RenderContextWebGL class
class RenderContextWebGL extends RenderContext {
final CanvasElement _canvasElement;
final int _backgroundColor;
final RenderProgramQuad _renderProgramQuad = new RenderProgramQuad();
final RenderProgramTriangle _renderProgramTriangle = new RenderProgramTriangle();
gl.RenderingContext _renderingContext;
RenderTexture _renderTexture;
RenderProgram _renderProgram;
int _maskDepth = 0;
RenderContextWebGL(CanvasElement canvasElement, int backgroundColor) :
_canvasElement = canvasElement,
_backgroundColor = _ensureInt(backgroundColor) {
_canvasElement.onWebGlContextLost.listen(_onContextLost);
_canvasElement.onWebGlContextRestored.listen(_onContextRestored);
var renderingContext = _canvasElement.getContext3d(
alpha: false, depth: false, stencil: true, antialias: false,
premultipliedAlpha: true, preserveDrawingBuffer: false);
if (renderingContext is! gl.RenderingContext) {
throw new StateError("Failed to get WebGL context.");
}
_renderingContext = renderingContext;
_renderingContext.enable(gl.BLEND);
_renderingContext.disable(gl.STENCIL_TEST);
_renderingContext.disable(gl.DEPTH_TEST);
_renderingContext.disable(gl.CULL_FACE);
_renderingContext.pixelStorei(gl.UNPACK_PREMULTIPLY_ALPHA_WEBGL, 1);
_renderingContext.blendFunc(gl.ONE, gl.ONE_MINUS_SRC_ALPHA);
_renderProgram = _renderProgramQuad;
_renderProgram.activate(this);
}
//-----------------------------------------------------------------------------------------------
String get renderEngine => RenderEngine.WebGL;
gl.RenderingContext get rawContext => _renderingContext;
Matrix get viewPortMatrix {
int width = _renderingContext.drawingBufferWidth;
int height = _renderingContext.drawingBufferHeight;
return new Matrix(2.0 / width, 0.0, 0.0, - 2.0 / height, -1.0, 1.0);
}
//-----------------------------------------------------------------------------------------------
void clear() {
int width = _renderingContext.drawingBufferWidth;
int height = _renderingContext.drawingBufferHeight;
num r = _colorGetR(_backgroundColor) / 255.0;
num g = _colorGetG(_backgroundColor) / 255.0;
num b = _colorGetB(_backgroundColor) / 255.0;
_renderingContext.viewport(0, 0, width, height);
_renderingContext.colorMask(true, true, true, true);
_renderingContext.clearColor(r, g, b, 1.0);
_renderingContext.clear(gl.COLOR_BUFFER_BIT | gl.STENCIL_BUFFER_BIT);
}
void renderQuad(RenderTextureQuad renderTextureQuad, Matrix matrix, num alpha) {
_updateState(_renderProgramQuad, renderTextureQuad.renderTexture);
_renderProgramQuad.renderQuad(renderTextureQuad, matrix, alpha);
}
void renderTriangle(num x1, num y1, num x2, num y2, num x3, num y3, Matrix matrix, int color) {
_updateState(_renderProgramTriangle, _renderTexture);
_renderProgramTriangle.renderTriangle(x1, y1, x2, y2, x3, y3, matrix, color);
}
void flush() {
_renderProgram.flush();
}
//-----------------------------------------------------------------------------------------------
void beginRenderMask(RenderState renderState, Mask mask, Matrix matrix) {
if (_maskDepth == 0) {
_renderProgram.flush();
_renderingContext.enable(gl.STENCIL_TEST);
}
_updateState(_renderProgramTriangle, null);
_renderingContext.stencilFunc(gl.EQUAL, _maskDepth, 0xFF);
_renderingContext.stencilOp(gl.KEEP, gl.KEEP, gl.INCR);
_renderingContext.stencilMask(0xFF);
_renderingContext.colorMask(false, false, false, false);
_maskDepth += 1;
mask._drawTriangles(this, matrix);
_updateState(_renderProgramQuad, null);
_renderingContext.stencilFunc(gl.EQUAL, _maskDepth, 0xFF);
_renderingContext.stencilMask(0x00);
_renderingContext.colorMask(true, true, true, true);
}
void endRenderMask(Mask mask) {
if (_maskDepth == 1) {
_renderProgram.flush();
_maskDepth = 0;
_renderingContext.stencilMask(0xFF);
_renderingContext.disable(gl.STENCIL_TEST);
_renderingContext.clear(gl.STENCIL_BUFFER_BIT);
_renderingContext.stencilMask(0);
} else {
_updateState(_renderProgramTriangle, null);
_renderingContext.stencilFunc(gl.EQUAL, _maskDepth, 0xFF);
_renderingContext.stencilOp(gl.KEEP, gl.KEEP, gl.DECR);
_renderingContext.stencilMask(0xFF);
_renderingContext.colorMask(false, false, false, false);
_maskDepth -= 1;
var matrix = _identityMatrix;
var color = Color.Magenta;
_renderProgramTriangle.renderTriangle(-1, -1, 1, -1, 1, 1, matrix, color);
_renderProgramTriangle.renderTriangle(-1, -1, 1, 1, -1, 1, matrix, color);
_updateState(_renderProgramQuad, null);
_renderingContext.stencilFunc(gl.EQUAL, _maskDepth, 0xFF);
_renderingContext.stencilMask(0x00);
_renderingContext.colorMask(true, true, true, true);
}
}
//-----------------------------------------------------------------------------------------------
void beginRenderShadow(RenderState renderState, Shadow shadow, Matrix matrix) {
// TODO: We will add this once we have WebGL filters.
}
void endRenderShadow(Shadow shadow) {
}
//-----------------------------------------------------------------------------------------------
_updateState(RenderProgram renderProgram, RenderTexture renderTexture) {
// dartbug.com/16286
if (renderProgram != null) {
if (identical(renderProgram, _renderProgram) == false) {
_renderProgram.flush();
_renderProgram = renderProgram;
_renderProgram.activate(this);
}
}
if (renderTexture != null) {
if (identical(renderTexture, _renderTexture) == false) {
_renderProgram.flush();
_renderTexture = renderTexture;
_renderTexture.activate(this, gl.TEXTURE0);
}
}
}
//-----------------------------------------------------------------------------------------------
_onContextLost(gl.ContextEvent contextEvent) {
contextEvent.preventDefault();
this.dispatchEvent(new Event("contextLost"));
}
_onContextRestored(gl.ContextEvent contextEvent) {
this.dispatchEvent(new Event("contextRestored"));
}
}
Extends
EventDispatcher > RenderContext > RenderContextWebGL
Constructors
new RenderContextWebGL(CanvasElement canvasElement, int backgroundColor) #
Creates a new Object instance.
Object instances have no meaningful state, and are only useful through their identity. An Object instance is equal to itself only.
docs inherited from Object
RenderContextWebGL(CanvasElement canvasElement, int backgroundColor) :
_canvasElement = canvasElement,
_backgroundColor = _ensureInt(backgroundColor) {
_canvasElement.onWebGlContextLost.listen(_onContextLost);
_canvasElement.onWebGlContextRestored.listen(_onContextRestored);
var renderingContext = _canvasElement.getContext3d(
alpha: false, depth: false, stencil: true, antialias: false,
premultipliedAlpha: true, preserveDrawingBuffer: false);
if (renderingContext is! gl.RenderingContext) {
throw new StateError("Failed to get WebGL context.");
}
_renderingContext = renderingContext;
_renderingContext.enable(gl.BLEND);
_renderingContext.disable(gl.STENCIL_TEST);
_renderingContext.disable(gl.DEPTH_TEST);
_renderingContext.disable(gl.CULL_FACE);
_renderingContext.pixelStorei(gl.UNPACK_PREMULTIPLY_ALPHA_WEBGL, 1);
_renderingContext.blendFunc(gl.ONE, gl.ONE_MINUS_SRC_ALPHA);
_renderProgram = _renderProgramQuad;
_renderProgram.activate(this);
}
Properties
final EventStream<Event> onContextLost #
inherited from RenderContext
EventStream<Event> get onContextLost => RenderContext.contextLostEvent.forTarget(this);
final EventStream<Event> onContextRestored #
inherited from RenderContext
EventStream<Event> get onContextRestored => RenderContext.contextRestoredEvent.forTarget(this);
final RenderingContext rawContext #
gl.RenderingContext get rawContext => _renderingContext;
Methods
StreamSubscription<Event> addEventListener(String eventType, EventListener eventListener, {bool useCapture: false, int priority: 0}) #
inherited from EventDispatcher
StreamSubscription<Event> addEventListener(String eventType, EventListener eventListener, {
bool useCapture: false, int priority: 0 }) {
return this.on(eventType)._subscribe(eventListener, useCapture, priority);
}
void beginRenderMask(RenderState renderState, Mask mask, Matrix matrix) #
void beginRenderMask(RenderState renderState, Mask mask, Matrix matrix) {
if (_maskDepth == 0) {
_renderProgram.flush();
_renderingContext.enable(gl.STENCIL_TEST);
}
_updateState(_renderProgramTriangle, null);
_renderingContext.stencilFunc(gl.EQUAL, _maskDepth, 0xFF);
_renderingContext.stencilOp(gl.KEEP, gl.KEEP, gl.INCR);
_renderingContext.stencilMask(0xFF);
_renderingContext.colorMask(false, false, false, false);
_maskDepth += 1;
mask._drawTriangles(this, matrix);
_updateState(_renderProgramQuad, null);
_renderingContext.stencilFunc(gl.EQUAL, _maskDepth, 0xFF);
_renderingContext.stencilMask(0x00);
_renderingContext.colorMask(true, true, true, true);
}
void beginRenderShadow(RenderState renderState, Shadow shadow, Matrix matrix) #
void beginRenderShadow(RenderState renderState, Shadow shadow, Matrix matrix) {
// TODO: We will add this once we have WebGL filters.
}
void clear() #
void clear() {
int width = _renderingContext.drawingBufferWidth;
int height = _renderingContext.drawingBufferHeight;
num r = _colorGetR(_backgroundColor) / 255.0;
num g = _colorGetG(_backgroundColor) / 255.0;
num b = _colorGetB(_backgroundColor) / 255.0;
_renderingContext.viewport(0, 0, width, height);
_renderingContext.colorMask(true, true, true, true);
_renderingContext.clearColor(r, g, b, 1.0);
_renderingContext.clear(gl.COLOR_BUFFER_BIT | gl.STENCIL_BUFFER_BIT);
}
void dispatchEvent(Event event) #
inherited from EventDispatcher
void dispatchEvent(Event event) {
_dispatchEventInternal(event, this, EventPhase.AT_TARGET);
}
void endRenderMask(Mask mask) #
void endRenderMask(Mask mask) {
if (_maskDepth == 1) {
_renderProgram.flush();
_maskDepth = 0;
_renderingContext.stencilMask(0xFF);
_renderingContext.disable(gl.STENCIL_TEST);
_renderingContext.clear(gl.STENCIL_BUFFER_BIT);
_renderingContext.stencilMask(0);
} else {
_updateState(_renderProgramTriangle, null);
_renderingContext.stencilFunc(gl.EQUAL, _maskDepth, 0xFF);
_renderingContext.stencilOp(gl.KEEP, gl.KEEP, gl.DECR);
_renderingContext.stencilMask(0xFF);
_renderingContext.colorMask(false, false, false, false);
_maskDepth -= 1;
var matrix = _identityMatrix;
var color = Color.Magenta;
_renderProgramTriangle.renderTriangle(-1, -1, 1, -1, 1, 1, matrix, color);
_renderProgramTriangle.renderTriangle(-1, -1, 1, 1, -1, 1, matrix, color);
_updateState(_renderProgramQuad, null);
_renderingContext.stencilFunc(gl.EQUAL, _maskDepth, 0xFF);
_renderingContext.stencilMask(0x00);
_renderingContext.colorMask(true, true, true, true);
}
}
void flush() #
void flush() {
_renderProgram.flush();
}
bool hasEventListener(String eventType) #
inherited from EventDispatcher
bool hasEventListener(String eventType) {
var eventStreams = _eventStreams;
if (eventStreams == null) return false;
var eventStream = eventStreams[eventType];
if (eventStream == null) return false;
return eventStream.hasSubscriptions;
}
EventStream<Event> on(String eventType) #
inherited from EventDispatcher
EventStream<Event> on(String eventType) {
var eventStreams = _eventStreams;
if (eventStreams == null) {
eventStreams = new Map<String, EventStream>();
_eventStreams = eventStreams;
}
var eventStream = eventStreams[eventType];
if (eventStream == null) {
eventStream = new EventStream._internal(this, eventType);
eventStreams[eventType] = eventStream;
}
return eventStream;
}
void removeEventListener(String eventType, EventListener eventListener, {bool useCapture: false}) #
inherited from EventDispatcher
void removeEventListener(String eventType, EventListener eventListener, {
bool useCapture: false }) {
this.on(eventType)._unsubscribe(eventListener, useCapture);
}
void removeEventListeners(String eventType) #
inherited from EventDispatcher
void removeEventListeners(String eventType) {
this.on(eventType).cancelSubscriptions();
}
void renderQuad(RenderTextureQuad renderTextureQuad, Matrix matrix, num alpha) #
void renderQuad(RenderTextureQuad renderTextureQuad, Matrix matrix, num alpha) {
_updateState(_renderProgramQuad, renderTextureQuad.renderTexture);
_renderProgramQuad.renderQuad(renderTextureQuad, matrix, alpha);
}
void renderTriangle(num x1, num y1, num x2, num y2, num x3, num y3, Matrix matrix, int color) #
void renderTriangle(num x1, num y1, num x2, num y2, num x3, num y3, Matrix matrix, int color) {
_updateState(_renderProgramTriangle, _renderTexture);
_renderProgramTriangle.renderTriangle(x1, y1, x2, y2, x3, y3, matrix, color);
}