GrBufferAllocPool.cpp revision d686ac77c2c485c4a3302eda9c1de597a6f8c568 
1
2/*
3 * Copyright 2010 Google Inc.
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8
9
10#include "GrBufferAllocPool.h"
11#include "GrTypes.h"
12#include "GrVertexBuffer.h"
13#include "GrIndexBuffer.h"
14#include "GrGpu.h"
15
16#if GR_DEBUG
17    #define VALIDATE validate
18#else
19    static void VALIDATE(bool x = false) {}
20#endif
21
22// page size
23#define GrBufferAllocPool_MIN_BLOCK_SIZE ((size_t)1 << 12)
24
25GrBufferAllocPool::GrBufferAllocPool(GrGpu* gpu,
26                                     BufferType bufferType,
27                                     bool frequentResetHint,
28                                     size_t blockSize,
29                                     int preallocBufferCnt) :
30        fBlocks(GrMax(8, 2*preallocBufferCnt)) {
31
32    GrAssert(NULL != gpu);
33    fGpu = gpu;
34    fGpu->ref();
35    fGpuIsReffed = true;
36
37    fBufferType = bufferType;
38    fFrequentResetHint = frequentResetHint;
39    fBufferPtr = NULL;
40    fMinBlockSize = GrMax(GrBufferAllocPool_MIN_BLOCK_SIZE, blockSize);
41
42    fBytesInUse = 0;
43
44    fPreallocBuffersInUse = 0;
45    fPreallocBufferStartIdx = 0;
46    for (int i = 0; i < preallocBufferCnt; ++i) {
47        GrGeometryBuffer* buffer = this->createBuffer(fMinBlockSize);
48        if (NULL != buffer) {
49            *fPreallocBuffers.append() = buffer;
50        }
51    }
52}
53
54GrBufferAllocPool::~GrBufferAllocPool() {
55    VALIDATE();
56    if (fBlocks.count()) {
57        GrGeometryBuffer* buffer = fBlocks.back().fBuffer;
58        if (buffer->isLocked()) {
59            buffer->unlock();
60        }
61    }
62    while (!fBlocks.empty()) {
63        destroyBlock();
64    }
65    fPreallocBuffers.unrefAll();
66    releaseGpuRef();
67}
68
69void GrBufferAllocPool::releaseGpuRef() {
70    if (fGpuIsReffed) {
71        fGpu->unref();
72        fGpuIsReffed = false;
73    }
74}
75
76void GrBufferAllocPool::reset() {
77    VALIDATE();
78    fBytesInUse = 0;
79    if (fBlocks.count()) {
80        GrGeometryBuffer* buffer = fBlocks.back().fBuffer;
81        if (buffer->isLocked()) {
82            buffer->unlock();
83        }
84    }
85    // fPreallocBuffersInUse will be decremented down to zero in the while loop
86    int preallocBuffersInUse = fPreallocBuffersInUse;
87    while (!fBlocks.empty()) {
88        this->destroyBlock();
89    }
90    if (fPreallocBuffers.count()) {
91        // must set this after above loop.
92        fPreallocBufferStartIdx = (fPreallocBufferStartIdx +
93                                   preallocBuffersInUse) %
94                                  fPreallocBuffers.count();
95    }
96    // we may have created a large cpu mirror of a large VB. Reset the size
97    // to match our pre-allocated VBs.
98    fCpuData.reset(fMinBlockSize);
99    GrAssert(0 == fPreallocBuffersInUse);
100    VALIDATE();
101}
102
103void GrBufferAllocPool::unlock() {
104    VALIDATE();
105
106    if (NULL != fBufferPtr) {
107        BufferBlock& block = fBlocks.back();
108        if (block.fBuffer->isLocked()) {
109            block.fBuffer->unlock();
110        } else {
111            size_t flushSize = block.fBuffer->sizeInBytes() - block.fBytesFree;
112            flushCpuData(fBlocks.back().fBuffer, flushSize);
113        }
114        fBufferPtr = NULL;
115    }
116    VALIDATE();
117}
118
119#if GR_DEBUG
120void GrBufferAllocPool::validate(bool unusedBlockAllowed) const {
121    if (NULL != fBufferPtr) {
122        GrAssert(!fBlocks.empty());
123        if (fBlocks.back().fBuffer->isLocked()) {
124            GrGeometryBuffer* buf = fBlocks.back().fBuffer;
125            GrAssert(buf->lockPtr() == fBufferPtr);
126        } else {
127            GrAssert(fCpuData.get() == fBufferPtr);
128        }
129    } else {
130        GrAssert(fBlocks.empty() || !fBlocks.back().fBuffer->isLocked());
131    }
132    size_t bytesInUse = 0;
133    for (int i = 0; i < fBlocks.count() - 1; ++i) {
134        GrAssert(!fBlocks[i].fBuffer->isLocked());
135    }
136    for (int i = 0; i < fBlocks.count(); ++i) {
137        size_t bytes = fBlocks[i].fBuffer->sizeInBytes() - fBlocks[i].fBytesFree;
138        bytesInUse += bytes;
139        GrAssert(bytes || unusedBlockAllowed);
140    }
141
142    GrAssert(bytesInUse == fBytesInUse);
143    if (unusedBlockAllowed) {
144        GrAssert((fBytesInUse && !fBlocks.empty()) ||
145                 (!fBytesInUse && (fBlocks.count() < 2)));
146    } else {
147        GrAssert((0 == fBytesInUse) == fBlocks.empty());
148    }
149}
150#endif
151
152void* GrBufferAllocPool::makeSpace(size_t size,
153                                   size_t alignment,
154                                   const GrGeometryBuffer** buffer,
155                                   size_t* offset) {
156    VALIDATE();
157
158    GrAssert(NULL != buffer);
159    GrAssert(NULL != offset);
160
161    if (NULL != fBufferPtr) {
162        BufferBlock& back = fBlocks.back();
163        size_t usedBytes = back.fBuffer->sizeInBytes() - back.fBytesFree;
164        size_t pad = GrSizeAlignUpPad(usedBytes,
165                                      alignment);
166        if ((size + pad) <= back.fBytesFree) {
167            usedBytes += pad;
168            *offset = usedBytes;
169            *buffer = back.fBuffer;
170            back.fBytesFree -= size + pad;
171            fBytesInUse += size + pad;
172            VALIDATE();
173            return (void*)(reinterpret_cast<intptr_t>(fBufferPtr) + usedBytes);
174        }
175    }
176
177    // We could honor the space request using by a partial update of the current
178    // VB (if there is room). But we don't currently use draw calls to GL that
179    // allow the driver to know that previously issued draws won't read from
180    // the part of the buffer we update. Also, the GL buffer implementation
181    // may be cheating on the actual buffer size by shrinking the buffer on
182    // updateData() if the amount of data passed is less than the full buffer
183    // size.
184
185    if (!createBlock(size)) {
186        return NULL;
187    }
188    GrAssert(NULL != fBufferPtr);
189
190    *offset = 0;
191    BufferBlock& back = fBlocks.back();
192    *buffer = back.fBuffer;
193    back.fBytesFree -= size;
194    fBytesInUse += size;
195    VALIDATE();
196    return fBufferPtr;
197}
198
199int GrBufferAllocPool::currentBufferItems(size_t itemSize) const {
200    VALIDATE();
201    if (NULL != fBufferPtr) {
202        const BufferBlock& back = fBlocks.back();
203        size_t usedBytes = back.fBuffer->sizeInBytes() - back.fBytesFree;
204        size_t pad = GrSizeAlignUpPad(usedBytes, itemSize);
205        return (back.fBytesFree - pad) / itemSize;
206    } else if (fPreallocBuffersInUse < fPreallocBuffers.count()) {
207        return fMinBlockSize / itemSize;
208    }
209    return 0;
210}
211
212int GrBufferAllocPool::preallocatedBuffersRemaining() const {
213    return fPreallocBuffers.count() - fPreallocBuffersInUse;
214}
215
216int GrBufferAllocPool::preallocatedBufferCount() const {
217    return fPreallocBuffers.count();
218}
219
220void GrBufferAllocPool::putBack(size_t bytes) {
221    VALIDATE();
222
223    // if the putBack unwinds all the preallocated buffers then we will
224    // advance the starting index. As blocks are destroyed fPreallocBuffersInUse
225    // will be decremented. I will reach zero if all blocks using preallocated
226    // buffers are released.
227    int preallocBuffersInUse = fPreallocBuffersInUse;
228
229    while (bytes) {
230        // caller shouldnt try to put back more than they've taken
231        GrAssert(!fBlocks.empty());
232        BufferBlock& block = fBlocks.back();
233        size_t bytesUsed = block.fBuffer->sizeInBytes() - block.fBytesFree;
234        if (bytes >= bytesUsed) {
235            bytes -= bytesUsed;
236            fBytesInUse -= bytesUsed;
237            // if we locked a vb to satisfy the make space and we're releasing
238            // beyond it, then unlock it.
239            if (block.fBuffer->isLocked()) {
240                block.fBuffer->unlock();
241            }
242            this->destroyBlock();
243        } else {
244            block.fBytesFree += bytes;
245            fBytesInUse -= bytes;
246            bytes = 0;
247            break;
248        }
249    }
250    if (!fPreallocBuffersInUse && fPreallocBuffers.count()) {
251            fPreallocBufferStartIdx = (fPreallocBufferStartIdx +
252                                       preallocBuffersInUse) %
253                                      fPreallocBuffers.count();
254    }
255    VALIDATE();
256}
257
258bool GrBufferAllocPool::createBlock(size_t requestSize) {
259
260    size_t size = GrMax(requestSize, fMinBlockSize);
261    GrAssert(size >= GrBufferAllocPool_MIN_BLOCK_SIZE);
262
263    VALIDATE();
264
265    BufferBlock& block = fBlocks.push_back();
266
267    if (size == fMinBlockSize &&
268        fPreallocBuffersInUse < fPreallocBuffers.count()) {
269
270        uint32_t nextBuffer = (fPreallocBuffersInUse +
271                               fPreallocBufferStartIdx) %
272                              fPreallocBuffers.count();
273        block.fBuffer = fPreallocBuffers[nextBuffer];
274        block.fBuffer->ref();
275        ++fPreallocBuffersInUse;
276    } else {
277        block.fBuffer = this->createBuffer(size);
278        if (NULL == block.fBuffer) {
279            fBlocks.pop_back();
280            return false;
281        }
282    }
283
284    block.fBytesFree = size;
285    if (NULL != fBufferPtr) {
286        GrAssert(fBlocks.count() > 1);
287        BufferBlock& prev = fBlocks.fromBack(1);
288        if (prev.fBuffer->isLocked()) {
289            prev.fBuffer->unlock();
290        } else {
291            flushCpuData(prev.fBuffer,
292                         prev.fBuffer->sizeInBytes() - prev.fBytesFree);
293        }
294        fBufferPtr = NULL;
295    }
296
297    GrAssert(NULL == fBufferPtr);
298
299    if (fGpu->getCaps().bufferLockSupport() &&
300        size > GR_GEOM_BUFFER_LOCK_THRESHOLD &&
301        (!fFrequentResetHint || requestSize > GR_GEOM_BUFFER_LOCK_THRESHOLD)) {
302        fBufferPtr = block.fBuffer->lock();
303    }
304
305    if (NULL == fBufferPtr) {
306        fBufferPtr = fCpuData.reset(size);
307    }
308
309    VALIDATE(true);
310
311    return true;
312}
313
314void GrBufferAllocPool::destroyBlock() {
315    GrAssert(!fBlocks.empty());
316
317    BufferBlock& block = fBlocks.back();
318    if (fPreallocBuffersInUse > 0) {
319        uint32_t prevPreallocBuffer = (fPreallocBuffersInUse +
320                                       fPreallocBufferStartIdx +
321                                       (fPreallocBuffers.count() - 1)) %
322                                      fPreallocBuffers.count();
323        if (block.fBuffer == fPreallocBuffers[prevPreallocBuffer]) {
324            --fPreallocBuffersInUse;
325        }
326    }
327    GrAssert(!block.fBuffer->isLocked());
328    block.fBuffer->unref();
329    fBlocks.pop_back();
330    fBufferPtr = NULL;
331}
332
333void GrBufferAllocPool::flushCpuData(GrGeometryBuffer* buffer,
334                                     size_t flushSize) {
335    GrAssert(NULL != buffer);
336    GrAssert(!buffer->isLocked());
337    GrAssert(fCpuData.get() == fBufferPtr);
338    GrAssert(flushSize <= buffer->sizeInBytes());
339    VALIDATE(true);
340
341    if (fGpu->getCaps().bufferLockSupport() &&
342        flushSize > GR_GEOM_BUFFER_LOCK_THRESHOLD) {
343        void* data = buffer->lock();
344        if (NULL != data) {
345            memcpy(data, fBufferPtr, flushSize);
346            buffer->unlock();
347            return;
348        }
349    }
350    buffer->updateData(fBufferPtr, flushSize);
351    VALIDATE(true);
352}
353
354GrGeometryBuffer* GrBufferAllocPool::createBuffer(size_t size) {
355    if (kIndex_BufferType == fBufferType) {
356        return fGpu->createIndexBuffer(size, true);
357    } else {
358        GrAssert(kVertex_BufferType == fBufferType);
359        return fGpu->createVertexBuffer(size, true);
360    }
361}
362
363////////////////////////////////////////////////////////////////////////////////
364
365GrVertexBufferAllocPool::GrVertexBufferAllocPool(GrGpu* gpu,
366                                                 bool frequentResetHint,
367                                                 size_t bufferSize,
368                                                 int preallocBufferCnt)
369: GrBufferAllocPool(gpu,
370                    kVertex_BufferType,
371                    frequentResetHint,
372                    bufferSize,
373                    preallocBufferCnt) {
374}
375
376void* GrVertexBufferAllocPool::makeSpace(size_t vertexSize,
377                                         int vertexCount,
378                                         const GrVertexBuffer** buffer,
379                                         int* startVertex) {
380
381    GrAssert(vertexCount >= 0);
382    GrAssert(NULL != buffer);
383    GrAssert(NULL != startVertex);
384
385    size_t offset = 0; // assign to suppress warning
386    const GrGeometryBuffer* geomBuffer = NULL; // assign to suppress warning
387    void* ptr = INHERITED::makeSpace(vertexSize * vertexCount,
388                                     vertexSize,
389                                     &geomBuffer,
390                                     &offset);
391
392    *buffer = (const GrVertexBuffer*) geomBuffer;
393    GrAssert(0 == offset % vertexSize);
394    *startVertex = offset / vertexSize;
395    return ptr;
396}
397
398bool GrVertexBufferAllocPool::appendVertices(size_t vertexSize,
399                                             int vertexCount,
400                                             const void* vertices,
401                                             const GrVertexBuffer** buffer,
402                                             int* startVertex) {
403    void* space = makeSpace(vertexSize, vertexCount, buffer, startVertex);
404    if (NULL != space) {
405        memcpy(space,
406               vertices,
407               vertexSize * vertexCount);
408        return true;
409    } else {
410        return false;
411    }
412}
413
414int GrVertexBufferAllocPool::preallocatedBufferVertices(size_t vertexSize) const {
415    return INHERITED::preallocatedBufferSize() / vertexSize;
416}
417
418int GrVertexBufferAllocPool::currentBufferVertices(size_t vertexSize) const {
419    return currentBufferItems(vertexSize);
420}
421
422////////////////////////////////////////////////////////////////////////////////
423
424GrIndexBufferAllocPool::GrIndexBufferAllocPool(GrGpu* gpu,
425                                               bool frequentResetHint,
426                                               size_t bufferSize,
427                                               int preallocBufferCnt)
428: GrBufferAllocPool(gpu,
429                    kIndex_BufferType,
430                    frequentResetHint,
431                    bufferSize,
432                    preallocBufferCnt) {
433}
434
435void* GrIndexBufferAllocPool::makeSpace(int indexCount,
436                                        const GrIndexBuffer** buffer,
437                                        int* startIndex) {
438
439    GrAssert(indexCount >= 0);
440    GrAssert(NULL != buffer);
441    GrAssert(NULL != startIndex);
442
443    size_t offset = 0; // assign to suppress warning
444    const GrGeometryBuffer* geomBuffer = NULL; // assign to suppress warning
445    void* ptr = INHERITED::makeSpace(indexCount * sizeof(uint16_t),
446                                     sizeof(uint16_t),
447                                     &geomBuffer,
448                                     &offset);
449
450    *buffer = (const GrIndexBuffer*) geomBuffer;
451    GrAssert(0 == offset % sizeof(uint16_t));
452    *startIndex = offset / sizeof(uint16_t);
453    return ptr;
454}
455
456bool GrIndexBufferAllocPool::appendIndices(int indexCount,
457                                           const void* indices,
458                                           const GrIndexBuffer** buffer,
459                                           int* startIndex) {
460    void* space = makeSpace(indexCount, buffer, startIndex);
461    if (NULL != space) {
462        memcpy(space, indices, sizeof(uint16_t) * indexCount);
463        return true;
464    } else {
465        return false;
466    }
467}
468
469int GrIndexBufferAllocPool::preallocatedBufferIndices() const {
470    return INHERITED::preallocatedBufferSize() / sizeof(uint16_t);
471}
472
473int GrIndexBufferAllocPool::currentBufferIndices() const {
474    return currentBufferItems(sizeof(uint16_t));
475}
476