Simplify normal map sample, fix toy box normals.

To fix the normals.

This was more complicated than it needed to be, and borrowed code from another project.
This code also used vec3 methods with two-element vectors, which might cause issues with future versions of 'wgpu-matrix'

* Use `const` declarations to name the various modes instead of magic literals.
* Calculate the `worldViewProj` and `worldView` matrices on the CPU and pass them in as part of the uniform buffer. Reduces duplicated work in the vertex shader, and reduces the amount of data needed to be passed in.
* Use `vec3f` for the light position instead of scalar. Pass in the position in view-space.
* Reduce the amount of data passed from vertex to fragment.
* Rename `tbn` to `tangent`, `bitangent` and `normal`.
* Remove unused function `when_greater`
* Split `parallax_uv` into two functions.
* Simplify steep-parallax loop. Pre-calculate the UV derivatives so we can break early from the loop.

Rename 'diffuse' textures to 'albedo'. Technically a diffuse texture already has diffuse lighting applied.

Fixed: #317

src/sample/normalMap/main.ts

@@ -1,4 +1,4 @@
-import { mat4 } from 'wgpu-matrix';
+import { mat4, vec3 } from 'wgpu-matrix';
 import { makeSample, SampleInit } from '../../components/SampleLayout';
 import normalMapWGSL from './normalMap.wgsl';
 import { createMeshRenderable } from '../../meshes/mesh';
@@ -33,7 +33,7 @@ const init: SampleInit = async ({ canvas, pageState, gui }) => {
 
   interface GUISettings {
     'Bump Mode':
-      | 'Diffuse Texture'
+      | 'Albedo Texture'
       | 'Normal Texture'
       | 'Depth Texture'
       | 'Normal Map'
@@ -60,7 +60,7 @@ const init: SampleInit = async ({ canvas, pageState, gui }) => {
     lightPosX: 1.7,
     lightPosY: 0.7,
     lightPosZ: -1.9,
-    lightIntensity: 0.02,
+    lightIntensity: 5.0,
     depthScale: 0.05,
     depthLayers: 16,
     Texture: 'Spiral',
@@ -76,24 +76,26 @@ const init: SampleInit = async ({ canvas, pageState, gui }) => {
     usage: GPUTextureUsage.RENDER_ATTACHMENT,
   });
 
-  const uniformBuffer = device.createBuffer({
+  const spaceTransformsBuffer = device.createBuffer({
     // Buffer holding projection, view, and model matrices plus padding bytes
     size: MAT4X4_BYTES * 4,
     usage: GPUBufferUsage.UNIFORM | GPUBufferUsage.COPY_DST,
   });
 
-  const mapMethodBuffer = device.createBuffer({
+  const mapInfoBuffer = device.createBuffer({
     // Buffer holding mapping type, light uniforms, and depth uniforms
-    size: Float32Array.BYTES_PER_ELEMENT * 7,
+    size: Float32Array.BYTES_PER_ELEMENT * 8,
     usage: GPUBufferUsage.UNIFORM | GPUBufferUsage.COPY_DST,
   });
+  const mapInfoArray = new ArrayBuffer(mapInfoBuffer.size);
+  const mapInfoView = new DataView(mapInfoArray, 0, mapInfoArray.byteLength);
 
   // Fetch the image and upload it into a GPUTexture.
-  let woodDiffuseTexture: GPUTexture;
+  let woodAlbedoTexture: GPUTexture;
   {
-    const response = await fetch('../assets/img/wood_diffuse.png');
+    const response = await fetch('../assets/img/wood_albedo.png');
     const imageBitmap = await createImageBitmap(await response.blob());
-    woodDiffuseTexture = createTextureFromImage(device, imageBitmap);
+    woodAlbedoTexture = createTextureFromImage(device, imageBitmap);
   }
 
   let spiralNormalTexture: GPUTexture;
@@ -124,11 +126,11 @@ const init: SampleInit = async ({ canvas, pageState, gui }) => {
     toyboxHeightTexture = createTextureFromImage(device, imageBitmap);
   }
 
-  let brickwallDiffuseTexture: GPUTexture;
+  let brickwallAlbedoTexture: GPUTexture;
   {
-    const response = await fetch('../assets/img/brickwall_diffuse.png');
+    const response = await fetch('../assets/img/brickwall_albedo.png');
     const imageBitmap = await createImageBitmap(await response.blob());
-    brickwallDiffuseTexture = createTextureFromImage(device, imageBitmap);
+    brickwallAlbedoTexture = createTextureFromImage(device, imageBitmap);
   }
 
   let brickwallNormalTexture: GPUTexture;
@@ -184,7 +186,7 @@ const init: SampleInit = async ({ canvas, pageState, gui }) => {
     ],
     ['buffer', 'buffer'],
     [{ type: 'uniform' }, { type: 'uniform' }],
-    [[{ buffer: uniformBuffer }, { buffer: mapMethodBuffer }]],
+    [[{ buffer: spaceTransformsBuffer }, { buffer: mapInfoBuffer }]],
     'Frame',
     device
   );
@@ -204,19 +206,19 @@ const init: SampleInit = async ({ canvas, pageState, gui }) => {
     [
       [
         sampler,
-        woodDiffuseTexture.createView(),
+        woodAlbedoTexture.createView(),
         spiralNormalTexture.createView(),
         spiralHeightTexture.createView(),
       ],
       [
         sampler,
-        woodDiffuseTexture.createView(),
+        woodAlbedoTexture.createView(),
         toyboxNormalTexture.createView(),
         toyboxHeightTexture.createView(),
       ],
       [
         sampler,
-        brickwallDiffuseTexture.createView(),
+        brickwallAlbedoTexture.createView(),
         brickwallNormalTexture.createView(),
         brickwallHeightTexture.createView(),
       ],
@@ -250,9 +252,9 @@ const init: SampleInit = async ({ canvas, pageState, gui }) => {
   }
 
   // Change the model mapping type
-  const getMappingType = (): number => {
+  const getMode = (): number => {
     switch (settings['Bump Mode']) {
-      case 'Diffuse Texture':
+      case 'Albedo Texture':
         return 0;
       case 'Normal Texture':
         return 1;
@@ -285,7 +287,7 @@ const init: SampleInit = async ({ canvas, pageState, gui }) => {
   };
 
   gui.add(settings, 'Bump Mode', [
-    'Diffuse Texture',
+    'Albedo Texture',
     'Normal Texture',
     'Depth Texture',
     'Normal Map',
@@ -301,7 +303,7 @@ const init: SampleInit = async ({ canvas, pageState, gui }) => {
     lightPosXController.setValue(1.7);
     lightPosYController.setValue(0.7);
     lightPosZController.setValue(-1.9);
-    lightIntensityController.setValue(0.02);
+    lightIntensityController.setValue(5.0);
   });
   const lightPosXController = lightFolder
     .add(settings, 'lightPosX', -5, 5)
@@ -313,53 +315,54 @@ const init: SampleInit = async ({ canvas, pageState, gui }) => {
     .add(settings, 'lightPosZ', -5, 5)
     .step(0.1);
   const lightIntensityController = lightFolder
-    .add(settings, 'lightIntensity', 0.0, 0.1)
-    .step(0.002);
+    .add(settings, 'lightIntensity', 0.0, 10)
+    .step(0.1);
   depthFolder.add(settings, 'depthScale', 0.0, 0.1).step(0.01);
   depthFolder.add(settings, 'depthLayers', 1, 32).step(1);
 
   function frame() {
     if (!pageState.active) return;
 
-    // Write to normal map shader
+    // Update spaceTransformsBuffer
     const viewMatrix = getViewMatrix();
-
-    const modelMatrix = getModelMatrix();
-
+    const worldViewMatrix = mat4.mul(viewMatrix, getModelMatrix());
+    const worldViewProjMatrix = mat4.mul(projectionMatrix, worldViewMatrix);
     const matrices = new Float32Array([
-      ...projectionMatrix,
-      ...viewMatrix,
-      ...modelMatrix,
+      ...worldViewProjMatrix,
+      ...worldViewMatrix,
     ]);
 
-    const mappingType = getMappingType();
-
+    // Update mapInfoBuffer
+    const lightPosWS = vec3.create(
+      settings.lightPosX,
+      settings.lightPosY,
+      settings.lightPosZ
+    );
+    const lightPosVS = vec3.transformMat4(lightPosWS, viewMatrix);
+    const mode = getMode();
     device.queue.writeBuffer(
-      uniformBuffer,
+      spaceTransformsBuffer,
       0,
       matrices.buffer,
       matrices.byteOffset,
       matrices.byteLength
     );
 
-    device.queue.writeBuffer(
-      mapMethodBuffer,
-      0,
-      new Uint32Array([mappingType])
-    );
-
-    device.queue.writeBuffer(
-      mapMethodBuffer,
-      4,
-      new Float32Array([
-        settings.lightPosX,
-        settings.lightPosY,
-        settings.lightPosZ,
-        settings.lightIntensity,
-        settings.depthScale,
-        settings.depthLayers,
-      ])
-    );
+    // struct MapInfo {
+    //   lightPosVS: vec3f,
+    //   mode: u32,
+    //   lightIntensity: f32,
+    //   depthScale: f32,
+    //   depthLayers: f32,
+    // }
+    mapInfoView.setFloat32(0, lightPosVS[0], true);
+    mapInfoView.setFloat32(4, lightPosVS[1], true);
+    mapInfoView.setFloat32(8, lightPosVS[2], true);
+    mapInfoView.setUint32(12, mode, true);
+    mapInfoView.setFloat32(16, settings.lightIntensity, true);
+    mapInfoView.setFloat32(20, settings.depthScale, true);
+    mapInfoView.setFloat32(24, settings.depthLayers, true);
+    device.queue.writeBuffer(mapInfoBuffer, 0, mapInfoArray);
 
     renderPassDescriptor.colorAttachments[0].view = context
       .getCurrentTexture()