libs/hwui/OpenGLRenderer.h

/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef ANDROID_UI_OPENGL_RENDERER_H
#define ANDROID_UI_OPENGL_RENDERER_H

#include <GLES2/gl2.h>
#include <GLES2/gl2ext.h>

#include <SkMatrix.h>
#include <SkXfermode.h>

#include <utils/KeyedVector.h>
#include <utils/RefBase.h>

#include "Matrix.h"
#include "Rect.h"

namespace android {
namespace uirenderer {

///////////////////////////////////////////////////////////////////////////////
// Support
///////////////////////////////////////////////////////////////////////////////

class Snapshot: public LightRefBase<Snapshot> {
public:
    Snapshot() {
    }

    Snapshot(const sp<Snapshot> s):
            transform(s->transform),
            clipRect(s->clipRect),
            flags(kFlagDirtyTransform),
            previous(s),
            layer(0.0f, 0.0f, 0.0f, 0.0f),
            texture(0),
            fbo(0),
            alpha(255) {
    }

    enum Flags {
        kFlagClipSet = 0x1,
        kFlagDirtyTransform = 0x2,
        kFlagIsLayer = 0x4,
    };

    const Rect& getMappedClip();

    // Local transformations
    mat4 transform;

    // Clipping rectangle at the time of this snapshot
    Rect clipRect;

    // Dirty flags
    int flags;

    // Previous snapshot in the frames stack
    sp<Snapshot> previous;

    // Layer, only set if kFlagIsLayer is set
    Rect layer;
    GLuint texture;
    GLuint fbo;
    float alpha;

private:
    // Clipping rectangle mapped with the transform
    Rect mappedClip;
}; // class Snapshot

struct SimpleVertex {
    float position[2];
}; // struct SimpleVertex

struct TextureVertex {
    float position[2];
    float texture[2];
}; // struct TextureVertex

class Program: public LightRefBase<Program> {
public:
    Program(const char* vertex, const char* fragment);
    ~Program();

    void use();

protected:
    int addAttrib(const char* name);
    int getAttrib(const char* name);

    int addUniform(const char* name);
    int getUniform(const char* name);

private:
    GLuint buildShader(const char* source, GLenum type);

    // Handle of the OpenGL program
    GLuint id;

    // Handles of the shaders
    GLuint vertexShader;
    GLuint fragmentShader;

    // Keeps track of attributes and uniforms slots
    KeyedVector<const char*, int> attributes;
    KeyedVector<const char*, int> uniforms;
}; // class Program

class DrawColorProgram: public Program {
public:
    DrawColorProgram();
    DrawColorProgram(const char* vertex, const char* fragment);

    void use(const GLfloat* projectionMatrix, const GLfloat* modelViewMatrix,
             const GLfloat* transformMatrix);

    int position;
    int color;

    int projection;
    int modelView;
    int transform;

protected:
    void getAttribsAndUniforms();
};

class DrawTextureProgram: public DrawColorProgram {
public:
    DrawTextureProgram();

    int sampler;
    int texCoords;
};

///////////////////////////////////////////////////////////////////////////////
// Renderer
///////////////////////////////////////////////////////////////////////////////

class OpenGLRenderer {
public:
    OpenGLRenderer();
    ~OpenGLRenderer();

    void setViewport(int width, int height);
    void prepare();

    int getSaveCount() const;
    int save(int flags);
    void restore();
    void restoreToCount(int saveCount);

    int saveLayer(float left, float top, float right, float bottom, const SkPaint* p, int flags);
    int saveLayerAlpha(float left, float top, float right, float bottom, int alpha, int flags);

    void translate(float dx, float dy);
    void rotate(float degrees);
    void scale(float sx, float sy);

    void setMatrix(SkMatrix* matrix);
    void getMatrix(SkMatrix* matrix);
    void concatMatrix(SkMatrix* matrix);

    const Rect& getClipBounds();
    bool quickReject(float left, float top, float right, float bottom);
    bool clipRect(float left, float top, float right, float bottom);

    void drawColor(int color, SkXfermode::Mode mode);
    void drawRect(float left, float top, float right, float bottom, const SkPaint* paint);

private:
    int saveSnapshot();
    bool restoreSnapshot();

    void setScissorFromClip();

    void drawColorRect(float left, float top, float right, float bottom, int color);
    void drawTextureRect(float left, float top, float right, float bottom, GLuint texture,
            float alpha);

    // Dimensions of the drawing surface
    int mWidth, mHeight;

    // Matrix used for ortho projection in shaders
    float mOrthoMatrix[16];

    // Model-view matrix used to position/size objects
    mat4 mModelView;

    // Number of saved states
    int mSaveCount;
    // Base state
    Snapshot mFirstSnapshot;
    // Current state
    sp<Snapshot> mSnapshot;

    // Shaders
    sp<DrawColorProgram> mDrawColorShader;
    sp<DrawTextureProgram> mDrawTextureShader;
}; // class OpenGLRenderer

}; // namespace uirenderer
}; // namespace android

#endif // ANDROID_UI_OPENGL_RENDERER_H