/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef GrDrawState_DEFINED
#define GrDrawState_DEFINED
#include "GrColor.h"
#include "GrMatrix.h"
#include "GrNoncopyable.h"
#include "GrSamplerState.h"
#include "GrStencil.h"
#include "SkXfermode.h"
class GrRenderTarget;
class GrTexture;
struct GrDrawState {
/**
* Number of texture stages. Each stage takes as input a color and
* 2D texture coordinates. The color input to the first enabled stage is the
* per-vertex color or the constant color (setColor/setAlpha) if there are
* no per-vertex colors. For subsequent stages the input color is the output
* color from the previous enabled stage. The output color of each stage is
* the input color modulated with the result of a texture lookup. Texture
* lookups are specified by a texture a sampler (setSamplerState). Texture
* coordinates for each stage come from the vertices based on a
* GrVertexLayout bitfield. The output fragment color is the output color of
* the last enabled stage. The presence or absence of texture coordinates
* for each stage in the vertex layout indicates whether a stage is enabled
* or not.
*/
enum {
kNumStages = 3,
kMaxTexCoords = kNumStages
};
/**
* Bitfield used to indicate a set of stages.
*/
typedef uint32_t StageMask;
GR_STATIC_ASSERT(sizeof(StageMask)*8 >= GrDrawState::kNumStages);
GrDrawState() {
this->reset();
}
GrDrawState(const GrDrawState& state) {
*this = state;
}
/**
* Resets to the default state. Sampler states will not be modified.
*/
void reset() {
// make sure any pad is zero for memcmp
// all GrDrawState members should default to something valid by the
// the memset except those initialized individually below. There should
// be no padding between the individually initialized members.
static const size_t kMemsetSize =
reinterpret_cast<intptr_t>(&fColor) -
reinterpret_cast<intptr_t>(this);
memset(this, 0, kMemsetSize);
// pedantic assertion that our ptrs will
// be NULL (0 ptr is mem addr 0)
GrAssert((intptr_t)(void*)NULL == 0LL);
GR_STATIC_ASSERT(0 == kBoth_DrawFace);
GrAssert(fStencilSettings.isDisabled());
// memset exceptions
fColor = 0xffffffff;
fCoverage = 0xffffffff;
fFirstCoverageStage = kNumStages;
fColorFilterMode = SkXfermode::kDst_Mode;
fSrcBlend = kOne_BlendCoeff;
fDstBlend = kZero_BlendCoeff;
fViewMatrix.reset();
// ensure values that will be memcmp'ed in == but not memset in reset()
// are tightly packed
GrAssert(kMemsetSize + sizeof(fColor) + sizeof(fCoverage) +
sizeof(fFirstCoverageStage) + sizeof(fColorFilterMode) +
sizeof(fSrcBlend) + sizeof(fDstBlend) + sizeof(GrMatrix) ==
reinterpret_cast<intptr_t>(&fEdgeAANumEdges) -
reinterpret_cast<intptr_t>(this));
fEdgeAANumEdges = 0;
}
///////////////////////////////////////////////////////////////////////////
/// @name Color
////
/**
* Sets color for next draw to a premultiplied-alpha color.
*
* @param color the color to set.
*/
void setColor(GrColor color) { fColor = color; }
GrColor getColor() const { return fColor; }
/**
* Sets the color to be used for the next draw to be
* (r,g,b,a) = (alpha, alpha, alpha, alpha).
*
* @param alpha The alpha value to set as the color.
*/
void setAlpha(uint8_t a) {
this->setColor((a << 24) | (a << 16) | (a << 8) | a);
}
/**
* Add a color filter that can be represented by a color and a mode. Applied
* after color-computing texture stages.
*/
void setColorFilter(GrColor c, SkXfermode::Mode mode) {
fColorFilterColor = c;
fColorFilterMode = mode;
}
GrColor getColorFilterColor() const { return fColorFilterColor; }
SkXfermode::Mode getColorFilterMode() const { return fColorFilterMode; }
/// @}
///////////////////////////////////////////////////////////////////////////
/// @name Coverage
////
/**
* Sets a constant fractional coverage to be applied to the draw. The
* initial value (after construction or reset()) is 0xff. The constant
* coverage is ignored when per-vertex coverage is provided.
*/
void setCoverage(uint8_t coverage) {
fCoverage = GrColorPackRGBA(coverage, coverage, coverage, coverage);
}
/**
* Version of above that specifies 4 channel per-vertex color. The value
* should be premultiplied.
*/
void setCoverage4(GrColor coverage) {
fCoverage = coverage;
}
GrColor getCoverage() const {
return fCoverage;
}
/// @}
///////////////////////////////////////////////////////////////////////////
/// @name Textures
////
/**
* Sets the texture used at the next drawing call
*
* @param stage The texture stage for which the texture will be set
*
* @param texture The texture to set. Can be NULL though there is no
* advantage to settings a NULL texture if doing non-textured drawing
*/
void setTexture(int stage, GrTexture* texture) {
GrAssert((unsigned)stage < kNumStages);
fTextures[stage] = texture;
}
/**
* Retrieves the currently set texture.
*
* @return The currently set texture. The return value will be NULL if no
* texture has been set, NULL was most recently passed to
* setTexture, or the last setTexture was destroyed.
*/
const GrTexture* getTexture(int stage) const {
GrAssert((unsigned)stage < kNumStages);
return fTextures[stage];
}
GrTexture* getTexture(int stage) {
GrAssert((unsigned)stage < kNumStages);
return fTextures[stage];
}
/// @}
///////////////////////////////////////////////////////////////////////////
/// @name Samplers
////
/**
* Returns the current sampler for a stage.
*/
const GrSamplerState& getSampler(int stage) const {
GrAssert((unsigned)stage < kNumStages);
return fSamplerStates[stage];
}
/**
* Writable pointer to a stage's sampler.
*/
GrSamplerState* sampler(int stage) {
GrAssert((unsigned)stage < kNumStages);
return fSamplerStates + stage;
}
/**
* Preconcats the matrix of all samplers in the mask with the same matrix.
*/
void preConcatSamplerMatrices(StageMask stageMask, const GrMatrix& matrix) {
GrAssert(!(stageMask & kIllegalStageMaskBits));
for (int i = 0; i < kNumStages; ++i) {
if ((1 << i) & stageMask) {
fSamplerStates[i].preConcatMatrix(matrix);
}
}
}
/// @}
///////////////////////////////////////////////////////////////////////////
/// @name Coverage / Color Stages
////
/**
* A common pattern is to compute a color with the initial stages and then
* modulate that color by a coverage value in later stage(s) (AA, mask-
* filters, glyph mask, etc). Color-filters, xfermodes, etc should be
* computed based on the pre-coverage-modulated color. The division of
* stages between color-computing and coverage-computing is specified by
* this method. Initially this is kNumStages (all stages
* are color-computing).
*/
void setFirstCoverageStage(int firstCoverageStage) {
GrAssert((unsigned)firstCoverageStage <= kNumStages);
fFirstCoverageStage = firstCoverageStage;
}
/**
* Gets the index of the first coverage-computing stage.
*/
int getFirstCoverageStage() const {
return fFirstCoverageStage;
}
///@}
///////////////////////////////////////////////////////////////////////////
/// @name Blending
////
/**
* Sets the blending function coeffecients.
*
* The blend function will be:
* D' = sat(S*srcCoef + D*dstCoef)
*
* where D is the existing destination color, S is the incoming source
* color, and D' is the new destination color that will be written. sat()
* is the saturation function.
*
* @param srcCoef coeffecient applied to the src color.
* @param dstCoef coeffecient applied to the dst color.
*/
void setBlendFunc(GrBlendCoeff srcCoeff, GrBlendCoeff dstCoeff) {
fSrcBlend = srcCoeff;
fDstBlend = dstCoeff;
#if GR_DEBUG
switch (dstCoeff) {
case kDC_BlendCoeff:
case kIDC_BlendCoeff:
case kDA_BlendCoeff:
case kIDA_BlendCoeff:
GrPrintf("Unexpected dst blend coeff. Won't work correctly with"
"coverage stages.\n");
break;
default:
break;
}
switch (srcCoeff) {
case kSC_BlendCoeff:
case kISC_BlendCoeff:
case kSA_BlendCoeff:
case kISA_BlendCoeff:
GrPrintf("Unexpected src blend coeff. Won't work correctly with"
"coverage stages.\n");
break;
default:
break;
}
#endif
}
GrBlendCoeff getSrcBlendCoeff() const { return fSrcBlend; }
GrBlendCoeff getDstBlendCoeff() const { return fDstBlend; }
void getDstBlendCoeff(GrBlendCoeff* srcBlendCoeff,
GrBlendCoeff* dstBlendCoeff) const {
*srcBlendCoeff = fSrcBlend;
*dstBlendCoeff = fDstBlend;
}
/**
* Sets the blending function constant referenced by the following blending
* coeffecients:
* kConstC_BlendCoeff
* kIConstC_BlendCoeff
* kConstA_BlendCoeff
* kIConstA_BlendCoeff
*
* @param constant the constant to set
*/
void setBlendConstant(GrColor constant) { fBlendConstant = constant; }
/**
* Retrieves the last value set by setBlendConstant()
* @return the blending constant value
*/
GrColor getBlendConstant() const { return fBlendConstant; }
/// @}
///////////////////////////////////////////////////////////////////////////
/// @name View Matrix
////
/**
* Sets the matrix applied to veretx positions.
*
* In the post-view-matrix space the rectangle [0,w]x[0,h]
* fully covers the render target. (w and h are the width and height of the
* the rendertarget.)
*/
void setViewMatrix(const GrMatrix& m) { fViewMatrix = m; }
/**
* Gets a writable pointer to the view matrix.
*/
GrMatrix* viewMatrix() { return &fViewMatrix; }
/**
* Multiplies the current view matrix by a matrix
*
* After this call V' = V*m where V is the old view matrix,
* m is the parameter to this function, and V' is the new view matrix.
* (We consider positions to be column vectors so position vector p is
* transformed by matrix X as p' = X*p.)
*
* @param m the matrix used to modify the view matrix.
*/
void preConcatViewMatrix(const GrMatrix& m) { fViewMatrix.preConcat(m); }
/**
* Multiplies the current view matrix by a matrix
*
* After this call V' = m*V where V is the old view matrix,
* m is the parameter to this function, and V' is the new view matrix.
* (We consider positions to be column vectors so position vector p is
* transformed by matrix X as p' = X*p.)
*
* @param m the matrix used to modify the view matrix.
*/
void postConcatViewMatrix(const GrMatrix& m) { fViewMatrix.postConcat(m); }
/**
* Retrieves the current view matrix
* @return the current view matrix.
*/
const GrMatrix& getViewMatrix() const { return fViewMatrix; }
/**
* Retrieves the inverse of the current view matrix.
*
* If the current view matrix is invertible, return true, and if matrix
* is non-null, copy the inverse into it. If the current view matrix is
* non-invertible, return false and ignore the matrix parameter.
*
* @param matrix if not null, will receive a copy of the current inverse.
*/
bool getViewInverse(GrMatrix* matrix) const {
// TODO: determine whether we really need to leave matrix unmodified
// at call sites when inversion fails.
GrMatrix inverse;
if (fViewMatrix.invert(&inverse)) {
if (matrix) {
*matrix = inverse;
}
return true;
}
return false;
}
class AutoViewMatrixRestore : public ::GrNoncopyable {
public:
AutoViewMatrixRestore() : fDrawState(NULL) {}
AutoViewMatrixRestore(GrDrawState* ds, const GrMatrix& newMatrix) {
fDrawState = NULL;
this->set(ds, newMatrix);
}
AutoViewMatrixRestore(GrDrawState* ds) {
fDrawState = NULL;
this->set(ds);
}
~AutoViewMatrixRestore() {
this->set(NULL, GrMatrix::I());
}
void set(GrDrawState* ds, const GrMatrix& newMatrix) {
if (NULL != fDrawState) {
fDrawState->setViewMatrix(fSavedMatrix);
}
if (NULL != ds) {
fSavedMatrix = ds->getViewMatrix();
ds->setViewMatrix(newMatrix);
}
fDrawState = ds;
}
void set(GrDrawState* ds) {
if (NULL != fDrawState) {
fDrawState->setViewMatrix(fSavedMatrix);
}
if (NULL != ds) {
fSavedMatrix = ds->getViewMatrix();
}
fDrawState = ds;
}
private:
GrDrawState* fDrawState;
GrMatrix fSavedMatrix;
};
/// @}
///////////////////////////////////////////////////////////////////////////
/// @name Render Target
////
/**
* Sets the rendertarget used at the next drawing call
*
* @param target The render target to set.
*/
void setRenderTarget(GrRenderTarget* target) { fRenderTarget = target; }
/**
* Retrieves the currently set rendertarget.
*
* @return The currently set render target.
*/
const GrRenderTarget* getRenderTarget() const { return fRenderTarget; }
GrRenderTarget* getRenderTarget() { return fRenderTarget; }
class AutoRenderTargetRestore : public ::GrNoncopyable {
public:
AutoRenderTargetRestore() : fDrawState(NULL), fSavedTarget(NULL) {}
AutoRenderTargetRestore(GrDrawState* ds, GrRenderTarget* newTarget) {
fDrawState = NULL;
this->set(ds, newTarget);
}
~AutoRenderTargetRestore() { this->set(NULL, NULL); }
void set(GrDrawState* ds, GrRenderTarget* newTarget) {
if (NULL != fDrawState) {
fDrawState->setRenderTarget(fSavedTarget);
}
if (NULL != ds) {
fSavedTarget = ds->getRenderTarget();
ds->setRenderTarget(newTarget);
}
fDrawState = ds;
}
private:
GrDrawState* fDrawState;
GrRenderTarget* fSavedTarget;
};
/// @}
///////////////////////////////////////////////////////////////////////////
/// @name Stencil
////
/**
* Sets the stencil settings to use for the next draw.
* Changing the clip has the side-effect of possibly zeroing
* out the client settable stencil bits. So multipass algorithms
* using stencil should not change the clip between passes.
* @param settings the stencil settings to use.
*/
void setStencil(const GrStencilSettings& settings) {
fStencilSettings = settings;
}
/**
* Shortcut to disable stencil testing and ops.
*/
void disableStencil() {
fStencilSettings.setDisabled();
}
const GrStencilSettings& getStencil() const { return fStencilSettings; }
GrStencilSettings* stencil() { return &fStencilSettings; }
/// @}
///////////////////////////////////////////////////////////////////////////
/// @name Color Matrix
////
/**
* Sets the color matrix to use for the next draw.
* @param matrix the 5x4 matrix to apply to the incoming color
*/
void setColorMatrix(const float matrix[20]) {
memcpy(fColorMatrix, matrix, sizeof(fColorMatrix));
}
const float* getColorMatrix() const { return fColorMatrix; }
/// @}
///////////////////////////////////////////////////////////////////////////
// @name Edge AA
// There are two ways to perform antialiasing using edge equations. One
// is to specify an (linear or quadratic) edge eq per-vertex. This requires
// splitting vertices shared by primitives.
//
// The other is via setEdgeAAData which sets a set of edges and each
// is tested against all the edges.
////
/**
* When specifying edges as vertex data this enum specifies what type of
* edges are in use. The edges are always 4 GrScalars in memory, even when
* the edge type requires fewer than 4.
*/
enum VertexEdgeType {
/* 1-pixel wide line
2D implicit line eq (a*x + b*y +c = 0). 4th component unused */
kHairLine_EdgeType,
/* Quadratic specified by u^2-v canonical coords (only 2
components used). Coverage based on signed distance with negative
being inside, positive outside.*/
kQuad_EdgeType,
/* Same as above but for hairline quadratics. Uses unsigned distance.
Coverage is min(0, 1-distance). */
kHairQuad_EdgeType,
kVertexEdgeTypeCnt
};
/**
* Determines the interpretation per-vertex edge data when the
* kEdge_VertexLayoutBit is set (see GrDrawTarget). When per-vertex edges
* are not specified the value of this setting has no effect.
*/
void setVertexEdgeType(VertexEdgeType type) {
GrAssert(type >=0 && type < kVertexEdgeTypeCnt);
fVertexEdgeType = type;
}
VertexEdgeType getVertexEdgeType() const { return fVertexEdgeType; }
/**
* The absolute maximum number of edges that may be specified for
* a single draw call when performing edge antialiasing. This is used for
* the size of several static buffers, so implementations of getMaxEdges()
* (below) should clamp to this value.
*/
enum {
// TODO: this should be 32 when GrTesselatedPathRenderer is used
// Visual Studio 2010 does not permit a member array of size 0.
kMaxEdges = 1
};
class Edge {
public:
Edge() {}
Edge(float x, float y, float z) : fX(x), fY(y), fZ(z) {}
GrPoint intersect(const Edge& other) {
return GrPoint::Make(
SkFloatToScalar((fY * other.fZ - other.fY * fZ) /
(fX * other.fY - other.fX * fY)),
SkFloatToScalar((fX * other.fZ - other.fX * fZ) /
(other.fX * fY - fX * other.fY)));
}
float fX, fY, fZ;
};
/**
* Sets the edge data required for edge antialiasing.
*
* @param edges 3 * numEdges float values, representing the edge
* equations in Ax + By + C form
*/
void setEdgeAAData(const Edge* edges, int numEdges) {
GrAssert(numEdges <= GrDrawState::kMaxEdges);
memcpy(fEdgeAAEdges, edges, numEdges * sizeof(GrDrawState::Edge));
fEdgeAANumEdges = numEdges;
}
int getNumAAEdges() const { return fEdgeAANumEdges; }
const Edge* getAAEdges() const { return fEdgeAAEdges; }
/// @}
///////////////////////////////////////////////////////////////////////////
/// @name State Flags
////
/**
* Flags that affect rendering. Controlled using enable/disableState(). All
* default to disabled.
*/
enum StateBits {
/**
* Perform dithering. TODO: Re-evaluate whether we need this bit
*/
kDither_StateBit = 0x01,
/**
* Perform HW anti-aliasing. This means either HW FSAA, if supported
* by the render target, or smooth-line rendering if a line primitive
* is drawn and line smoothing is supported by the 3D API.
*/
kHWAntialias_StateBit = 0x02,
/**
* Draws will respect the clip, otherwise the clip is ignored.
*/
kClip_StateBit = 0x04,
/**
* Disables writing to the color buffer. Useful when performing stencil
* operations.
*/
kNoColorWrites_StateBit = 0x08,
/**
* Modifies the behavior of edge AA specified by setEdgeAA. If set,
* will test edge pairs for convexity when rasterizing. Set this if the
* source polygon is non-convex.
*/
kEdgeAAConcave_StateBit = 0x10,
/**
* Draws will apply the color matrix, otherwise the color matrix is
* ignored.
*/
kColorMatrix_StateBit = 0x20,
// Users of the class may add additional bits to the vector
kDummyStateBit,
kLastPublicStateBit = kDummyStateBit-1,
};
void resetStateFlags() {
fFlagBits = 0;
}
/**
* Enable render state settings.
*
* @param flags bitfield of StateBits specifing the states to enable
*/
void enableState(uint32_t stateBits) {
fFlagBits |= stateBits;
}
/**
* Disable render state settings.
*
* @param flags bitfield of StateBits specifing the states to disable
*/
void disableState(uint32_t stateBits) {
fFlagBits &= ~(stateBits);
}
bool isDitherState() const {
return 0 != (fFlagBits & kDither_StateBit);
}
bool isHWAntialiasState() const {
return 0 != (fFlagBits & kHWAntialias_StateBit);
}
bool isClipState() const {
return 0 != (fFlagBits & kClip_StateBit);
}
bool isColorWriteDisabled() const {
return 0 != (fFlagBits & kNoColorWrites_StateBit);
}
bool isConcaveEdgeAAState() const {
return 0 != (fFlagBits & kEdgeAAConcave_StateBit);
}
bool isStateFlagEnabled(uint32_t stateBit) const {
return 0 != (stateBit & fFlagBits);
}
void copyStateFlags(const GrDrawState& ds) {
fFlagBits = ds.fFlagBits;
}
/// @}
///////////////////////////////////////////////////////////////////////////
/// @name Face Culling
////
enum DrawFace {
kBoth_DrawFace,
kCCW_DrawFace,
kCW_DrawFace,
};
/**
* Controls whether clockwise, counterclockwise, or both faces are drawn.
* @param face the face(s) to draw.
*/
void setDrawFace(DrawFace face) {
fDrawFace = face;
}
/**
* Gets whether the target is drawing clockwise, counterclockwise,
* or both faces.
* @return the current draw face(s).
*/
DrawFace getDrawFace() const { return fDrawFace; }
/// @}
///////////////////////////////////////////////////////////////////////////
// Most stages are usually not used, so conditionals here
// reduce the expected number of bytes touched by 50%.
bool operator ==(const GrDrawState& s) const {
if (memcmp(this, &s, this->leadingBytes())) return false;
for (int i = 0; i < kNumStages; i++) {
if (fTextures[i] &&
memcmp(&this->fSamplerStates[i], &s.fSamplerStates[i],
sizeof(GrSamplerState))) {
return false;
}
}
return true;
}
bool operator !=(const GrDrawState& s) const { return !(*this == s); }
// Most stages are usually not used, so conditionals here
// reduce the expected number of bytes touched by 50%.
GrDrawState& operator =(const GrDrawState& s) {
memcpy(this, &s, this->leadingBytes());
for (int i = 0; i < kNumStages; i++) {
if (s.fTextures[i]) {
memcpy(&this->fSamplerStates[i], &s.fSamplerStates[i],
sizeof(GrSamplerState));
}
}
return *this;
}
private:
static const StageMask kIllegalStageMaskBits = ~((1 << kNumStages)-1);
// @{ these fields can be initialized with memset to 0
GrColor fBlendConstant;
GrTexture* fTextures[kNumStages];
GrColor fColorFilterColor;
uint32_t fFlagBits;
DrawFace fDrawFace;
VertexEdgeType fVertexEdgeType;
GrStencilSettings fStencilSettings;
float fColorMatrix[20]; // 5 x 4 matrix
GrRenderTarget* fRenderTarget;
// @}
// @{ Initialized to values other than zero
GrColor fColor;
GrColor fCoverage;
int fFirstCoverageStage;
SkXfermode::Mode fColorFilterMode;
GrBlendCoeff fSrcBlend;
GrBlendCoeff fDstBlend;
GrMatrix fViewMatrix;
// @}
// @{ Data for GrTesselatedPathRenderer
// TODO: currently ignored in copying & comparison for performance.
// Must be considered if GrTesselatedPathRenderer is being used.
int fEdgeAANumEdges;
Edge fEdgeAAEdges[kMaxEdges];
// @}
// This field must be last; it will not be copied or compared
// if the corresponding fTexture[] is NULL.
GrSamplerState fSamplerStates[kNumStages];
size_t leadingBytes() const {
// Can't use offsetof() with non-POD types, so stuck with pointer math.
// TODO: ignores GrTesselatedPathRenderer data structures. We don't
// have a compile-time flag that lets us know if it's being used, and
// checking at runtime seems to cost 5% performance.
return (size_t) ((unsigned char*)&fEdgeAANumEdges -
(unsigned char*)&fBlendConstant);
}
};
#endif