Make GrVertexBatch objects hold their own draws during GrDrawTarget flush

src/gpu/GrBatchFlushState.h

+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrBatchBuffer_DEFINED
+#define GrBatchBuffer_DEFINED
+
+#include "GrBufferAllocPool.h"
+#include "batches/GrVertexBatch.h"
+
+class GrResourceProvider;
+
+/** Simple class that performs the upload on behalf of a GrBatchUploader. */
+class GrBatchUploader::TextureUploader {
+public:
+    TextureUploader(GrGpu* gpu) : fGpu(gpu) { SkASSERT(gpu); }
+
+    /**
+        * Updates the pixels in a rectangle of a texture.
+        *
+        * @param left          left edge of the rectangle to write (inclusive)
+        * @param top           top edge of the rectangle to write (inclusive)
+        * @param width         width of rectangle to write in pixels.
+        * @param height        height of rectangle to write in pixels.
+        * @param config        the pixel config of the source buffer
+        * @param buffer        memory to read pixels from
+        * @param rowBytes      number of bytes between consecutive rows. Zero
+        *                      means rows are tightly packed.
+        */
+    bool writeTexturePixels(GrTexture* texture,
+                            int left, int top, int width, int height,
+                            GrPixelConfig config, const void* buffer,
+                            size_t rowBytes) {
+        return fGpu->writePixels(texture, left, top, width, height, config, buffer, rowBytes);
+    }
+
+private:
+    GrGpu* fGpu;
+};
+
+/** Tracks the state across all the GrBatches in a GrDrawTarget flush. */
+class GrBatchFlushState {
+public:
+    GrBatchFlushState(GrGpu*, GrResourceProvider*, GrBatchToken lastFlushedToken);
+
+    ~GrBatchFlushState() { SkASSERT(fLastFlushedToken == fCurrentToken); }
+
+    void advanceToken() { ++fCurrentToken; }
+
+    void advanceLastFlushedToken() { ++fLastFlushedToken; }
+
+    /** Inserts an upload to be executred after all batches in the flush prepared their draws
+        but before the draws are executed to the backend 3D API. */
+    void addASAPUpload(GrBatchUploader* upload) {
+        fAsapUploads.push_back().reset(SkRef(upload));
+    }
+
+    const GrCaps& caps() const { return *fGpu->caps(); }
+    GrResourceProvider* resourceProvider() const { return fResourceProvider; }
+
+    /** Has the token been flushed to the backend 3D API. */
+    bool hasTokenBeenFlushed(GrBatchToken token) const { return fLastFlushedToken >= token; }
+
+    /** The current token advances once for every contiguous set of uninterrupted draws prepared
+        by a batch. */
+    GrBatchToken currentToken() const { return fCurrentToken; }
+
+    /** The last token flushed to all the way to the backend API. */
+    GrBatchToken lastFlushedToken() const { return fLastFlushedToken; }
+
+    /** This is a magic token that can be used to indicate that an upload should occur before
+        any draws for any batch in the current flush execute. */
+    GrBatchToken asapToken() const { return fLastFlushedToken + 1; }
+
+    void* makeVertexSpace(size_t vertexSize, int vertexCount,
+                          const GrVertexBuffer** buffer, int* startVertex);
+    uint16_t* makeIndexSpace(int indexCount, const GrIndexBuffer** buffer, int* startIndex);
+
+    /** This is called after each batch has a chance to prepare its draws and before the draws
+        are issued. */
+    void preIssueDraws() {
+        fVertexPool.unmap();
+        fIndexPool.unmap();
+        int uploadCount = fAsapUploads.count();
+        for (int i = 0; i < uploadCount; i++) {
+            fAsapUploads[i]->upload(&fUploader);
+        }
+        fAsapUploads.reset();
+    }
+
+    void putBackIndices(size_t indices) { fIndexPool.putBack(indices * sizeof(uint16_t)); }
+
+    void putBackVertexSpace(size_t sizeInBytes) { fVertexPool.putBack(sizeInBytes); }
+
+    GrBatchUploader::TextureUploader* uploader() { return &fUploader; }
+
+    GrGpu* gpu() { return fGpu; }
+
+private:
+    GrGpu*                                          fGpu;
+    GrBatchUploader::TextureUploader                fUploader;
+
+    GrResourceProvider*                             fResourceProvider;
+
+    GrVertexBufferAllocPool                         fVertexPool;
+    GrIndexBufferAllocPool                          fIndexPool;
+
+    SkTArray<SkAutoTUnref<GrBatchUploader>, true>   fAsapUploads;
+
+    GrBatchToken                                    fCurrentToken;
+
+    GrBatchToken                                    fLastFlushedToken;
+};
+
+/**
+ * GrDrawBatch instances use this object to allocate space for their geometry and to issue the draws
+ * that render their batch.
+ */
+class GrDrawBatch::Target {
+public:
+    Target(GrBatchFlushState* state, GrDrawBatch* batch) : fState(state), fBatch(batch) {}
+
+    void upload(GrBatchUploader* upload) {
+        if (this->asapToken() == upload->lastUploadToken()) {
+            fState->addASAPUpload(upload);
+        } else {
+            fBatch->fInlineUploads.push_back().reset(SkRef(upload));
+        }
+    }
+
+    bool hasTokenBeenFlushed(GrBatchToken token) const {
+        return fState->hasTokenBeenFlushed(token);
+    }
+    GrBatchToken currentToken() const { return fState->currentToken(); }
+    GrBatchToken asapToken() const { return fState->asapToken(); }
+
+    const GrCaps& caps() const { return fState->caps(); }
+
+    GrResourceProvider* resourceProvider() const { return fState->resourceProvider(); }
+
+protected:
+    GrDrawBatch* batch() { return fBatch; }
+    GrBatchFlushState* state() { return fState; }
+
+private:
+    GrBatchFlushState*  fState;
+    GrDrawBatch*        fBatch;
+};
+
+/** Extension of GrDrawBatch::Target for use by GrVertexBatch. Adds the ability to create vertex
+    draws. */
+class GrVertexBatch::Target : public GrDrawBatch::Target {
+public:
+    Target(GrBatchFlushState* state, GrVertexBatch* batch) : INHERITED(state, batch) {}
+
+    void initDraw(const GrPrimitiveProcessor* primProc, const GrPipeline* pipeline) {
+        GrVertexBatch::DrawArray* draws = this->vertexBatch()->fDrawArrays.addToTail();
+        draws->fPrimitiveProcessor.reset(primProc);
+        this->state()->advanceToken();
+    }
+
+    void draw(const GrVertices& vertices) {
+        this->vertexBatch()->fDrawArrays.tail()->fDraws.push_back(vertices);
+    }
+
+    void* makeVertexSpace(size_t vertexSize, int vertexCount,
+                          const GrVertexBuffer** buffer, int* startVertex) {
+        return this->state()->makeVertexSpace(vertexSize, vertexCount, buffer, startVertex);
+    }
+
+    uint16_t* makeIndexSpace(int indexCount, const GrIndexBuffer** buffer, int* startIndex) {
+        return this->state()->makeIndexSpace(indexCount, buffer, startIndex);
+    }
+
+    /** Helpers for batches which over-allocate and then return data to the pool. */
+    void putBackIndices(int indices) { this->state()->putBackIndices(indices); }
+    void putBackVertices(int vertices, size_t vertexStride) {
+        this->state()->putBackVertexSpace(vertices * vertexStride);
+    }
+
+private:
+    GrVertexBatch* vertexBatch() { return static_cast<GrVertexBatch*>(this->batch()); }
+    typedef GrDrawBatch::Target INHERITED;
+};
+
+#endif