Renderer Interface - yvt/openspades GitHub Wiki

Rendering is done through an interface called spades::client::IRenderer. This abstracts the actual rendering APIs.

How to render scene

  1. Setup a struct SceneDefinition and give it to BeginScene
  2. Add objects to the scene by renderer commands (this must be done for every frame since the renderer doesn't remember them over a frame):
  • Models
  • Dynamic Light
  • Sprites
  • Debug Line
  1. Call EndScene to tell the renderer that we have nothing to add to the scene anymore
  2. Draw 2D images
  3. Call FrameDone.
  4. Call Flip. The renderer will transfer the rendered image to the screen.

Renderer Commands

Init

Initializes all subsystems of the renderer.

Shutdown

Destroys every objects needed by the renderer and releases memory used by them.

RegisterImage

Returns an image object with the specified file name. Loaded images are cached during the lifetime of the renderer (that is, the renderer keeps a reference to the image).

RegisterModel

Returns a model object with the specified file name. Loaded models are cached during the lifetime of the renderer (that is, the renderer keeps a reference to the model).

CreateImage

Creates a temporary image object from the given bitmap.

CreateModel

Creates a temporary model object from the given voxel bitmap.

SetGameMap

Tells the renderer to render the given game map instead of the currently set one.

SetFogColor

Specifies the fog color.

StartScene

Tells the renderer to get ready for the 3D renderer commands.

EndScene

Tells the renderer that there are no more 3D renderers commands for the current frame.

AddLight [3D]

Adds a point light or spotlight to the scene. This should not be called outside of BeginScene ... EndScene.

RenderModel [3D]

Adds a model to the scene. This should not be called outside of BeginScene ... EndScene.

AddDebugLine [3D]

Adds a 3D line segment to the scene. (Actually this should be used for debugging)

This should not be called outside of BeginScene ... EndScene.

AddSprite [3D]

Adds a sprite particle. This should not be called outside of BeginScene ... EndScene.

AddLongSprite [3D]

Adds a long sprite. This is mainly used for long bright objects without an exact shape, such as bullet tracers. This should not be called outside of BeginScene ... EndScene.

SetColor

Specifies the color used by AddSprite, AddLongSprite, and DrawImage.

  • DrawImage treats this color value as "non-alpha premultiplied." So when A = 0, the renderer image becomes completely invisible.
  • AddSprite and AddLongSprite treat this color value as "alpha premultiplied." Therefore when A = 0, additive blending occurs.

DrawImage [2D]

Draws an image in the screen coordinate system. This should not be called between BeginScene and EndScene.

DrawFlatGameMap [2D]

Draws a 2D view of the current game map in the specified rectangle. This should not be called between BeginScene and EndScene.

FrameDone

Tells the renderer that there are no more things to render in the current frame. This should not be called between BeginScene and EndScene.

Flip

Displays the rendered image to the screen. This should not be called between BeginScene and EndScene.

ReadBitmap

Returns the current renderer image as a bitmap. Note that usually this operation is extremely slow.

This should not be called between BeginScene and EndScene.

GLRenderer Implementation

GLRenderer is an OpenGL 2.0/3.0 implementation of IRenderer and supports all required function. GLRenderer is currently the only implementation of IRenderer.

  • BeginScene just initializes the rendering
  • EndScene renders the scene in multiple passes:
    • Preparation
    • Shadow Maps Generation
    • Ocean Reflection Pass
    • Sun-light Pass
    • Dynamic Light Pass
    • Post-process
  • FrameDone flushes 2D rendering command buffer.
  • Flip calls Swap of the OpenGL device.

SWRenderer Implementation

SWRenderer is a multi-threaded software implementation (similar to VOXLAP) of IRenderer and supports the following fundamental features.

  • Map
  • Models
  • 2D Images
  • Sprites

Fast mode (r_swUndersampling) can be used to boost the performance up by reducing the ray tracing density (effectively lowering the screen resolution).

Performance

  • Intel Core i5 1.7GHz (Dual Core, HTT enabled, Clang 3.3?, OS X)
    • 30FPS @ 1280x720
    • 55FPS @ 800x600
  • Intel Core 2 Duo 1.4GHz (Dual Core, Microsoft Visual C++ 2013, Windows 8)
    • 20FPS @ 800x600
  • AMD E-450 (Dual Core, Microsoft Visual C++ 2013, Windows 7)
    • 15FPS @ 800x600

SMP Renderer (obsolete)

Obsolete feature: This was removed in 0.2.0.

When cg_smp is set to 1, multi-threaded rendering architecture is enabled. Client issues commands to AsyncRenderer, and AsyncRenderer sends the commands to IRenderer in a separate thread.

This architecture is similar to cg_smp of id Software's Quake 3.

Note that SMP renderer is unstable, difficult to trace errors, and there is some lag because of thread scheduling. Logging facility might not work expectedly.