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* 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 GrGLProcessor_DEFINED
#define GrGLProcessor_DEFINED
#include "GrGLProgramDataManager.h"
#include "GrProcessor.h"
#include "GrTextureAccess.h"
/** @file
This file contains specializations for OpenGL of the shader stages declared in
include/gpu/GrProcessor.h. Objects of type GrGLProcessor are responsible for emitting the
GLSL code that implements a GrProcessor and for uploading uniforms at draw time. If they don't
always emit the same GLSL code, they must have a function:
static inline void GenKey(const GrProcessor&, const GrGLSLCaps&, GrProcessorKeyBuilder*)
that is used to implement a program cache. When two GrProcessors produce the same key this means
that their GrGLProcessors would emit the same GLSL code.
The GrGLProcessor subclass must also have a constructor of the form:
ProcessorSubclass::ProcessorSubclass(const GrBackendProcessorFactory&, const GrProcessor&)
These objects are created by the factory object returned by the GrProcessor::getFactory().
// TODO delete this and make TextureSampler its own thing
class GrGLProcessor {
typedef GrGLProgramDataManager::UniformHandle UniformHandle;
* Passed to GrGLProcessors so they can add transformed coordinates to their shader code.
typedef GrShaderVar TransformedCoords;
typedef SkTArray<GrShaderVar> TransformedCoordsArray;
* Passed to GrGLProcessors so they can add texture reads to their shader code.
class TextureSampler {
TextureSampler(UniformHandle uniform, const GrTextureAccess& access)
: fSamplerUniform(uniform)
, fConfigComponentMask(GrPixelConfigComponentMask(access.getTexture()->config())) {
SkASSERT(0 != fConfigComponentMask);
memcpy(fSwizzle, access.getSwizzle(), 5);
// bitfield of GrColorComponentFlags present in the texture's config.
uint32_t configComponentMask() const { return fConfigComponentMask; }
// this is .abcd
const char* swizzle() const { return fSwizzle; }
UniformHandle fSamplerUniform;
uint32_t fConfigComponentMask;
char fSwizzle[5];
friend class GrGLShaderBuilder;
typedef SkTArray<TextureSampler> TextureSamplerArray;
class GrGLFPBuilder;
class GrGLFragmentProcessor {
GrGLFragmentProcessor() {}
virtual ~GrGLFragmentProcessor() {}
typedef GrGLProgramDataManager::UniformHandle UniformHandle;
typedef GrGLProcessor::TransformedCoordsArray TransformedCoordsArray;
typedef GrGLProcessor::TextureSamplerArray TextureSamplerArray;
/** 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
@param builder Interface used to emit code in the shaders.
@param processor The processor that generated this program stage.
@param key The key that was computed by GenKey() from the generating GrProcessor.
@param outputColor A predefined vec4 in the FS in which the stage should place its output
color (or coverage).
@param inputColor A vec4 that holds the input color to the stage in the FS. This may be
NULL in which case the implied input is solid white (all ones).
TODO: Better system for communicating optimization info (e.g. input
color is solid white, trans black, known to be opaque, etc.) that allows
the processor to communicate back similar known info about its output.
@param samplers Contains one entry for each GrTextureAccess of the GrProcessor. These
can be passed to the builder to emit texture reads in the generated
TODO this should take a struct
virtual void emitCode(GrGLFPBuilder* builder,
const GrFragmentProcessor&,
const char* outputColor,
const char* inputColor,
const TransformedCoordsArray& coords,
const TextureSamplerArray& samplers) = 0;
/** A GrGLFragmentProcessor instance can be reused with any GrFragmentProcessor that produces
the same stage key; this function reads data from a GrFragmentProcessor and uploads any
uniform variables required by the shaders created in emitCode(). The GrFragmentProcessor
parameter is guaranteed to be of the same type that created this GrGLFragmentProcessor and
to have an identical processor key as the one that created this GrGLFragmentProcessor. */
// TODO update this to pass in GrFragmentProcessor
virtual void setData(const GrGLProgramDataManager&, const GrProcessor&) {}
static void GenKey(const GrProcessor&, const GrGLSLCaps&, GrProcessorKeyBuilder*) {}
typedef GrGLProcessor INHERITED;