Reland r6233 with fix.
git-svn-id: http://skia.googlecode.com/svn/trunk@6241 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/gl/GrGLEffectMatrix.h b/src/gpu/gl/GrGLEffectMatrix.h
new file mode 100644
index 0000000..9e45f3e
--- /dev/null
+++ b/src/gpu/gl/GrGLEffectMatrix.h
@@ -0,0 +1,97 @@
+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrGLEffectMatrix_DEFINED
+#define GrGLEffectMatrix_DEFINED
+
+#include "GrGLEffect.h"
+#include "SkMatrix.h"
+
+class GrTexture;
+class SkRandom;
+
+/**
+ * This is a helper to implement a texture matrix in a GrGLEffect.
+ */
+class GrGLEffectMatrix {
+public:
+ typedef GrGLEffect::EffectKey EffectKey;
+ /**
+ * The matrix uses kKeyBits of the effect's EffectKey. A GrGLEffect may place these bits at an
+ * arbitrary shift in its final key. However, when GrGLEffectMatrix::emitCode*() code is called
+ * the relevant bits must be in the lower kKeyBits of the key parameter.
+ */
+ enum {
+ kKeyBits = 2,
+ kKeyMask = (1 << kKeyBits) - 1,
+ };
+
+ GrGLEffectMatrix() : fUni(GrGLUniformManager::kInvalidUniformHandle) {
+ fPrevMatrix = SkMatrix::InvalidMatrix();
+ }
+
+ /**
+ * Generates the key for the portion of the code emitted by this class's emitCode() function.
+ * Pass a texture to make GrGLEffectMatrix automatically adjust for the texture's origin. Pass
+ * NULL when not using the EffectMatrix for a texture lookups, or if the GrGLEffect subclass
+ * wants to handle origin adjustments in some other manner. coordChangeMatrix is the matrix
+ * from GrEffectStage.
+ */
+ static EffectKey GenKey(const SkMatrix& effectMatrix,
+ const SkMatrix& coordChangeMatrix,
+ const GrTexture*);
+
+ /**
+ * Emits code to implement the matrix in the VS. A varying is added as an output of the VS and
+ * input to the FS. The varying may be either a vec2f or vec3f depending upon whether
+ * perspective interpolation is required or not. The names of the varying in the VS and FS are
+ * are returned as output parameters and the type of the varying is the return value. The suffix
+ * is an optional parameter that can be used to make all variables emitted by the object
+ * unique within a stage. It is only necessary if multiple GrGLEffectMatrix objects are used by
+ * a GrGLEffect.
+ */
+ GrSLType emitCode(GrGLShaderBuilder*,
+ EffectKey,
+ const char* vertexCoords,
+ const char** fsCoordName, /* optional */
+ const char** vsCoordName = NULL,
+ const char* suffix = NULL);
+
+ /**
+ * This is similar to emitCode except that it performs perspective division in the FS if the
+ * texture coordinates have a w coordinate. The fsCoordName always refers to a vec2f.
+ */
+ void emitCodeMakeFSCoords2D(GrGLShaderBuilder*,
+ EffectKey,
+ const char* vertexCoords,
+ const char** fsCoordName, /* optional */
+ const char** vsVaryingName = NULL,
+ GrSLType* vsVaryingType = NULL,
+ const char* suffix = NULL);
+ /**
+ * Call from a GrGLEffect's subclass to update the texture matrix. The matrix,
+ * coordChangeMatrix, and texture params should match those used with GenKey.
+ */
+ void setData(const GrGLUniformManager& uniformManager,
+ const SkMatrix& effectMatrix,
+ const SkMatrix& coordChangeMatrix,
+ const GrTexture*);
+
+private:
+ enum {
+ kIdentity_Key = 0,
+ kTrans_Key = 1,
+ kNoPersp_Key = 2,
+ kGeneral_Key = 3,
+ };
+
+ GrGLUniformManager::UniformHandle fUni;
+ GrSLType fUniType;
+ SkMatrix fPrevMatrix;
+};
+
+#endif
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