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Piyush3dB/WebGLFlowChart1.txt

Last active February 12, 2019 16:58
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WebGLFlowChart1.txt
@startuml
skinparam classFontName Century
start
:canvas = document.getElementById("canvas");
note left: <canvas id="canvas"></canvas>
:gl = canvas.getContext("webgl");;
fork
:vertexShader = gl.createShader(gl.VERTEX_SHADER);
:gl.shaderSource(vertexShader, source);
note left: <script id="2d-vertex-shader" type="notjs">\n attribute vec4 a_position;\n void main() {\n gl_Position = a_position;\n }\n</script>
:gl.compileShader(vertexShader);
fork again
:fragmentShader = gl.createShader(gl.FRAGMENT_SHADER);
:gl.shaderSource(fragmentShader, source);
note right: <script id="2d-fragment-shader" type="notjs">\n precision mediump float;\n void main() {\n gl_FragColor = vec4(1, 0, 0.5, 1);\n }\n</script>
:gl.compileShader(fragmentShader);
end fork
:program = gl.createProgram();\ngl.attachShader(program, vertexShader);\ngl.attachShader(program, fragmentShader);\ngl.linkProgram(program);
:positionAttributeLocation = gl.getAttribLocation(program, "a_position");
note left: <script id="2d-vertex-shader" type="notjs">\n attribute vec4 a_position;\n void main() {\n gl_Position = a_position;\n }\n</script>
:positionBuffer = gl.createBuffer();
:gl.bindBuffer(gl.ARRAY_BUFFER, positionBuffer);
:gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(positions), gl.STATIC_DRAW);
note left: var positions = [\n 0, 0,\n 0, 0.5,\n 0.7, 0,\n];
:webglUtils.resizeCanvasToDisplaySize(gl.canvas);\ngl.viewport(0, 0, gl.canvas.width, gl.canvas.height);
:gl.clearColor(0, 0, 0, 0);\ngl.clear(gl.COLOR_BUFFER_BIT);
:gl.useProgram(program);
:gl.enableVertexAttribArray(positionAttributeLocation);
note left: positionAttributeLocation = gl.getAttribLocation(program, "a_position");
:gl.vertexAttribPointer(positionAttributeLocation, size, type, normalize, stride, offset);
:gl.drawArrays(primitiveType, offset, count);
@enduml
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