Implement support for mixed sampled render targets
Adds a new FBO type kStencil_MSFBOType that is selected whenever
NV_framebuffer_mixed_samples extension is available. In this new
FBO type a non-msaa color buffer is created with a multisampled
stencil buffer attachment.
Replaces numSamples() with separate numColorSamples and numStencilSamples
methods in RenderTarget.
In mixed samples mode non-MSAA codepaths are used to draw simple shapes,
while NVPR-rendered paths and text are rendered with a multisampled
stencil.
BUG=skia:3177
Review URL: https://codereview.chromium.org/1001503002
diff --git a/include/gpu/GrRenderTarget.h b/include/gpu/GrRenderTarget.h
index 5984bf7..91a67ae 100644
--- a/include/gpu/GrRenderTarget.h
+++ b/include/gpu/GrRenderTarget.h
@@ -31,14 +31,65 @@
// GrRenderTarget
/**
- * @return true if the surface is multisampled, false otherwise
- */
- bool isMultisampled() const { return 0 != fDesc.fSampleCnt; }
+ * On some hardware it is possible for a render target to have multisampling
+ * only in certain buffers.
+ * Enforce only two legal sample configs.
+ * kUnified_SampleConfig signifies multisampling in both color and stencil
+ * buffers and is available across all hardware.
+ * kStencil_SampleConfig means multisampling is present in stencil buffer
+ * only; this config requires hardware support of
+ * NV_framebuffer_mixed_samples.
+ */
+ enum SampleConfig {
+ kUnified_SampleConfig = 0,
+ kStencil_SampleConfig = 1
+ };
/**
- * @return the number of samples-per-pixel or zero if non-MSAA.
+ * @return true if the surface is multisampled in all buffers,
+ * false otherwise
*/
- int numSamples() const { return fDesc.fSampleCnt; }
+ bool isUnifiedMultisampled() const {
+ if (fSampleConfig != kUnified_SampleConfig) {
+ return false;
+ }
+ return 0 != fDesc.fSampleCnt;
+ }
+
+ /**
+ * @return true if the surface is multisampled in the stencil buffer,
+ * false otherwise
+ */
+ bool isStencilBufferMultisampled() const {
+ return 0 != fDesc.fSampleCnt;
+ }
+
+ /**
+ * @return the number of color samples-per-pixel, or zero if non-MSAA or
+ * multisampled in the stencil buffer only.
+ */
+ int numColorSamples() const {
+ if (fSampleConfig == kUnified_SampleConfig) {
+ return fDesc.fSampleCnt;
+ }
+ return 0;
+ }
+
+ /**
+ * @return the number of stencil samples-per-pixel, or zero if non-MSAA.
+ */
+ int numStencilSamples() const {
+ return fDesc.fSampleCnt;
+ }
+
+ /**
+ * @return true if the surface is mixed sampled, false otherwise.
+ */
+ bool hasMixedSamples() const {
+ SkASSERT(kStencil_SampleConfig != fSampleConfig ||
+ this->isStencilBufferMultisampled());
+ return kStencil_SampleConfig == fSampleConfig;
+ }
/**
* Call to indicate the multisample contents were modified such that the
@@ -94,9 +145,11 @@
const GrRenderTargetPriv renderTargetPriv() const;
protected:
- GrRenderTarget(GrGpu* gpu, LifeCycle lifeCycle, const GrSurfaceDesc& desc)
+ GrRenderTarget(GrGpu* gpu, LifeCycle lifeCycle, const GrSurfaceDesc& desc,
+ SampleConfig sampleConfig)
: INHERITED(gpu, lifeCycle, desc)
- , fStencilAttachment(NULL) {
+ , fStencilAttachment(NULL)
+ , fSampleConfig(sampleConfig) {
fResolveRect.setLargestInverted();
}
@@ -111,10 +164,12 @@
friend class GrRenderTargetPriv;
GrStencilAttachment* fStencilAttachment;
+ SampleConfig fSampleConfig;
SkIRect fResolveRect;
typedef GrSurface INHERITED;
};
+
#endif