/**
* A function which emits a meta key into the key builder. This is required because shader code may
* be dependent on properties of the effect that the effect itself doesn't use
* in its key (e.g. the pixel format of textures used). So we create a meta-key for
* every effect using this function. It is also responsible for inserting the effect's class ID
* which must be different for every GrProcessor subclass. It can fail if an effect uses too many
* textures, transforms, etc, for the space allotted in the meta-key. NOTE, both FPs and GPs share
* this function because it is hairy, though FPs do not have attribs, and GPs do not have transforms
*/
static bool get_meta_key(const GrProcessor& proc,
const GrGLCaps& caps,
uint32_t transformKey,
uint32_t attribKey,
GrProcessorKeyBuilder* b,
uint16_t* processorKeySize) {
const GrBackendProcessorFactory& factory = proc.getFactory();
factory.getGLProcessorKey(proc, caps, b);
size_t size = b->size();
if (size > SK_MaxU16) {
*processorKeySize = 0; // suppresses a warning.
return false;
}
*processorKeySize = SkToU16(size);
uint32_t textureKey = gen_texture_key(proc, caps);
uint32_t classID = proc.getFactory().classID();
// Currently we allow 16 bits for each of the above portions of the meta-key. Fail if they
// don't fit.
static const uint32_t kMetaKeyInvalidMask = ~((uint32_t) SK_MaxU16);
if ((textureKey | transformKey | classID) & kMetaKeyInvalidMask) {
return false;
}
uint32_t* key = b->add32n(2);
key[0] = (textureKey << 16 | transformKey);
key[1] = (classID << 16);
return true;
}
