Merge pull request #13200 from Popov72/fix-motionblur

Motion blur: Fix motion blur when not in the "object based" mode
BabylonJS · Nov 4, 2022 · 8b3fe48 · 8b3fe48
2 parents 0eb224c + 01e2365
commit 8b3fe48
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Showing 2 changed files with 15 additions and 9 deletions.
diff --git a/packages/dev/core/src/PostProcesses/motionBlurPostProcess.ts b/packages/dev/core/src/PostProcesses/motionBlurPostProcess.ts
@@ -1,6 +1,6 @@
 import type { Nullable } from "../types";
 import { Logger } from "../Misc/logger";
-import { Matrix, Vector2 } from "../Maths/math.vector";
+import { Matrix, TmpVectors, Vector2 } from "../Maths/math.vector";
 import type { Camera } from "../Cameras/camera";
 import type { Effect } from "../Materials/effect";
 import type { PostProcessOptions } from "./postProcess";
@@ -135,8 +135,8 @@ export class MotionBlurPostProcess extends PostProcess {
         super(
             name,
             "motionBlur",
-            ["motionStrength", "motionScale", "screenSize", "inverseViewProjection", "prevViewProjection"],
-            ["velocitySampler", "textureSampler", "depthSampler"],
+            ["motionStrength", "motionScale", "screenSize", "inverseViewProjection", "prevViewProjection", "projection"],
+            ["velocitySampler", "depthSampler"],
             options,
             camera,
             samplingMode,
@@ -250,7 +250,7 @@ export class MotionBlurPostProcess extends PostProcess {
             this.onApply = (effect: Effect) => this._onApplyObjectBased(effect);
         } else {
             this._invViewProjection = Matrix.Identity();
-            this._previousViewProjection = Matrix.Identity();
+            this._previousViewProjection = this._scene.getTransformMatrix().clone();
 
             if (this._prePassRenderer && this._prePassEffectConfiguration) {
                 this._prePassEffectConfiguration.texturesRequired[0] = Constants.PREPASS_DEPTH_TEXTURE_TYPE;
@@ -284,13 +284,16 @@ export class MotionBlurPostProcess extends PostProcess {
      * @param effect
      */
     private _onApplyScreenBased(effect: Effect): void {
-        const viewProjection = this._scene.getProjectionMatrix().multiply(this._scene.getViewMatrix());
+        const viewProjection = TmpVectors.Matrix[0];
+        viewProjection.copyFrom(this._scene.getTransformMatrix());
 
         viewProjection.invertToRef(this._invViewProjection!);
         effect.setMatrix("inverseViewProjection", this._invViewProjection!);
 
         effect.setMatrix("prevViewProjection", this._previousViewProjection!);
-        this._previousViewProjection = viewProjection;
+        this._previousViewProjection!.copyFrom(viewProjection);
+
+        effect.setMatrix("projection", this._scene.getProjectionMatrix());
 
         effect.setVector2("screenSize", new Vector2(this.width, this.height));
 

diff --git a/packages/dev/core/src/Shaders/motionBlur.fragment.fx b/packages/dev/core/src/Shaders/motionBlur.fragment.fx
@@ -13,6 +13,7 @@ uniform sampler2D depthSampler;
 
 uniform mat4 inverseViewProjection;
 uniform mat4 prevViewProjection;
+uniform mat4 projection;
 #endif
 
 
@@ -49,12 +50,14 @@ void main(void)
         #else
             vec2 texelSize = 1.0 / screenSize;
             float depth = texture2D(depthSampler, vUV).r;
+            depth = projection[2].z + projection[3].z / depth; // convert from view linear z to NDC z
 
             vec4 cpos = vec4(vUV * 2.0 - 1.0, depth, 1.0);
-            cpos = cpos * inverseViewProjection;
+            cpos = inverseViewProjection * cpos;
+            cpos /= cpos.w;
 
-            vec4 ppos = cpos * prevViewProjection;
-            ppos.xyz /= ppos.w;
+            vec4 ppos = prevViewProjection * cpos;
+            ppos /= ppos.w;
             ppos.xy = ppos.xy * 0.5 + 0.5;
 
             vec2 velocity = (ppos.xy - vUV) * motionScale * motionStrength;