Initial refactor of shaderbuilder to prepare for geometry shaders
gitignore for eclipse
BUG=skia:
R=bsalomon@google.com, bsalomon@chromium.org
Author: joshualitt@chromium.org
Review URL: https://codereview.chromium.org/491673002
diff --git a/src/gpu/gl/builders/GrGLFragmentShaderBuilder.h b/src/gpu/gl/builders/GrGLFragmentShaderBuilder.h
new file mode 100644
index 0000000..0f700bd
--- /dev/null
+++ b/src/gpu/gl/builders/GrGLFragmentShaderBuilder.h
@@ -0,0 +1,118 @@
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrGLFragmentShaderBuilder_DEFINED
+#define GrGLFragmentShaderBuilder_DEFINED
+#include "GrGLShaderBuilder.h"
+
+class GrGLProgramBuilder;
+
+class GrGLFragmentShaderBuilder : public GrGLShaderBuilder {
+public:
+ typedef uint8_t DstReadKey;
+ typedef uint8_t FragPosKey;
+
+ /** Returns a key for adding code to read the copy-of-dst color in service of effects that
+ require reading the dst. It must not return 0 because 0 indicates that there is no dst
+ copy read at all (in which case this function should not be called). */
+ static DstReadKey KeyForDstRead(const GrTexture* dstCopy, const GrGLCaps&);
+
+ /** Returns a key for reading the fragment location. This should only be called if there is an
+ effect that will requires the fragment position. If the fragment position is not required,
+ the key is 0. */
+ static FragPosKey KeyForFragmentPosition(const GrRenderTarget* dst, const GrGLCaps&);
+
+ GrGLFragmentShaderBuilder(GrGLProgramBuilder* program, const GrGLProgramDesc& desc);
+
+ /** Returns the variable name that holds the color of the destination pixel. This may be NULL if
+ no effect advertised that it will read the destination. */
+ const char* dstColor();
+
+ /**
+ * Use of these features may require a GLSL extension to be enabled. Shaders may not compile
+ * if code is added that uses one of these features without calling enableFeature()
+ */
+ enum GLSLFeature {
+ kStandardDerivatives_GLSLFeature = 0,
+ kLastGLSLFeature = kStandardDerivatives_GLSLFeature
+ };
+
+ /**
+ * If the feature is supported then true is returned and any necessary #extension declarations
+ * are added to the shaders. If the feature is not supported then false will be returned.
+ */
+ bool enableFeature(GLSLFeature);
+
+ /**
+ * This returns a variable name to access the 2D, perspective correct version of the coords in
+ * the fragment shader. If the coordinates at index are 3-dimensional, it immediately emits a
+ * perspective divide into the fragment shader (xy / z) to convert them to 2D.
+ */
+ SkString ensureFSCoords2D(const TransformedCoordsArray& coords, int index);
+
+
+ /** Returns a variable name that represents the position of the fragment in the FS. The position
+ is in device space (e.g. 0,0 is the top left and pixel centers are at half-integers). */
+ const char* fragmentPosition();
+
+private:
+ /*
+ * An internal call for GrGLFullProgramBuilder to use to add varyings to the vertex shader
+ */
+ void addVarying(GrSLType type,
+ const char* name,
+ const char** fsInName);
+
+ /*
+ * Private functions used by GrGLProgramBuilder for compilation
+ */
+ void bindProgramLocations(GrGLuint programId);
+ bool compileAndAttachShaders(GrGLuint programId, SkTDArray<GrGLuint>* shaderIds) const;
+ void emitCodeBeforeEffects();
+ void emitCodeAfterEffects(const GrGLSLExpr4& inputColor, const GrGLSLExpr4& inputCoverage);
+
+ /** Enables using the secondary color output and returns the name of the var in which it is
+ to be stored */
+ const char* enableSecondaryOutput();
+
+ /** Gets the name of the primary color output. */
+ const char* getColorOutputName() const;
+
+ /**
+ * Features that should only be enabled by GrGLFragmentShaderBuilder itself.
+ */
+ enum GLSLPrivateFeature {
+ kFragCoordConventions_GLSLPrivateFeature = kLastGLSLFeature + 1,
+ kLastGLSLPrivateFeature = kFragCoordConventions_GLSLPrivateFeature
+ };
+
+ // Interpretation of DstReadKey when generating code
+ enum {
+ kNoDstRead_DstReadKey = 0,
+ kYesDstRead_DstReadKeyBit = 0x1, // Set if we do a dst-copy-read.
+ kUseAlphaConfig_DstReadKeyBit = 0x2, // Set if dst-copy config is alpha only.
+ kTopLeftOrigin_DstReadKeyBit = 0x4, // Set if dst-copy origin is top-left.
+ };
+
+ enum {
+ kNoFragPosRead_FragPosKey = 0, // The fragment positition will not be needed.
+ kTopLeftFragPosRead_FragPosKey = 0x1,// Read frag pos relative to top-left.
+ kBottomLeftFragPosRead_FragPosKey = 0x2,// Read frag pos relative to bottom-left.
+ };
+
+ bool fHasCustomColorOutput;
+ bool fHasSecondaryOutput;
+ bool fSetupFragPosition;
+ bool fTopLeftFragPosRead;
+
+ friend class GrGLProgramBuilder;
+ friend class GrGLFullProgramBuilder;
+
+ typedef GrGLShaderBuilder INHERITED;
+};
+
+#endif