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 <SkBitmap.h>
#include <SkMatrix.h>
#include <SkPaint.h>
#include <SkRegion.h>
#include <SkShader.h>
#include <SkXfermode.h>

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

#include "Extensions.h"
#include "Matrix.h"
#include "Program.h"
#include "Rect.h"
#include "Snapshot.h"
#include "Vertex.h"
#include "SkiaShader.h"
#include "SkiaColorFilter.h"
#include "Caches.h"

namespace android {
namespace uirenderer {

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

/**
 * OpenGL renderer used to draw accelerated 2D graphics. The API is a
 * simplified version of Skia's Canvas API.
 */
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, SkRegion::Op op);

    void drawBitmap(SkBitmap* bitmap, float left, float top, const SkPaint* paint);
    void drawBitmap(SkBitmap* bitmap, const SkMatrix* matrix, const SkPaint* paint);
    void drawBitmap(SkBitmap* bitmap, float srcLeft, float srcTop, float srcRight, float srcBottom,
            float dstLeft, float dstTop, float dstRight, float dstBottom, const SkPaint* paint);
    void drawPatch(SkBitmap* bitmap, Res_png_9patch* patch, float left, float top,
            float right, float bottom, const SkPaint* paint);
    void drawColor(int color, SkXfermode::Mode mode);
    void drawRect(float left, float top, float right, float bottom, const SkPaint* paint);
    void drawPath(SkPath* path, SkPaint* paint);

    void resetShader();
    void setupShader(SkiaShader* shader);

    void resetColorFilter();
    void setupColorFilter(SkiaColorFilter* filter);

    void resetShadow();
    void setupShadow(float radius, float dx, float dy, int color);

    void drawText(const char* text, int bytesCount, int count, float x, float y, SkPaint* paint);

private:
    /**
     * Saves the current state of the renderer as a new snapshot.
     * The new snapshot is saved in mSnapshot and the previous snapshot
     * is linked from mSnapshot->previous.
     *
     * @return The new save count. This value can be passed to #restoreToCount()
     */
    int saveSnapshot();

    /**
     * Restores the current snapshot; mSnapshot becomes mSnapshot->previous.
     *
     * @return True if the clip was modified.
     */
    bool restoreSnapshot();

    /**
     * Sets the clipping rectangle using glScissor. The clip is defined by
     * the current snapshot's clipRect member.
     */
    void setScissorFromClip();

    /**
     * Compose the layer defined in the current snapshot with the layer
     * defined by the previous snapshot.
     *
     * The current snapshot *must* be a layer (flag kFlagIsLayer set.)
     *
     * @param curent The current snapshot containing the layer to compose
     * @param previous The previous snapshot to compose the current layer with
     */
    void composeLayer(sp<Snapshot> current, sp<Snapshot> previous);

    /**
     * Creates a new layer stored in the specified snapshot.
     *
     * @param snapshot The snapshot associated with the new layer
     * @param left The left coordinate of the layer
     * @param top The top coordinate of the layer
     * @param right The right coordinate of the layer
     * @param bottom The bottom coordinate of the layer
     * @param alpha The translucency of the layer
     * @param mode The blending mode of the layer
     * @param flags The layer save flags
     *
     * @return True if the layer was successfully created, false otherwise
     */
    bool createLayer(sp<Snapshot> snapshot, float left, float top, float right, float bottom,
            int alpha, SkXfermode::Mode mode, int flags);

    /**
     * Draws a colored rectangle with the specified color. The specified coordinates
     * are transformed by the current snapshot's transform matrix.
     *
     * @param left The left coordinate of the rectangle
     * @param top The top coordinate of the rectangle
     * @param right The right coordinate of the rectangle
     * @param bottom The bottom coordinate of the rectangle
     * @param color The rectangle's ARGB color, defined as a packed 32 bits word
     * @param mode The Skia xfermode to use
     * @param ignoreTransform True if the current transform should be ignored
     */
    void drawColorRect(float left, float top, float right, float bottom,
    		int color, SkXfermode::Mode mode, bool ignoreTransform = false);

    /**
     * Draws a textured rectangle with the specified texture. The specified coordinates
     * are transformed by the current snapshot's transform matrix.
     *
     * @param left The left coordinate of the rectangle
     * @param top The top coordinate of the rectangle
     * @param right The right coordinate of the rectangle
     * @param bottom The bottom coordinate of the rectangle
     * @param texture The texture name to map onto the rectangle
     * @param alpha An additional translucency parameter, between 0.0f and 1.0f
     * @param mode The blending mode
     * @param blend True if the texture contains an alpha channel
     */
    void drawTextureRect(float left, float top, float right, float bottom, GLuint texture,
            float alpha, SkXfermode::Mode mode, bool blend);

    /**
     * Draws a textured rectangle with the specified texture. The specified coordinates
     * are transformed by the current snapshot's transform matrix.
     *
     * @param left The left coordinate of the rectangle
     * @param top The top coordinate of the rectangle
     * @param right The right coordinate of the rectangle
     * @param bottom The bottom coordinate of the rectangle
     * @param texture The texture to use
     * @param paint The paint containing the alpha, blending mode, etc.
     */
    void drawTextureRect(float left, float top, float right, float bottom,
            const Texture* texture, const SkPaint* paint);

    /**
     * Draws a textured mesh with the specified texture. If the indices are omitted, the
     * mesh is drawn as a simple quad.
     *
     * @param left The left coordinate of the rectangle
     * @param top The top coordinate of the rectangle
     * @param right The right coordinate of the rectangle
     * @param bottom The bottom coordinate of the rectangle
     * @param texture The texture name to map onto the rectangle
     * @param alpha An additional translucency parameter, between 0.0f and 1.0f
     * @param mode The blending mode
     * @param blend True if the texture contains an alpha channel
     * @param vertices The vertices that define the mesh
     * @param texCoords The texture coordinates of each vertex
     * @param indices The indices of the vertices, can be NULL
     * @param elementsCount The number of elements in the mesh, required by indices
     */
    void drawTextureMesh(float left, float top, float right, float bottom, GLuint texture,
            float alpha, SkXfermode::Mode mode, bool blend,
            GLvoid* vertices, GLvoid* texCoords, GLvoid* indices, GLsizei elementsCount = 0);

    /**
     * Prepares the renderer to draw the specified shadow.
     *
     * @param texture The shadow texture
     * @param x The x coordinate of the shadow
     * @param y The y coordinate of the shadow
     * @param mode The blending mode
     * @param alpha The alpha value
     */
    void setupShadow(const ShadowTexture* texture, float x, float y, SkXfermode::Mode mode,
            float alpha);

    /**
     * Prepares the renderer to draw the specified Alpha8 texture as a rectangle.
     *
     * @param texture The texture to render with
     * @param textureUnit The texture unit to use, may be modified
     * @param x The x coordinate of the rectangle to draw
     * @param y The y coordinate of the rectangle to draw
     * @param r The red component of the color
     * @param g The green component of the color
     * @param b The blue component of the color
     * @param a The alpha component of the color
     * @param mode The blending mode
     * @param transforms True if the matrix passed to the shader should be multiplied
     *        by the model-view matrix
     * @param applyFilters Whether or not to take color filters and
     *        shaders into account
     */
    void setupTextureAlpha8(const Texture* texture, GLuint& textureUnit, float x, float y,
            float r, float g, float b, float a, SkXfermode::Mode mode, bool transforms,
            bool applyFilters);

    /**
     * Prepares the renderer to draw the specified Alpha8 texture as a rectangle.
     *
     * @param texture The texture to render with
     * @param width The width of the texture
     * @param height The height of the texture
     * @param textureUnit The texture unit to use, may be modified
     * @param x The x coordinate of the rectangle to draw
     * @param y The y coordinate of the rectangle to draw
     * @param r The red component of the color
     * @param g The green component of the color
     * @param b The blue component of the color
     * @param a The alpha component of the color
     * @param mode The blending mode
     * @param transforms True if the matrix passed to the shader should be multiplied
     *        by the model-view matrix
     * @param applyFilters Whether or not to take color filters and
     *        shaders into account
     */
    void setupTextureAlpha8(GLuint texture, uint32_t width, uint32_t height,
            GLuint& textureUnit, float x, float y, float r, float g, float b, float a,
            SkXfermode::Mode mode, bool transforms, bool applyFilters);

    /**
     * Draws text underline and strike-through if needed.
     *
     * @param text The text to decor
     * @param bytesCount The number of bytes in the text
     * @param length The length in pixels of the text, can be <= 0.0f to force a measurement
     * @param x The x coordinate where the text will be drawn
     * @param y The y coordinate where the text will be drawn
     * @param paint The paint to draw the text with
     */
    void drawTextDecorations(const char* text, int bytesCount, float length,
            float x, float y, SkPaint* paint);

    /**
     * Resets the texture coordinates stored in mMeshVertices. Setting the values
     * back to default is achieved by calling:
     *
     * resetDrawTextureTexCoords(0.0f, 0.0f, 1.0f, 1.0f);
     *
     * @param u1 The left coordinate of the texture
     * @param v1 The bottom coordinate of the texture
     * @param u2 The right coordinate of the texture
     * @param v2 The top coordinate of the texture
     */
    void resetDrawTextureTexCoords(float u1, float v1, float u2, float v2);

    /**
     * Gets the alpha and xfermode out of a paint object. If the paint is null
     * alpha will be 255 and the xfermode will be SRC_OVER.
     *
     * @param paint The paint to extract values from
     * @param alpha Where to store the resulting alpha
     * @param mode Where to store the resulting xfermode
     */
    inline void getAlphaAndMode(const SkPaint* paint, int* alpha, SkXfermode::Mode* mode);

    /**
     * Binds the specified texture with the specified wrap modes.
     */
    inline void bindTexture(GLuint texture, GLenum wrapS, GLenum wrapT, GLuint textureUnit = 0);

    /**
     * Enable or disable blending as necessary. This function sets the appropriate
     * blend function based on the specified xfermode.
     */
    inline void chooseBlending(bool blend, SkXfermode::Mode mode, bool isPremultiplied = true);

    /**
     * Use the specified program with the current GL context. If the program is already
     * in use, it will not be bound again. If it is not in use, the current program is
     * marked unused and the specified program becomes used and becomes the new
     * current program.
     *
     * @param program The program to use
     *
     * @return true If the specified program was already in use, false otherwise.
     */
    inline bool useProgram(Program* program);

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

    // Matrix used for ortho projection in shaders
    mat4 mOrthoMatrix;

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

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

    // Shaders
    SkiaShader* mShader;

    // Color filters
    SkiaColorFilter* mColorFilter;

    // Used to draw textured quads
    TextureVertex mMeshVertices[4];

    // GL extensions
    Extensions mExtensions;

    // Drop shadow
    bool mHasShadow;
    float mShadowRadius;
    float mShadowDx;
    float mShadowDy;
    int mShadowColor;

    // Various caches
    Caches& mCaches;
}; // class OpenGLRenderer

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

#endif // ANDROID_UI_OPENGL_RENDERER_H