A class to describe a high-performance drawing surface for textures.
Each p5.Framebuffer object provides a dedicated drawing surface called a framebuffer. They're similar to p5.Graphics objects but can run much faster. Performance is improved because the framebuffer shares the same WebGL context as the canvas used to create it.
p5.Framebuffer objects have all the drawing features of the main canvas. Drawing instructions meant for the framebuffer must be placed between calls to myBuffer.begin() and myBuffer.end(). The resulting image can be applied as a texture by passing the p5.Framebuffer object to the texture() function, as in texture(myBuffer). It can also be displayed on the main canvas by passing it to the image() function, as in image(myBuffer, 0, 0).
Note: createFramebuffer() is the recommended way to create an instance of this class.
语法
p5.Framebuffer(target, [settings])参数
sketch instance or p5.Graphics object.
configuration options.
字段
An array containing the color of each pixel in the framebuffer.
myBuffer.loadPixels() must be called before accessing the myBuffer.pixels array. myBuffer.updatePixels() must be called after any changes are made.
Note: Updating pixels via this property is slower than drawing to the framebuffer directly. Consider using a p5.Shader object instead of looping over myBuffer.pixels.
An object that stores the framebuffer's color data.
Each framebuffer uses a WebGLTexture object internally to store its color data. The myBuffer.color property makes it possible to pass this data directly to other functions. For example, calling texture(myBuffer.color) or myShader.setUniform('colorTexture', myBuffer.color) may be helpful for advanced use cases.
Note: By default, a framebuffer's y-coordinates are flipped compared to images and videos. It's easy to flip a framebuffer's y-coordinates as needed when applying it as a texture. For example, calling plane(myBuffer.width, -myBuffer.height) will flip the framebuffer.
An object that stores the framebuffer's dpeth data.
Each framebuffer uses a WebGLTexture object internally to store its depth data. The myBuffer.depth property makes it possible to pass this data directly to other functions. For example, calling texture(myBuffer.depth) or myShader.setUniform('depthTexture', myBuffer.depth) may be helpful for advanced use cases.
Note: By default, a framebuffer's y-coordinates are flipped compared to images and videos. It's easy to flip a framebuffer's y-coordinates as needed when applying it as a texture. For example, calling plane(myBuffer.width, -myBuffer.height) will flip the framebuffer.
方法
Resizes the framebuffer to a given width and height.
The parameters, width and height, set the dimensions of the framebuffer. For example, calling myBuffer.resize(300, 500) resizes the framebuffer to 300×500 pixels, then sets myBuffer.width to 300 and myBuffer.height 500.
Sets the framebuffer's pixel density or returns its current density.
Computer displays are grids of little lights called pixels. A display's pixel density describes how many pixels it packs into an area. Displays with smaller pixels have a higher pixel density and create sharper images.
The parameter, density, is optional. If a number is passed, as in myBuffer.pixelDensity(1), it sets the framebuffer's pixel density. By default, the framebuffer's pixel density will match that of the canvas where it was created. All canvases default to match the display's pixel density.
Calling myBuffer.pixelDensity() without an argument returns its current pixel density.
Toggles the framebuffer's autosizing mode or returns the current mode.
By default, the framebuffer automatically resizes to match the canvas that created it. Calling myBuffer.autoSized(false) disables this behavior and calling myBuffer.autoSized(true) re-enables it.
Calling myBuffer.autoSized() without an argument returns true if the framebuffer automatically resizes and false if not.
Creates a new p5.Camera object to use with the framebuffer.
The new camera is initialized with a default position (0, 0, 800) and a default perspective projection. Its properties can be controlled with p5.Camera methods such as myCamera.lookAt(0, 0, 0).
Framebuffer cameras should be created between calls to myBuffer.begin() and myBuffer.end() like so:
let myCamera;
myBuffer.begin();
// Create the camera for the framebuffer.
myCamera = myBuffer.createCamera();
myBuffer.end();
Calling setCamera() updates the framebuffer's projection using the camera. resetMatrix() must also be called for the view to change properly:
myBuffer.begin();
// Set the camera for the framebuffer.
setCamera(myCamera);
// Reset all transformations.
resetMatrix();
// Draw stuff...
myBuffer.end();
Deletes the framebuffer from GPU memory.
Calling myBuffer.remove() frees the GPU memory used by the framebuffer. The framebuffer also uses a bit of memory on the CPU which can be freed like so:
// Delete the framebuffer from GPU memory.
myBuffer.remove();
// Delete the framebuffer from CPU memory.
myBuffer = undefined;
Note: All variables that reference the framebuffer must be assigned the value undefined to delete the framebuffer from CPU memory. If any variable still refers to the framebuffer, then it won't be garbage collected.
Begins drawing shapes to the framebuffer.
myBuffer.begin() and myBuffer.end() allow shapes to be drawn to the framebuffer. myBuffer.begin() begins drawing to the framebuffer and myBuffer.end() stops drawing to the framebuffer. Changes won't be visible until the framebuffer is displayed as an image or texture.
Stops drawing shapes to the framebuffer.
myBuffer.begin() and myBuffer.end() allow shapes to be drawn to the framebuffer. myBuffer.begin() begins drawing to the framebuffer and myBuffer.end() stops drawing to the framebuffer. Changes won't be visible until the framebuffer is displayed as an image or texture.
Draws to the framebuffer by calling a function that contains drawing instructions.
The parameter, callback, is a function with the drawing instructions for the framebuffer. For example, calling myBuffer.draw(myFunction) will call a function named myFunction() to draw to the framebuffer. Doing so has the same effect as the following:
myBuffer.begin();
myFunction();
myBuffer.end();
Loads the current value of each pixel in the framebuffer into its pixels array.
myBuffer.loadPixels() must be called before reading from or writing to myBuffer.pixels.
Gets a pixel or a region of pixels from the framebuffer.
myBuffer.get() is easy to use but it's not as fast as myBuffer.pixels. Use myBuffer.pixels to read many pixel values.
The version of myBuffer.get() with no parameters returns the entire framebuffer as a a p5.Image object.
The version of myBuffer.get() with two parameters interprets them as coordinates. It returns an array with the [R, G, B, A] values of the pixel at the given point.
The version of myBuffer.get() with four parameters interprets them as coordinates and dimensions. It returns a subsection of the framebuffer as a p5.Image object. The first two parameters are the coordinates for the upper-left corner of the subsection. The last two parameters are the width and height of the subsection.
Updates the framebuffer with the RGBA values in the pixels array.
myBuffer.updatePixels() only needs to be called after changing values in the myBuffer.pixels array. Such changes can be made directly after calling myBuffer.loadPixels().