Extract GrDrawTarget::DrState into independent GrDrawState struct.
This is intended to be a first step towards making the stack of states
maintained by GrDrawTarget cheaper to maintain.
git-svn-id: http://skia.googlecode.com/svn/trunk@2544 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrDrawState.h b/src/gpu/GrDrawState.h
new file mode 100644
index 0000000..37baee8
--- /dev/null
+++ b/src/gpu/GrDrawState.h
@@ -0,0 +1,129 @@
+/*
+ * Copyright 2011 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrDrawState_DEFINED
+#define GrDrawState_DEFINED
+
+#include "GrColor.h"
+#include "GrMatrix.h"
+#include "GrSamplerState.h"
+#include "GrStencil.h"
+
+#include "SkXfermode.h"
+
+class GrRenderTarget;
+class GrTexture;
+
+struct GrDrawState {
+
+ /**
+ * Number of texture stages. Each stage takes as input a color and
+ * 2D texture coordinates. The color input to the first enabled stage is the
+ * per-vertex color or the constant color (setColor/setAlpha) if there are
+ * no per-vertex colors. For subsequent stages the input color is the output
+ * color from the previous enabled stage. The output color of each stage is
+ * the input color modulated with the result of a texture lookup. Texture
+ * lookups are specified by a texture a sampler (setSamplerState). Texture
+ * coordinates for each stage come from the vertices based on a
+ * GrVertexLayout bitfield. The output fragment color is the output color of
+ * the last enabled stage. The presence or absence of texture coordinates
+ * for each stage in the vertex layout indicates whether a stage is enabled
+ * or not.
+ */
+ enum {
+ kNumStages = 3,
+ kMaxTexCoords = kNumStages
+ };
+
+ enum DrawFace {
+ kBoth_DrawFace,
+ kCCW_DrawFace,
+ kCW_DrawFace,
+ };
+
+ /**
+ * When specifying edges as vertex data this enum specifies what type of
+ * edges are in use. The edges are always 4 GrScalars in memory, even when
+ * the edge type requires fewer than 4.
+ */
+ enum VertexEdgeType {
+ /* 1-pixel wide line
+ 2D implicit line eq (a*x + b*y +c = 0). 4th component unused */
+ kHairLine_EdgeType,
+ /* 1-pixel wide quadratic
+ u^2-v canonical coords (only 2 components used) */
+ kHairQuad_EdgeType
+ };
+
+ /**
+ * The absolute maximum number of edges that may be specified for
+ * a single draw call when performing edge antialiasing. This is used for
+ * the size of several static buffers, so implementations of getMaxEdges()
+ * (below) should clamp to this value.
+ */
+ enum {
+ kMaxEdges = 32
+ };
+
+ class Edge {
+ public:
+ Edge() {}
+ Edge(float x, float y, float z) : fX(x), fY(y), fZ(z) {}
+ GrPoint intersect(const Edge& other) {
+ return GrPoint::Make(
+ (fY * other.fZ - other.fY * fZ) /
+ (fX * other.fY - other.fX * fY),
+ (fX * other.fZ - other.fX * fZ) /
+ (other.fX * fY - fX * other.fY));
+ }
+ float fX, fY, fZ;
+ };
+
+ GrDrawState() {
+ // make sure any pad is zero for memcmp
+ // all GrDrawState members should default to something
+ // valid by the memset
+ memset(this, 0, sizeof(GrDrawState));
+
+ // memset exceptions
+ fColorFilterXfermode = SkXfermode::kDstIn_Mode;
+ fFirstCoverageStage = kNumStages;
+
+ // pedantic assertion that our ptrs will
+ // be NULL (0 ptr is mem addr 0)
+ GrAssert((intptr_t)(void*)NULL == 0LL);
+
+ // default stencil setting should be disabled
+ GrAssert(fStencilSettings.isDisabled());
+ fFirstCoverageStage = kNumStages;
+ }
+
+ uint32_t fFlagBits;
+ GrBlendCoeff fSrcBlend;
+ GrBlendCoeff fDstBlend;
+ GrColor fBlendConstant;
+ GrTexture* fTextures[kNumStages];
+ GrSamplerState fSamplerStates[kNumStages];
+ int fFirstCoverageStage;
+ GrRenderTarget* fRenderTarget;
+ GrColor fColor;
+ DrawFace fDrawFace;
+ GrColor fColorFilterColor;
+ SkXfermode::Mode fColorFilterXfermode;
+
+ GrStencilSettings fStencilSettings;
+ GrMatrix fViewMatrix;
+ VertexEdgeType fVertexEdgeType;
+ Edge fEdgeAAEdges[kMaxEdges];
+ int fEdgeAANumEdges;
+ bool operator ==(const GrDrawState& s) const {
+ return 0 == memcmp(this, &s, sizeof(GrDrawState));
+ }
+ bool operator !=(const GrDrawState& s) const { return !(*this == s); }
+};
+
+#endif