webgl/src/client/draw.ts

import {initMatrices, initModelAndNormalMatrices} from './matrix';
import {initVertexAttribs} from './vertexattrib';

/**
 * Draws a webgl scene
 * @param {any} gl the WebGL context
 * @param {any} programInfo WebGL program information
 * @param {any} buffers the buffers to draw
 * @param {number} params various parameterss
 * @param {any} texture the texture to load
 * @param {Array<any>} scene the scene array
 * @param {number} now the current time
 */
export function drawScene(gl: any,
	programInfo: any,
	buffers: any,
	params: any,
	texture: any,
	scene: Array<any>,
	now: number) {
	gl.clearColor(0.0, 0.0, 0.0, 1.0);
	gl.clearDepth(1.0);
	gl.enable(gl.DEPTH_TEST);
	gl.depthFunc(gl.LEQUAL);
	gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);

	initVertexAttribs(gl, programInfo, buffers);
	gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, buffers.indices);
	gl.useProgram(programInfo.program);
	gl.activeTexture(gl.TEXTURE0);
	gl.bindTexture(gl.TEXTURE_2D, texture);
	gl.uniform1i(programInfo.uniformLocations.uSampler, 0);
	gl.uniform1f(programInfo.uniformLocations.time, now);

	const [
		projectionMatrix,
		viewMatrix,
		modelMatrix,
		normalMatrix,
	] = initMatrices(gl, params);
	for (let i = 0; i < params.instanceNumber; i++) {
		gl.uniformMatrix4fv(
			programInfo.uniformLocations.projectionMatrix,
			false,
			projectionMatrix);
		gl.uniformMatrix4fv(
			programInfo.uniformLocations.viewMatrix,
			false,
			viewMatrix);
		gl.uniformMatrix4fv(
			programInfo.uniformLocations.modelMatrix,
			false,
			modelMatrix[i]);
		gl.uniformMatrix4fv(
			programInfo.uniformLocations.normalMatrix,
			false,
			normalMatrix[i]);
		const vertexCount = params.len;
		const type = gl.UNSIGNED_SHORT;
		const offset = 0;
		gl.drawElements(gl.TRIANGLES, vertexCount, type, offset);
	}

	for (let i = 0; i < scene.length; i++) {
		initVertexAttribs(gl, scene[i].programInfo, scene[i].buffers);
		gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, scene[i].buffers.indices);
		gl.useProgram(scene[i].programInfo.program);
		gl.activeTexture(gl.TEXTURE0);
		gl.bindTexture(gl.TEXTURE_2D, scene[i].texture);
		gl.uniform1i(scene[i].programInfo.uniformLocations.uSampler, 0);
		gl.uniform1f(scene[i].programInfo.uniformLocations.time, now);

		const [
			modelMatrix,
			normalMatrix,
		] = initModelAndNormalMatrices(scene[i].params);
		for (let j = 0; j < scene[i].params.instanceNumber; j++) {
			gl.uniformMatrix4fv(
				scene[i].programInfo.uniformLocations.projectionMatrix,
				false,
				projectionMatrix);
			gl.uniformMatrix4fv(
				scene[i].programInfo.uniformLocations.viewMatrix,
				false,
				viewMatrix);
			gl.uniformMatrix4fv(
				scene[i].programInfo.uniformLocations.modelMatrix,
				false,
				modelMatrix[j]);
			gl.uniformMatrix4fv(
				scene[i].programInfo.uniformLocations.normalMatrix,
				false,
				normalMatrix[j]);
			const vertexCount = scene[i].params.len;
			const type = gl.UNSIGNED_SHORT;
			const offset = 0;
			gl.drawElements(gl.TRIANGLES, vertexCount, type, offset);
		}
	}
}