From 24b58c655a28cb545f51eefd498dfb9493baca1e Mon Sep 17 00:00:00 2001
From: Per Melin <git@melin.net>
Date: Sat, 2 Mar 2024 18:39:24 +0100
Subject: [PATCH] Fix USERDATA built-ins for GLES3 particle shaders

---
 drivers/gles3/shaders/particles.glsl        | 30 ++++++++++++++++-----
 drivers/gles3/storage/particles_storage.cpp |  6 +++--
 2 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/drivers/gles3/shaders/particles.glsl b/drivers/gles3/shaders/particles.glsl
index 64ef26b0756c..d95f7f430996 100644
--- a/drivers/gles3/shaders/particles.glsl
+++ b/drivers/gles3/shaders/particles.glsl
@@ -112,22 +112,22 @@ layout(location = 4) in highp vec4 xform_2;
 layout(location = 5) in highp vec4 xform_3;
 #endif
 #ifdef USERDATA1_USED
-layout(location = 6) in highp vec4 userdata1;
+in highp vec4 userdata1;
 #endif
 #ifdef USERDATA2_USED
-layout(location = 7) in highp vec4 userdata2;
+in highp vec4 userdata2;
 #endif
 #ifdef USERDATA3_USED
-layout(location = 8) in highp vec4 userdata3;
+in highp vec4 userdata3;
 #endif
 #ifdef USERDATA4_USED
-layout(location = 9) in highp vec4 userdata4;
+in highp vec4 userdata4;
 #endif
 #ifdef USERDATA5_USED
-layout(location = 10) in highp vec4 userdata5;
+in highp vec4 userdata5;
 #endif
 #ifdef USERDATA6_USED
-layout(location = 11) in highp vec4 userdata6;
+in highp vec4 userdata6;
 #endif
 
 out highp vec4 out_color; //tfb:
@@ -219,6 +219,24 @@ void main() {
 #endif
 		xform = transpose(xform);
 		flags = floatBitsToUint(velocity_flags.w);
+#ifdef USERDATA1_USED
+		out_userdata1 = userdata1;
+#endif
+#ifdef USERDATA2_USED
+		out_userdata2 = userdata2;
+#endif
+#ifdef USERDATA3_USED
+		out_userdata3 = userdata3;
+#endif
+#ifdef USERDATA4_USED
+		out_userdata4 = userdata4;
+#endif
+#ifdef USERDATA5_USED
+		out_userdata5 = userdata5;
+#endif
+#ifdef USERDATA6_USED
+		out_userdata6 = userdata6;
+#endif
 	}
 
 	//clear started flag if set
diff --git a/drivers/gles3/storage/particles_storage.cpp b/drivers/gles3/storage/particles_storage.cpp
index c5a97bdbd51e..8e48d0695ae2 100644
--- a/drivers/gles3/storage/particles_storage.cpp
+++ b/drivers/gles3/storage/particles_storage.cpp
@@ -728,8 +728,10 @@ void ParticlesStorage::_particles_process(Particles *p_particles, double p_delta
 	ParticlesShaderGLES3::ShaderVariant variant = ParticlesShaderGLES3::MODE_DEFAULT;
 
 	uint32_t specialization = 0;
-	for (uint32_t i = 0; i < p_particles->userdata_count; i++) {
-		specialization |= (1 << i);
+	for (uint32_t i = 0; i < PARTICLES_MAX_USERDATAS; i++) {
+		if (m->shader_data->userdatas_used[i]) {
+			specialization |= ParticlesShaderGLES3::USERDATA1_USED << i;
+		}
 	}
 
 	if (p_particles->mode == RS::ParticlesMode::PARTICLES_MODE_3D) {