urho3d/Engine/Graphics/OpenGL/OGLGraphics.h

//
// Urho3D Engine
// Copyright (c) 2008-2012 Lasse Öörni
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//

#pragma once

#include "ArrayPtr.h"
#include "Color.h"
#include "GraphicsDefs.h"
#include "HashMap.h"
#include "Image.h"
#include "Matrix3x4.h"
#include "Object.h"
#include "Rect.h"

class Image;
class IndexBuffer;
class Matrix3;
class Matrix4;
class Matrix3x4;
class GPUObject;
class GraphicsImpl;
class RenderSurface;
class ShaderProgram;
class ShaderVariation;
class Texture;
class Texture2D;
class TextureCube;
class Vector3;
class Vector4;
class VertexBuffer;

typedef HashMap<Pair<ShaderVariation*, ShaderVariation*>, SharedPtr<ShaderProgram> > ShaderProgramMap;

static const unsigned NUM_SCREEN_BUFFERS = 2;
static const unsigned NUM_TEMP_MATRICES = 8;

/// CPU-side scratch buffer for vertex data updates.
struct ScratchBuffer
{
    ScratchBuffer() :
        size_(0),
        reserved_(false)
    {
    }
    
    /// Buffer data.
    SharedArrayPtr<unsigned char> data_;
    /// Data size.
    unsigned size_;
    /// Reserved flag.
    bool reserved_;
};

/// %Graphics subsystem. Manages the application window, rendering state and GPU resources.
class Graphics : public Object
{
    OBJECT(Graphics);
    
public:
    /// Construct.
    Graphics(Context* context_);
    /// Destruct. Release the OpenGL context and close the window.
    virtual ~Graphics();
    
    /// Set external window handle. Only effective before setting the initial screen mode. On Windows it is necessary to set up OpenGL pixel format manually for the window.
    void SetExternalWindow(void* window);
    /// Set window title.
    void SetWindowTitle(const String& windowTitle);
    /// Set screen mode. Return true if successful.
    bool SetMode(int width, int height, bool fullscreen, bool vsync, bool tripleBuffer, int multiSample);
    /// Set screen resolution only. Return true if successful.
    bool SetMode(int width, int height);
    /// Toggle between full screen and windowed mode.
    bool ToggleFullscreen();
    /// Close the window.
    void Close();
    /// Take a screenshot.
    bool TakeScreenShot(Image& destImage);
    /// Begin frame rendering. Return true if device available and can render.
    bool BeginFrame();
    /// End frame rendering and swap buffers.
    void EndFrame();
    /// Clear any or all of rendertarget, depth buffer and stencil buffer.
    void Clear(unsigned flags, const Color& color = Color(0.0f, 0.0f, 0.0f, 0.0f), float depth = 1.0f, unsigned stencil = 0);
    /// Resolve multisampled backbuffer to a texture rendertarget.
    bool ResolveToTexture(Texture2D* destination, const IntRect& viewport);
    /// Draw non-indexed geometry.
    void Draw(PrimitiveType type, unsigned vertexStart, unsigned vertexCount);
    /// Draw indexed geometry.
    void Draw(PrimitiveType type, unsigned indexStart, unsigned indexCount, unsigned minVertex, unsigned vertexCount);
    /// Draw indexed, instanced geometry. No-op on OpenGL.
    void DrawInstanced(PrimitiveType type, unsigned indexStart, unsigned indexCount, unsigned minVertex, unsigned vertexCount, unsigned instanceCount);
    /// Set vertex buffer.
    void SetVertexBuffer(VertexBuffer* buffer);
    /// Set multiple vertex buffers.
    bool SetVertexBuffers(const Vector<VertexBuffer*>& buffers, const PODVector<unsigned>& elementMasks, unsigned instanceOffset = 0);
    /// Set multiple vertex buffers.
    bool SetVertexBuffers(const Vector<SharedPtr<VertexBuffer> >& buffers, const PODVector<unsigned>& elementMasks, unsigned instanceOffset = 0);
    /// Set index buffer.
    void SetIndexBuffer(IndexBuffer* buffer);
    /// Set shaders.
    void SetShaders(ShaderVariation* vs, ShaderVariation* ps);
    /// Set shader float constants.
    void SetShaderParameter(StringHash param, const float* data, unsigned count);
    /// Set shader float constant.
    void SetShaderParameter(StringHash param, float value);
    /// Set shader color constant.
    void SetShaderParameter(StringHash param, const Color& color);
    /// Set shader 3x3 matrix constant.
    void SetShaderParameter(StringHash param, const Matrix3& matrix);
    /// Set shader 3D vector constant.
    void SetShaderParameter(StringHash param, const Vector3& vector);
    /// Set shader 4x4 matrix constant.
    void SetShaderParameter(StringHash param, const Matrix4& matrix);
    /// Set shader 4D vector constant.
    void SetShaderParameter(StringHash param, const Vector4& vector);
    /// Set shader 4x3 matrix constant.
    void SetShaderParameter(StringHash param, const Matrix3x4& matrix);
    /// Check whether a shader parameter group needs update. Does not actually check whether parameters exist in the shaders.
    bool NeedParameterUpdate(ShaderParameterGroup group, const void* source);
    /// Check whether a shader parameter exists on the currently set shaders.
    bool HasShaderParameter(ShaderType type, StringHash param);
    /// Check whether the current pixel shader uses a texture unit.
    bool HasTextureUnit(TextureUnit unit);
    /// Clear remembered shader parameter source group.
    void ClearParameterSource(ShaderParameterGroup group);
    /// Clear remembered shader parameter sources.
    void ClearParameterSources();
    /// Clear remembered transform shader parameter sources.
    void ClearTransformSources();
    /// Clean up unused shader programs.
    void CleanupShaderPrograms();
    /// Set texture.
    void SetTexture(unsigned index, Texture* texture);
    /// Bind texture unit 0 for update. Called by Texture.
    void SetTextureForUpdate(Texture* texture);
    /// Set default texture filtering mode.
    void SetDefaultTextureFilterMode(TextureFilterMode mode);
    /// Set texture anisotropy.
    void SetTextureAnisotropy(unsigned level);
    /// Dirty texture parameters of all textures (when global settings change.)
    void SetTextureParametersDirty();
    /// Reset all rendertargets, depth-stencil surface and viewport.
    void ResetRenderTargets();
    /// Reset specific rendertarget.
    void ResetRenderTarget(unsigned index);
    /// Reset depth-stencil surface.
    void ResetDepthStencil();
    /// Set rendertarget.
    void SetRenderTarget(unsigned index, RenderSurface* renderTarget);
    /// Set rendertarget.
    void SetRenderTarget(unsigned index, Texture2D* texture);
    /// Set depth-stencil surface.
    void SetDepthStencil(RenderSurface* depthStencil);
    /// Set depth-stencil surface.
    void SetDepthStencil(Texture2D* texture);
    /// Set view texture (deferred rendering final output rendertarget) to prevent it from being sampled.
    void SetViewTexture(Texture* texture);
    /// Set viewport.
    void SetViewport(const IntRect& rect);
    /// Set blending mode.
    void SetBlendMode(BlendMode mode);
    /// Set color write on/off.
    void SetColorWrite(bool enable);
    /// Set hardware culling mode.
    void SetCullMode(CullMode mode);
    /// Set depth bias.
    void SetDepthBias(float constantBias, float slopeScaledBias);
    /// Set depth compare.
    void SetDepthTest(CompareMode mode);
    /// Set depth write on/off.
    void SetDepthWrite(bool enable);
    /// Set scissor test.
    void SetScissorTest(bool enable, const Rect& rect = Rect::FULL, bool borderInclusive = true);
    /// Set scissor test.
    void SetScissorTest(bool enable, const IntRect& rect);
    /// Set stencil test.
    void SetStencilTest(bool enable, CompareMode mode = CMP_ALWAYS, StencilOp pass = OP_KEEP, StencilOp fail = OP_KEEP, StencilOp zFail = OP_KEEP, unsigned stencilRef = 0, unsigned compareMask = M_MAX_UNSIGNED, unsigned writeMask = M_MAX_UNSIGNED);
    /// Set vertex buffer stream frequency. No-op on OpenGL.
    void SetStreamFrequency(unsigned index, unsigned frequency);
    /// Reset stream frequencies. No-op on OpenGL.
    void ResetStreamFrequencies();
    /// Set force Shader Model 2 flag. No-op on OpenGL.
    void SetForceSM2(bool enable);

    /// Return whether rendering initialized.
    bool IsInitialized() const;
    /// Return graphics implementation, which holds the actual API-specific resources.
    GraphicsImpl* GetImpl() const { return impl_; }
    /// Return OS-specific external window handle. Null if not in use.
    void* GetExternalWindow() const { return externalWindow_; }
    /// Return window title.
    const String& GetWindowTitle() const { return windowTitle_; }
    /// Return window width.
    int GetWidth() const { return width_; }
    /// Return window height.
    int GetHeight() const { return height_; }
    /// Return multisample mode (1 = no multisampling.)
    int GetMultiSample() const { return multiSample_; }
    /// Return whether window is fullscreen.
    bool GetFullscreen() const { return fullscreen_; }
    /// Return whether vertical sync is on.
    bool GetVSync() const { return vsync_; }
    /// Return whether triple buffering is enabled.
    bool GetTripleBuffer() const { return tripleBuffer_; }
    /// Return whether device is lost, and can not yet render.
    bool IsDeviceLost() const;
    /// Return number of primitives drawn this frame.
    unsigned GetNumPrimitives() const { return numPrimitives_; }
    /// Return number of batches drawn this frame.
    unsigned GetNumBatches() const { return numBatches_; }
    /// Return dummy color texture format for shadow maps.
    unsigned GetDummyColorFormat() const { return 0; }
    /// Return shadow map depth texture format, or 0 if not supported.
    unsigned GetShadowMapFormat() const { return shadowMapFormat_; }
    /// Return 24-bit shadow map depth texture format, or 0 if not supported.
    unsigned GetHiresShadowMapFormat() const { return hiresShadowMapFormat_; }
    /// Return whether Shader Model 3 is supported. Always false on OpenGL.
    bool GetSM3Support() const { return false; }
    /// Return whether light pre-pass rendering is supported.
    bool GetLightPrepassSupport() const { return lightPrepassSupport_; }
    /// Return whether deferred rendering is supported.
    bool GetDeferredSupport() const { return deferredSupport_; }
    /// Return whether hardware depth texture is supported. On OpenGL ES this means the depth texture extension.
    bool GetHardwareDepthSupport() const { return hardwareDepthSupport_; }
    /// Return whether anisotropic texture filtering is supported.
    bool GetAnisotropySupport() const { return anisotropySupport_; }
    /// Return whether shadow map depth compare is done in hardware. Always true on OpenGL.
    bool GetHardwareShadowSupport() const { return true; }
    /// Return whether stream offset is supported. Always false on OpenGL.
    bool GetStreamOffsetSupport() const { return false; }
    /// Return supported fullscreen resolutions.
    PODVector<IntVector2> GetResolutions() const;
    /// Return supported multisampling levels.
    PODVector<int> GetMultiSampleLevels() const;
    /// Return hardware format for a compressed image format, or 0 if unsupported.
    unsigned GetFormat(CompressedFormat format) const;
    /// Return vertex buffer by index.
    VertexBuffer* GetVertexBuffer(unsigned index) const;
    /// Return index buffer.
    IndexBuffer* GetIndexBuffer() const { return indexBuffer_; }
    /// Return vertex shader.
    ShaderVariation* GetVertexShader() const { return vertexShader_; }
    /// Return pixel shader.
    ShaderVariation* GetPixelShader() const { return pixelShader_; }
    /// Return shader program.
    ShaderProgram* GetShaderProgram() const { return shaderProgram_; }
    /// Return texture unit index by name.
    TextureUnit GetTextureUnit(const String& name);
    /// Return texture unit name by index.
    const String& GetTextureUnitName(TextureUnit unit);
    /// Return texture by texture unit index.
    Texture* GetTexture(unsigned index) const;
    /// Return default texture filtering mode.
    TextureFilterMode GetDefaultTextureFilterMode() const { return defaultTextureFilterMode_; }
    /// Return rendertarget by index.
    RenderSurface* GetRenderTarget(unsigned index) const;
    /// Return depth-stencil surface.
    RenderSurface* GetDepthStencil() const { return depthStencil_; }
    /// Return readable depth-stencil texture. Not created automatically on OpenGL.
    Texture2D* GetDepthTexture() const { return 0; }
    /// Return the viewport coordinates.
    IntRect GetViewport() const { return viewport_; }
    /// Return texture anisotropy.
    unsigned GetTextureAnisotropy() const { return textureAnisotropy_; }
    /// Return blending mode.
    BlendMode GetBlendMode() const { return blendMode_; }
    /// Return whether color write is enabled.
    bool GetColorWrite() const { return colorWrite_; }
    /// Return hardware culling mode.
    CullMode GetCullMode() const { return cullMode_; }
    /// Return depth constant bias.
    float GetDepthConstantBias() const { return constantDepthBias_; }
    /// Return depth slope scaled bias.
    float GetDepthSlopeScaledBias() const { return slopeScaledDepthBias_; }
    /// Return depth compare mode.
    CompareMode GetDepthTest() const { return depthTestMode_; }
    /// Return whether depth write is enabled.
    bool GetDepthWrite() const { return depthWrite_; }
    /// Return whether stencil test is enabled.
    bool GetStencilTest() const { return stencilTest_; }
    /// Return whether scissor test is enabled.
    bool GetScissorTest() const { return scissorTest_; }
    /// Return scissor rectangle coordinates.
    const IntRect& GetScissorRect() const { return scissorRect_; }
    /// Return stencil compare mode.
    CompareMode GetStencilTestMode() const { return stencilTestMode_; }
    /// Return stencil operation to do if stencil test passes.
    StencilOp GetStencilPass() const { return stencilPass_; }
    /// Return stencil operation to do if stencil test fails.
    StencilOp GetStencilFail() const { return stencilFail_; }
    /// Return stencil operation to do if depth compare fails.
    StencilOp GetStencilZFail() const { return stencilZFail_; }
    /// Return stencil reference value.
    unsigned GetStencilRef() const { return stencilRef_; }
    /// Return stencil compare bitmask.
    unsigned GetStencilCompareMask() const { return stencilCompareMask_; }
    /// Return stencil write bitmask.
    unsigned GetStencilWriteMask() const { return stencilWriteMask_; }
    /// Return stream frequency by vertex buffer index. Always returns 0 on OpenGL.
    unsigned GetStreamFrequency(unsigned index) const { return 0; }
    /// Return rendertarget width and height.
    IntVector2 GetRenderTargetDimensions() const;
    /// Return force Shader Model 2 flag. Always false on OpenGL.
    bool GetForceSM2() const { return false; }

    /// Add a GPU object to keep track of. Called by GPUObject.
    void AddGPUObject(GPUObject* object);
    /// Remove a GPU object. Called by GPUObject.
    void RemoveGPUObject(GPUObject* object);
    /// Reserve a CPU-side scratch buffer.
    void* ReserveScratchBuffer(unsigned size);
    /// Free a CPU-side scratch buffer.
    void FreeScratchBuffer(void* buffer);
    /// Clean up too large scratch buffers.
    void CleanupScratchBuffers();
    /// Release/clear GPU objects and optionally close the window.
    void Release(bool clearGPUObjects, bool closeWindow);
    /// Restore GPU objects and reinitialize state. Requires an open window.
    void Restore();
    /// Clean up a render surface from all FBOs.
    void CleanupRenderSurface(RenderSurface* surface);
    
    /// Return the API-specific alpha texture format.
    static unsigned GetAlphaFormat();
    /// Return the API-specific luminance texture format.
    static unsigned GetLuminanceFormat();
    /// Return the API-specific luminance alpha texture format.
    static unsigned GetLuminanceAlphaFormat();
    /// Return the API-specific RGB texture format.
    static unsigned GetRGBFormat();
    /// Return the API-specific RGBA texture format.
    static unsigned GetRGBAFormat();
    /// Return the API-specific single channel float texture format.
    static unsigned GetFloatFormat();
    /// Return the API-specific linear depth texture format.
    static unsigned GetLinearDepthFormat();
    /// Return the API-specific hardware depth-stencil texture format.
    static unsigned GetDepthStencilFormat();
    
private:
    /// Check supported rendering features.
    void CheckFeatureSupport();
    /// Select FBO and commit changes.
    void CommitFramebuffer();
    /// Check FBO completeness.
    bool CheckFramebuffer();
    /// Cleanup unused and unbound FBO's.
    void CleanupFramebuffers(bool contextLost);
    /// Reset cached rendering state.
    void ResetCachedState();
    /// Initialize texture unit mappings.
    void SetTextureUnitMappings();
    
    /// Implementation.
    GraphicsImpl* impl_;
    /// Window title.
    String windowTitle_;
    /// External window, null if not in use (default.)
    void* externalWindow_;
    /// Window width.
    int width_;
    /// Window height.
    int height_;
    /// Multisampling mode.
    int multiSample_;
    /// Fullscreen flag.
    bool fullscreen_;
    /// Vertical sync flag.
    bool vsync_;
    /// Triple buffering flag.
    bool tripleBuffer_;
    /// Light prepass support flag.
    bool lightPrepassSupport_;
    /// Deferred rendering support flag.
    bool deferredSupport_;
    /// Hardware depth support flag.
    bool hardwareDepthSupport_;
    /// Anisotropic filtering support flag.
    bool anisotropySupport_;
    /// DXT format support flag.
    bool dxtTextureSupport_;
    /// ETC1 format support flag.
    bool etcTextureSupport_;
    /// PVRTC formats support flag.
    bool pvrtcTextureSupport_;
    /// Number of primitives this frame.
    unsigned numPrimitives_;
    /// Number of batches this frame.
    unsigned numBatches_;
    /// Largest scratch buffer request this frame.
    unsigned maxScratchBufferRequest_;
    /// GPU objects.
    Vector<GPUObject*> gpuObjects_;
    /// Scratch buffers.
    Vector<ScratchBuffer> scratchBuffers_;
    /// Shadow map depth texture format.
    unsigned shadowMapFormat_;
    /// Shadow map 24-bit depth texture format.
    unsigned hiresShadowMapFormat_;
    /// Vertex buffers in use.
    VertexBuffer* vertexBuffers_[MAX_VERTEX_STREAMS];
    /// Element mask in use.
    unsigned elementMasks_[MAX_VERTEX_STREAMS];
    /// Index buffer in use.
    IndexBuffer* indexBuffer_;
    /// Vertex shader in use.
    ShaderVariation* vertexShader_;
    /// Pixel shader in use.
    ShaderVariation* pixelShader_;
    /// Shader program in use.
    ShaderProgram* shaderProgram_;
    /// Linked shader programs.
    ShaderProgramMap shaderPrograms_;
    /// Textures in use.
    Texture* textures_[MAX_TEXTURE_UNITS];
    /// OpenGL texture types in use.
    unsigned textureTypes_[MAX_TEXTURE_UNITS];
    /// Texture unit mappings.
    HashMap<String, TextureUnit> textureUnits_;
    /// Rendertargets in use.
    RenderSurface* renderTargets_[MAX_RENDERTARGETS];
    /// Depth-stencil surface in use.
    RenderSurface* depthStencil_;
    /// View texture.
    Texture* viewTexture_;
    /// Viewport coordinates.
    IntRect viewport_;
    /// Texture anisotropy level.
    unsigned textureAnisotropy_;
    /// Blending mode.
    BlendMode blendMode_;
    /// Color write enable.
    bool colorWrite_;
    /// Hardware culling mode.
    CullMode cullMode_;
    /// Depth constant bias.
    float constantDepthBias_;
    /// Depth slope scaled bias.
    float slopeScaledDepthBias_;
    /// Depth compare mode.
    CompareMode depthTestMode_;
    /// Depth write enable flag.
    bool depthWrite_;
    /// Scissor test rectangle.
    IntRect scissorRect_;
    /// Scissor test enable flag.
    bool scissorTest_;
    /// Stencil test compare mode.
    CompareMode stencilTestMode_;
    /// Stencil operation on pass.
    StencilOp stencilPass_;
    /// Stencil operation on fail.
    StencilOp stencilFail_;
    /// Stencil operation on depth fail.
    StencilOp stencilZFail_;
    /// Stencil test enable flag.
    bool stencilTest_;
    /// Stencil test reference value.
    unsigned stencilRef_;
    /// Stencil compare bitmask.
    unsigned stencilCompareMask_;
    /// Stencil write bitmask.
    unsigned stencilWriteMask_;
    /// Default texture filtering mode.
    TextureFilterMode defaultTextureFilterMode_;
    /// Map for additional depth textures, to emulate Direct3D9 ability to mix render texture and backbuffer rendering.
    HashMap<int, SharedPtr<Texture2D> > depthTextures_;
    /// Remembered shader parameter sources.
    const void* shaderParameterSources_[MAX_SHADER_PARAMETER_GROUPS];
    /// Temp matrices for transposing shader parameters.
    Matrix3 tempMatrices3_[NUM_TEMP_MATRICES];
    /// Temp matrices for transposing shader parameters.
    Matrix4 tempMatrices4_[NUM_TEMP_MATRICES];
};

/// Register Graphics library objects.
void RegisterGraphicsLibrary(Context* context_);