Class: ProjectionSystem

This is not used internally. It is not advised to use this feature specifically unless you know what you're doing. The update method will default to this frame if you do not pass the destination frame.

The destination frame is the rectangle in the render-target into which contents are rendered. If rendering to the screen, the origin is on the top-left. If rendering to a framebuffer, the origin is on the bottom-left. This "flipping" phenomenon is because of WebGL convention for (shader) texture coordinates, where the bottom-left corner is (0,0). It allows display-objects to map their (0,0) position in local-space (top-left) to (0,0) in texture space (bottom-left). In other words, a sprite's top-left corner actually renders the texture's bottom-left corner. You will also notice this when using a tool like SpectorJS to view your textures at runtime.

The destination frame's dimensions (width,height) should be equal to the source frame. This is because, otherwise, the contents will be scaled to fill the destination frame. Similarly, the destination frame's (x,y) coordinates are (0,0) unless you know what you're doing.

This matrix can be used to transform points from world space to normalized device coordinates, and is calculated from the sourceFrame → destinationFrame mapping provided.

The renderer's globalUniforms keeps a reference to this, and so it is available for all shaders to use as a uniform.

The source frame is the rectangle in world space containing the contents to be rendered.

This can be used to transform points in world-space one last time before they are outputted by the shader. You can use to rotate the whole scene, for example. Remember to clear it once you've rendered everything.

NOTE: It is expected you call renderer.framebuffer.setViewport(destinationFrame) after this. This is because the framebuffer viewport converts shader vertex output in normalized device coordinates to window coordinates.

NOTE-2: RenderTextureSystem#bind updates the projection-matrix when you bind a render-texture. It is expected that you dirty the current bindings when calling this manually.