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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 GrTextureDomainEffect_DEFINED
#define GrTextureDomainEffect_DEFINED
#include "GrSingleTextureEffect.h"
#include "gl/GrGLFragmentProcessor.h"
class GrGLProgramBuilder;
class GrGLShaderBuilder;
class GrInvariantOutput;
struct SkRect;
/**
* Limits a texture's lookup coordinates to a domain. Samples outside the domain are either clamped
* the edge of the domain or result in a vec4 of zeros (decal mode). The domain is clipped to
* normalized texture coords ([0,1]x[0,1] square). Bilinear filtering can cause texels outside the
* domain to affect the read value unless the caller considers this when calculating the domain.
*/
class GrTextureDomain {
public:
enum Mode {
// Ignore the texture domain rectangle.
kIgnore_Mode,
// Clamp texture coords to the domain rectangle.
kClamp_Mode,
// Treat the area outside the domain rectangle as fully transparent.
kDecal_Mode,
// Wrap texture coordinates. NOTE: filtering may not work as expected because Bilerp will
// read texels outside of the domain. We could perform additional texture reads and filter
// in the shader, but are not currently doing this for performance reasons
kRepeat_Mode,
kLastMode = kRepeat_Mode
};
static const int kModeCount = kLastMode + 1;
static const GrTextureDomain& IgnoredDomain() {
static const SkRect gDummyRect = {0, 0, 0, 0};
static const GrTextureDomain gDomain(gDummyRect, kIgnore_Mode);
return gDomain;
}
/**
* @param index Pass a value >= 0 if using multiple texture domains in the same effect.
* It is used to keep inserted variables from causing name collisions.
*/
GrTextureDomain(const SkRect& domain, Mode, int index = -1);
const SkRect& domain() const { return fDomain; }
Mode mode() const { return fMode; }
/* Computes a domain that bounds all the texels in texelRect. Note that with bilerp enabled
texels neighboring the domain may be read. */
static const SkRect MakeTexelDomain(const GrTexture* texture, const SkIRect& texelRect) {
SkScalar wInv = SK_Scalar1 / texture->width();
SkScalar hInv = SK_Scalar1 / texture->height();
SkRect result = {
texelRect.fLeft * wInv,
texelRect.fTop * hInv,
texelRect.fRight * wInv,
texelRect.fBottom * hInv
};
return result;
}
static const SkRect MakeTexelDomainForMode(const GrTexture* texture, const SkIRect& texelRect, Mode mode) {
// For Clamp mode, inset by half a texel.
SkScalar wInv = SK_Scalar1 / texture->width();
SkScalar hInv = SK_Scalar1 / texture->height();
SkScalar inset = (mode == kClamp_Mode && !texelRect.isEmpty()) ? SK_ScalarHalf : 0;
return SkRect::MakeLTRB(
(texelRect.fLeft + inset) * wInv,
(texelRect.fTop + inset) * hInv,
(texelRect.fRight - inset) * wInv,
(texelRect.fBottom - inset) * hInv
);
}
bool operator== (const GrTextureDomain& that) const {
return fMode == that.fMode && (kIgnore_Mode == fMode || fDomain == that.fDomain);
}
/**
* A GrGLProcessor subclass that corresponds to a GrProcessor subclass that uses GrTextureDomain
* should include this helper. It generates the texture domain GLSL, produces the part of the
* effect key that reflects the texture domain code, and performs the uniform uploads necessary
* for texture domains.
*/
class GLDomain {
public:
GLDomain() {
fPrevDomain[0] = SK_FloatNaN;
SkDEBUGCODE(fMode = (Mode) -1;)
}
/**
* Call this from GrGLProcessor::emitCode() to sample the texture W.R.T. the domain and
* mode.
*
* @param outcolor name of vec4 variable to hold the sampled color.
* @param inCoords name of vec2 variable containing the coords to be used with the domain.
* It is assumed that this is a variable and not an expression.
* @param inModulateColor if non-NULL the sampled color will be modulated with this
* expression before being written to outColor.
*/
void sampleTexture(GrGLShaderBuilder* builder,
const GrTextureDomain& textureDomain,
const char* outColor,
const SkString& inCoords,
const GrGLProcessor::TextureSampler sampler,
const char* inModulateColor = NULL);
/**
* Call this from GrGLProcessor::setData() to upload uniforms necessary for the texture
* domain. The rectangle is automatically adjusted to account for the texture's origin.
*/
void setData(const GrGLProgramDataManager& pdman, const GrTextureDomain& textureDomain,
GrSurfaceOrigin textureOrigin);
enum {
kDomainKeyBits = 2, // See DomainKey().
};
/**
* GrGLProcessor::GenKey() must call this and include the returned value in it's computed
* key. The returned will be limited to the lower kDomainKeyBits bits.
*/
static uint32_t DomainKey(const GrTextureDomain& domain) {
GR_STATIC_ASSERT(kModeCount <= 4);
return domain.mode();
}
private:
SkDEBUGCODE(Mode fMode;)
GrGLProgramDataManager::UniformHandle fDomainUni;
SkString fDomainName;
GrGLfloat fPrevDomain[4];
};
protected:
Mode fMode;
SkRect fDomain;
int fIndex;
typedef GrSingleTextureEffect INHERITED;
};
/**
* A basic texture effect that uses GrTextureDomain.
*/
class GrTextureDomainEffect : public GrSingleTextureEffect {
public:
static GrFragmentProcessor* Create(GrProcessorDataManager*,
GrTexture*,
const SkMatrix&,
const SkRect& domain,
GrTextureDomain::Mode,
GrTextureParams::FilterMode filterMode,
GrCoordSet = kLocal_GrCoordSet);
virtual ~GrTextureDomainEffect();
const char* name() const override { return "TextureDomain"; }
const GrTextureDomain& textureDomain() const { return fTextureDomain; }
protected:
GrTextureDomain fTextureDomain;
private:
GrTextureDomainEffect(GrProcessorDataManager*,
GrTexture*,
const SkMatrix&,
const SkRect& domain,
GrTextureDomain::Mode,
GrTextureParams::FilterMode,
GrCoordSet);
GrGLFragmentProcessor* onCreateGLInstance() const override;
void onGetGLProcessorKey(const GrGLSLCaps&, GrProcessorKeyBuilder*) const override;
bool onIsEqual(const GrFragmentProcessor&) const override;
void onComputeInvariantOutput(GrInvariantOutput* inout) const override;
GR_DECLARE_FRAGMENT_PROCESSOR_TEST;
typedef GrSingleTextureEffect INHERITED;
};
#endif
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