Make GPU coord transforms automatic

src/gpu/gl/GrGLEffect.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrGLEffect_DEFINED
 #define GrGLEffect_DEFINED
 
 #include "GrBackendEffectFactory.h"
 #include "GrGLShaderBuilder.h"
 #include "GrGLShaderVar.h"
 #include "GrGLSL.h"
 
 class GrGLTexture;
 
 /** @file
     This file contains specializations for OpenGL of the shader stages declared in
     include/gpu/GrEffect.h. Objects of type GrGLEffect are responsible for emitting the
-    GLSL code that implements a GrEffect and for uploading uniforms at draw time. They also
-    must have a function:
+    GLSL code that implements a GrEffect and for uploading uniforms at draw time. If they don't
+    always emit the same GLSL code, they must have a function:
         static inline EffectKey GenKey(const GrDrawEffect&, const GrGLCaps&)
     that is used to implement a program cache. When two GrEffects produce the same key this means
     that their GrGLEffects would emit the same GLSL code.
 
     The GrGLEffect subclass must also have a constructor of the form:
         EffectSubclass::EffectSubclass(const GrBackendEffectFactory&, const GrDrawEffect&)
     The effect held by the GrDrawEffect is guaranteed to be of the type that generated the
     GrGLEffect subclass instance.
 
     These objects are created by the factory object returned by the GrEffect::getFactory().
 */
 
 class GrDrawEffect;
 
 class GrGLEffect {
 
 public:
     typedef GrBackendEffectFactory::EffectKey EffectKey;
 
     enum {
         kNoEffectKey = GrBackendEffectFactory::kNoEffectKey,
         // the number of bits in EffectKey available to GenKey
         kEffectKeyBits = GrBackendEffectFactory::kEffectKeyBits,
     };
 
+    typedef GrGLShaderBuilder::TransformedCoordsArray TransformedCoordsArray;
     typedef GrGLShaderBuilder::TextureSamplerArray TextureSamplerArray;
 
     GrGLEffect(const GrBackendEffectFactory&);
 
     virtual ~GrGLEffect();
 
     /** Called when the program stage should insert its code into the shaders. The code in each
         shader will be in its own block ({}) and so locally scoped names will not collide across
         stages.
 
@@ skipping 11 matching lines @@
                             the effect to communicate back similar known info about its output.
         @param samplers     One entry for each GrTextureAccess of the GrEffect that generated the
                             GrGLEffect. These can be passed to the builder to emit texture
                             reads in the generated code.
         */
     virtual void emitCode(GrGLShaderBuilder* builder,
                           const GrDrawEffect& drawEffect,
                           EffectKey key,
                           const char* outputColor,
                           const char* inputColor,
+                          const TransformedCoordsArray& coords,
                           const TextureSamplerArray& samplers) = 0;
 
     /** A GrGLEffect instance can be reused with any GrEffect that produces the same stage
         key; this function reads data from a stage and uploads any uniform variables required
         by the shaders created in emitCode(). The GrEffect installed in the GrEffectStage is
         guaranteed to be of the same type that created this GrGLEffect and to have an identical
         EffectKey as the one that created this GrGLEffect. Effects that use local coords have
         to consider whether the GrEffectStage's coord change matrix should be used. When explicit
         local coordinates are used it can be ignored. */
     virtual void setData(const GrGLUniformManager&, const GrDrawEffect&);
 
     const char* name() const { return fFactory.name(); }
 
+    static inline EffectKey GenKey(const GrDrawEffect&, const GrGLCaps&) { return 0; }

[bsalomon, 2013/09/27 20:04:25]

does this get called?

[Chris Dalton, 2013/09/27 23:33:45]

Yeah. A lot of effects don't need to make their own GenKey method anymore.
(That's why I modified the comment at the top to say "If they don't always emit
the same GLSL code," they must have a GenKey function ...)

[bsalomon, 2013/09/30 13:24:41]

Oh wow. I don't think I ever seen this pattern of static function overloading,
but it makes sense.

+
     static EffectKey GenTextureKey(const GrDrawEffect&, const GrGLCaps&);
+    static EffectKey GenTransformKey(const GrDrawEffect&);
     static EffectKey GenAttribKey(const GrDrawEffect& stage);
 
 protected:
     const GrBackendEffectFactory& fFactory;
 };
 
 #endif