Shader with instance uniforms fails in compatibility

[mooflu]

Tested versions

v4.4.dev4.official [36e6207]

System information

Godot v4.4.dev4 - Windows 10.0.22631 - Multi-window, 2 monitors - OpenGL 3 (Compatibility) - NVIDIA GeForce RTX 2070 SUPER (NVIDIA; 32.0.15.6094) - 13th Gen Intel(R) Core(TM) i7-13700KF (24 threads)

Issue description

Attached project uses both a global and 2 instance uniforms.

Actual error is:

E 0:00:01:0046   _display_error_with_code: SceneShaderGLES3: Fragment shader compilation failed:
0(445) : error C1503: undefined variable "instance_offset"

Looks like definition is after use.
From the output log (filtered by instance_offset):

445: 		vec2 m_d=vec2((((global_shader_uniforms[m_iTime].x) * 0.00050000002375) + (global_shader_uniforms[(instance_offset+1u)].x)), 0.0);
672: uniform highp uint instance_offset;

Steps to reproduce

Run attached project.

Minimal reproduction project (MRP)

instance-test.zip

[peterdang1502]

looked into this a little bit and correct me if i'm wrong but i believe the error is coming from one of these function calls

godot/drivers/gles3/shader_gles3.cpp

Lines 373 to 376 in eb51030

	glShaderSource(spec.frag_id, 1, &cstr, nullptr);
	glCompileShader(spec.frag_id);
	glGetShaderiv(spec.frag_id, GL_COMPILE_STATUS, &status);

which are OpenGL functions. not too sure how to proceed from here

[mooflu]

It's a shader source compile error. Godot generates the shader code from a template. See https://github.com/godotengine/godot/blob/master/drivers/gles3/shaders/scene.glsl

If I move the declaration for instance_offset up, it works.
I can make a PR for the diff below, but I'm not sure if I moved it to a "good" place (right after scene_data) and/or if the other variables in that block should maybe be moved, too.

diff --git a/drivers/gles3/shaders/scene.glsl b/drivers/gles3/shaders/scene.glsl
index 2022c8ee43..778c4f953d 100644
--- a/drivers/gles3/shaders/scene.glsl
+++ b/drivers/gles3/shaders/scene.glsl
@@ -206,6 +206,8 @@ layout(std140) uniform SceneData { // ubo:2
 }
 scene_data;
 
+uniform highp uint instance_offset;
+
 #ifdef USE_ADDITIVE_LIGHTING
 
 #if defined(ADDITIVE_OMNI) || defined(ADDITIVE_SPOT)
@@ -430,7 +432,6 @@ uniform highp mat4 world_transform;
 uniform highp vec3 compressed_aabb_position;
 uniform highp vec3 compressed_aabb_size;
 uniform highp vec4 uv_scale;
-uniform highp uint instance_offset;
 
 uniform highp uint model_flags;
 
@@ -965,6 +966,8 @@ layout(std140) uniform SceneData { // ubo:2
 }
 scene_data;
 
+uniform highp uint instance_offset;
+
 #ifdef USE_MULTIVIEW
 layout(std140) uniform MultiviewData { // ubo:8
        highp mat4 projection_matrix_view[MAX_VIEWS];
@@ -1202,7 +1205,6 @@ ivec2 multiview_uv(ivec2 uv) {
 uniform highp mat4 world_transform;
 uniform mediump float opaque_prepass_threshold;
 uniform highp uint model_flags;
-uniform highp uint instance_offset;
 
 #if defined(RENDER_MATERIAL)
 layout(location = 0) out vec4 albedo_output_buffer;