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328 lines
8.5 KiB
Markdown
328 lines
8.5 KiB
Markdown
# Model
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A `Group` is a subclass of `ScenegraphNode` that holds a reference to a mesh with a transformation matrix that describes its position and orientation.
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A `Model` holds all the data necessary to draw an object, e.g.:
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* **shaders** (via a [`Program`](/docs/api-reference/webgl/program) instance)
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* **uniforms** these can also reference textures.
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* **vertex attributes** (holds a [`Mesh`] or a [`Geometry`](/docs/api-reference/engine/geometry) instance, plus any additional attributes for instanced rendering)
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The `Model` class also provides the following features:
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* Shader Module integration: [see `Shader Assembly`](/docs/api-reference/shadertools/assemble-shaders)
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* Automatic creation of GPU `Buffer`s from typed array attributes
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* Detailed debug logging of draw calls
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* Exposes the functionality provided by the managed WebGL resources
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## Usage
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### Provide attribute data using Geometry object
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Create model object by passing shaders, uniforms, geometry and render it by passing updated uniforms.
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```js
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// construct the model.
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const model = new Model(gl, {
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vs: VERTEX_SHADER,
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fs: FRAGMENT_SHADER,
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uniforms: {uSampler: texture},
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geometry: geometryObject,
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})
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// and on each frame update any uniforms (typically matrices) and call render.
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model
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.setUniforms({
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uPMatrix: currentProjectionMatrix,
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uMVMatrix: current ModelViewMatrix
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})
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.draw();
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```
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### Provide attribute data using Buffer
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When using `Buffer` objects, data remains on GPU and same `Buffer` object can be shared between multiple models.
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```js
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// construct the model.
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const model = new Model(gl, {
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vs: VERTEX_SHADER,
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fs: FRAGMENT_SHADER,
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uniforms: {uSampler: texture},
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attributes: {
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attributeName1: bufferObject,
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attributeName2: [new Buffer(gl, new Float32Array(...)), {size: 3, type: GL.FLOAT}]
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}
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drawMode: gl.TRIANGLE_FAN,
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vertexCount: 3,
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})
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// and on each frame update any uniforms (typically matrices) and call render.
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model
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.setUniforms({
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uPMatrix: currentProjectionMatrix,
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uMVMatrix: current ModelViewMatrix
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})
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.draw();
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```
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### Provide attribute data using VertexArray object
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A `VertexArray` object can be build and passed to `Model.draw()` to provide attribute data. Attribute data can be changed by changing `VertexArray` object.
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```js
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// construct the model.
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const model = new Model(gl, {
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vs: VERTEX_SHADER,
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fs: FRAGMENT_SHADER,
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uniforms: {uSampler: texture},
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drawMode: gl.TRIANGLE_FAN,
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vertexCount: 3,
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})
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const ATTRIBUTE1_LOCATION = 0;
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const ATTRIBUTE2_LOCATION = 1;
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const vertexArray1 = new VertexArray(gl, {
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buffers: {
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[ATTRIBUTE1_LOCATION]: buffer1,
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[ATTRIBUTE2_LOCATION]: buffer2
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}
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});
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const vertexArray2 = new VertexArray(gl, {
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buffers: {
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[ATTRIBUTE1_LOCATION]: buffer3,
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[ATTRIBUTE2_LOCATION]: buffer4
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}
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});
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//Render using attribute data from vertexArray1.
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model.draw({
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uniforms: {
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uPMatrix: currentProjectionMatrix,
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uMVMatrix: currentModelViewMatrix
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},
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vertexArray: vertexArray1
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});
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// Switch attribute data to vertexArray2
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model.draw({
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uniforms: {
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uPMatrix: currentProjectionMatrix,
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uMVMatrix: currentModelViewMatrix
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},
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vertexArray: vertexArray2
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});
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```
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## Properties
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`Model` extends the `BaseModel` class and inherits all properties from that class.
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### moduleSettings : Object
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any uniforms needed by shader modules.
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### uniforms : Object
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uniform values to be used for drawing.
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### onBeforeRender
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function to be called before every time this model is drawn.
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### onAfterRender
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function to be called after every time this model is drawn.
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### mesh
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`Mesh` instance.
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## Deprecated Properties in v7
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### geometry
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`Geometry` object, from which attributes, vertex count and drawing mode are deduced.
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### isInstanced : Boolean
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default value is false.
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### instanceCount : Number
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default value is 0.
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### vertexCount : Number
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when not provided will be deduced from `geometry` object.
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## Constructor
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### Model(gl: WebGLRenderingContext, props: Object)
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The constructor for the Model class. Use this to create a new Model.
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* `vs` - (VertexShader|*string*) - A vertex shader object, or source as a string.
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* `fs` - (FragmentShader|*string*) - A fragment shader object, or source as a string.
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* `varyings` (WebGL 2) - An array of vertex shader output variables, that needs to be recorded (used in TransformFeedback flow).
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* `bufferMode` (WebGL 2) - Mode to be used when recording vertex shader outputs (used in TransformFeedback flow). Default value is `gl.SEPARATE_ATTRIBS`.
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* `modules` - shader modules to be applied.
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* `program` - pre created program to use, when provided, vs, ps and modules are not used.
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* `programManager` - `ProgramManager` to use for program creation and caching.
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* `transpileToGLSL100` - Transpile vertex and fragment shaders to GLSL 1.0.
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### delete() : Model
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Free WebGL resources associated with this model
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## Methods
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### setProps(props : Object) : Model
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Updates properties
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### isAnimated() : Boolean
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Returns `true` if the model is animated (i.e. needs to be redrawn every frame).
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### getProgram() : Program
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Get model's `Program` instance
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### getUniforms() : Object
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Returns map of currently stored uniforms
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### setUniforms(uniforms : Object) : Model
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Stores named uniforms {key, value}
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### updateModuleSettings(moduleSettings : Object) : Model
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### draw(options : Object) : Model
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Renders the model with provided uniforms, attributes and samplers
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```js
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model.draw({
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moduleSettings = null,
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uniforms = {},
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attributes = {},
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samplers = {},
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parameters = {},
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settings,
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framebuffer = null,
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vertexArray = null,
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transformFeedback = null
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});
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```
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`Model.draw()` calls `Program.draw()` but adds and extends the available parameters as follows:
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* `moduleSettings`=`null` (Object) - any uniforms needed by shader modules.
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* `attributes`=`{}` (Object) - attribute definitions to be used for drawing. In additions to `Buffer` and constant values, `Model`s can also accept typed arrays and attribute descriptor objects which it converts to buffers.
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* `uniforms`=`{}` (Object) - uniform values to be used for drawing. In addition to normal uniform values, `Model` can also accept function valued uniforms which will be evaluated before every draw call.
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* `animationProps` (Object) - if any function valued uniforms are set on the `Model`, `animationProps` must be provided to the draw call. The `animationProps` are passed as parameter to the uniform functions.
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The remaining draw options are passed directly to `Program.draw()`:
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* `uniforms`=`{}` (Object) - uniform values to be used for drawing.
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* `samplers`=`{}` (Object) - texture mappings to be used for drawing.
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* `parameters`=`{}` (Object) - temporary gl settings to be applied to this draw call.
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* `framebuffer`=`null` (`Framebuffer`) - if provided, renders into the supplied framebuffer, otherwise renders to the default framebuffer.
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* `transformFeedback` - an instance `TranformFeedback` object, that gets activated for this rendering.
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* `vertexArray` - an instance of `VertexArray` object, that holds required buffer bindings for vertex shader inputs.
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### transform(options : Object) : Model
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Renders the model with provided uniforms, and samplers. Calls `Program.draw()` with rasterization turned off.
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* `discard`=`true` (Boolean) - Turns off rasterization
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* `feedbackBuffers`=`null` (Object) - Optional map of feedback buffers. A `TransformFeedback` object will be created, initialized with these buffers, and passed to `Model.draw`.
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* `unbindModels`=`[]` (Model[]) - Array of models whose VertexAttributes will be temporarily unbound during the transform feeback to avoid triggering a possible [Khronos/Chrome bug](https://github.com/KhronosGroup/WebGL/issues/2346).
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.
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```js
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model.transform({
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discard:
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});
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```
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## Deprecated Methods in v7
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### getDrawMode() : Enum
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Gets the WebGL drawMode
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### getVertexCount() : GLInt
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Gets vertex count
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Note: might be autocalculated from `Geometry`
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### getInstanceCount() : GLInt
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Defaults to 0
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### getAttributes() : Object
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Get a map of named attributes
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### setDrawMode() : Model
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Sets the WebGL `drawMode`.
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`GL.POINTS` etc.
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### setVertexCount() : Model
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Sets the number of vertices
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### setInstanceCount() : Model
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How many instances will be rendered
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### setGeometry() : Model
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Use a `Geometry` instance to define attribute buffers
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### setAttributes(attributes : Object) : Model
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Sets map of attributes (passes through to [VertexArray.setAttributes](/docs/api-reference/webgl/vertex-array))
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## Remarks
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* The `Model` class is arguably the most useful class for typical applications. It manages the WebGL resources needed to perform draw calls and provide additional functionality as described below.
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