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230 lines
8.1 KiB
Markdown
230 lines
8.1 KiB
Markdown
# Model
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> Proposed luma.gl v9 API. Open for comments.
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The `Model` is the primary class for most luma.gl applications.
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A `Model` brings together a range of different luma.gl functions in one class. It holds all the data necessary to perform draw calls:
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- **shaders** (via a [`Program`](/docs/api-reference/webgl/program) instance)
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- **bindings** these can reference uniforms and textures.
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- **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 integrates with the `@luma.gl/shadertools` shader module system: [see `Shader Assembly`](/docs/api-reference/shadertools/assemble-shaders).
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TBD
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- Automatically creates 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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```typescript
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// construct the model.
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const model = new Model(device, {
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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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```typescript
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// construct the model.
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const model = new Model(device, {
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vs: VERTEX_SHADER,
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fs: FRAGMENT_SHADER,
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topology: 'triangle-list',
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vertexCount: 3,
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attributes: {
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attributeName1: bufferObject,
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attributeName2: device.createBuffer(new Float32Array(...))
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},
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uniforms: {uSampler: texture},
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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: currentModelViewMatrix
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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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```typescript
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// construct the model.
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const model = new Model(device, {
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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 = device.createVertexArray({
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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 = device.createVertexArray({
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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.setUniforms({
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uPMatrix: currentProjectionMatrix,
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uMVMatrix: currentModelViewMatrix
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})
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model.setVertexArray(vertexArray2);
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model.draw({...});
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```
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## Properties
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| Property | Type | Description |
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| ------------- | ------------------------ | --------------------------------------------------------------------------------------- |
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| `vs` | `Shader` \| _string_ | A vertex shader object, or source as a string. |
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| `fs` | `Shader` \| _string_ | A fragment shader object, or source as a string. |
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| `layout` | `ShaderLayout` | Describes how shader attributes and bindings are laid out. |
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| `modules` | | shader modules to be applied (shadertools). |
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| `pipeline` | | pre created program to use, when provided, vs, ps and modules are not used. |
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| `topology?` | | `'point-list'`, `'line-list'`, `'line-strip'`, `'triangle-list'` or `'triangle-strip'`, |
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| `parameters?` | RenderPipelineParameters | |
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- `programManager` | | `ProgramManager` to use for program creation and caching. |
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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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- `transpileToGLSL100` | | Transpile vertex and fragment shaders to GLSL 1.0. |
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## Properties
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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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## Methods
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### Model(device: Device, props: ModelProps)
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The constructor for the Model class. Use this to create a new Model.
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### destroy()
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Free WebGL resources associated with this model
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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); this
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Stores named uniforms {key, value}
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### updateModuleSettings(moduleSettings: object); this
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### draw(options: object): boolean
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Renders the model with provided uniforms, attributes and samplers
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```typescript
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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); this
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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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```typescript
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model.transform({
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discard: false
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});
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```
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