1/*
2 * Copyright 2010 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#ifndef GrDrawTarget_DEFINED
9#define GrDrawTarget_DEFINED
10
11#include "GrClipData.h"
12#include "GrContext.h"
13#include "GrDrawState.h"
14#include "GrIndexBuffer.h"
15#include "GrTraceMarker.h"
16
17#include "SkClipStack.h"
18#include "SkMatrix.h"
19#include "SkPath.h"
20#include "SkStrokeRec.h"
21#include "SkTArray.h"
22#include "SkTLazy.h"
23#include "SkTypes.h"
24#include "SkXfermode.h"
25
26class GrClipData;
27class GrDrawTargetCaps;
28class GrPath;
29class GrVertexBuffer;
30
31class GrDrawTarget : public SkRefCnt {
32protected:
33    class DrawInfo;
34
35public:
36    SK_DECLARE_INST_COUNT(GrDrawTarget)
37
38    ///////////////////////////////////////////////////////////////////////////
39
40    // The context may not be fully constructed and should not be used during GrDrawTarget
41    // construction.
42    GrDrawTarget(GrContext* context);
43    virtual ~GrDrawTarget();
44
45    /**
46     * Gets the capabilities of the draw target.
47     */
48    const GrDrawTargetCaps* caps() const { return fCaps.get(); }
49
50    /**
51     * Sets the current clip to the region specified by clip. All draws will be
52     * clipped against this clip if kClip_StateBit is enabled.
53     *
54     * Setting the clip may (or may not) zero out the client's stencil bits.
55     *
56     * @param description of the clipping region
57     */
58    void setClip(const GrClipData* clip);
59
60    /**
61     * Gets the current clip.
62     *
63     * @return the clip.
64     */
65    const GrClipData* getClip() const;
66
67    /**
68     * Sets the draw state object for the draw target. Note that this does not
69     * make a copy. The GrDrawTarget will take a reference to passed object.
70     * Passing NULL will cause the GrDrawTarget to use its own internal draw
71     * state object rather than an externally provided one.
72     */
73    void setDrawState(GrDrawState*  drawState);
74
75    /**
76     * Read-only access to the GrDrawTarget's current draw state.
77     */
78    const GrDrawState& getDrawState() const { return *fDrawState; }
79
80    /**
81     * Read-write access to the GrDrawTarget's current draw state. Note that
82     * this doesn't ref.
83     */
84    GrDrawState* drawState() { return fDrawState; }
85
86    /**
87     * Color alpha and coverage are two inputs to the drawing pipeline. For some
88     * blend modes it is safe to fold the coverage into constant or per-vertex
89     * color alpha value. For other blend modes they must be handled separately.
90     * Depending on features available in the underlying 3D API this may or may
91     * not be possible.
92     *
93     * This function considers the current draw state and the draw target's
94     * capabilities to determine whether coverage can be handled correctly. The
95     * following assumptions are made:
96     *    1. The caller intends to somehow specify coverage. This can be
97     *       specified either by enabling a coverage stage on the GrDrawState or
98     *       via the vertex layout.
99     *    2. Other than enabling coverage stages or enabling coverage in the
100     *       layout, the current configuration of the target's GrDrawState is as
101     *       it will be at draw time.
102     */
103    bool canApplyCoverage() const;
104
105    /** When we're using coverage AA but the blend is incompatible (given gpu
106     * limitations) we should disable AA. */
107    bool shouldDisableCoverageAAForBlend() {
108        // Enable below if we should draw with AA even when it produces
109        // incorrect blending.
110        // return false;
111        return !this->canApplyCoverage();
112    }
113
114    /**
115     * Given the current draw state and hw support, will HW AA lines be used (if
116     * a line primitive type is drawn)?
117     */
118    bool willUseHWAALines() const;
119
120    /**
121     * There are three types of "sources" of geometry (vertices and indices) for
122     * draw calls made on the target. When performing an indexed draw, the
123     * indices and vertices can use different source types. Once a source is
124     * specified it can be used for multiple draws. However, the time at which
125     * the geometry data is no longer editable depends on the source type.
126     *
127     * Sometimes it is necessary to perform a draw while upstack code has
128     * already specified geometry that it isn't finished with. So there are push
129     * and pop methods. This allows the client to push the sources, draw
130     * something using alternate sources, and then pop to restore the original
131     * sources.
132     *
133     * Aside from pushes and pops, a source remains valid until another source
134     * is set or resetVertexSource / resetIndexSource is called. Drawing from
135     * a reset source is an error.
136     *
137     * The three types of sources are:
138     *
139     * 1. A cpu array (set*SourceToArray). This is useful when the caller
140     *    already provided vertex data in a format compatible with a
141     *    GrVertexLayout. The data in the array is consumed at the time that
142     *    set*SourceToArray is called and subsequent edits to the array will not
143     *    be reflected in draws.
144     *
145     * 2. Reserve. This is most useful when the caller has data it must
146     *    transform before drawing and is not long-lived. The caller requests
147     *    that the draw target make room for some amount of vertex and/or index
148     *    data. The target provides ptrs to hold the vertex and/or index data.
149     *
150     *    The data is writable up until the next drawIndexed, drawNonIndexed,
151     *    drawIndexedInstances, drawRect, copySurface, or pushGeometrySource. At
152     *    this point the data is frozen and the ptrs are no longer valid.
153     *
154     *    Where the space is allocated and how it is uploaded to the GPU is
155     *    subclass-dependent.
156     *
157     * 3. Vertex and Index Buffers. This is most useful for geometry that will
158     *    is long-lived. When the data in the buffer is consumed depends on the
159     *    GrDrawTarget subclass. For deferred subclasses the caller has to
160     *    guarantee that the data is still available in the buffers at playback.
161     *    (TODO: Make this more automatic as we have done for read/write pixels)
162     *
163     * The size of each vertex is determined by querying the current GrDrawState.
164     */
165
166    /**
167     * Reserves space for vertices and/or indices. Zero can be specifed as
168     * either the vertex or index count if the caller desires to only reserve
169     * space for only indices or only vertices. If zero is specifed for
170     * vertexCount then the vertex source will be unmodified and likewise for
171     * indexCount.
172     *
173     * If the function returns true then the reserve suceeded and the vertices
174     * and indices pointers will point to the space created.
175     *
176     * If the target cannot make space for the request then this function will
177     * return false. If vertexCount was non-zero then upon failure the vertex
178     * source is reset and likewise for indexCount.
179     *
180     * The pointers to the space allocated for vertices and indices remain valid
181     * until a drawIndexed, drawNonIndexed, drawIndexedInstances, drawRect,
182     * copySurface, or push/popGeomtrySource is called. At that point logically a
183     * snapshot of the data is made and the pointers are invalid.
184     *
185     * @param vertexCount  the number of vertices to reserve space for. Can be
186     *                     0. Vertex size is queried from the current GrDrawState.
187     * @param indexCount   the number of indices to reserve space for. Can be 0.
188     * @param vertices     will point to reserved vertex space if vertexCount is
189     *                     non-zero. Illegal to pass NULL if vertexCount > 0.
190     * @param indices      will point to reserved index space if indexCount is
191     *                     non-zero. Illegal to pass NULL if indexCount > 0.
192     */
193     bool reserveVertexAndIndexSpace(int vertexCount,
194                                     int indexCount,
195                                     void** vertices,
196                                     void** indices);
197
198    /**
199     * Provides hints to caller about the number of vertices and indices
200     * that can be allocated cheaply. This can be useful if caller is reserving
201     * space but doesn't know exactly how much geometry is needed.
202     *
203     * Also may hint whether the draw target should be flushed first. This is
204     * useful for deferred targets.
205     *
206     * @param vertexCount  in: hint about how many vertices the caller would
207     *                     like to allocate. Vertex size is queried from the
208     *                     current GrDrawState.
209     *                     out: a hint about the number of vertices that can be
210     *                     allocated cheaply. Negative means no hint.
211     *                     Ignored if NULL.
212     * @param indexCount   in: hint about how many indices the caller would
213     *                     like to allocate.
214     *                     out: a hint about the number of indices that can be
215     *                     allocated cheaply. Negative means no hint.
216     *                     Ignored if NULL.
217     *
218     * @return  true if target should be flushed based on the input values.
219     */
220    virtual bool geometryHints(int* vertexCount,
221                               int* indexCount) const;
222
223    /**
224     * Sets source of vertex data for the next draw. Array must contain
225     * the vertex data when this is called.
226     *
227     * @param vertexArray   cpu array containing vertex data.
228     * @param vertexCount   the number of vertices in the array. Vertex size is
229     *                      queried from the current GrDrawState.
230     */
231    void setVertexSourceToArray(const void* vertexArray, int vertexCount);
232
233    /**
234     * Sets source of index data for the next indexed draw. Array must contain
235     * the indices when this is called.
236     *
237     * @param indexArray    cpu array containing index data.
238     * @param indexCount    the number of indices in the array.
239     */
240    void setIndexSourceToArray(const void* indexArray, int indexCount);
241
242    /**
243     * Sets source of vertex data for the next draw. Data does not have to be
244     * in the buffer until drawIndexed, drawNonIndexed, or drawIndexedInstances.
245     *
246     * @param buffer        vertex buffer containing vertex data. Must be
247     *                      unlocked before draw call. Vertex size is queried
248     *                      from current GrDrawState.
249     */
250    void setVertexSourceToBuffer(const GrVertexBuffer* buffer);
251
252    /**
253     * Sets source of index data for the next indexed draw. Data does not have
254     * to be in the buffer until drawIndexed.
255     *
256     * @param buffer index buffer containing indices. Must be unlocked
257     *               before indexed draw call.
258     */
259    void setIndexSourceToBuffer(const GrIndexBuffer* buffer);
260
261    /**
262     * Resets vertex source. Drawing from reset vertices is illegal. Set vertex
263     * source to reserved, array, or buffer before next draw. May be able to free
264     * up temporary storage allocated by setVertexSourceToArray or
265     * reserveVertexSpace.
266     */
267    void resetVertexSource();
268
269    /**
270     * Resets index source. Indexed Drawing from reset indices is illegal. Set
271     * index source to reserved, array, or buffer before next indexed draw. May
272     * be able to free up temporary storage allocated by setIndexSourceToArray
273     * or reserveIndexSpace.
274     */
275    void resetIndexSource();
276
277    /**
278     * Query to find out if the vertex or index source is reserved.
279     */
280    bool hasReservedVerticesOrIndices() const {
281        return kReserved_GeometrySrcType == this->getGeomSrc().fVertexSrc ||
282        kReserved_GeometrySrcType == this->getGeomSrc().fIndexSrc;
283    }
284
285    /**
286     * Pushes and resets the vertex/index sources. Any reserved vertex / index
287     * data is finalized (i.e. cannot be updated after the matching pop but can
288     * be drawn from). Must be balanced by a pop.
289     */
290    void pushGeometrySource();
291
292    /**
293     * Pops the vertex / index sources from the matching push.
294     */
295    void popGeometrySource();
296
297    /**
298     * Draws indexed geometry using the current state and current vertex / index
299     * sources.
300     *
301     * @param type         The type of primitives to draw.
302     * @param startVertex  the vertex in the vertex array/buffer corresponding
303     *                     to index 0
304     * @param startIndex   first index to read from index src.
305     * @param vertexCount  one greater than the max index.
306     * @param indexCount   the number of index elements to read. The index count
307     *                     is effectively trimmed to the last completely
308     *                     specified primitive.
309     * @param devBounds    optional bounds hint. This is a promise from the caller,
310     *                     not a request for clipping.
311     */
312    void drawIndexed(GrPrimitiveType type,
313                     int startVertex,
314                     int startIndex,
315                     int vertexCount,
316                     int indexCount,
317                     const SkRect* devBounds = NULL);
318
319    /**
320     * Draws non-indexed geometry using the current state and current vertex
321     * sources.
322     *
323     * @param type         The type of primitives to draw.
324     * @param startVertex  the vertex in the vertex array/buffer corresponding
325     *                     to index 0
326     * @param vertexCount  one greater than the max index.
327     * @param devBounds    optional bounds hint. This is a promise from the caller,
328     *                     not a request for clipping.
329     */
330    void drawNonIndexed(GrPrimitiveType type,
331                        int startVertex,
332                        int vertexCount,
333                        const SkRect* devBounds = NULL);
334
335    /**
336     * Draws path into the stencil buffer. The fill must be either even/odd or
337     * winding (not inverse or hairline). It will respect the HW antialias flag
338     * on the draw state (if possible in the 3D API).
339     */
340    void stencilPath(const GrPath*, SkPath::FillType fill);
341
342    /**
343     * Draws a path. Fill must not be a hairline. It will respect the HW
344     * antialias flag on the draw state (if possible in the 3D API).
345     */
346    void drawPath(const GrPath*, SkPath::FillType fill);
347
348    /**
349     * Draws many paths. It will respect the HW
350     * antialias flag on the draw state (if possible in the 3D API).
351     *
352     * @param transforms array of 2d affine transformations, one for each path.
353     * @param fill the fill type for drawing all the paths. Fill must not be a
354     *             hairline.
355     * @param stroke the stroke for drawing all the paths.
356     */
357    void drawPaths(int pathCount, const GrPath** paths,
358                   const SkMatrix* transforms, SkPath::FillType fill,
359                   SkStrokeRec::Style stroke);
360
361    /**
362     * Helper function for drawing rects. It performs a geometry src push and pop
363     * and thus will finalize any reserved geometry.
364     *
365     * @param rect        the rect to draw
366     * @param matrix      optional matrix applied to rect (before viewMatrix)
367     * @param localRect   optional rect that specifies local coords to map onto
368     *                    rect. If NULL then rect serves as the local coords.
369     * @param localMatrix optional matrix applied to localRect. If
370     *                    srcRect is non-NULL and srcMatrix is non-NULL
371     *                    then srcRect will be transformed by srcMatrix.
372     *                    srcMatrix can be NULL when no srcMatrix is desired.
373     */
374    void drawRect(const SkRect& rect,
375                  const SkMatrix* matrix,
376                  const SkRect* localRect,
377                  const SkMatrix* localMatrix) {
378        AutoGeometryPush agp(this);
379        this->onDrawRect(rect, matrix, localRect, localMatrix);
380    }
381
382    /**
383     * Helper for drawRect when the caller doesn't need separate local rects or matrices.
384     */
385    void drawSimpleRect(const SkRect& rect, const SkMatrix* matrix = NULL) {
386        this->drawRect(rect, matrix, NULL, NULL);
387    }
388    void drawSimpleRect(const SkIRect& irect, const SkMatrix* matrix = NULL) {
389        SkRect rect = SkRect::Make(irect);
390        this->drawRect(rect, matrix, NULL, NULL);
391    }
392
393    /**
394     * This call is used to draw multiple instances of some geometry with a
395     * given number of vertices (V) and indices (I) per-instance. The indices in
396     * the index source must have the form i[k+I] == i[k] + V. Also, all indices
397     * i[kI] ... i[(k+1)I-1] must be elements of the range kV ... (k+1)V-1. As a
398     * concrete example, the following index buffer for drawing a series of
399     * quads each as two triangles each satisfies these conditions with V=4 and
400     * I=6:
401     *      (0,1,2,0,2,3, 4,5,6,4,6,7, 8,9,10,8,10,11, ...)
402     *
403     * The call assumes that the pattern of indices fills the entire index
404     * source. The size of the index buffer limits the number of instances that
405     * can be drawn by the GPU in a single draw. However, the caller may specify
406     * any (positive) number for instanceCount and if necessary multiple GPU
407     * draws will be issued. Moreover, when drawIndexedInstances is called
408     * multiple times it may be possible for GrDrawTarget to group them into a
409     * single GPU draw.
410     *
411     * @param type          the type of primitives to draw
412     * @param instanceCount the number of instances to draw. Each instance
413     *                      consists of verticesPerInstance vertices indexed by
414     *                      indicesPerInstance indices drawn as the primitive
415     *                      type specified by type.
416     * @param verticesPerInstance   The number of vertices in each instance (V
417     *                              in the above description).
418     * @param indicesPerInstance    The number of indices in each instance (I
419     *                              in the above description).
420     * @param devBounds    optional bounds hint. This is a promise from the caller,
421     *                     not a request for clipping.
422     */
423    void drawIndexedInstances(GrPrimitiveType type,
424                              int instanceCount,
425                              int verticesPerInstance,
426                              int indicesPerInstance,
427                              const SkRect* devBounds = NULL);
428
429    /**
430     * Clear the current render target if one isn't passed in. Ignores the
431     * clip and all other draw state (blend mode, stages, etc). Clears the
432     * whole thing if rect is NULL, otherwise just the rect. If canIgnoreRect
433     * is set then the entire render target can be optionally cleared.
434     */
435    virtual void clear(const SkIRect* rect,
436                       GrColor color,
437                       bool canIgnoreRect,
438                       GrRenderTarget* renderTarget = NULL) = 0;
439
440    /**
441     * Discards the contents render target. NULL indicates that the current render target should
442     * be discarded.
443     **/
444    virtual void discard(GrRenderTarget* = NULL) = 0;
445
446    /**
447     * Called at start and end of gpu trace marking
448     * GR_CREATE_GPU_TRACE_MARKER(marker_str, target) will automatically call these at the start
449     * and end of a code block respectively
450     */
451    void addGpuTraceMarker(const GrGpuTraceMarker* marker);
452    void removeGpuTraceMarker(const GrGpuTraceMarker* marker);
453
454    /**
455     * Takes the current active set of markers and stores them for later use. Any current marker
456     * in the active set is removed from the active set and the targets remove function is called.
457     * These functions do not work as a stack so you cannot call save a second time before calling
458     * restore. Also, it is assumed that when restore is called the current active set of markers
459     * is empty. When the stored markers are added back into the active set, the targets add marker
460     * is called.
461     */
462    void saveActiveTraceMarkers();
463    void restoreActiveTraceMarkers();
464
465    /**
466     * Copies a pixel rectangle from one surface to another. This call may finalize
467     * reserved vertex/index data (as though a draw call was made). The src pixels
468     * copied are specified by srcRect. They are copied to a rect of the same
469     * size in dst with top left at dstPoint. If the src rect is clipped by the
470     * src bounds then  pixel values in the dst rect corresponding to area clipped
471     * by the src rect are not overwritten. This method can fail and return false
472     * depending on the type of surface, configs, etc, and the backend-specific
473     * limitations. If rect is clipped out entirely by the src or dst bounds then
474     * true is returned since there is no actual copy necessary to succeed.
475     */
476    bool copySurface(GrSurface* dst,
477                     GrSurface* src,
478                     const SkIRect& srcRect,
479                     const SkIPoint& dstPoint);
480    /**
481     * Function that determines whether a copySurface call would succeed without
482     * performing the copy.
483     */
484    bool canCopySurface(GrSurface* dst,
485                        GrSurface* src,
486                        const SkIRect& srcRect,
487                        const SkIPoint& dstPoint);
488
489    /**
490     * This is can be called before allocating a texture to be a dst for copySurface. It will
491     * populate the origin, config, and flags fields of the desc such that copySurface is more
492     * likely to succeed and be efficient.
493     */
494    virtual void initCopySurfaceDstDesc(const GrSurface* src, GrTextureDesc* desc);
495
496
497    /**
498     * Release any resources that are cached but not currently in use. This
499     * is intended to give an application some recourse when resources are low.
500     */
501    virtual void purgeResources() {};
502
503    /**
504     * For subclass internal use to invoke a call to onDraw(). See DrawInfo below.
505     */
506    void executeDraw(const DrawInfo& info) { this->onDraw(info); }
507
508    /**
509     * For subclass internal use to invoke a call to onDrawPath().
510     */
511    void executeDrawPath(const GrPath* path, SkPath::FillType fill,
512                         const GrDeviceCoordTexture* dstCopy) {
513        this->onDrawPath(path, fill, dstCopy);
514    }
515
516    /**
517     * For subclass internal use to invoke a call to onDrawPaths().
518     */
519    void executeDrawPaths(int pathCount, const GrPath** paths,
520                          const SkMatrix* transforms, SkPath::FillType fill,
521                          SkStrokeRec::Style stroke,
522                          const GrDeviceCoordTexture* dstCopy) {
523        this->onDrawPaths(pathCount, paths, transforms, fill, stroke, dstCopy);
524    }
525
526    inline bool isGpuTracingEnabled() const {
527        return this->getContext()->isGpuTracingEnabled();
528    }
529
530    ////////////////////////////////////////////////////////////////////////////
531
532    /**
533     * See AutoStateRestore below.
534     */
535    enum ASRInit {
536        kPreserve_ASRInit,
537        kReset_ASRInit
538    };
539
540    /**
541     * Saves off the current state and restores it in the destructor. It will
542     * install a new GrDrawState object on the target (setDrawState) and restore
543     * the previous one in the destructor. The caller should call drawState() to
544     * get the new draw state after the ASR is installed.
545     *
546     * GrDrawState* state = target->drawState();
547     * AutoStateRestore asr(target, GrDrawTarget::kReset_ASRInit).
548     * state->setRenderTarget(rt); // state refers to the GrDrawState set on
549     *                             // target before asr was initialized.
550     *                             // Therefore, rt is set on the GrDrawState
551     *                             // that will be restored after asr's
552     *                             // destructor rather than target's current
553     *                             // GrDrawState.
554     */
555    class AutoStateRestore : public ::SkNoncopyable {
556    public:
557        /**
558         * Default ASR will have no effect unless set() is subsequently called.
559         */
560        AutoStateRestore();
561
562        /**
563         * Saves the state on target. The state will be restored when the ASR
564         * is destroyed. If this constructor is used do not call set().
565         *
566         * @param init  Should the newly installed GrDrawState be a copy of the
567         *              previous state or a default-initialized GrDrawState.
568         * @param viewMatrix Optional view matrix. If init = kPreserve then the draw state's
569         *                   matrix will be preconcat'ed with the param. All stages will be
570                             updated to compensate for the matrix change. If init == kReset
571                             then the draw state's matrix will be this matrix.
572         */
573        AutoStateRestore(GrDrawTarget* target, ASRInit init, const SkMatrix* viewMatrix = NULL);
574
575        ~AutoStateRestore();
576
577        /**
578         * Saves the state on target. The state will be restored when the ASR
579         * is destroyed. This should only be called once per ASR object and only
580         * when the default constructor was used. For nested saves use multiple
581         * ASR objects.
582         *
583         * @param init  Should the newly installed GrDrawState be a copy of the
584         *              previous state or a default-initialized GrDrawState.
585         * @param viewMatrix Optional view matrix. If init = kPreserve then the draw state's
586         *                   matrix will be preconcat'ed with the param. All stages will be
587                             updated to compensate for the matrix change. If init == kReset
588                             then the draw state's matrix will be this matrix.
589         */
590        void set(GrDrawTarget* target, ASRInit init, const SkMatrix* viewMatrix = NULL);
591
592        /**
593         * Like set() but makes the view matrix identity. When init is kReset it is as though
594         * NULL was passed to set's viewMatrix param. When init is kPreserve it is as though
595         * the inverse view matrix was passed. If kPreserve is passed and the draw state's matrix
596         * is not invertible then this may fail.
597         */
598        bool setIdentity(GrDrawTarget* target, ASRInit init);
599
600    private:
601        GrDrawTarget*                       fDrawTarget;
602        SkTLazy<GrDrawState>                fTempState;
603        GrDrawState*                        fSavedState;
604    };
605
606    ////////////////////////////////////////////////////////////////////////////
607
608    class AutoReleaseGeometry : public ::SkNoncopyable {
609    public:
610        AutoReleaseGeometry(GrDrawTarget*  target,
611                            int            vertexCount,
612                            int            indexCount);
613        AutoReleaseGeometry();
614        ~AutoReleaseGeometry();
615        bool set(GrDrawTarget*  target,
616                 int            vertexCount,
617                 int            indexCount);
618        bool succeeded() const { return NULL != fTarget; }
619        void* vertices() const { SkASSERT(this->succeeded()); return fVertices; }
620        void* indices() const { SkASSERT(this->succeeded()); return fIndices; }
621        SkPoint* positions() const {
622            return static_cast<SkPoint*>(this->vertices());
623        }
624
625    private:
626        void reset();
627
628        GrDrawTarget* fTarget;
629        void*         fVertices;
630        void*         fIndices;
631    };
632
633    ////////////////////////////////////////////////////////////////////////////
634
635    class AutoClipRestore : public ::SkNoncopyable {
636    public:
637        AutoClipRestore(GrDrawTarget* target) {
638            fTarget = target;
639            fClip = fTarget->getClip();
640        }
641
642        AutoClipRestore(GrDrawTarget* target, const SkIRect& newClip);
643
644        ~AutoClipRestore() {
645            fTarget->setClip(fClip);
646        }
647    private:
648        GrDrawTarget*           fTarget;
649        const GrClipData*       fClip;
650        SkTLazy<SkClipStack>    fStack;
651        GrClipData              fReplacementClip;
652    };
653
654    ////////////////////////////////////////////////////////////////////////////
655
656    /**
657     * Saves the geometry src state at construction and restores in the destructor. It also saves
658     * and then restores the vertex attrib state.
659     */
660    class AutoGeometryPush : public ::SkNoncopyable {
661    public:
662        AutoGeometryPush(GrDrawTarget* target)
663            : fAttribRestore(target->drawState()) {
664            SkASSERT(NULL != target);
665            fTarget = target;
666            target->pushGeometrySource();
667        }
668
669        ~AutoGeometryPush() { fTarget->popGeometrySource(); }
670
671    private:
672        GrDrawTarget*                           fTarget;
673        GrDrawState::AutoVertexAttribRestore    fAttribRestore;
674    };
675
676    /**
677     * Combination of AutoGeometryPush and AutoStateRestore. The vertex attribs will be in default
678     * state regardless of ASRInit value.
679     */
680    class AutoGeometryAndStatePush : public ::SkNoncopyable {
681    public:
682        AutoGeometryAndStatePush(GrDrawTarget* target,
683                                 ASRInit init,
684                                 const SkMatrix* viewMatrix = NULL)
685            : fState(target, init, viewMatrix) {
686            SkASSERT(NULL != target);
687            fTarget = target;
688            target->pushGeometrySource();
689            if (kPreserve_ASRInit == init) {
690                target->drawState()->setDefaultVertexAttribs();
691            }
692        }
693
694        ~AutoGeometryAndStatePush() { fTarget->popGeometrySource(); }
695
696    private:
697        AutoStateRestore fState;
698        GrDrawTarget*    fTarget;
699    };
700
701    ///////////////////////////////////////////////////////////////////////////
702    // Draw execution tracking (for font atlases and other resources)
703    class DrawToken {
704    public:
705        DrawToken(GrDrawTarget* drawTarget, uint32_t drawID) :
706                  fDrawTarget(drawTarget), fDrawID(drawID) {}
707
708        bool isIssued() { return NULL != fDrawTarget && fDrawTarget->isIssued(fDrawID); }
709
710    private:
711        GrDrawTarget*  fDrawTarget;
712        uint32_t       fDrawID;   // this may wrap, but we're doing direct comparison
713                                  // so that should be okay
714    };
715
716    virtual DrawToken getCurrentDrawToken() { return DrawToken(this, 0); }
717
718protected:
719
720    enum GeometrySrcType {
721        kNone_GeometrySrcType,     //<! src has not been specified
722        kReserved_GeometrySrcType, //<! src was set using reserve*Space
723        kArray_GeometrySrcType,    //<! src was set using set*SourceToArray
724        kBuffer_GeometrySrcType    //<! src was set using set*SourceToBuffer
725    };
726
727    struct GeometrySrcState {
728        GeometrySrcType         fVertexSrc;
729        union {
730            // valid if src type is buffer
731            const GrVertexBuffer*   fVertexBuffer;
732            // valid if src type is reserved or array
733            int                     fVertexCount;
734        };
735
736        GeometrySrcType         fIndexSrc;
737        union {
738            // valid if src type is buffer
739            const GrIndexBuffer*    fIndexBuffer;
740            // valid if src type is reserved or array
741            int                     fIndexCount;
742        };
743
744        size_t                  fVertexSize;
745    };
746
747    int indexCountInCurrentSource() const {
748        const GeometrySrcState& src = this->getGeomSrc();
749        switch (src.fIndexSrc) {
750            case kNone_GeometrySrcType:
751                return 0;
752            case kReserved_GeometrySrcType:
753            case kArray_GeometrySrcType:
754                return src.fIndexCount;
755            case kBuffer_GeometrySrcType:
756                return static_cast<int>(src.fIndexBuffer->gpuMemorySize() / sizeof(uint16_t));
757            default:
758                SkFAIL("Unexpected Index Source.");
759                return 0;
760        }
761    }
762
763    // This method is called by copySurface  The srcRect is guaranteed to be entirely within the
764    // src bounds. Likewise, the dst rect implied by dstPoint and srcRect's width and height falls
765    // entirely within the dst. The default implementation will draw a rect from the src to the
766    // dst if the src is a texture and the dst is a render target and fail otherwise.
767    virtual bool onCopySurface(GrSurface* dst,
768                               GrSurface* src,
769                               const SkIRect& srcRect,
770                               const SkIPoint& dstPoint);
771
772    // Called to determine whether an onCopySurface call would succeed or not. This is useful for
773    // proxy subclasses to test whether the copy would succeed without executing it yet. Derived
774    // classes must keep this consistent with their implementation of onCopySurface(). The inputs
775    // are the same as onCopySurface(), i.e. srcRect and dstPoint are clipped to be inside the src
776    // and dst bounds.
777    virtual bool onCanCopySurface(GrSurface* dst,
778                                  GrSurface* src,
779                                  const SkIRect& srcRect,
780                                  const SkIPoint& dstPoint);
781
782    GrContext* getContext() { return fContext; }
783    const GrContext* getContext() const { return fContext; }
784
785    // A subclass may override this function if it wishes to be notified when the clip is changed.
786    // The override should call INHERITED::clipWillBeSet().
787    virtual void clipWillBeSet(const GrClipData* clipData);
788
789    // subclasses must call this in their destructors to ensure all vertex
790    // and index sources have been released (including those held by
791    // pushGeometrySource())
792    void releaseGeometry();
793
794    // accessors for derived classes
795    const GeometrySrcState& getGeomSrc() const { return fGeoSrcStateStack.back(); }
796    // it is preferable to call this rather than getGeomSrc()->fVertexSize because of the assert.
797    size_t getVertexSize() const {
798        // the vertex layout is only valid if a vertex source has been specified.
799        SkASSERT(this->getGeomSrc().fVertexSrc != kNone_GeometrySrcType);
800        return this->getGeomSrc().fVertexSize;
801    }
802
803    // Subclass must initialize this in its constructor.
804    SkAutoTUnref<const GrDrawTargetCaps> fCaps;
805
806    const GrTraceMarkerSet& getActiveTraceMarkers() { return fActiveTraceMarkers; }
807
808    /**
809     * Used to communicate draws to subclass's onDraw function.
810     */
811    class DrawInfo {
812    public:
813        DrawInfo(const DrawInfo& di) { (*this) = di; }
814        DrawInfo& operator =(const DrawInfo& di);
815
816        GrPrimitiveType primitiveType() const { return fPrimitiveType; }
817        int startVertex() const { return fStartVertex; }
818        int startIndex() const { return fStartIndex; }
819        int vertexCount() const { return fVertexCount; }
820        int indexCount() const { return fIndexCount; }
821        int verticesPerInstance() const { return fVerticesPerInstance; }
822        int indicesPerInstance() const { return fIndicesPerInstance; }
823        int instanceCount() const { return fInstanceCount; }
824
825        bool isIndexed() const { return fIndexCount > 0; }
826#ifdef SK_DEBUG
827        bool isInstanced() const; // this version is longer because of asserts
828#else
829        bool isInstanced() const { return fInstanceCount > 0; }
830#endif
831
832        // adds or remove instances
833        void adjustInstanceCount(int instanceOffset);
834        // shifts the start vertex
835        void adjustStartVertex(int vertexOffset);
836        // shifts the start index
837        void adjustStartIndex(int indexOffset);
838
839        void setDevBounds(const SkRect& bounds) {
840            fDevBoundsStorage = bounds;
841            fDevBounds = &fDevBoundsStorage;
842        }
843        const SkRect* getDevBounds() const { return fDevBounds; }
844
845        // NULL if no copy of the dst is needed for the draw.
846        const GrDeviceCoordTexture* getDstCopy() const {
847            if (NULL != fDstCopy.texture()) {
848                return &fDstCopy;
849            } else {
850                return NULL;
851            }
852        }
853
854    private:
855        DrawInfo() { fDevBounds = NULL; }
856
857        friend class GrDrawTarget;
858
859        GrPrimitiveType         fPrimitiveType;
860
861        int                     fStartVertex;
862        int                     fStartIndex;
863        int                     fVertexCount;
864        int                     fIndexCount;
865
866        int                     fInstanceCount;
867        int                     fVerticesPerInstance;
868        int                     fIndicesPerInstance;
869
870        SkRect                  fDevBoundsStorage;
871        SkRect*                 fDevBounds;
872
873        GrDeviceCoordTexture    fDstCopy;
874    };
875
876private:
877    // A subclass can optionally overload this function to be notified before
878    // vertex and index space is reserved.
879    virtual void willReserveVertexAndIndexSpace(int vertexCount, int indexCount) {}
880
881    // implemented by subclass to allocate space for reserved geom
882    virtual bool onReserveVertexSpace(size_t vertexSize, int vertexCount, void** vertices) = 0;
883    virtual bool onReserveIndexSpace(int indexCount, void** indices) = 0;
884    // implemented by subclass to handle release of reserved geom space
885    virtual void releaseReservedVertexSpace() = 0;
886    virtual void releaseReservedIndexSpace() = 0;
887    // subclass must consume array contents when set
888    virtual void onSetVertexSourceToArray(const void* vertexArray, int vertexCount) = 0;
889    virtual void onSetIndexSourceToArray(const void* indexArray, int indexCount) = 0;
890    // subclass is notified that geom source will be set away from an array
891    virtual void releaseVertexArray() = 0;
892    virtual void releaseIndexArray() = 0;
893    // subclass overrides to be notified just before geo src state is pushed/popped.
894    virtual void geometrySourceWillPush() = 0;
895    virtual void geometrySourceWillPop(const GeometrySrcState& restoredState) = 0;
896    // subclass called to perform drawing
897    virtual void onDraw(const DrawInfo&) = 0;
898    // Implementation of drawRect. The geometry src and vertex attribs will already
899    // be saved before this is called and restored afterwards. A subclass may override
900    // this to perform more optimal rect rendering. Its draws should be funneled through
901    // one of the public GrDrawTarget draw methods (e.g. drawNonIndexed,
902    // drawIndexedInstances, ...). The base class draws a two triangle fan using
903    // drawNonIndexed from reserved vertex space.
904    virtual void onDrawRect(const SkRect& rect,
905                            const SkMatrix* matrix,
906                            const SkRect* localRect,
907                            const SkMatrix* localMatrix);
908
909    virtual void onStencilPath(const GrPath*, SkPath::FillType) = 0;
910    virtual void onDrawPath(const GrPath*, SkPath::FillType,
911                            const GrDeviceCoordTexture* dstCopy) = 0;
912    virtual void onDrawPaths(int, const GrPath**, const SkMatrix*,
913                             SkPath::FillType, SkStrokeRec::Style,
914                             const GrDeviceCoordTexture* dstCopy) = 0;
915
916    virtual void didAddGpuTraceMarker() = 0;
917    virtual void didRemoveGpuTraceMarker() = 0;
918
919    // helpers for reserving vertex and index space.
920    bool reserveVertexSpace(size_t vertexSize,
921                            int vertexCount,
922                            void** vertices);
923    bool reserveIndexSpace(int indexCount, void** indices);
924
925    // called by drawIndexed and drawNonIndexed. Use a negative indexCount to
926    // indicate non-indexed drawing.
927    bool checkDraw(GrPrimitiveType type, int startVertex,
928                   int startIndex, int vertexCount,
929                   int indexCount) const;
930    // called when setting a new vert/idx source to unref prev vb/ib
931    void releasePreviousVertexSource();
932    void releasePreviousIndexSource();
933
934    // Makes a copy of the dst if it is necessary for the draw. Returns false if a copy is required
935    // but couldn't be made. Otherwise, returns true.
936    bool setupDstReadIfNecessary(DrawInfo* info) {
937        return this->setupDstReadIfNecessary(&info->fDstCopy, info->getDevBounds());
938    }
939    bool setupDstReadIfNecessary(GrDeviceCoordTexture* dstCopy, const SkRect* drawBounds);
940
941    // Check to see if this set of draw commands has been sent out
942    virtual bool       isIssued(uint32_t drawID) { return true; }
943
944    enum {
945        kPreallocGeoSrcStateStackCnt = 4,
946    };
947    SkSTArray<kPreallocGeoSrcStateStackCnt, GeometrySrcState, true> fGeoSrcStateStack;
948    const GrClipData*                                               fClip;
949    GrDrawState*                                                    fDrawState;
950    GrDrawState                                                     fDefaultDrawState;
951    // The context owns us, not vice-versa, so this ptr is not ref'ed by DrawTarget.
952    GrContext*                                                      fContext;
953    // To keep track that we always have at least as many debug marker adds as removes
954    int                                                             fGpuTraceMarkerCount;
955    GrTraceMarkerSet                                                fActiveTraceMarkers;
956    GrTraceMarkerSet                                                fStoredTraceMarkers;
957
958    typedef SkRefCnt INHERITED;
959};
960
961#endif
962