D3D/OGL: implement BackbufferState helping to know backbuffer params

Engine/gfx/ali3dogl.h

@@ -302,22 +302,45 @@ class OGLGraphicsDriver : public VideoMemoryGraphicsDriver
     int device_screen_physical_width;
     int device_screen_physical_height;
 
-    // Viewport and scissor rect, in OpenGL screen coordinates (0,0 is at left-bottom)
-    Rect _viewportRect {};
-
+    // Final fbo, depends on platform we run on
+    GLint _screenFramebuffer = 0u;
     // Capability flags
     bool _glCapsNonPowerOfTwo = false;
     // These two flags define whether driver can, and should (respectively)
     // render sprites to texture, and then texture to screen, as opposed to
     // rendering to screen directly. This is known as supersampling mode
-    bool _can_render_to_texture {};
-    bool _do_render_to_texture {};
+    bool _canRenderToTexture {};
+    bool _doRenderToTexture {};
     // Backbuffer texture multiplier, used to determine a size of texture
     // relative to the native game size.
-    int _super_sampling {};
+    int _superSampling {};
     // Texture for rendering in native resolution
     OGLBitmap *_nativeSurface = nullptr;
-    GLint _screenFramebuffer = 0;
+
+    // TODO: find a way to merge this with Render Targets from sprite batches,
+    // have a SINGLE STACK of "render target states", where backbuffer is at the bottom
+    struct BackbufferState
+    {
+        GLuint Fbo = 0u;
+        Size SurfSize;
+        // Viewport and scissor rect, in OpenGL screen coordinates (0,0 is at left-bottom)
+        Rect Viewport;
+        glm::mat4 Projection;
+        PlaneScaling Scaling;
+        int Filter = 0;
+        int TxClamp = 0;
+
+        BackbufferState() = default;
+        BackbufferState(GLuint fbo, const Size &size, const Rect &view, const glm::mat4 &proj,
+            const PlaneScaling &scale, int filter, int txclamp)
+            : Fbo(fbo), SurfSize(size), Viewport(view), Projection(proj)
+            , Scaling(scale), Filter(filter), TxClamp(txclamp) {}
+        ~BackbufferState() = default;
+    };
+
+    BackbufferState _screenBackbuffer;
+    BackbufferState _nativeBackbuffer;
+    BackbufferState *_currentBackbuffer = nullptr;
 
     // Sprite batches (parent scene nodes)
     OGLSpriteBatches _spriteBatches;
@@ -370,8 +393,7 @@ class OGLGraphicsDriver : public VideoMemoryGraphicsDriver
         const glm::mat4 &projection, const glm::mat4 &matGlobal,
         const SpriteColorTransform &color, const Size &surface_size);
     void SetupViewport();
-    // Converts rectangle in top->down coordinates into OpenGL's native bottom->up coordinates
-    Rect ConvertTopDownRect(const Rect &top_down_rect, int surface_height);
+
     // Sets uniform GL blend settings, same for both RGB and alpha component
     void SetBlendOpUniform(GLenum blend_op, GLenum src_factor, GLenum dst_factor);
     // Sets GL blend settings for RGB only, and keeps saved alpha blend settings
@@ -387,13 +409,16 @@ class OGLGraphicsDriver : public VideoMemoryGraphicsDriver
     // Deletes draw list backups
     void ClearDrawBackups();
     void _render(bool clearDrawListAfterwards);
+    // Set current backbuffer state, which properties are used when refering to backbuffer
+    // TODO: find a good way to merge with SetRenderTarget
+    void SetBackbufferState(BackbufferState *state);
     // Sets the scissor (render clip), clip rect is passed in the "native" coordinates.
     // Optionally pass surface_size if the rendering is done to texture, in native coords,
     // otherwise we assume it is set on a whole screen, scaled to the screen coords.
     void SetScissor(const Rect &clip, bool render_on_texture, const Size &surface_size);
     // Configures rendering mode for the render target, depending on its properties
     void SetRenderTarget(const OGLSpriteBatch *batch, Size &surface_sz, glm::mat4 &projection, bool clear);
-    void RenderSpriteBatches(const glm::mat4 &projection);
+    void RenderSpriteBatches();
     size_t RenderSpriteBatch(const OGLSpriteBatch &batch, size_t from, const glm::mat4 &projection,
         const Size &surface_size);
     void _reDrawLastFrame();

Engine/gfx/gfxfilter_aad3d.cpp

@@ -34,6 +34,11 @@ const GfxFilterInfo &AAD3DGfxFilter::GetInfo() const
     return FilterInfo;
 }
 
+int AAD3DGfxFilter::GetSamplerStateForStandardSprite()
+{
+    return D3DTEXF_LINEAR;
+}
+
 void AAD3DGfxFilter::SetSamplerStateForStandardSprite(void *direct3ddevice9)
 {
     IDirect3DDevice9* d3d9 = ((IDirect3DDevice9*)direct3ddevice9);

Engine/gfx/gfxfilter_aad3d.h

@@ -33,6 +33,7 @@ class AAD3DGfxFilter : public D3DGfxFilter
 public:
     const GfxFilterInfo &GetInfo() const override;
 
+    int  GetSamplerStateForStandardSprite() override;
     void SetSamplerStateForStandardSprite(void *direct3ddevice9) override;
     bool NeedToColourEdgeLines() override;
 

Engine/gfx/gfxfilter_aaogl.cpp

@@ -33,6 +33,12 @@ bool AAOGLGfxFilter::UseLinearFiltering() const
     return true;
 }
 
+void AAOGLGfxFilter::GetFilteringForStandardSprite(int &filter, int &clamp)
+{
+    filter = GL_LINEAR;
+    clamp = GL_CLAMP_TO_EDGE;
+}
+
 void AAOGLGfxFilter::SetFilteringForStandardSprite()
 {
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

Engine/gfx/gfxfilter_aaogl.h

@@ -34,6 +34,7 @@ class AAOGLGfxFilter : public OGLGfxFilter
     const GfxFilterInfo &GetInfo() const override;
 
     bool UseLinearFiltering() const override;
+    void GetFilteringForStandardSprite(int &filter, int &clamp) override;
     void SetFilteringForStandardSprite() override;
 
     static const GfxFilterInfo FilterInfo;

Engine/gfx/gfxfilter_d3d.cpp

@@ -33,6 +33,11 @@ const GfxFilterInfo &D3DGfxFilter::GetInfo() const
     return FilterInfo;
 }
 
+int D3DGfxFilter::GetSamplerStateForStandardSprite()
+{
+    return D3DTEXF_POINT;
+}
+
 void D3DGfxFilter::SetSamplerStateForStandardSprite(void *direct3ddevice9)
 {
     IDirect3DDevice9* d3d9 = ((IDirect3DDevice9*)direct3ddevice9);

Engine/gfx/gfxfilter_d3d.h

@@ -32,6 +32,7 @@ class D3DGfxFilter : public ScalingGfxFilter
 public:
     const GfxFilterInfo &GetInfo() const override;
 
+    virtual int  GetSamplerStateForStandardSprite();
     virtual void SetSamplerStateForStandardSprite(void *direct3ddevice9);
     virtual bool NeedToColourEdgeLines();
 

Engine/gfx/gfxfilter_ogl.cpp

@@ -33,6 +33,12 @@ bool OGLGfxFilter::UseLinearFiltering() const
     return false;
 }
 
+void OGLGfxFilter::GetFilteringForStandardSprite(int &filter, int &clamp)
+{
+    filter = GL_NEAREST;
+    clamp = GL_CLAMP;
+}
+
 void OGLGfxFilter::SetFilteringForStandardSprite()
 {
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

Engine/gfx/gfxfilter_ogl.h

@@ -34,6 +34,7 @@ class OGLGfxFilter : public ScalingGfxFilter
     const GfxFilterInfo &GetInfo() const override;
 
     virtual bool UseLinearFiltering() const;
+    virtual void GetFilteringForStandardSprite(int &filter, int &clamp);
     virtual void SetFilteringForStandardSprite();
 
     static const GfxFilterInfo FilterInfo;