;
-  } else {
-    if (ext.HaveAndDesire("GL_OES_texture_float")) {
-      enable_texture_float = true;
-      if (ext.HaveAndDesire("GL_OES_texture_float_linear")) {
-        enable_texture_float_linear = true;
-      }
-    }
-    if (ext.HaveAndDesire("GL_OES_texture_half_float")) {
-      enable_texture_half_float = true;
-      if (ext.HaveAndDesire("GL_OES_texture_half_float_linear")) {
-        enable_texture_half_float_linear = true;
-      }
-    }
-  }
 
+  // Note that we do not allow requests for the GL_ARB_texture_float
+  // extension directly, since it implies the existence of internal
+  // formats that don't exist in GL_OES_texture_float.
+  DoSimpleTestForEnablingExtension(
+      &ext, "GL_OES_texture_float", "GL_ARB_texture_float",
+      &enable_texture_float);
+  DoSimpleTestForEnablingExtension(
+      &ext, "GL_OES_texture_float_linear", "GL_ARB_texture_float",
+      &enable_texture_float_linear);
+  DoSimpleTestForEnablingExtension(
+      &ext, "GL_OES_texture_half_float", "GL_ARB_texture_float",
+      &enable_texture_half_float);
+  DoSimpleTestForEnablingExtension(
+      &ext, "GL_OES_texture_half_float_linear", "GL_ARB_texture_float",
+      &enable_texture_half_float_linear);
+
   if (enable_texture_float) {
     validators_.pixel_type.AddValue(GL_FLOAT);
     AddExtensionString("GL_OES_texture_float");
@@ -289,12 +299,76 @@
   feature_flags_.npot_ok = npot_ok;
 }
 
+const std::string& FeatureInfo::RequestableExtensions() {
+  if (requestable_extensions_dirty_) {
+    requestable_extensions_ = "";
+    for (size_t i = 0; i < requestable_extensions_list_.size(); ++i) {
+      if (i > 0)
+        requestable_extensions_ += " ";
+      requestable_extensions_ += requestable_extensions_list_[i];
+    }
+  }
+  return requestable_extensions_;
+}
+
+void FeatureInfo::DoSimpleTestForEnablingExtension(
+    void* extensions_helper, const char* extension, bool* should_enable) {
+  *should_enable = false;
+  ExtensionHelper* helper = static_cast<ExtensionHelper*>(extensions_helper);
+  if (helper->Have(extension)) {
+    if (helper->Desire(extension)) {
+      *should_enable = true;
+    } else {
+      AddRequestableExtensionString(extension);
+    }
+  }
+}
+
+void FeatureInfo::DoSimpleTestForEnablingExtension(
+    void* extensions_helper, const char* extension,
+    const char* alternate_extension, bool* should_enable) {
+  *should_enable = false;
+  ExtensionHelper* helper = static_cast<ExtensionHelper*>(extensions_helper);
+  if (helper->Have(extension) ||
+      helper->Have(alternate_extension)) {
+    if (helper->Desire(extension)) {
+      *should_enable = true;
+    } else {
+      AddRequestableExtensionString(extension);
+    }
+  }
+}
+
 void FeatureInfo::AddExtensionString(const std::string& str) {
   if (extensions_.find(str) == std::string::npos) {
     extensions_ += (extensions_.empty() ? "" : " ") + str;
+    RemoveRequestableExtensionString(str);

[greggman, 2010/12/04 01:28:44]

Why remove added extensions? Shouldn't the list of requestable extensions
include extensions added?

   }
 }
 
+void FeatureInfo::AddRequestableExtensionString(const std::string& str) {
+  if (extensions_.find(str) == std::string::npos) {
+    for (size_t i = 0; i < requestable_extensions_list_.size(); ++i) {
+      if (requestable_extensions_list_[i] == str) {
+        break;
+      }
+    }
+    requestable_extensions_list_.push_back(str);
+    requestable_extensions_dirty_ = true;
+  }
+}
+
+void FeatureInfo::RemoveRequestableExtensionString(const std::string& str) {
+  for (size_t i = 0; i < requestable_extensions_list_.size(); ++i) {
+    if (requestable_extensions_list_[i] == str) {
+      requestable_extensions_list_.erase(
+          requestable_extensions_list_.begin() + i);
+      requestable_extensions_dirty_ = true;
+      break;
+    }
+  }
+}
+
 }  // namespace gles2
 }  // namespace gpu