blob: 5035ad0f5362113e2e395a1e575071f80c8a4eed [file] [log] [blame]
* Copyright 2013 Google Inc.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
#ifndef GrGeometryProcessor_DEFINED
#define GrGeometryProcessor_DEFINED
#include "GrPrimitiveProcessor.h"
* A GrGeometryProcessor is a flexible method for rendering a primitive. The GrGeometryProcessor
* has complete control over vertex attributes and uniforms(aside from the render target) but it
* must obey the same contract as any GrPrimitiveProcessor, specifically it must emit a color and
* coverage into the fragment shader. Where this color and coverage come from is completely the
* responsibility of the GrGeometryProcessor.
class GrGeometryProcessor : public GrPrimitiveProcessor {
GrGeometryProcessor(ClassID classID)
, fWillUseGeoShader(false)
, fSampleShading(0.0) {}
bool willUseGeoShader() const final { return fWillUseGeoShader; }
* Returns the minimum fraction of samples for which the fragment shader will be run. For
* instance, if sampleShading is 0.5 in MSAA16 mode, the fragment shader will run a minimum of
* 8 times per pixel. The default value is zero.
float getSampleShading() const final { return fSampleShading; }
void setWillUseGeoShader() { fWillUseGeoShader = true; }
void setSampleShading(float sampleShading) {
fSampleShading = sampleShading;
* Recursive helpers for implementing onVertexAttribute or onInstanceAttribute.
template <typename... Args>
static const Attribute& IthAttribute(int i, const Attribute& attr0, const Args&... attrs) {
return (0 == i) ? attr0 : IthAttribute(i - 1, attrs...);
static const Attribute& IthAttribute(int i) {
SK_ABORT("Illegal attribute Index");
static constexpr Attribute kBogus;
return kBogus;
template <typename... Args>
static const Attribute& IthInitializedAttribute(int i, const Attribute& attr0,
const Args&... attrs) {
if (attr0.isInitialized()) {
if (0 == i) {
return attr0;
i -= 1;
return IthInitializedAttribute(i, attrs...);
static const Attribute& IthInitializedAttribute(int i) { return IthAttribute(i); }
// Since most subclasses don't use instancing provide a default implementation for that case.
const Attribute& onInstanceAttribute(int i) const override {
SK_ABORT("No instanced attributes");
static constexpr Attribute kBogus;
return kBogus;
bool fWillUseGeoShader;
float fSampleShading;
typedef GrPrimitiveProcessor INHERITED;