Add arb_texture_rectangle support properly in GLES3 shaders

src/gpu/gl/GrGLCaps.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "GrGLCaps.h"
 
@@ skipping 208 matching lines @@
     if (ctxInfo.hasExtension("GL_OES_EGL_image_external")) {
         if (ctxInfo.glslGeneration() == k110_GrGLSLGeneration) {
             fExternalTextureSupport = true;
         } else if (ctxInfo.hasExtension("GL_OES_EGL_image_external_essl3") ||
                    ctxInfo.hasExtension("OES_EGL_image_external_essl3")) {
             // At least one driver has been found that has this extension without the "GL_" prefix.
             fExternalTextureSupport = true;
         }
     }
 
-    if ((kGL_GrGLStandard == standard && version >= GR_GL_VER(3, 1)) ||
-        ctxInfo.hasExtension("GL_ARB_texture_rectangle")) {
-        // We also require textureSize() support for rectangle 2D samplers which was added in GLSL
-        // 1.40.
-        if (ctxInfo.glslGeneration() >= k140_GrGLSLGeneration) {
-            fRectangleTextureSupport = true;
-        }
-    }
-
     if (kGL_GrGLStandard == standard) {
+        if (version >= GR_GL_VER(3, 1) || ctxInfo.hasExtension("GL_ARB_texture_rectangle")) {
+            // We also require textureSize() support for rectangle 2D samplers which was added in
+            // GLSL 1.40.
+            if (ctxInfo.glslGeneration() >= k140_GrGLSLGeneration) {
+                fRectangleTextureSupport = true;
+            }
+        }
+    } else {
+        // Command buffer exposes this in GL ES context for Chromium reasons,
+        // but it should not be used. Also, at the time of writing command buffer
+        // lacks TexImage2D support and ANGLE lacks GL ES 3.0 support.
+        fRectangleTextureSupport = ctxInfo.hasExtension("GL_ARB_texture_rectangle");
+    }
+
+    if (kGL_GrGLStandard == standard) {
         if (version >= GR_GL_VER(3,3) || ctxInfo.hasExtension("GL_ARB_texture_swizzle")) {
             fTextureSwizzleSupport = true;
         }
     } else {
         if (version >= GR_GL_VER(3,0)) {
             fTextureSwizzleSupport = true;
         }
     }
 
 #ifdef SK_BUILD_FOR_WIN
@@ skipping 376 matching lines @@
         glslCaps->fSecondaryOutputExtensionString = "GL_EXT_blend_func_extended";
     }
 
     if (fExternalTextureSupport) {
         if (ctxInfo.glslGeneration() == k110_GrGLSLGeneration) {
             glslCaps->fExternalTextureExtensionString = "GL_OES_EGL_image_external";
         } else {
             glslCaps->fExternalTextureExtensionString = "GL_OES_EGL_image_external_essl3";
         }
     }
+    if (fRectangleTextureSupport) {
+        if (kGL_GrGLStandard == standard) {
+            // "Conceptually, you can consider the declaration
+            // #extension GL_ARB_texture_rectangle : require, to allow support
+            // for texture rectangles, to be implicitly prepended to every
+            // GLSL shader when ARB_texture_rectangle is advertised."
+            // -->  glslCaps->fRectangleTextureExtensionString == nullptr.
+            glslCaps->fRectangleTextureUseUnifiedTextureFunctionName =
+                    ctxInfo.glslGeneration() >= k130_GrGLSLGeneration;
+        } else {
+            //"All future GLSL extensions should follow the "OpenGL Shading Language
+            // Extension Conventions" however."
+            // We imagine ANGLE implementation allowing ARB_texture_rectangle being
+            // based on an extension text requires the extension string.
+            glslCaps->fRectangleTextureExtensionString = "GL_ARB_texture_rectangle";
+            glslCaps->fRectangleTextureUseUnifiedTextureFunctionName =
+                    ctxInfo.glslGeneration() == k330_GrGLSLGeneration;
+        }
+    }
 
     // The Tegra3 compiler will sometimes never return if we have min(abs(x), 1.0), so we must do
     // the abs first in a separate expression.
     if (kTegra3_GrGLRenderer == ctxInfo.renderer()) {
         glslCaps->fCanUseMinAndAbsTogether = false;
     }
 
     // On Intel GPU there is an issue where it reads the second argument to atan "- %s.x" as an int
     // thus must us -1.0 * %s.x to work correctly
     if (kIntel_GrGLVendor == ctxInfo.vendor()) {
@@ skipping 1019 matching lines @@
         for (int j = 0; j < kExternalFormatUsageCnt; ++j) {
             SkASSERT(defaultEntry.fFormats.fExternalFormat[j] !=
                      fConfigTable[i].fFormats.fExternalFormat[j]);
         }
         SkASSERT(defaultEntry.fFormats.fExternalType != fConfigTable[i].fFormats.fExternalType);
     }
 #endif
 }
 
 void GrGLCaps::onApplyOptionsOverrides(const GrContextOptions& options) {}