fix: fix incorrect rotation of tangent frame

bhouston · Jul 4, 2020 · 838130e · 838130e
1 parent 50cf10f
commit 838130e
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Showing 4 changed files with 13 additions and 11 deletions.
diff --git a/src/examples/brdfs/04_normals/fragment.glsl b/src/examples/brdfs/04_normals/fragment.glsl
@@ -27,7 +27,7 @@ void main() {
   float specularRoughness = 0.25;
   vec3 specularF0 = specularIntensityToF0( specular );
 
-  vec3 normal = vec3( normalModulator, 1. ) * rgbToNormal( texture2D( normalMap, v_uv0 ).grb );
+  vec3 normal = vec3( normalModulator, 1. ) * rgbToNormal( texture2D( normalMap, v_uv0 ).rgb );
 
   Surface surface;
   surface.position = v_viewSurfacePosition;

diff --git a/src/examples/brdfs/08_displacement/fragment.glsl b/src/examples/brdfs/08_displacement/fragment.glsl
@@ -9,7 +9,8 @@ uniform vec3 pointLightColor;
 uniform float pointLightRange;
 
 uniform sampler2D normalMap;
-uniform float normalScale;
+uniform vec2 normalScale;
+uniform float displacementScale;
 
 #pragma include <brdfs/common>
 #pragma include <lighting/punctual>
@@ -22,21 +23,19 @@ uniform float normalScale;
 void main() {
 
   vec3 ambient = vec3(0.);
-  vec3 albedo = mix( vec3(0.2), vec3( 1., 0., 0. ), normalScale );
+  vec3 albedo = mix( vec3(0.2), vec3( 1., 0., 0. ), normalScale.x );
   vec3 specular = vec3(1.);
   float specularRoughness = 0.25;
   vec3 specularF0 = specularIntensityToF0( specular );
-  vec3 normal = rgbToNormal( texture2D( normalMap, vec2(1.0)-v_uv0 ).grb ) * vec3( 1., -1., 1. );
+  vec3 normal = normalize( rgbToNormal( texture2D( normalMap, vec2(1.0)-v_uv0 ).rgb ) * vec3( normalScale, 1. ) );
 
   Surface surface;
   surface.position = v_viewSurfacePosition;
   surface.normal = normalize( v_viewSurfaceNormal );
   surface.viewDirection = normalize( -v_viewSurfacePosition );
 
   uvToTangentFrame( surface, v_uv0 );
-  vec3 oldNormal = surface.normal;
   perturbSurfaceNormal_TangentSpace( surface, normal );
-  surface.normal = normalize( mix( oldNormal, surface.normal, normalScale ) );
 
   PunctualLight punctualLight;
   punctualLight.position = pointLightViewPosition;

diff --git a/src/examples/brdfs/08_displacement/index.ts b/src/examples/brdfs/08_displacement/index.ts
@@ -10,6 +10,7 @@ import {
   makeMatrix4Scale,
   makeMatrix4Translation,
 } from "../../../lib/math/Matrix4.Functions";
+import { Vector2 } from "../../../lib/math/Vector2";
 import { Vector3 } from "../../../lib/math/Vector3";
 import { makeBufferGeometryFromGeometry } from "../../../lib/renderers/webgl/buffers/BufferGeometry";
 import { ClearState } from "../../../lib/renderers/webgl/ClearState";
@@ -58,7 +59,7 @@ async function init(): Promise<null> {
 
     // materials
     normalMap: normalMap,
-    normalScale: 1.0,
+    normalScale: new Vector2(1.0, -1.0),
     displacementMap: displacementMap,
     displacementScale: 1.0,
   };
@@ -74,8 +75,10 @@ async function init(): Promise<null> {
       new Euler(0.15 * Math.PI, now * 0.0002, 0, EulerOrder.XZY),
       uniforms.localToWorld,
     );
-    uniforms.normalScale = Math.cos(now * 0.0008) * 0.5 + 0.5;
-    uniforms.displacementScale = uniforms.normalScale * 0.1;
+
+    const effectScale = Math.cos(now * 0.0008) * 0.5 + 0.5;
+    uniforms.normalScale = new Vector2(1.0, -1.0).multiplyByScalar(effectScale);
+    uniforms.displacementScale = effectScale * 0.1;
     uniforms.pointLightViewPosition = new Vector3(Math.cos(now * 0.001) * 3.0, 2.0, 0.5);
 
     canvasFramebuffer.clear(AttachmentBits.All);

diff --git a/src/lib/shaders/includes/brdfs/common.glsl b/src/lib/shaders/includes/brdfs/common.glsl
@@ -26,8 +26,8 @@ void uvToTangentFrame( inout Surface surface, in vec2 uv ) {
   vec3 tempTangent = dFdx( uv.y ) * dFdy(surface.position) - dFdy( uv.y ) * dFdx(surface.position);
 
   surface.normal = normalize(surface.normal);
-  surface.bitangent = -normalize(tempTangent - surface.normal * dot(surface.normal, tempTangent));
-  surface.tangent = -cross(surface.normal, surface.bitangent);
+  surface.tangent = normalize(tempTangent - surface.normal * dot(surface.normal, tempTangent));
+  surface.bitangent = cross(surface.normal, surface.bitangent);
 }
 
 void rotateTangentFrame( inout Surface surface, in vec2 anisotropicDirection ) {