Many fixes regarding depth buffer clearing, closes #25994, closes #25975

drivers/gles3/rasterizer_scene_gles3.cpp

@@ -3286,6 +3286,16 @@ void RasterizerSceneGLES3::_render_mrts(Environment *env, const CameraMatrix &p_
 	glDisable(GL_CULL_FACE);
 	glDisable(GL_BLEND);
 
+	if (!state.used_depth_prepass_and_resolved) {
+		//resolve depth buffer
+		glBindFramebuffer(GL_READ_FRAMEBUFFER, storage->frame.current_rt->buffers.fbo);
+		glReadBuffer(GL_COLOR_ATTACHMENT0);
+		glBindFramebuffer(GL_DRAW_FRAMEBUFFER, storage->frame.current_rt->fbo);
+		glBlitFramebuffer(0, 0, storage->frame.current_rt->width, storage->frame.current_rt->height, 0, 0, storage->frame.current_rt->width, storage->frame.current_rt->height, GL_DEPTH_BUFFER_BIT, GL_NEAREST);
+		glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
+		glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
+	}
+
 	if (env->ssao_enabled || env->ssr_enabled) {
 
 		//copy normal and roughness to effect buffer
@@ -4138,6 +4148,7 @@ void RasterizerSceneGLES3::render_scene(const Transform &p_cam_transform, const
 	glDepthFunc(GL_LEQUAL);
 
 	state.used_contact_shadows = false;
+	state.used_depth_prepass_and_resolved = false;
 
 	for (int i = 0; i < p_light_cull_count; i++) {
 
@@ -4185,13 +4196,14 @@ void RasterizerSceneGLES3::render_scene(const Transform &p_cam_transform, const
 			//bind depth for read
 			glActiveTexture(GL_TEXTURE0 + storage->config.max_texture_image_units - 8);
 			glBindTexture(GL_TEXTURE_2D, storage->frame.current_rt->depth);
+			state.used_depth_prepass_and_resolved = true;
 		}
 
 		fb_cleared = true;
 		render_pass++;
-		state.using_contact_shadows = true;
+		state.used_depth_prepass = true;
 	} else {
-		state.using_contact_shadows = false;
+		state.used_depth_prepass = false;
 	}
 
 	_setup_lights(p_light_cull_result, p_light_cull_count, p_cam_transform.affine_inverse(), p_cam_projection, p_shadow_atlas);
@@ -4288,7 +4300,8 @@ void RasterizerSceneGLES3::render_scene(const Transform &p_cam_transform, const
 	}
 
 	if (!fb_cleared) {
-		glClearBufferfi(GL_DEPTH, 0, 1.0, 0);
+		glClearDepth(1.0f);
+		glClear(GL_DEPTH_BUFFER_BIT);
 	}
 
 	Color clear_color(0, 0, 0, 0);
@@ -4438,6 +4451,7 @@ void RasterizerSceneGLES3::render_scene(const Transform &p_cam_transform, const
 	//state.scene_shader.set_conditional( SceneShaderGLES3::USE_FOG,false);
 
 	if (use_mrt) {
+
 		_render_mrts(env, p_cam_projection);
 	} else {
 		//FIXME: check that this is possible to use
@@ -4562,7 +4576,7 @@ void RasterizerSceneGLES3::render_shadow(RID p_light, RID p_shadow_atlas, int p_
 	float bias = 0;
 	float normal_bias = 0;
 
-	state.using_contact_shadows = false;
+	state.used_depth_prepass = false;
 
 	CameraMatrix light_projection;
 	Transform light_transform;

drivers/gles3/rasterizer_scene_gles3.h

@@ -205,7 +205,8 @@ public:
 		bool used_sss;
 		bool used_screen_texture;
 		bool used_depth_texture;
-		bool using_contact_shadows;
+		bool used_depth_prepass;
+		bool used_depth_prepass_and_resolved;
 
 		VS::ViewportDebugDraw debug_draw;
 	} state;