include/gpu/GrSamplerState.h - platform/external/skia - Git at Google


 /*
  * Copyright 2010 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */


 #ifndef GrSamplerState_DEFINED
 #define GrSamplerState_DEFINED

 #include "GrTypes.h"
 #include "GrMatrix.h"

 #define MAX_KERNEL_WIDTH 25

 class GrSamplerState {
 public:
     enum Filter {
         /**
          * Read the closest src texel to the sample position
          */
         kNearest_Filter,
         /**
          * Blend between closest 4 src texels to sample position (tent filter)
          */
         kBilinear_Filter,
         /**
          * Average of 4 bilinear filterings spaced +/- 1 texel from sample
          * position in x and y. Intended for averaging 16 texels in a downsample
          * pass. (rasterizing such that texture samples fall exactly halfway
          * between texels in x and y spaced 4 texels apart.) Only supported
          * on shader backends.
          */
         k4x4Downsample_Filter,
         /**
          * Apply a separable convolution kernel.
          */
         kConvolution_Filter,
         /**
          * Apply a dilate filter (max over a 1D radius).
          */
         kDilate_Filter,
         /**
          * Apply an erode filter (min over a 1D radius).
          */
         kErode_Filter,

         kDefault_Filter = kNearest_Filter
     };

     /**
      * The intepretation of the texture matrix depends on the sample mode. The
      * texture matrix is applied both when the texture coordinates are explicit
      * and  when vertex positions are used as texture  coordinates. In the latter
      * case the texture matrix is applied to the pre-view-matrix position
      * values.
      *
      * kNormal_SampleMode
      *  The post-matrix texture coordinates are in normalize space with (0,0) at
      *  the top-left and (1,1) at the bottom right.
      * kRadial_SampleMode
      *  The matrix specifies the radial gradient parameters.
      *  (0,0) in the post-matrix space is center of the radial gradient.
      * kRadial2_SampleMode
      *   Matrix transforms to space where first circle is centered at the
      *   origin. The second circle will be centered (x, 0) where x may be
      *   0 and is provided by setRadial2Params. The post-matrix space is
      *   normalized such that 1 is the second radius - first radius.
      * kSweepSampleMode
      *  The angle from the origin of texture coordinates in post-matrix space
      *  determines the gradient value.
      */
     enum SampleMode {
         kNormal_SampleMode,     //!< sample color directly
         kRadial_SampleMode,     //!< treat as radial gradient
         kRadial2_SampleMode,    //!< treat as 2-point radial gradient
         kSweep_SampleMode,      //!< treat as sweep gradient

         kDefault_SampleMode = kNormal_SampleMode
     };

     /**
      * Describes how a texture is sampled when coordinates are outside the
      * texture border
      */
     enum WrapMode {
         kClamp_WrapMode,
         kRepeat_WrapMode,
         kMirror_WrapMode,

         kDefault_WrapMode = kClamp_WrapMode
     };

     /**
      * For the filters which perform more than one texture sample (convolution,
      * erode, dilate), this determines the direction in which the texture
      * coordinates will be incremented.
      */
     enum FilterDirection {
         kX_FilterDirection,
         kY_FilterDirection,

         kDefault_FilterDirection = kX_FilterDirection,
     };
     /**
      * Default sampler state is set to clamp, use normal sampling mode, be
      * unfiltered, and use identity matrix.
      */
     GrSamplerState()
     : fRadial2CenterX1()
     , fRadial2Radius0()
     , fRadial2PosRoot() {
         this->reset();
     }

     WrapMode getWrapX() const { return fWrapX; }
     WrapMode getWrapY() const { return fWrapY; }
     FilterDirection getFilterDirection() const { return fFilterDirection; }
     SampleMode getSampleMode() const { return fSampleMode; }
     const GrMatrix& getMatrix() const { return fMatrix; }
     const GrRect& getTextureDomain() const { return fTextureDomain; }
     bool hasTextureDomain() const {return SkIntToScalar(0) != fTextureDomain.right();}
     Filter getFilter() const { return fFilter; }
     int getKernelWidth() const { return fKernelWidth; }
     const float* getKernel() const { return fKernel; }
     bool swapsRAndB() const { return fSwapRAndB; }

     bool isGradient() const {
         return  kRadial_SampleMode == fSampleMode ||
                 kRadial2_SampleMode == fSampleMode ||
                 kSweep_SampleMode == fSampleMode;
     }

     void setWrapX(WrapMode mode) { fWrapX = mode; }
     void setWrapY(WrapMode mode) { fWrapY = mode; }
     void setSampleMode(SampleMode mode) { fSampleMode = mode; }
     void setFilterDirection(FilterDirection mode) { fFilterDirection = mode; }

     /**
      * Access the sampler's matrix. See SampleMode for explanation of
      * relationship between the matrix and sample mode.
      */
     GrMatrix* matrix() { return &fMatrix; }

     /**
      * Sets the sampler's texture coordinate domain to a
      * custom rectangle, rather than the default (0,1).
      * This option is currently only supported with kClamp_WrapMode
      */
     void setTextureDomain(const GrRect& textureDomain) { fTextureDomain = textureDomain; }

     /**
      * Swaps the R and B components when reading from the texture. Has no effect
      * if the texture is alpha only.
      */
     void setRAndBSwap(bool swap) { fSwapRAndB = swap; }

     /**
      *  Multiplies the current sampler matrix  a matrix
      *
      *  After this call M' = M*m where M is the old matrix, m is the parameter
      *  to this function, and M' is the new matrix. (We consider points to
      *  be column vectors so tex cood vector t is transformed by matrix X as
      *  t' = X*t.)
      *
      *  @param matrix   the matrix used to modify the matrix.
      */
     void preConcatMatrix(const GrMatrix& matrix) { fMatrix.preConcat(matrix); }

     /**
      * Sets filtering type.
      * @param filter    type of filtering to apply
      */
     void setFilter(Filter filter) { fFilter = filter; }

     void reset(WrapMode wrapXAndY,
                Filter filter,
                FilterDirection direction,
                const GrMatrix& matrix) {
         fWrapX = wrapXAndY;
         fWrapY = wrapXAndY;
         fSampleMode = kDefault_SampleMode;
         fFilter = filter;
         fFilterDirection = direction;
         fMatrix = matrix;
         fTextureDomain.setEmpty();
         fSwapRAndB = false;
     }
     void reset(WrapMode wrapXAndY, Filter filter, const GrMatrix& matrix) {
         this->reset(wrapXAndY, filter, kDefault_FilterDirection, matrix);
     }
     void reset(WrapMode wrapXAndY,
                Filter filter) {
         this->reset(wrapXAndY, filter, kDefault_FilterDirection, GrMatrix::I());
     }
     void reset(const GrMatrix& matrix) {
         this->reset(kDefault_WrapMode, kDefault_Filter, kDefault_FilterDirection, matrix);
     }
     void reset() {
         this->reset(kDefault_WrapMode, kDefault_Filter, kDefault_FilterDirection, GrMatrix::I());
     }

     GrScalar getRadial2CenterX1() const { return fRadial2CenterX1; }
     GrScalar getRadial2Radius0() const { return fRadial2Radius0; }
     bool     isRadial2PosRoot() const { return SkToBool(fRadial2PosRoot); }
     // do the radial gradient params lead to a linear (rather than quadratic)
     // equation.
     bool radial2IsDegenerate() const { return GR_Scalar1 == fRadial2CenterX1; }

     /**
      * Sets the parameters for kRadial2_SampleMode. The texture
      * matrix must be set so that the first point is at (0,0) and the second
      * point lies on the x-axis. The second radius minus the first is 1 unit.
      * The additional parameters to define the gradient are specified by this
      * function.
      */
     void setRadial2Params(GrScalar centerX1, GrScalar radius0, bool posRoot) {
         fRadial2CenterX1 = centerX1;
         fRadial2Radius0 = radius0;
         fRadial2PosRoot = posRoot;
     }

     void setConvolutionParams(int kernelWidth, const float* kernel) {
         GrAssert(kernelWidth >= 0 && kernelWidth <= MAX_KERNEL_WIDTH);
         fKernelWidth = kernelWidth;
         if (NULL != kernel) {
             memcpy(fKernel, kernel, kernelWidth * sizeof(float));
         }
     }

     void setMorphologyRadius(int radius) {
         GrAssert(radius >= 0 && radius <= MAX_KERNEL_WIDTH);
         fKernelWidth = radius;
     }

 private:
     WrapMode            fWrapX : 8;
     WrapMode            fWrapY : 8;
     FilterDirection     fFilterDirection : 8;
     SampleMode          fSampleMode : 8;
     Filter              fFilter : 8;
     GrMatrix            fMatrix;
     bool                fSwapRAndB;
     GrRect              fTextureDomain;

     // these are undefined unless fSampleMode == kRadial2_SampleMode
     GrScalar            fRadial2CenterX1;
     GrScalar            fRadial2Radius0;
     SkBool8             fRadial2PosRoot;

     // These are undefined unless fFilter == kConvolution_Filter
     uint8_t             fKernelWidth;
     float               fKernel[MAX_KERNEL_WIDTH];
 };

 #endif

	/*
	* Copyright 2010 Google Inc.
	*
	* Use of this source code is governed by a BSD-style license that can be
	* found in the LICENSE file.
	*/



	#ifndef GrSamplerState_DEFINED
	#define GrSamplerState_DEFINED

	#include "GrTypes.h"
	#include "GrMatrix.h"

	#define MAX_KERNEL_WIDTH 25

	class GrSamplerState {
	public:
	enum Filter {
	/**
	* Read the closest src texel to the sample position
	*/
	kNearest_Filter,
	/**
	* Blend between closest 4 src texels to sample position (tent filter)
	*/
	kBilinear_Filter,
	/**
	* Average of 4 bilinear filterings spaced +/- 1 texel from sample
	* position in x and y. Intended for averaging 16 texels in a downsample
	* pass. (rasterizing such that texture samples fall exactly halfway
	* between texels in x and y spaced 4 texels apart.) Only supported
	* on shader backends.
	*/
	k4x4Downsample_Filter,
	/**
	* Apply a separable convolution kernel.
	*/
	kConvolution_Filter,
	/**
	* Apply a dilate filter (max over a 1D radius).
	*/
	kDilate_Filter,
	/**
	* Apply an erode filter (min over a 1D radius).
	*/
	kErode_Filter,

	kDefault_Filter = kNearest_Filter
	};

	/**
	* The intepretation of the texture matrix depends on the sample mode. The
	* texture matrix is applied both when the texture coordinates are explicit
	* and when vertex positions are used as texture coordinates. In the latter
	* case the texture matrix is applied to the pre-view-matrix position
	* values.
	*
	* kNormal_SampleMode
	* The post-matrix texture coordinates are in normalize space with (0,0) at
	* the top-left and (1,1) at the bottom right.
	* kRadial_SampleMode
	* The matrix specifies the radial gradient parameters.
	* (0,0) in the post-matrix space is center of the radial gradient.
	* kRadial2_SampleMode
	* Matrix transforms to space where first circle is centered at the
	* origin. The second circle will be centered (x, 0) where x may be
	* 0 and is provided by setRadial2Params. The post-matrix space is
	* normalized such that 1 is the second radius - first radius.
	* kSweepSampleMode
	* The angle from the origin of texture coordinates in post-matrix space
	* determines the gradient value.
	*/
	enum SampleMode {
	kNormal_SampleMode, //!< sample color directly
	kRadial_SampleMode, //!< treat as radial gradient
	kRadial2_SampleMode, //!< treat as 2-point radial gradient
	kSweep_SampleMode, //!< treat as sweep gradient

	kDefault_SampleMode = kNormal_SampleMode
	};

	/**
	* Describes how a texture is sampled when coordinates are outside the
	* texture border
	*/
	enum WrapMode {
	kClamp_WrapMode,
	kRepeat_WrapMode,
	kMirror_WrapMode,

	kDefault_WrapMode = kClamp_WrapMode
	};

	/**
	* For the filters which perform more than one texture sample (convolution,
	* erode, dilate), this determines the direction in which the texture
	* coordinates will be incremented.
	*/
	enum FilterDirection {
	kX_FilterDirection,
	kY_FilterDirection,

	kDefault_FilterDirection = kX_FilterDirection,
	};
	/**
	* Default sampler state is set to clamp, use normal sampling mode, be
	* unfiltered, and use identity matrix.
	*/
	GrSamplerState()
	: fRadial2CenterX1()
	, fRadial2Radius0()
	, fRadial2PosRoot() {
	this->reset();
	}

	WrapMode getWrapX() const { return fWrapX; }
	WrapMode getWrapY() const { return fWrapY; }
	FilterDirection getFilterDirection() const { return fFilterDirection; }
	SampleMode getSampleMode() const { return fSampleMode; }
	const GrMatrix& getMatrix() const { return fMatrix; }
	const GrRect& getTextureDomain() const { return fTextureDomain; }
	bool hasTextureDomain() const {return SkIntToScalar(0) != fTextureDomain.right();}
	Filter getFilter() const { return fFilter; }
	int getKernelWidth() const { return fKernelWidth; }
	const float* getKernel() const { return fKernel; }
	bool swapsRAndB() const { return fSwapRAndB; }

	bool isGradient() const {
	return kRadial_SampleMode == fSampleMode \|\|
	kRadial2_SampleMode == fSampleMode \|\|
	kSweep_SampleMode == fSampleMode;
	}

	void setWrapX(WrapMode mode) { fWrapX = mode; }
	void setWrapY(WrapMode mode) { fWrapY = mode; }
	void setSampleMode(SampleMode mode) { fSampleMode = mode; }
	void setFilterDirection(FilterDirection mode) { fFilterDirection = mode; }

	/**
	* Access the sampler's matrix. See SampleMode for explanation of
	* relationship between the matrix and sample mode.
	*/
	GrMatrix* matrix() { return &fMatrix; }

	/**
	* Sets the sampler's texture coordinate domain to a
	* custom rectangle, rather than the default (0,1).
	* This option is currently only supported with kClamp_WrapMode
	*/
	void setTextureDomain(const GrRect& textureDomain) { fTextureDomain = textureDomain; }

	/**
	* Swaps the R and B components when reading from the texture. Has no effect
	* if the texture is alpha only.
	*/
	void setRAndBSwap(bool swap) { fSwapRAndB = swap; }

	/**
	* Multiplies the current sampler matrix a matrix
	*
	* After this call M' = M*m where M is the old matrix, m is the parameter
	* to this function, and M' is the new matrix. (We consider points to
	* be column vectors so tex cood vector t is transformed by matrix X as
	* t' = X*t.)
	*
	* @param matrix the matrix used to modify the matrix.
	*/
	void preConcatMatrix(const GrMatrix& matrix) { fMatrix.preConcat(matrix); }

	/**
	* Sets filtering type.
	* @param filter type of filtering to apply
	*/
	void setFilter(Filter filter) { fFilter = filter; }

	void reset(WrapMode wrapXAndY,
	Filter filter,
	FilterDirection direction,
	const GrMatrix& matrix) {
	fWrapX = wrapXAndY;
	fWrapY = wrapXAndY;
	fSampleMode = kDefault_SampleMode;
	fFilter = filter;
	fFilterDirection = direction;
	fMatrix = matrix;
	fTextureDomain.setEmpty();
	fSwapRAndB = false;
	}
	void reset(WrapMode wrapXAndY, Filter filter, const GrMatrix& matrix) {
	this->reset(wrapXAndY, filter, kDefault_FilterDirection, matrix);
	}
	void reset(WrapMode wrapXAndY,
	Filter filter) {
	this->reset(wrapXAndY, filter, kDefault_FilterDirection, GrMatrix::I());
	}
	void reset(const GrMatrix& matrix) {
	this->reset(kDefault_WrapMode, kDefault_Filter, kDefault_FilterDirection, matrix);
	}
	void reset() {
	this->reset(kDefault_WrapMode, kDefault_Filter, kDefault_FilterDirection, GrMatrix::I());
	}

	GrScalar getRadial2CenterX1() const { return fRadial2CenterX1; }
	GrScalar getRadial2Radius0() const { return fRadial2Radius0; }
	bool isRadial2PosRoot() const { return SkToBool(fRadial2PosRoot); }
	// do the radial gradient params lead to a linear (rather than quadratic)
	// equation.
	bool radial2IsDegenerate() const { return GR_Scalar1 == fRadial2CenterX1; }

	/**
	* Sets the parameters for kRadial2_SampleMode. The texture
	* matrix must be set so that the first point is at (0,0) and the second
	* point lies on the x-axis. The second radius minus the first is 1 unit.
	* The additional parameters to define the gradient are specified by this
	* function.
	*/
	void setRadial2Params(GrScalar centerX1, GrScalar radius0, bool posRoot) {
	fRadial2CenterX1 = centerX1;
	fRadial2Radius0 = radius0;
	fRadial2PosRoot = posRoot;
	}

	void setConvolutionParams(int kernelWidth, const float* kernel) {
	GrAssert(kernelWidth >= 0 && kernelWidth <= MAX_KERNEL_WIDTH);
	fKernelWidth = kernelWidth;
	if (NULL != kernel) {
	memcpy(fKernel, kernel, kernelWidth * sizeof(float));
	}
	}

	void setMorphologyRadius(int radius) {
	GrAssert(radius >= 0 && radius <= MAX_KERNEL_WIDTH);
	fKernelWidth = radius;
	}

	private:
	WrapMode fWrapX : 8;
	WrapMode fWrapY : 8;
	FilterDirection fFilterDirection : 8;
	SampleMode fSampleMode : 8;
	Filter fFilter : 8;
	GrMatrix fMatrix;
	bool fSwapRAndB;
	GrRect fTextureDomain;

	// these are undefined unless fSampleMode == kRadial2_SampleMode
	GrScalar fRadial2CenterX1;
	GrScalar fRadial2Radius0;
	SkBool8 fRadial2PosRoot;

	// These are undefined unless fFilter == kConvolution_Filter
	uint8_t fKernelWidth;
	float fKernel[MAX_KERNEL_WIDTH];
	};

	#endif