Reland image storage with fixes.

Revert "Revert "Initial OpenGL Image support.""

This reverts commit 59dc41175d99d0a31c046aec0c26c4d82a3a3574.

BUG=skia:

Change-Id: Ibe3c87ce7f746f065fdbcc5a518388cc291112f5
Reviewed-on: https://skia-review.googlesource.com/5131
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/src/gpu/glsl/GrGLSLShaderBuilder.h b/src/gpu/glsl/GrGLSLShaderBuilder.h
index b568369cca..983d50b926 100644
--- a/src/gpu/glsl/GrGLSLShaderBuilder.h
+++ b/src/gpu/glsl/GrGLSLShaderBuilder.h
@@ -25,7 +25,8 @@ public:
     GrGLSLShaderBuilder(GrGLSLProgramBuilder* program);
     virtual ~GrGLSLShaderBuilder() {}
 
-    typedef GrGLSLUniformHandler::SamplerHandle SamplerHandle;
+    using SamplerHandle      = GrGLSLUniformHandler::SamplerHandle;
+    using ImageStorageHandle = GrGLSLUniformHandler::ImageStorageHandle;
 
     /** Appends a 2D texture sample with projection if necessary. coordType must either be Vec2f or
         Vec3f. The latter is interpreted as projective texture coords. The vec length and swizzle
@@ -72,6 +73,11 @@ public:
     /** Version of above that appends the result to the shader code instead.*/
     void appendTexelFetch(SamplerHandle, const char* coordExpr);
 
+    /** Creates a string of shader code that performs an image load. */
+    void appendImageStorageLoad(SkString* out, ImageStorageHandle, const char* coordExpr);
+    /** Version of above that appends the result to the shader code instead. */
+    void appendImageStorageLoad(ImageStorageHandle, const char* coordExpr);
+
     /**
     * Adds a constant declaration to the top of the shader.
     */