Add 4x4 downsample filter with 4 bilinear texture reads, use for ssaa.
Review URL: http://codereview.appspot.com/4483042/
git-svn-id: http://skia.googlecode.com/svn/trunk@1250 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gpu/include/GrContext_impl.h b/gpu/include/GrContext_impl.h
index 0fa3b8d..fae4e92 100644
--- a/gpu/include/GrContext_impl.h
+++ b/gpu/include/GrContext_impl.h
@@ -21,6 +21,11 @@
OffscreenRecord() { fEntry0 = NULL; fEntry1 = NULL; }
~OffscreenRecord() { GrAssert(NULL == fEntry0 && NULL == fEntry1); }
+ enum Downsample {
+ k4x4TwoPass_Downsample,
+ k4x4SinglePass_Downsample,
+ kFSAA_Downsample
+ } fDownsample;
GrTextureEntry* fEntry0;
GrTextureEntry* fEntry1;
GrDrawTarget::SavedDrawState fSavedState;
diff --git a/gpu/include/GrGpu.h b/gpu/include/GrGpu.h
index 5602d1a..e44956f 100644
--- a/gpu/include/GrGpu.h
+++ b/gpu/include/GrGpu.h
@@ -199,6 +199,11 @@
bool supportsAALines() const { return fAALineSupport; }
/**
+ * Does the subclass support GrSamplerState::k4x4Downsample_Filter
+ */
+ bool supports4x4DownsampleFilter() const { return f4X4DownsampleFilterSupport; }
+
+ /**
* Gets the minimum width of a render target. If a texture/rt is created
* with a width less than this size the GrGpu object will clamp it to this
* value.
@@ -379,6 +384,7 @@
bool fStencilWrapOpsSupport;
bool fAALineSupport;
bool fFSAASupport;
+ bool f4X4DownsampleFilterSupport; // supports GrSamplerState::k4x4Downsample_Filter
// set by subclass to true if index and vertex buffers can be locked, false
// otherwise.
diff --git a/gpu/include/GrSamplerState.h b/gpu/include/GrSamplerState.h
index 910bc74..dd47c53 100644
--- a/gpu/include/GrSamplerState.h
+++ b/gpu/include/GrSamplerState.h
@@ -23,6 +23,24 @@
class GrSamplerState {
public:
+ enum Filter {
+ /**
+ * Read the closest src texel to the sample position
+ */
+ kNearest_Filter,
+ /**
+ * Blend between closest 4 src texels to sample position (tent filter)
+ */
+ kBilinear_Filter,
+ /**
+ * Average of 4 bilinear filterings spaced +/- 1 texel from sample
+ * position in x and y. Intended for averaging 16 texels in a downsample
+ * pass. (rasterizing such that texture samples fall exactly halfway
+ * between texels in x and y spaced 4 texels apart.)
+ */
+ k4x4Downsample_Filter,
+ };
+
/**
* The intepretation of the texture matrix depends on the sample mode. The
* texture matrix is applied both when the texture coordinates are explicit
@@ -70,7 +88,7 @@
this->setClampNoFilter();
}
- explicit GrSamplerState(bool filter) {
+ explicit GrSamplerState(Filter filter) {
fWrapX = kClamp_WrapMode;
fWrapY = kClamp_WrapMode;
fSampleMode = kNormal_SampleMode;
@@ -78,7 +96,7 @@
fMatrix.setIdentity();
}
- GrSamplerState(WrapMode wx, WrapMode wy, bool filter) {
+ GrSamplerState(WrapMode wx, WrapMode wy, Filter filter) {
fWrapX = wx;
fWrapY = wy;
fSampleMode = kNormal_SampleMode;
@@ -86,7 +104,8 @@
fMatrix.setIdentity();
}
- GrSamplerState(WrapMode wx, WrapMode wy, const GrMatrix& matrix, bool filter) {
+ GrSamplerState(WrapMode wx, WrapMode wy,
+ const GrMatrix& matrix, Filter filter) {
fWrapX = wx;
fWrapY = wy;
fSampleMode = kNormal_SampleMode;
@@ -94,7 +113,8 @@
fMatrix = matrix;
}
- GrSamplerState(WrapMode wx, WrapMode wy, SampleMode sample, const GrMatrix& matrix, bool filter) {
+ GrSamplerState(WrapMode wx, WrapMode wy, SampleMode sample,
+ const GrMatrix& matrix, Filter filter) {
fWrapX = wx;
fWrapY = wy;
fSampleMode = sample;
@@ -106,7 +126,7 @@
WrapMode getWrapY() const { return fWrapY; }
SampleMode getSampleMode() const { return fSampleMode; }
const GrMatrix& getMatrix() const { return fMatrix; }
- bool isFilter() const { return fFilter; }
+ Filter getFilter() const { return fFilter; }
bool isGradient() const {
return kRadial_SampleMode == fSampleMode ||
@@ -138,16 +158,16 @@
void preConcatMatrix(const GrMatrix& matrix) { fMatrix.preConcat(matrix); }
/**
- * Enables or disables filtering.
- * @param filter indicates whether filtering is applied.
+ * Sets filtering type.
+ * @param filter type of filtering to apply
*/
- void setFilter(bool filter) { fFilter = filter; }
+ void setFilter(Filter filter) { fFilter = filter; }
void setClampNoFilter() {
fWrapX = kClamp_WrapMode;
fWrapY = kClamp_WrapMode;
fSampleMode = kNormal_SampleMode;
- fFilter = false;
+ fFilter = kNearest_Filter;
fMatrix.setIdentity();
}
@@ -176,7 +196,7 @@
WrapMode fWrapX;
WrapMode fWrapY;
SampleMode fSampleMode;
- bool fFilter;
+ Filter fFilter;
GrMatrix fMatrix;
// these are undefined unless fSampleMode == kRadial2_SampleMode