void GLInstancedRendering::onBeginFlush(GrResourceProvider* rp) {
// Count what there is to draw.
BatchList::Iter iter;
iter.init(this->trackedBatches(), BatchList::Iter::kHead_IterStart);
int numGLInstances = 0;
int numGLDrawCmds = 0;
while (Batch* b = iter.get()) {
GLBatch* batch = static_cast<GLBatch*>(b);
iter.next();
numGLInstances += batch->fNumDraws;
numGLDrawCmds += batch->numGLCommands();
}
if (!numGLDrawCmds) {
return;
}
SkASSERT(numGLInstances);
// Lazily create a vertex array object.
if (!fVertexArrayID) {
GL_CALL(GenVertexArrays(1, &fVertexArrayID));
if (!fVertexArrayID) {
return;
}
this->glGpu()->bindVertexArray(fVertexArrayID);
// Attach our index buffer to the vertex array.
SkASSERT(!this->indexBuffer()->isCPUBacked());
GL_CALL(BindBuffer(GR_GL_ELEMENT_ARRAY_BUFFER,
static_cast<const GrGLBuffer*>(this->indexBuffer())->bufferID()));
// Set up the non-instanced attribs.
this->glGpu()->bindBuffer(kVertex_GrBufferType, this->vertexBuffer());
GL_CALL(EnableVertexAttribArray((int)Attrib::kShapeCoords));
GL_CALL(VertexAttribPointer((int)Attrib::kShapeCoords, 2, GR_GL_FLOAT, GR_GL_FALSE,
sizeof(ShapeVertex), (void*) offsetof(ShapeVertex, fX)));
GL_CALL(EnableVertexAttribArray((int)Attrib::kVertexAttrs));
GL_CALL(VertexAttribIPointer((int)Attrib::kVertexAttrs, 1, GR_GL_INT, sizeof(ShapeVertex),
(void*) offsetof(ShapeVertex, fAttrs)));
SkASSERT(SK_InvalidUniqueID == fInstanceAttribsBufferUniqueId);
}
// Create and map instance and draw-indirect buffers.
SkASSERT(!fInstanceBuffer);
fInstanceBuffer.reset(
rp->createBuffer(sizeof(Instance) * numGLInstances, kVertex_GrBufferType,
kDynamic_GrAccessPattern,
GrResourceProvider::kNoPendingIO_Flag |
GrResourceProvider::kRequireGpuMemory_Flag));
if (!fInstanceBuffer) {
return;
}
SkASSERT(!fDrawIndirectBuffer);
fDrawIndirectBuffer.reset(
rp->createBuffer(sizeof(GrGLDrawElementsIndirectCommand) * numGLDrawCmds,
kDrawIndirect_GrBufferType, kDynamic_GrAccessPattern,
GrResourceProvider::kNoPendingIO_Flag |
GrResourceProvider::kRequireGpuMemory_Flag));
if (!fDrawIndirectBuffer) {
return;
}
Instance* glMappedInstances = static_cast<Instance*>(fInstanceBuffer->map());
int glInstancesIdx = 0;
auto* glMappedCmds = static_cast<GrGLDrawElementsIndirectCommand*>(fDrawIndirectBuffer->map());
int glDrawCmdsIdx = 0;
bool baseInstanceSupport = this->glGpu()->glCaps().baseInstanceSupport();
if (GR_GL_LOG_INSTANCED_BATCHES || !baseInstanceSupport) {
fGLDrawCmdsInfo.reset(numGLDrawCmds);
}
// Generate the instance and draw-indirect buffer contents based on the tracked batches.
iter.init(this->trackedBatches(), BatchList::Iter::kHead_IterStart);
while (Batch* b = iter.get()) {
GLBatch* batch = static_cast<GLBatch*>(b);
iter.next();
batch->fEmulatedBaseInstance = baseInstanceSupport ? 0 : glInstancesIdx;
batch->fGLDrawCmdsIdx = glDrawCmdsIdx;
const Batch::Draw* draw = batch->fHeadDraw;
SkASSERT(draw);
do {
int instanceCount = 0;
IndexRange geometry = draw->fGeometry;
SkASSERT(!geometry.isEmpty());
do {
glMappedInstances[glInstancesIdx + instanceCount++] = draw->fInstance;
draw = draw->fNext;
} while (draw && draw->fGeometry == geometry);
GrGLDrawElementsIndirectCommand& glCmd = glMappedCmds[glDrawCmdsIdx];
glCmd.fCount = geometry.fCount;
glCmd.fInstanceCount = instanceCount;
glCmd.fFirstIndex = geometry.fStart;
glCmd.fBaseVertex = 0;
glCmd.fBaseInstance = baseInstanceSupport ? glInstancesIdx : 0;
if (GR_GL_LOG_INSTANCED_BATCHES || !baseInstanceSupport) {
fGLDrawCmdsInfo[glDrawCmdsIdx].fInstanceCount = instanceCount;
#if GR_GL_LOG_INSTANCED_BATCHES
fGLDrawCmdsInfo[glDrawCmdsIdx].fGeometry = geometry;
#endif
}
glInstancesIdx += instanceCount;
++glDrawCmdsIdx;
} while (draw);
}
SkASSERT(glDrawCmdsIdx == numGLDrawCmds);
fDrawIndirectBuffer->unmap();
SkASSERT(glInstancesIdx == numGLInstances);
fInstanceBuffer->unmap();
}
