Custom user chunks to customize lit / standard shaders

src/scene/materials/lit-material-options-builder.js

@@ -50,7 +50,6 @@ class LitMaterialOptionsBuilder {
 
     static updateMaterialOptions(litOptions, material) {
         litOptions.separateAmbient = false;    // store ambient light color in separate variable, instead of adding it to diffuse directly
-        litOptions.customFragmentShader = null;
         litOptions.pixelSnap = material.pixelSnap;
 
         litOptions.ambientSH = material.ambientSH;

src/scene/materials/standard-material-options-builder.js

@@ -262,7 +262,6 @@ class StandardMaterialOptionsBuilder {
 
         // LIT OPTIONS
         options.litOptions.separateAmbient = false;    // store ambient light color in separate variable, instead of adding it to diffuse directly
-        options.litOptions.customFragmentShader = stdMat.customFragmentShader;
         options.litOptions.pixelSnap = stdMat.pixelSnap;
 
         options.litOptions.ambientSH = !!stdMat.ambientSH;

src/scene/shader-lib/chunks-wgsl/chunks-wgsl.js

@@ -80,6 +80,7 @@ import litForwardDeclarationPS from './lit/frag/pass-forward/litForwardDeclarati
 import litForwardMainPS from './lit/frag/pass-forward/litForwardMain.js';
 import litForwardPostCodePS from './lit/frag/pass-forward/litForwardPostCode.js';
 import litForwardPreCodePS from './lit/frag/pass-forward/litForwardPreCode.js';
+import litMainPS from './lit/frag/litMain.js';
 import litMainVS from './lit/vert/litMain.js';
 import litOtherMainPS from './lit/frag/pass-other/litOtherMain.js';
 import litShaderArgsPS from './standard/frag/litShaderArgs.js';
@@ -253,6 +254,8 @@ const shaderChunksWGSL = {
     floatAsUintPS,
     fogPS,
     fresnelSchlickPS,
+    frontendCodePS: '',  // empty chunk, supplied by the shader generator
+    frontendDeclPS: '',  // empty chunk, supplied by the shader generator
     fullscreenQuadVS,
     gammaPS,
     glossPS,
@@ -293,11 +296,20 @@ const shaderChunksWGSL = {
     litForwardMainPS,
     litForwardPostCodePS,
     litForwardPreCodePS,
+    litMainPS,
     litMainVS,
     litOtherMainPS,
     litShaderArgsPS,
     litShaderCorePS,
     litShadowMainPS,
+    litUserDeclarationPS: '',  // empty chunk allowing user to add custom code
+    litUserDeclarationVS: '',  // empty chunk allowing user to add custom code
+    litUserCodePS: '',  // empty chunk allowing user to add custom code
+    litUserCodeVS: '',  // empty chunk allowing user to add custom code
+    litUserMainStartPS: '',  // empty chunk allowing user to add custom code
+    litUserMainStartVS: '',  // empty chunk allowing user to add custom code
+    litUserMainEndPS: '',  // empty chunk allowing user to add custom code
+    litUserMainEndVS: '',  // empty chunk allowing user to add custom code
     ltcPS,
     metalnessPS,
     metalnessModulatePS,

src/scene/shader-lib/chunks-wgsl/lit/frag/litMain.js

@@ -0,0 +1,32 @@
+// main shader of the lit fragment shader
+export default /* wgsl */`
+
+#include "varyingsPS"
+#include "litUserDeclarationPS"
+#include "frontendDeclPS"
+
+#if defined(PICK_PASS) || definde(PREPASS_PASS)
+
+    #include "frontendCodePS"
+    #include "litUserCodePS"
+    #include "litOtherMainPS"
+
+#elif defined(SHADOW_PASS)
+
+    #include "frontendCodePS"
+    #include "litUserCodePS"
+    #include "litShadowMainPS"
+
+#else // FORWARD_PASS
+
+    #include "litForwardDeclarationPS"
+    #include "litForwardPreCodePS"
+    #include "frontendCodePS"
+    #include "litForwardPostCodePS"
+    #include "litForwardBackendPS"
+    #include "litUserCodePS"
+    #include "litForwardMainPS"
+
+#endif
+
+`;

src/scene/shader-lib/chunks-wgsl/lit/frag/pass-forward/litForwardMain.js

@@ -4,6 +4,8 @@ export default /* wgsl */`
 @fragment
 fn fragmentMain(input: FragmentInput) -> FragmentOutput {
 
+    #include "litUserMainStartPS"
+
     dReflection = vec4f(0.0);
 
     #ifdef LIT_CLEARCOAT
@@ -45,6 +47,8 @@ fn fragmentMain(input: FragmentInput) -> FragmentOutput {
 
     var output: FragmentOutput = evaluateBackend();
 
+    #include "litUserMainEndPS"
+
     return output;
 }
 `;

src/scene/shader-lib/chunks-wgsl/lit/frag/pass-other/litOtherMain.js

@@ -11,6 +11,9 @@ export default /* wgsl */`
 
 @fragment
 fn fragmentMain(input: FragmentInput) -> FragmentOutput {
+
+    #include "litUserMainStartPS"
+
     var output: FragmentOutput;
 
     evaluateFrontend();
@@ -23,6 +26,8 @@ fn fragmentMain(input: FragmentInput) -> FragmentOutput {
         output.color = float2vec4(vLinearDepth);
     #endif
 
+    #include "litUserMainEndPS"
+
     return output;
 }
 `;

src/scene/shader-lib/chunks-wgsl/lit/frag/pass-shadow/litShadowMain.js

@@ -12,6 +12,9 @@ export default /* wgsl */`
 
 @fragment
 fn fragmentMain(input: FragmentInput) -> FragmentOutput {
+
+    #include "litUserMainStartPS"
+
     var output: FragmentOutput;
 
     evaluateFrontend();
@@ -57,6 +60,8 @@ fn fragmentMain(input: FragmentInput) -> FragmentOutput {
         #endif
     #endif
 
+    #include "litUserMainEndPS"
+
     return output;
 }
 `;

src/scene/shader-lib/chunks-wgsl/lit/frag/refractionDynamic.js

@@ -86,4 +86,5 @@ fn addRefraction(
         #endif
         );
     dDiffuseLight = mix(dDiffuseLight, refraction * transmittance * fresnel, transmission);
-}`;
+}
+`;

src/scene/shader-lib/chunks-wgsl/lit/vert/litMain.js

@@ -1,5 +1,10 @@
 // main shader of the lit vertex shader
 export default /* wgsl */`
+
+#include "varyingsVS"
+
+#include  "litUserDeclarationVS"
+
 #ifdef VERTEX_COLOR
     attribute vertex_color: vec4f;
 #endif
@@ -59,8 +64,13 @@ var<private> dModelMatrix: mat4x4f;
     #include "msdfVS"
 #endif
 
+#include  "litUserCodeVS"
+
 @vertex
 fn vertexMain(input : VertexInput) -> VertexOutput {
+
+    #include "litUserMainStartVS"
+
     var output : VertexOutput;
     output.position = getPosition();
     output.vPositionW = getWorldPosition();
@@ -116,6 +126,8 @@ fn vertexMain(input : VertexInput) -> VertexOutput {
         output.vTiledUv = dTiledUvGlobal;
     #endif
 
+    #include "litUserMainEndVS"
+
     return output;
 }
 `;

src/scene/shader-lib/chunks/chunks.js

@@ -85,6 +85,7 @@ import litForwardDeclarationPS from './lit/frag/pass-forward/litForwardDeclarati
 import litForwardMainPS from './lit/frag/pass-forward/litForwardMain.js';
 import litForwardPostCodePS from './lit/frag/pass-forward/litForwardPostCode.js';
 import litForwardPreCodePS from './lit/frag/pass-forward/litForwardPreCode.js';
+import litMainPS from './lit/frag/litMain.js';
 import litMainVS from './lit/vert/litMain.js';
 import litOtherMainPS from './lit/frag/pass-other/litOtherMain.js';
 import litShaderArgsPS from './standard/frag/litShaderArgs.js';
@@ -258,6 +259,8 @@ const shaderChunks = {
     floatAsUintPS,
     fogPS,
     fresnelSchlickPS,
+    frontendCodePS: '',  // empty chunk, supplied by the shader generator
+    frontendDeclPS: '',  // empty chunk, supplied by the shader generator
     fullscreenQuadVS,
     gammaPS,
     gles3PS,
@@ -303,11 +306,20 @@ const shaderChunks = {
     litForwardMainPS,
     litForwardPostCodePS,
     litForwardPreCodePS,
+    litMainPS,
     litMainVS,
     litOtherMainPS,
     litShaderArgsPS,
     litShaderCorePS,
     litShadowMainPS,
+    litUserDeclarationPS: '',  // empty chunk allowing user to add custom code
+    litUserDeclarationVS: '',  // empty chunk allowing user to add custom code
+    litUserCodePS: '',  // empty chunk allowing user to add custom code
+    litUserCodeVS: '',  // empty chunk allowing user to add custom code
+    litUserMainStartPS: '',  // empty chunk allowing user to add custom code
+    litUserMainStartVS: '',  // empty chunk allowing user to add custom code
+    litUserMainEndPS: '',  // empty chunk allowing user to add custom code
+    litUserMainEndVS: '',  // empty chunk allowing user to add custom code
     ltcPS,
     metalnessPS,
     metalnessModulatePS,
@@ -423,6 +435,8 @@ const shaderChunks = {
     uvTransformVS,
     uvTransformUniformsPS,
     viewDirPS,
+    varyingsPS: '',  // empty chunk, supplied by the shader generator
+    varyingsVS: '',  // empty chunk, supplied by the shader generator
     webgpuPS,
     webgpuVS
 };

src/scene/shader-lib/chunks/lit/frag/litMain.js

@@ -0,0 +1,32 @@
+// main shader of the lit fragment shader
+export default /* glsl */`
+
+#include "varyingsPS"
+#include "litUserDeclarationPS"
+#include "frontendDeclPS"
+
+#if defined(PICK_PASS) || definde(PREPASS_PASS)
+
+    #include "frontendCodePS"
+    #include "litUserCodePS"
+    #include "litOtherMainPS"
+
+#elif defined(SHADOW_PASS)
+
+    #include "frontendCodePS"
+    #include "litUserCodePS"
+    #include "litShadowMainPS"
+
+#else // FORWARD_PASS
+
+    #include "litForwardDeclarationPS"
+    #include "litForwardPreCodePS"
+    #include "frontendCodePS"
+    #include "litForwardPostCodePS"
+    #include "litForwardBackendPS"
+    #include "litUserCodePS"
+    #include "litForwardMainPS"
+
+#endif
+
+`;

src/scene/shader-lib/chunks/lit/frag/pass-forward/litForwardMain.js

@@ -2,6 +2,9 @@
 export default /* glsl */`
 
 void main(void) {
+
+    #include "litUserMainStartPS"
+
     dReflection = vec4(0);
 
     #ifdef LIT_CLEARCOAT
@@ -42,5 +45,7 @@ void main(void) {
     #include "debugProcessFrontendPS"
 
     evaluateBackend();
+
+    #include "litUserMainEndPS"
 }
 `;

src/scene/shader-lib/chunks/lit/frag/pass-other/litOtherMain.js

@@ -10,6 +10,9 @@ export default /* glsl */`
 #endif
 
 void main(void) {
+
+    #include "litUserMainStartPS"
+
     evaluateFrontend();
 
     #ifdef PICK_PASS
@@ -19,5 +22,7 @@ void main(void) {
     #ifdef PREPASS_PASS
         gl_FragColor = float2vec4(vLinearDepth);
     #endif
+
+    #include "litUserMainEndPS"
 }
 `;

src/scene/shader-lib/chunks/lit/frag/pass-shadow/litShadowMain.js

@@ -11,6 +11,9 @@ export default /* glsl */`
 #endif
 
 void main(void) {
+
+    #include "litUserMainStartPS"
+
     evaluateFrontend();
 
     // using non-standard depth, i.e gl_FragCoord.z
@@ -53,5 +56,7 @@ void main(void) {
             gl_FragColor = vec4(1.0);
         #endif
     #endif
+
+    #include "litUserMainEndPS"
 }
 `;

src/scene/shader-lib/chunks/lit/vert/litMain.js

@@ -1,5 +1,10 @@
 // main shader of the lit vertex shader
 export default /* glsl */`
+
+#include "varyingsVS"
+
+#include  "litUserDeclarationVS"
+
 #ifdef VERTEX_COLOR
     attribute vec4 vertex_color;
 #endif
@@ -56,7 +61,12 @@ mat4 dModelMatrix;
     #include "msdfVS"
 #endif
 
+#include  "litUserCodeVS"
+
 void main(void) {
+
+    #include "litUserMainStartVS"
+
     gl_Position = getPosition();
     vPositionW = getWorldPosition();
 
@@ -100,5 +110,7 @@ void main(void) {
     #ifdef MSDF
         unpackMsdfParams();
     #endif
+
+    #include "litUserMainEndVS"
 }
 `;

src/scene/shader-lib/programs/lit-shader-options.js

@@ -93,13 +93,6 @@ class LitShaderOptions {
 
     diffuseMapEnabled = false;
 
-    /**
-     * Replaced the whole fragment shader with this string.
-     *
-     * @type {string}
-     */
-    customFragmentShader = null;
-
     pixelSnap = false;
 
     /**