From 0c6d978442b244ca3f29c1ffdd44b5007ae7ad93 Mon Sep 17 00:00:00 2001
From: Ilion Beyst <ilion.beyst@gmail.com>
Date: Wed, 29 Dec 2021 21:24:57 +0100
Subject: separate out visualizer library

---
 web/pw-visualizer/src/webgl/vertexBufferLayout.ts | 115 ++++++++++++++++++++++
 1 file changed, 115 insertions(+)
 create mode 100644 web/pw-visualizer/src/webgl/vertexBufferLayout.ts

(limited to 'web/pw-visualizer/src/webgl/vertexBufferLayout.ts')

diff --git a/web/pw-visualizer/src/webgl/vertexBufferLayout.ts b/web/pw-visualizer/src/webgl/vertexBufferLayout.ts
new file mode 100644
index 0000000..f44ed47
--- /dev/null
+++ b/web/pw-visualizer/src/webgl/vertexBufferLayout.ts
@@ -0,0 +1,115 @@
+import type { VertexBuffer } from './buffer';
+import type { Shader } from './shader';
+
+export class VertexBufferElement {
+    type: number;
+    amount: number;
+    type_size: number;
+    normalized: boolean;
+    index: string;
+
+    constructor(
+        type: number,
+        amount: number,
+        type_size: number,
+        index: string,
+        normalized: boolean,
+    ) {
+        this.type = type;
+        this.amount = amount;
+        this.type_size = type_size;
+        this.normalized = normalized;
+        this.index = index;
+    }
+}
+
+export class VertexBufferLayout {
+    elements: VertexBufferElement[];
+    stride: number;
+    offset: number;
+
+    constructor(offset = 0) {
+        this.elements = [];
+        this.stride = 0;
+        this.offset = offset;
+    }
+
+    // Maybe wrong normalized type
+    push(
+        type: number,
+        amount: number,
+        type_size: number,
+        index: string,
+        normalized = false,
+    ) {
+        this.elements.push(new VertexBufferElement(type, amount, type_size, index, normalized));
+        this.stride += amount * type_size;
+    }
+
+    getElements(): VertexBufferElement[] {
+        return this.elements;
+    }
+
+    getStride(): number {
+        return this.stride;
+    }
+}
+
+// glEnableVertexAttribArray is to specify what location of the current program the follow data is needed
+// glVertexAttribPointer tells gl that that data is at which location in the supplied data
+export class VertexArray {
+    // There is no renderer ID, always at bind buffers and use glVertexAttribPointer
+    buffers: VertexBuffer[];
+    layouts: VertexBufferLayout[];
+
+    constructor() {
+        this.buffers = [];
+        this.layouts = [];
+    }
+
+    addBuffer(vb: VertexBuffer, layout: VertexBufferLayout) {
+        this.buffers.push(vb);
+        this.layouts.push(layout);
+    }
+
+    updateBuffer(gl: WebGLRenderingContext, index: number, data: number[]) {
+        this.buffers[index].updateData(gl, data);
+    }
+
+    /// Bind buffers providing program data
+    bind(gl: WebGLRenderingContext, shader: Shader) {
+        shader.bind(gl);
+        for(let i = 0; i < this.buffers.length; i ++) {
+            const buffer = this.buffers[i];
+            const layout = this.layouts[i];
+
+            buffer.bind(gl);
+            const elements = layout.getElements();
+            let offset = layout.offset;
+
+            for (let j = 0; j < elements.length; j ++) {
+                const element = elements[j];
+                const location = shader.getAttribLocation(gl, element.index);
+
+                if (location >= 0) {
+                    gl.enableVertexAttribArray(location);
+                    gl.vertexAttribPointer(
+                        location, element.amount, element.type,
+                        element.normalized, layout.stride, offset
+                    );
+                }
+
+                offset += element.amount * element.type_size;
+            }
+        }
+    }
+
+    /// Undo bind operation
+    unbind(gl: WebGLRenderingContext) {
+        this.layouts.forEach((layout) => {
+            layout.getElements().forEach((_, index) => {
+                gl.disableVertexAttribArray(index);
+            });
+        })
+    }
+}
-- 
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