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/*
* 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 GrDrawTarget_DEFINED
#define GrDrawTarget_DEFINED
#include "GrDrawState.h"
#include "GrIndexBuffer.h"
#include "GrMatrix.h"
#include "GrRefCnt.h"
#include "GrTemplates.h"
#include "SkXfermode.h"
#include "SkTLazy.h"
#include "SkTArray.h"
class GrClipData;
class GrPath;
class GrVertexBuffer;
class GrDrawTarget : public GrRefCnt {
public:
SK_DECLARE_INST_COUNT(GrDrawTarget)
/**
* Represents the draw target capabilities.
*/
struct Caps {
Caps() { memset(this, 0, sizeof(Caps)); }
Caps(const Caps& c) { *this = c; }
Caps& operator= (const Caps& c) {
memcpy(this, &c, sizeof(Caps));
return *this;
}
void print() const;
bool f8BitPaletteSupport : 1;
bool fNPOTTextureTileSupport : 1;
bool fTwoSidedStencilSupport : 1;
bool fStencilWrapOpsSupport : 1;
bool fHWAALineSupport : 1;
bool fShaderDerivativeSupport : 1;
bool fGeometryShaderSupport : 1;
bool fFSAASupport : 1;
bool fDualSourceBlendingSupport : 1;
bool fBufferLockSupport : 1;
bool fPathStencilingSupport : 1;
int fMaxRenderTargetSize;
int fMaxTextureSize;
};
///////////////////////////////////////////////////////////////////////////
GrDrawTarget();
virtual ~GrDrawTarget();
/**
* Gets the capabilities of the draw target.
*/
const Caps& getCaps() const { return fCaps; }
/**
* Sets the current clip to the region specified by clip. All draws will be
* clipped against this clip if kClip_StateBit is enabled.
*
* Setting the clip may (or may not) zero out the client's stencil bits.
*
* @param description of the clipping region
*/
void setClip(const GrClipData* clip);
/**
* Gets the current clip.
*
* @return the clip.
*/
const GrClipData* getClip() const;
/**
* Sets the draw state object for the draw target. Note that this does not
* make a copy. The GrDrawTarget will take a reference to passed object.
* Passing NULL will cause the GrDrawTarget to use its own internal draw
* state object rather than an externally provided one.
*/
void setDrawState(GrDrawState* drawState);
/**
* Read-only access to the GrDrawTarget's current draw state.
*/
const GrDrawState& getDrawState() const { return *fDrawState; }
/**
* Read-write access to the GrDrawTarget's current draw state. Note that
* this doesn't ref.
*/
GrDrawState* drawState() { return fDrawState; }
/**
* Color alpha and coverage are two inputs to the drawing pipeline. For some
* blend modes it is safe to fold the coverage into constant or per-vertex
* color alpha value. For other blend modes they must be handled separately.
* Depending on features available in the underlying 3D API this may or may
* not be possible.
*
* This function considers the current draw state and the draw target's
* capabilities to determine whether coverage can be handled correctly. The
* following assumptions are made:
* 1. The caller intends to somehow specify coverage. This can be
* specified either by enabling a coverage stage on the GrDrawState or
* via the vertex layout.
* 2. Other than enabling coverage stages, the current configuration of
* the target's GrDrawState is as it will be at draw time.
* 3. If a vertex source has not yet been specified then all stages with
* non-NULL textures will be referenced by the vertex layout.
*/
bool canApplyCoverage() const;
/**
* Determines whether incorporating partial pixel coverage into the constant
* color specified by setColor or per-vertex colors will give the right
* blending result. If a vertex source has not yet been specified then
* the function assumes that all stages with non-NULL textures will be
* referenced by the vertex layout.
*/
bool canTweakAlphaForCoverage() const;
/**
* Given the current draw state and hw support, will HW AA lines be used
* (if line primitive type is drawn)? If a vertex source has not yet been
* specified then the function assumes that all stages with non-NULL
* textures will be referenced by the vertex layout.
*/
bool willUseHWAALines() const;
/**
* The format of vertices is represented as a bitfield of flags.
* Flags that indicate the layout of vertex data. Vertices always contain
* positions and may also contain up to GrDrawState::kMaxTexCoords sets
* of 2D texture coordinates, per-vertex colors, and per-vertex coverage.
* Each stage can
* use any of the texture coordinates as its input texture coordinates or it
* may use the positions as texture coordinates.
*
* If no texture coordinates are specified for a stage then the stage is
* disabled.
*
* Only one type of texture coord can be specified per stage. For
* example StageTexCoordVertexLayoutBit(0, 2) and
* StagePosAsTexCoordVertexLayoutBit(0) cannot both be specified.
*
* The order in memory is always (position, texture coord 0, ..., color,
* coverage) with any unused fields omitted. Note that this means that if
* only texture coordinates 1 is referenced then there is no texture
* coordinates 0 and the order would be (position, texture coordinate 1
* [, color][, coverage]).
*/
/**
* Generates a bit indicating that a texture stage uses texture coordinates
*
* @param stage the stage that will use texture coordinates.
* @param texCoordIdx the index of the texture coordinates to use
*
* @return the bit to add to a GrVertexLayout bitfield.
*/
static int StageTexCoordVertexLayoutBit(int stage, int texCoordIdx) {
GrAssert(stage < GrDrawState::kNumStages);
GrAssert(texCoordIdx < GrDrawState::kMaxTexCoords);
return 1 << (stage + (texCoordIdx * GrDrawState::kNumStages));
}
static bool StageUsesTexCoords(GrVertexLayout layout, int stage);
private:
// non-stage bits start at this index.
static const int STAGE_BIT_CNT = GrDrawState::kNumStages *
GrDrawState::kMaxTexCoords;
public:
/**
* Additional Bits that can be specified in GrVertexLayout.
*/
enum VertexLayoutBits {
/* vertices have colors (GrColor) */
kColor_VertexLayoutBit = 1 << (STAGE_BIT_CNT + 0),
/* vertices have coverage (GrColor)
*/
kCoverage_VertexLayoutBit = 1 << (STAGE_BIT_CNT + 1),
/* Use text vertices. (Pos and tex coords may be a different type for
* text [GrGpuTextVertex vs GrPoint].)
*/
kTextFormat_VertexLayoutBit = 1 << (STAGE_BIT_CNT + 2),
/* Each vertex specificies an edge. Distance to the edge is used to
* compute a coverage. See GrDrawState::setVertexEdgeType().
*/
kEdge_VertexLayoutBit = 1 << (STAGE_BIT_CNT + 3),
// for below assert
kDummyVertexLayoutBit,
kHighVertexLayoutBit = kDummyVertexLayoutBit - 1
};
// make sure we haven't exceeded the number of bits in GrVertexLayout.
GR_STATIC_ASSERT(kHighVertexLayoutBit < ((uint64_t)1 << 8*sizeof(GrVertexLayout)));
/**
* There are three types of "sources" of geometry (vertices and indices) for
* draw calls made on the target. When performing an indexed draw, the
* indices and vertices can use different source types. Once a source is
* specified it can be used for multiple draws. However, the time at which
* the geometry data is no longer editable depends on the source type.
*
* Sometimes it is necessary to perform a draw while upstack code has
* already specified geometry that it isn't finished with. So there are push
* and pop methods. This allows the client to push the sources, draw
* something using alternate sources, and then pop to restore the original
* sources.
*
* Aside from pushes and pops, a source remains valid until another source
* is set or resetVertexSource / resetIndexSource is called. Drawing from
* a reset source is an error.
*
* The three types of sources are:
*
* 1. A cpu array (set*SourceToArray). This is useful when the caller
* already provided vertex data in a format compatible with a
* GrVertexLayout. The data in the array is consumed at the time that
* set*SourceToArray is called and subsequent edits to the array will not
* be reflected in draws.
*
* 2. Reserve. This is most useful when the caller has data it must
* transform before drawing and is not long-lived. The caller requests
* that the draw target make room for some amount of vertex and/or index
* data. The target provides ptrs to hold the vertex and/or index data.
*
* The data is writable up until the next drawIndexed, drawNonIndexed,
* drawIndexedInstances, or pushGeometrySource. At this point the data is
* frozen and the ptrs are no longer valid.
*
* Where the space is allocated and how it is uploaded to the GPU is
* subclass-dependent.
*
* 3. Vertex and Index Buffers. This is most useful for geometry that will
* is long-lived. When the data in the buffer is consumed depends on the
* GrDrawTarget subclass. For deferred subclasses the caller has to
* guarantee that the data is still available in the buffers at playback.
* (TODO: Make this more automatic as we have done for read/write pixels)
*/
/**
* Reserves space for vertices and/or indices. Zero can be specifed as
* either the vertex or index count if the caller desires to only reserve
* space for only indices or only vertices. If zero is specifed for
* vertexCount then the vertex source will be unmodified and likewise for
* indexCount.
*
* If the function returns true then the reserve suceeded and the vertices
* and indices pointers will point to the space created.
*
* If the target cannot make space for the request then this function will
* return false. If vertexCount was non-zero then upon failure the vertex
* source is reset and likewise for indexCount.
*
* The pointers to the space allocated for vertices and indices remain valid
* until a drawIndexed, drawNonIndexed, drawIndexedInstances, or push/
* popGeomtrySource is called. At that point logically a snapshot of the
* data is made and the pointers are invalid.
*
* @param vertexLayout the format of vertices (ignored if vertexCount == 0).
* @param vertexCount the number of vertices to reserve space for. Can be
* 0.
* @param indexCount the number of indices to reserve space for. Can be 0.
* @param vertices will point to reserved vertex space if vertexCount is
* non-zero. Illegal to pass NULL if vertexCount > 0.
* @param indices will point to reserved index space if indexCount is
* non-zero. Illegal to pass NULL if indexCount > 0.
*/
bool reserveVertexAndIndexSpace(GrVertexLayout vertexLayout,
int vertexCount,
int indexCount,
void** vertices,
void** indices);
/**
* Provides hints to caller about the number of vertices and indices
* that can be allocated cheaply. This can be useful if caller is reserving
* space but doesn't know exactly how much geometry is needed.
*
* Also may hint whether the draw target should be flushed first. This is
* useful for deferred targets.
*
* @param vertexLayout layout of vertices caller would like to reserve
* @param vertexCount in: hint about how many vertices the caller would
* like to allocate.
* out: a hint about the number of vertices that can be
* allocated cheaply. Negative means no hint.
* Ignored if NULL.
* @param indexCount in: hint about how many indices the caller would
* like to allocate.
* out: a hint about the number of indices that can be
* allocated cheaply. Negative means no hint.
* Ignored if NULL.
*
* @return true if target should be flushed based on the input values.
*/
virtual bool geometryHints(GrVertexLayout vertexLayout,
int* vertexCount,
int* indexCount) const;
/**
* Sets source of vertex data for the next draw. Array must contain
* the vertex data when this is called.
*
* @param array cpu array containing vertex data.
* @param size size of the vertex data.
* @param vertexCount the number of vertices in the array.
*/
void setVertexSourceToArray(GrVertexLayout vertexLayout,
const void* vertexArray,
int vertexCount);
/**
* Sets source of index data for the next indexed draw. Array must contain
* the indices when this is called.
*
* @param array cpu array containing index data.
* @param indexCount the number of indices in the array.
*/
void setIndexSourceToArray(const void* indexArray, int indexCount);
/**
* Sets source of vertex data for the next draw. Data does not have to be
* in the buffer until drawIndexed, drawNonIndexed, or drawIndexedInstances.
*
* @param buffer vertex buffer containing vertex data. Must be
* unlocked before draw call.
* @param vertexLayout layout of the vertex data in the buffer.
*/
void setVertexSourceToBuffer(GrVertexLayout vertexLayout,
const GrVertexBuffer* buffer);
/**
* Sets source of index data for the next indexed draw. Data does not have
* to be in the buffer until drawIndexed.
*
* @param buffer index buffer containing indices. Must be unlocked
* before indexed draw call.
*/
void setIndexSourceToBuffer(const GrIndexBuffer* buffer);
/**
* Resets vertex source. Drawing from reset vertices is illegal. Set vertex
* source to reserved, array, or buffer before next draw. May be able to free
* up temporary storage allocated by setVertexSourceToArray or
* reserveVertexSpace.
*/
void resetVertexSource();
/**
* Resets index source. Indexed Drawing from reset indices is illegal. Set
* index source to reserved, array, or buffer before next indexed draw. May
* be able to free up temporary storage allocated by setIndexSourceToArray
* or reserveIndexSpace.
*/
void resetIndexSource();
/**
* Query to find out if the vertex or index source is reserved.
*/
bool hasReservedVerticesOrIndices() const {
return kReserved_GeometrySrcType == this->getGeomSrc().fVertexSrc ||
kReserved_GeometrySrcType == this->getGeomSrc().fIndexSrc;
}
/**
* Pushes and resets the vertex/index sources. Any reserved vertex / index
* data is finalized (i.e. cannot be updated after the matching pop but can
* be drawn from). Must be balanced by a pop.
*/
void pushGeometrySource();
/**
* Pops the vertex / index sources from the matching push.
*/
void popGeometrySource();
/**
* Draws indexed geometry using the current state and current vertex / index
* sources.
*
* @param type The type of primitives to draw.
* @param startVertex the vertex in the vertex array/buffer corresponding
* to index 0
* @param startIndex first index to read from index src.
* @param vertexCount one greater than the max index.
* @param indexCount the number of index elements to read. The index count
* is effectively trimmed to the last completely
* specified primitive.
*/
void drawIndexed(GrPrimitiveType type,
int startVertex,
int startIndex,
int vertexCount,
int indexCount);
/**
* Draws non-indexed geometry using the current state and current vertex
* sources.
*
* @param type The type of primitives to draw.
* @param startVertex the vertex in the vertex array/buffer corresponding
* to index 0
* @param vertexCount one greater than the max index.
*/
void drawNonIndexed(GrPrimitiveType type,
int startVertex,
int vertexCount);
/**
* Draws path into the stencil buffer. The fill must be either even/odd or
* winding (not inverse or hairline). It will respect the HW antialias flag
* on the draw state (if possible in the 3D API).
*/
void stencilPath(const GrPath*, GrPathFill);
/**
* Helper function for drawing rects. This does not use the current index
* and vertex sources. After returning, the vertex and index sources may
* have changed. They should be reestablished before the next drawIndexed
* or drawNonIndexed. This cannot be called between reserving and releasing
* geometry. The GrDrawTarget subclass may be able to perform additional
* optimizations if drawRect is used rather than drawIndexed or
* drawNonIndexed.
* @param rect the rect to draw
* @param matrix optional matrix applied to rect (before viewMatrix)
* @param srcRects specifies rects for stages enabled by stageEnableMask.
* if stageEnableMask bit i is 1, srcRects is not NULL,
* and srcRects[i] is not NULL, then srcRects[i] will be
* used as coordinates for stage i. Otherwise, if stage i
* is enabled then rect is used as the coordinates.
* @param srcMatrices optional matrices applied to srcRects. If
* srcRect[i] is non-NULL and srcMatrices[i] is
* non-NULL then srcRect[i] will be transformed by
* srcMatrix[i]. srcMatrices can be NULL when no
* srcMatrices are desired.
*/
virtual void drawRect(const GrRect& rect,
const GrMatrix* matrix,
const GrRect* srcRects[],
const GrMatrix* srcMatrices[]);
/**
* This call is used to draw multiple instances of some geometry with a
* given number of vertices (V) and indices (I) per-instance. The indices in
* the index source must have the form i[k+I] == i[k] + V. Also, all indices
* i[kI] ... i[(k+1)I-1] must be elements of the range kV ... (k+1)V-1. As a
* concrete example, the following index buffer for drawing a series of
* quads each as two triangles each satisfies these conditions with V=4 and
* I=6:
* (0,1,2,0,2,3, 4,5,6,4,6,7, 8,9,10,8,10,11, ...)
*
* The call assumes that the pattern of indices fills the entire index
* source. The size of the index buffer limits the number of instances that
* can be drawn by the GPU in a single draw. However, the caller may specify
* any (positive) number for instanceCount and if necessary multiple GPU
* draws will be issued. Morever, when drawIndexedInstances is called
* multiple times it may be possible for GrDrawTarget to group them into a
* single GPU draw.
*
* @param type the type of primitives to draw
* @param instanceCount the number of instances to draw. Each instance
* consists of verticesPerInstance vertices indexed by
* indicesPerInstance indices drawn as the primitive
* type specified by type.
* @param verticesPerInstance The number of vertices in each instance (V
* in the above description).
* @param indicesPerInstance The number of indices in each instance (I
* in the above description).
*/
virtual void drawIndexedInstances(GrPrimitiveType type,
int instanceCount,
int verticesPerInstance,
int indicesPerInstance);
/**
* Helper for drawRect when the caller doesn't need separate src rects or
* matrices.
*/
void drawSimpleRect(const GrRect& rect,
const GrMatrix* matrix) {
drawRect(rect, matrix, NULL, NULL);
}
/**
* Clear the current render target if one isn't passed in. Ignores the
* clip and all other draw state (blend mode, stages, etc). Clears the
* whole thing if rect is NULL, otherwise just the rect.
*/
virtual void clear(const GrIRect* rect,
GrColor color,
GrRenderTarget* renderTarget = NULL) = 0;
/**
* Release any resources that are cached but not currently in use. This
* is intended to give an application some recourse when resources are low.
*/
virtual void purgeResources() {};
////////////////////////////////////////////////////////////////////////////
/**
* See AutoStateRestore below.
*/
enum ASRInit {
kPreserve_ASRInit,
kReset_ASRInit
};
/**
* Saves off the current state and restores it in the destructor. It will
* install a new GrDrawState object on the target (setDrawState) and restore
* the previous one in the destructor. The caller should call drawState() to
* get the new draw state after the ASR is installed.
*
* GrDrawState* state = target->drawState();
* AutoStateRestore asr(target, GrDrawTarget::kReset_ASRInit).
* state->setRenderTarget(rt); // state refers to the GrDrawState set on
* // target before asr was initialized.
* // Therefore, rt is set on the GrDrawState
* // that will be restored after asr's
* // destructor rather than target's current
* // GrDrawState.
*/
class AutoStateRestore : ::GrNoncopyable {
public:
/**
* Default ASR will have no effect unless set() is subsequently called.
*/
AutoStateRestore();
/**
* Saves the state on target. The state will be restored when the ASR
* is destroyed. If this constructor is used do not call set().
*
* @param init Should the newly installed GrDrawState be a copy of the
* previous state or a default-initialized GrDrawState.
*/
AutoStateRestore(GrDrawTarget* target, ASRInit init);
~AutoStateRestore();
/**
* Saves the state on target. The state will be restored when the ASR
* is destroyed. This should only be called once per ASR object and only
* when the default constructor was used. For nested saves use multiple
* ASR objects.
*
* @param init Should the newly installed GrDrawState be a copy of the
* previous state or a default-initialized GrDrawState.
*/
void set(GrDrawTarget* target, ASRInit init);
private:
GrDrawTarget* fDrawTarget;
SkTLazy<GrDrawState> fTempState;
GrDrawState* fSavedState;
};
////////////////////////////////////////////////////////////////////////////
/**
* Sets the view matrix to I and preconcats all stage matrices enabled in
* mask by the view inverse. Destructor undoes these changes.
*/
class AutoDeviceCoordDraw : ::GrNoncopyable {
public:
/**
* If a stage's texture matrix is applied to explicit per-vertex coords,
* rather than to positions, then we don't want to modify its matrix.
* The explicitCoordStageMask is used to specify such stages.
*
* TODO: Remove this when custom stage's control their own texture
* matrix and there is a "view matrix has changed" notification to the
* custom stages.
*/
AutoDeviceCoordDraw(GrDrawTarget* target,
uint32_t explicitCoordStageMask = 0);
bool succeeded() const { return NULL != fDrawTarget; }
~AutoDeviceCoordDraw();
private:
GrDrawTarget* fDrawTarget;
GrMatrix fViewMatrix;
GrMatrix fSamplerMatrices[GrDrawState::kNumStages];
int fRestoreMask;
};
////////////////////////////////////////////////////////////////////////////
class AutoReleaseGeometry : ::GrNoncopyable {
public:
AutoReleaseGeometry(GrDrawTarget* target,
GrVertexLayout vertexLayout,
int vertexCount,
int indexCount);
AutoReleaseGeometry();
~AutoReleaseGeometry();
bool set(GrDrawTarget* target,
GrVertexLayout vertexLayout,
int vertexCount,
int indexCount);
bool succeeded() const { return NULL != fTarget; }
void* vertices() const { GrAssert(this->succeeded()); return fVertices; }
void* indices() const { GrAssert(this->succeeded()); return fIndices; }
GrPoint* positions() const {
return static_cast<GrPoint*>(this->vertices());
}
private:
void reset();
GrDrawTarget* fTarget;
void* fVertices;
void* fIndices;
};
////////////////////////////////////////////////////////////////////////////
class AutoClipRestore : ::GrNoncopyable {
public:
AutoClipRestore(GrDrawTarget* target) {
fTarget = target;
fClip = fTarget->getClip();
}
~AutoClipRestore() {
fTarget->setClip(fClip);
}
private:
GrDrawTarget* fTarget;
const GrClipData* fClip;
};
////////////////////////////////////////////////////////////////////////////
class AutoGeometryPush : ::GrNoncopyable {
public:
AutoGeometryPush(GrDrawTarget* target) {
GrAssert(NULL != target);
fTarget = target;
target->pushGeometrySource();
}
~AutoGeometryPush() {
fTarget->popGeometrySource();
}
private:
GrDrawTarget* fTarget;
};
////////////////////////////////////////////////////////////////////////////
// Helpers for picking apart vertex layouts
/**
* Helper function to compute the size of a vertex from a vertex layout
* @return size of a single vertex.
*/
static size_t VertexSize(GrVertexLayout vertexLayout);
/**
* Helper function for determining the index of texture coordinates that
* is input for a texture stage. Note that a stage may instead use positions
* as texture coordinates, in which case the result of the function is
* indistinguishable from the case when the stage is disabled.
*
* @param stage the stage to query
* @param vertexLayout layout to query
*
* @return the texture coordinate index or -1 if the stage doesn't use
* separate (non-position) texture coordinates.
*/
static int VertexTexCoordsForStage(int stage, GrVertexLayout vertexLayout);
/**
* Helper function to compute the offset of texture coordinates in a vertex
* @return offset of texture coordinates in vertex layout or -1 if the
* layout has no texture coordinates. Will be 0 if positions are
* used as texture coordinates for the stage.
*/
static int VertexStageCoordOffset(int stage, GrVertexLayout vertexLayout);
/**
* Helper function to compute the offset of the color in a vertex
* @return offset of color in vertex layout or -1 if the
* layout has no color.
*/
static int VertexColorOffset(GrVertexLayout vertexLayout);
/**
* Helper function to compute the offset of the coverage in a vertex
* @return offset of coverage in vertex layout or -1 if the
* layout has no coverage.
*/
static int VertexCoverageOffset(GrVertexLayout vertexLayout);
/**
* Helper function to compute the offset of the edge pts in a vertex
* @return offset of edge in vertex layout or -1 if the
* layout has no edge.
*/
static int VertexEdgeOffset(GrVertexLayout vertexLayout);
/**
* Helper function to determine if vertex layout contains explicit texture
* coordinates of some index.
*
* @param coordIndex the tex coord index to query
* @param vertexLayout layout to query
*
* @return true if vertex specifies texture coordinates for the index,
* false otherwise.
*/
static bool VertexUsesTexCoordIdx(int coordIndex,
GrVertexLayout vertexLayout);
/**
* Helper function to compute the size of each vertex and the offsets of
* texture coordinates and color. Determines tex coord offsets by tex coord
* index rather than by stage. (Each stage can be mapped to any t.c. index
* by StageTexCoordVertexLayoutBit.)
*
* @param vertexLayout the layout to query
* @param texCoordOffsetsByIdx after return it is the offset of each
* tex coord index in the vertex or -1 if
* index isn't used. (optional)
* @param colorOffset after return it is the offset of the
* color field in each vertex, or -1 if
* there aren't per-vertex colors. (optional)
* @param coverageOffset after return it is the offset of the
* coverage field in each vertex, or -1 if
* there aren't per-vertex coeverages.
* (optional)
* @param edgeOffset after return it is the offset of the
* edge eq field in each vertex, or -1 if
* there aren't per-vertex edge equations.
* (optional)
* @return size of a single vertex
*/
static int VertexSizeAndOffsetsByIdx(GrVertexLayout vertexLayout,
int texCoordOffsetsByIdx[GrDrawState::kMaxTexCoords],
int *colorOffset,
int *coverageOffset,
int* edgeOffset);
/**
* Helper function to compute the size of each vertex and the offsets of
* texture coordinates and color. Determines tex coord offsets by stage
* rather than by index. (Each stage can be mapped to any t.c. index
* by StageTexCoordVertexLayoutBit.) If a stage uses positions for
* tex coords then that stage's offset will be 0 (positions are always at 0).
*
* @param vertexLayout the layout to query
* @param texCoordOffsetsByStage after return it is the offset of each
* tex coord index in the vertex or -1 if
* index isn't used. (optional)
* @param colorOffset after return it is the offset of the
* color field in each vertex, or -1 if
* there aren't per-vertex colors.
* (optional)
* @param coverageOffset after return it is the offset of the
* coverage field in each vertex, or -1 if
* there aren't per-vertex coeverages.
* (optional)
* @param edgeOffset after return it is the offset of the
* edge eq field in each vertex, or -1 if
* there aren't per-vertex edge equations.
* (optional)
* @return size of a single vertex
*/
static int VertexSizeAndOffsetsByStage(GrVertexLayout vertexLayout,
int texCoordOffsetsByStage[GrDrawState::kNumStages],
int* colorOffset,
int* coverageOffset,
int* edgeOffset);
/**
* Accessing positions, texture coords, or colors, of a vertex within an
* array is a hassle involving casts and simple math. These helpers exist
* to keep GrDrawTarget clients' code a bit nicer looking.
*/
/**
* Gets a pointer to a GrPoint of a vertex's position or texture
* coordinate.
* @param vertices the vetex array
* @param vertexIndex the index of the vertex in the array
* @param vertexSize the size of each vertex in the array
* @param offset the offset in bytes of the vertex component.
* Defaults to zero (corresponding to vertex position)
* @return pointer to the vertex component as a GrPoint
*/
static GrPoint* GetVertexPoint(void* vertices,
int vertexIndex,
int vertexSize,
int offset = 0) {
intptr_t start = GrTCast<intptr_t>(vertices);
return GrTCast<GrPoint*>(start + offset +
vertexIndex * vertexSize);
}
static const GrPoint* GetVertexPoint(const void* vertices,
int vertexIndex,
int vertexSize,
int offset = 0) {
intptr_t start = GrTCast<intptr_t>(vertices);
return GrTCast<const GrPoint*>(start + offset +
vertexIndex * vertexSize);
}
/**
* Gets a pointer to a GrColor inside a vertex within a vertex array.
* @param vertices the vetex array
* @param vertexIndex the index of the vertex in the array
* @param vertexSize the size of each vertex in the array
* @param offset the offset in bytes of the vertex color
* @return pointer to the vertex component as a GrColor
*/
static GrColor* GetVertexColor(void* vertices,
int vertexIndex,
int vertexSize,
int offset) {
intptr_t start = GrTCast<intptr_t>(vertices);
return GrTCast<GrColor*>(start + offset +
vertexIndex * vertexSize);
}
static const GrColor* GetVertexColor(const void* vertices,
int vertexIndex,
int vertexSize,
int offset) {
const intptr_t start = GrTCast<intptr_t>(vertices);
return GrTCast<const GrColor*>(start + offset +
vertexIndex * vertexSize);
}
static void VertexLayoutUnitTest();
protected:
/**
* Optimizations for blending / coverage to be applied based on the current
* state.
* Subclasses that actually draw (as opposed to those that just buffer for
* playback) must implement the flags that replace the output color.
*/
enum BlendOptFlags {
/**
* No optimization
*/
kNone_BlendOpt = 0,
/**
* Don't draw at all
*/
kSkipDraw_BlendOptFlag = 0x2,
/**
* Emit the src color, disable HW blending (replace dst with src)
*/
kDisableBlend_BlendOptFlag = 0x4,
/**
* The coverage value does not have to be computed separately from
* alpha, the the output color can be the modulation of the two.
*/
kCoverageAsAlpha_BlendOptFlag = 0x1,
/**
* Instead of emitting a src color, emit coverage in the alpha channel
* and r,g,b are "don't cares".
*/
kEmitCoverage_BlendOptFlag = 0x10,
/**
* Emit transparent black instead of the src color, no need to compute
* coverage.
*/
kEmitTransBlack_BlendOptFlag = 0x8,
};
GR_DECL_BITFIELD_OPS_FRIENDS(BlendOptFlags);
// Determines what optimizations can be applied based on the blend.
// The coeffecients may have to be tweaked in order for the optimization
// to work. srcCoeff and dstCoeff are optional params that receive the
// tweaked coeffecients.
// Normally the function looks at the current state to see if coverage
// is enabled. By setting forceCoverage the caller can speculatively
// determine the blend optimizations that would be used if there was
// partial pixel coverage
BlendOptFlags getBlendOpts(bool forceCoverage = false,
GrBlendCoeff* srcCoeff = NULL,
GrBlendCoeff* dstCoeff = NULL) const;
// determine if src alpha is guaranteed to be one for all src pixels
bool srcAlphaWillBeOne(GrVertexLayout vertexLayout) const;
enum GeometrySrcType {
kNone_GeometrySrcType, //<! src has not been specified
kReserved_GeometrySrcType, //<! src was set using reserve*Space
kArray_GeometrySrcType, //<! src was set using set*SourceToArray
kBuffer_GeometrySrcType //<! src was set using set*SourceToBuffer
};
struct GeometrySrcState {
GeometrySrcType fVertexSrc;
union {
// valid if src type is buffer
const GrVertexBuffer* fVertexBuffer;
// valid if src type is reserved or array
int fVertexCount;
};
GeometrySrcType fIndexSrc;
union {
// valid if src type is buffer
const GrIndexBuffer* fIndexBuffer;
// valid if src type is reserved or array
int fIndexCount;
};
GrVertexLayout fVertexLayout;
};
int indexCountInCurrentSource() const {
const GeometrySrcState& src = this->getGeomSrc();
switch (src.fIndexSrc) {
case kNone_GeometrySrcType:
return 0;
case kReserved_GeometrySrcType:
case kArray_GeometrySrcType:
return src.fIndexCount;
case kBuffer_GeometrySrcType:
return src.fIndexBuffer->sizeInBytes() / sizeof(uint16_t);
default:
GrCrash("Unexpected Index Source.");
return 0;
}
}
bool isStageEnabled(int stage) const {
return this->getDrawState().isStageEnabled(stage);
}
// A sublcass can optionally overload this function to be notified before
// vertex and index space is reserved.
virtual void willReserveVertexAndIndexSpace(GrVertexLayout vertexLayout,
int vertexCount,
int indexCount) {}
// implemented by subclass to allocate space for reserved geom
virtual bool onReserveVertexSpace(GrVertexLayout vertexLayout,
int vertexCount,
void** vertices) = 0;
virtual bool onReserveIndexSpace(int indexCount, void** indices) = 0;
// implemented by subclass to handle release of reserved geom space
virtual void releaseReservedVertexSpace() = 0;
virtual void releaseReservedIndexSpace() = 0;
// subclass must consume array contents when set
virtual void onSetVertexSourceToArray(const void* vertexArray,
int vertexCount) = 0;
virtual void onSetIndexSourceToArray(const void* indexArray,
int indexCount) = 0;
// subclass is notified that geom source will be set away from an array
virtual void releaseVertexArray() = 0;
virtual void releaseIndexArray() = 0;
// subclass overrides to be notified just before geo src state
// is pushed/popped.
virtual void geometrySourceWillPush() = 0;
virtual void geometrySourceWillPop(const GeometrySrcState& restoredState) = 0;
// subclass called to perform drawing
virtual void onDrawIndexed(GrPrimitiveType type,
int startVertex,
int startIndex,
int vertexCount,
int indexCount) = 0;
virtual void onDrawNonIndexed(GrPrimitiveType type,
int startVertex,
int vertexCount) = 0;
virtual void onStencilPath(const GrPath*, GrPathFill) = 0;
// subclass overrides to be notified when clip is set. Must call
// INHERITED::clipwillBeSet
virtual void clipWillBeSet(const GrClipData* clipData) {}
// Helpers for drawRect, protected so subclasses that override drawRect
// can use them.
static GrVertexLayout GetRectVertexLayout(const GrRect* srcRects[]);
static void SetRectVertices(const GrRect& rect,
const GrMatrix* matrix,
const GrRect* srcRects[],
const GrMatrix* srcMatrices[],
GrVertexLayout layout,
void* vertices);
// accessors for derived classes
const GeometrySrcState& getGeomSrc() const {
return fGeoSrcStateStack.back();
}
// it is prefereable to call this rather than getGeomSrc()->fVertexLayout
// because of the assert.
GrVertexLayout getVertexLayout() const {
// the vertex layout is only valid if a vertex source has been
// specified.
GrAssert(this->getGeomSrc().fVertexSrc != kNone_GeometrySrcType);
return this->getGeomSrc().fVertexLayout;
}
const GrClipData* fClip;
GrDrawState* fDrawState;
GrDrawState fDefaultDrawState;
Caps fCaps;
// subclasses must call this in their destructors to ensure all vertex
// and index sources have been released (including those held by
// pushGeometrySource())
void releaseGeometry();
private:
// helpers for reserving vertex and index space.
bool reserveVertexSpace(GrVertexLayout vertexLayout,
int vertexCount,
void** vertices);
bool reserveIndexSpace(int indexCount, void** indices);
// called by drawIndexed and drawNonIndexed. Use a negative indexCount to
// indicate non-indexed drawing.
bool checkDraw(GrPrimitiveType type, int startVertex,
int startIndex, int vertexCount,
int indexCount) const;
// called when setting a new vert/idx source to unref prev vb/ib
void releasePreviousVertexSource();
void releasePreviousIndexSource();
enum {
kPreallocGeoSrcStateStackCnt = 4,
};
SkSTArray<kPreallocGeoSrcStateStackCnt,
GeometrySrcState, true> fGeoSrcStateStack;
typedef GrRefCnt INHERITED;
};
GR_MAKE_BITFIELD_OPS(GrDrawTarget::BlendOptFlags);
#endif