48 lines
1.6 KiB
TypeScript
48 lines
1.6 KiB
TypeScript
class WebGLUtils {
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public static getWebGL(): WebGLRenderingContext {
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if (egret.WebGLUtils.checkCanUseWebGL())
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return document.querySelector("canvas").getContext("webgl");
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throw new Error("cannot get webgl");
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}
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public static drawUserIndexPrimitives<T>(primitiveType: number, vertexData: T[], vertexOffset: number,
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numVertices: number, indexData: number[], indexOffset: number, primitiveCount: number) {
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let GL = this.getWebGL();
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GL.bindBuffer(GL.ARRAY_BUFFER, 0);
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this.checkGLError();
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GL.bindBuffer(GL.ELEMENT_ARRAY_BUFFER, 0);
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this.checkGLError();
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GL.drawElements(primitiveType,
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this.getElementCountArray(primitiveType, primitiveCount),
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GL.UNSIGNED_SHORT,
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indexOffset * 2);
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this.checkGLError();
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}
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private static getElementCountArray(primitiveType: number, primitiveCount: number) {
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let GL = this.getWebGL();
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switch (primitiveType) {
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case GL.LINES:
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return primitiveCount * 2;
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case GL.LINE_STRIP:
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return primitiveCount + 1;
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case GL.TRIANGLES:
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return primitiveCount * 3;
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case GL.TRIANGLE_STRIP:
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return primitiveCount + 2;
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}
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throw new Error("not support");
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}
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public static checkGLError() {
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let GL = this.getWebGL();
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let error = GL.getError();
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if (error != GL.NO_ERROR) {
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throw new Error("GL.GetError() returned" + error);
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}
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}
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} |