Optimize disabling ARB_texture_rectangle

extensions/ANGLE_webgl_compatibility.txt

@@ -9,6 +9,7 @@ Name Strings
 Contributors
 
     Geoff Lang
+    James Darpinian
 
 Contact
 
@@ -25,7 +26,7 @@ Status
 
 Version
 
-    Version 2, November 28, 2016
+    Version 3, October 3, 2019
 
 Number
 
@@ -40,6 +41,8 @@ Dependencies
     Interacts with EGL_ANGLE_create_context_webgl_compatibility (or equivalent)
     extension.
 
+    Interacts with the ARB_texture_rectangle/ANGLE_texture_rectangle extension.
+
 Overview
 
     With this extension enabled, the OpenGL ES context will have additional
@@ -60,6 +63,16 @@ Additions to the OpenGL ES Specification
     the WebGL specification entitled "Differences Between WebGL and OpenGL ES
     2.0" and "Differences Between WebGL and OpenGL ES 3.0".
 
+    When the ANGLE_texture_rectangle extension is supported then Enable,
+    Disable, and IsEnabled accept the symbolic constant
+    TEXTURE_RECTANGLE_ANGLE, which controls whether ARB_texture_rectangle is
+    allowed to be used by shaders at compilation time. This is initially
+    enabled. WebGL implementations may want to use ARB_texture_rectangle when
+    compiling their own shaders but not expose the extension to WebGL user
+    shaders. This only affects shader compilation and not any other part of
+    the ANGLE_texture_rectangle extension, nor the behavior of already
+    compiled shaders.
+
 New State
 
     None
@@ -79,3 +92,4 @@ Revision History
       1   Sept 16, 2016  geofflang  Initial version
       2    Nov 28, 2016  geofflang  Break the extension requests into a
                                     separate extension.
+      3     Oct 3, 2019  jdarpinian Allow disabling ARB_texture_rectangle

include/GLSLANG/ShaderLang.h

@@ -323,6 +323,11 @@ const ShCompileOptions SH_DONT_TRANSLATE_UNIFORM_BLOCK_TO_STRUCTUREDBUFFER = UIN
 // implemented for the Vulkan backend.
 const ShCompileOptions SH_ADD_BRESENHAM_LINE_RASTER_EMULATION = UINT64_C(1) << 51;
 
+// This flag allows disabling ARB_texture_rectangle on a per-compile basis. This is necessary
+// for WebGL contexts becuase ARB_texture_rectangle may be necessary for the WebGL implementation
+// internally but shouldn't be exposed to WebGL user code.
+const ShCompileOptions SH_DISABLE_ARB_TEXTURE_RECTANGLE = UINT64_C(1) << 52;
+
 // Defines alternate strategies for implementing array index clamping.
 enum ShArrayIndexClampingStrategy
 {

src/compiler/translator/Compiler.cpp

@@ -352,6 +352,15 @@ TIntermBlock *TCompiler::compileTreeImpl(const char *const shaderStrings[],
     // Reset the extension behavior for each compilation unit.
     ResetExtensionBehavior(mExtensionBehavior);
 
+    if (compileOptions & SH_DISABLE_ARB_TEXTURE_RECTANGLE)
+    {
+        auto it = mExtensionBehavior.find(TExtension::ARB_texture_rectangle);
+        if (it != mExtensionBehavior.end())
+        {
+            mExtensionBehavior.erase(it);
+        }
+    }
+
     // If gl_DrawID is not supported, remove it from the available extensions
     // Currently we only allow emulation of gl_DrawID
     const bool glDrawIDSupported = (compileOptions & SH_EMULATE_GL_DRAW_ID) != 0u;

src/libANGLE/State.cpp

@@ -300,6 +300,7 @@ State::State(ContextID contextIn,
       mFramebufferSRGB(true),
       mRobustResourceInit(robustResourceInit),
       mProgramBinaryCacheEnabled(programBinaryCacheEnabled),
+      mTextureRectangleEnabled(true),
       mMaxShaderCompilerThreads(std::numeric_limits<GLuint>::max()),
       mOverlay(overlay)
 {}
@@ -940,6 +941,9 @@ void State::setEnableFeature(GLenum feature, bool enabled)
         case GL_FRAMEBUFFER_SRGB_EXT:
             setFramebufferSRGB(enabled);
             break;
+        case GL_TEXTURE_RECTANGLE_ANGLE:
+            mTextureRectangleEnabled = enabled;
+            break;
 
         // GLES1 emulation
         case GL_ALPHA_TEST:
@@ -1047,6 +1051,8 @@ bool State::getEnableFeature(GLenum feature) const
             return mRobustResourceInit;
         case GL_PROGRAM_CACHE_ENABLED_ANGLE:
             return mProgramBinaryCacheEnabled;
+        case GL_TEXTURE_RECTANGLE_ANGLE:
+            return mTextureRectangleEnabled;
 
         // GLES1 emulation
         case GL_ALPHA_TEST:
@@ -1920,6 +1926,9 @@ void State::getBooleanv(GLenum pname, GLboolean *params)
         case GL_PROGRAM_CACHE_ENABLED_ANGLE:
             *params = mProgramBinaryCacheEnabled ? GL_TRUE : GL_FALSE;
             break;
+        case GL_TEXTURE_RECTANGLE_ANGLE:
+            *params = mTextureRectangleEnabled ? GL_TRUE : GL_FALSE;
+            break;
         case GL_LIGHT_MODEL_TWO_SIDE:
             *params = IsLightModelTwoSided(&mGLES1State);
             break;

src/libANGLE/State.h

@@ -913,6 +913,9 @@ class State : angle::NonCopyable
     // GL_ANGLE_program_cache_control
     const bool mProgramBinaryCacheEnabled;
 
+    // GL_ANGLE_webgl_compatibility
+    bool mTextureRectangleEnabled;
+
     // GL_KHR_parallel_shader_compile
     GLuint mMaxShaderCompilerThreads;
 

src/libANGLE/renderer/gl/ShaderGL.cpp

@@ -250,6 +250,11 @@ std::shared_ptr<WaitableCompileEvent> ShaderGL::compile(const gl::Context *conte
         additionalOptions |= SH_INIT_OUTPUT_VARIABLES;
     }
 
+    if (isWebGL && !context->getState().getEnableFeature(GL_TEXTURE_RECTANGLE_ANGLE))
+    {
+        additionalOptions |= SH_DISABLE_ARB_TEXTURE_RECTANGLE;
+    }
+
     const angle::FeaturesGL &features = GetFeaturesGL(context);
 
     if (features.doWhileGLSLCausesGPUHang.enabled)

src/libANGLE/validationES2.cpp

@@ -879,6 +879,8 @@ bool ValidCap(const Context *context, GLenum cap, bool queryOnly)
         case GL_POINT_SPRITE_OES:
             return context->getClientVersion() < Version(2, 0) &&
                    context->getExtensions().pointSprite;
+        case GL_TEXTURE_RECTANGLE_ANGLE:
+            return context->getExtensions().webglCompatibility;
         default:
             return false;
     }