Include/Context.h

//
// Copyright (c) 2002-2010 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//

// Context.h: Defines the gl::Context class, managing all GL state and performing
// rendering operations. It is the GLES2 specific implementation of EGLContext.

#ifndef INCLUDE_CONTEXT_H_
#define INCLUDE_CONTEXT_H_

#define GL_APICALL
#include <GLES2/gl2.h>
#define EGLAPI
#include <EGL/egl.h>
#include <d3d9.h>

#include <map>

#include "angleutils.h"

namespace egl
{
class Display;
class Surface;
class Config;
}

namespace gl
{
class Buffer;
class Shader;
class Program;
class Texture;
class Texture2D;
class TextureCubeMap;
class Framebuffer;
class Renderbuffer;
class Colorbuffer;
class Depthbuffer;
class Stencilbuffer;

enum
{
    MAX_VERTEX_ATTRIBS = 8,
    MAX_VERTEX_UNIFORM_VECTORS = 128,
    MAX_VARYING_VECTORS = 8,
    MAX_COMBINED_TEXTURE_IMAGE_UNITS = 8,
    MAX_VERTEX_TEXTURE_IMAGE_UNITS = 0,
    MAX_TEXTURE_IMAGE_UNITS = 8,
    MAX_FRAGMENT_UNIFORM_VECTORS = 16,
    MAX_RENDERBUFFER_SIZE = 4096,   // FIXME: Verify
    MAX_DRAW_BUFFERS = 1,

    IMPLEMENTATION_COLOR_READ_FORMAT = GL_RGB,
    IMPLEMENTATION_COLOR_READ_TYPE = GL_UNSIGNED_SHORT_5_6_5
};

struct Color
{
    float red;
    float green;
    float blue;
    float alpha;
};

// Helper structure describing a single vertex attribute array
struct Array
{
    Array();

    bool enabled;
    GLuint boundBuffer;
    GLint size;
    GLenum type;
    GLboolean normalized;
    GLsizei stride;
    const void *pointer;
};

// Helper structure to store all raw state
struct State
{
    Color colorClearValue;
    GLclampf depthClearValue;
    int stencilClearValue;

    bool cullFace;
    GLenum cullMode;
    GLenum frontFace;
    bool depthTest;
    GLenum depthFunc;
    bool blend;
    GLenum sourceBlendRGB;
    GLenum destBlendRGB;
    GLenum sourceBlendAlpha;
    GLenum destBlendAlpha;
    GLenum blendEquationRGB;
    GLenum blendEquationAlpha;
    Color blendColor;
    bool stencilTest;
    GLenum stencilFunc;
    GLint stencilRef;
    GLuint stencilMask;
    GLenum stencilFail;
    GLenum stencilPassDepthFail;
    GLenum stencilPassDepthPass;
    GLuint stencilWritemask;
    GLenum stencilBackFunc;
    GLint stencilBackRef;
    GLuint stencilBackMask;
    GLenum stencilBackFail;
    GLenum stencilBackPassDepthFail;
    GLenum stencilBackPassDepthPass;
    GLuint stencilBackWritemask;
    bool polygonOffsetFill;
    bool sampleAlphaToCoverage;
    bool sampleCoverage;
    GLclampf sampleCoverageValue;
    GLboolean sampleCoverageInvert;
    bool scissorTest;
    bool dither;

    GLint viewportX;
    GLint viewportY;
    GLsizei viewportWidth;
    GLsizei viewportHeight;
    float zNear;
    float zFar;

    GLint scissorX;
    GLint scissorY;
    GLsizei scissorWidth;
    GLsizei scissorHeight;

    bool colorMaskRed;
    bool colorMaskGreen;
    bool colorMaskBlue;
    bool colorMaskAlpha;
    bool depthMask;
    
    int activeSampler;   // Active texture unit selector - GL_TEXTURE0
    GLuint arrayBuffer;
    GLuint elementArrayBuffer;
    GLuint texture2D;
    GLuint textureCubeMap;
    GLuint framebuffer;
    GLuint renderbuffer;
    GLuint currentProgram;

    Array vertexAttribute[MAX_VERTEX_ATTRIBS];
    GLuint samplerTexture[MAX_TEXTURE_IMAGE_UNITS];

    unsigned int startIndex;
};

class Context : public State
{
  public:
    Context(const egl::Config *config);

    ~Context();

    void makeCurrent(egl::Display *display, egl::Surface *surface);

    void setClearColor(float red, float green, float blue, float alpha);
    void setClearDepth(float depth);
    void setClearStencil(int stencil);

    GLuint createBuffer();
    GLuint createShader(GLenum type);
    GLuint createProgram();
    GLuint createTexture();
    GLuint createFramebuffer();
    GLuint createRenderbuffer();

    void deleteBuffer(GLuint buffer);
    void deleteShader(GLuint shader);
    void deleteProgram(GLuint program);
    void deleteTexture(GLuint texture);
    void deleteFramebuffer(GLuint framebuffer);
    void deleteRenderbuffer(GLuint renderbuffer);

    void bindArrayBuffer(GLuint buffer);
    void bindElementArrayBuffer(GLuint buffer);
    void bindTexture2D(GLuint texture);
    void bindTextureCubeMap(GLuint texture);
    void bindFramebuffer(GLuint framebuffer);
    void bindRenderbuffer(GLuint renderbuffer);
    void useProgram(GLuint program);

    void setFramebufferZero(Framebuffer *framebuffer);
    void setColorbufferZero(Colorbuffer *renderbuffer);
    void setDepthbufferZero(Depthbuffer *depthBuffer);
    void setStencilbufferZero(Stencilbuffer *stencilBuffer);
    void setRenderbuffer(Renderbuffer *renderbuffer);

    Buffer *getBuffer(GLuint handle);
    Shader *getShader(GLuint handle);
    Program *getProgram(GLuint handle);
    Texture *getTexture(GLuint handle);
    Framebuffer *getFramebuffer(GLuint handle);
    Renderbuffer *getRenderbuffer(GLuint handle);
    Colorbuffer *getColorbuffer(GLuint handle);
    Depthbuffer *getDepthbuffer(GLuint handle);
    Stencilbuffer *getStencilbuffer(GLuint handle);

    Buffer *getArrayBuffer();
    Buffer *getElementArrayBuffer();
    Program *getCurrentProgram();
    Texture2D *getTexture2D();
    TextureCubeMap *getTextureCubeMap();
    Texture *getSamplerTexture(unsigned int sampler);
    Framebuffer *getFramebuffer();

    bool applyRenderTarget(bool ignoreViewport);
    void applyState();
    void applyVertexBuffer(int count);
    void applyIndexBuffer(const void *indices, int length);
    void applyShaders();
    void applyTextures();

    void readPixels(GLint x, GLint y, GLsizei width, GLsizei height, GLenum format, GLenum type, void* pixels);
    void clear(GLbitfield mask);
    void drawArrays(GLenum mode, GLint first, GLsizei count);
    void drawElements(GLenum mode, GLsizei count, GLenum type, const void* indices);
    void finish();
    void flush();

    void recordInvalidEnum();
    void recordInvalidValue();
    void recordInvalidOperation();
    void recordOutOfMemory();
    void recordInvalidFramebufferOperation();

    GLenum getError();

  private:
    DISALLOW_COPY_AND_ASSIGN(Context);

    void detachBuffer(GLuint buffer);
    void detachTexture(GLuint texture);
    void detachFramebuffer(GLuint framebuffer);
    void detachRenderbuffer(GLuint renderbuffer);

    const egl::Config *const mConfig;

    Texture2D *mTexture2DZero;
    TextureCubeMap *mTextureCubeMapZero;

    Colorbuffer *mColorbufferZero;
    Depthbuffer *mDepthbufferZero;
    Stencilbuffer *mStencilbufferZero;

    typedef std::map<GLuint, Buffer*> BufferMap;
    BufferMap mBufferMap;

    typedef std::map<GLuint, Shader*> ShaderMap;
    ShaderMap mShaderMap;

    typedef std::map<GLuint, Program*> ProgramMap;
    ProgramMap mProgramMap;

    typedef std::map<GLuint, Texture*> TextureMap;
    TextureMap mTextureMap;

    typedef std::map<GLuint, Framebuffer*> FramebufferMap;
    FramebufferMap mFramebufferMap;

    typedef std::map<GLuint, Renderbuffer*> RenderbufferMap;
    RenderbufferMap mRenderbufferMap;

    // Recorded errors
    bool mInvalidEnum;
    bool mInvalidValue;
    bool mInvalidOperation;
    bool mOutOfMemory;
    bool mInvalidFramebufferOperation;
};
}

extern "C"
{
// Exported functions for use by EGL
gl::Context *glCreateContext(const egl::Config *config);
void glDestroyContext(gl::Context *context);
void glMakeCurrent(gl::Context *context, egl::Display *display, egl::Surface *surface);
gl::Context *glGetCurrentContext();
}

#endif   // INCLUDE_CONTEXT_H_