Disable shadow map sampling when shadows are not used in GLES3

Fixes #20742

2 files changed, 15 insertions, 7 deletions

diff --git a/drivers/gles3/rasterizer_scene_gles3.cpp b/drivers/gles3/rasterizer_scene_gles3.cpp
index 9815936d1e..66ff0a1845 100644
--- a/drivers/gles3/rasterizer_scene_gles3.cpp
+++ b/drivers/gles3/rasterizer_scene_gles3.cpp
@@ -4147,7 +4147,11 @@ void RasterizerSceneGLES3::render_scene(const Transform &p_cam_transform, const
 	ShadowAtlas *shadow_atlas = shadow_atlas_owner.getornull(p_shadow_atlas);
 	ReflectionAtlas *reflection_atlas = reflection_atlas_owner.getornull(p_reflection_atlas);
 
-	if (shadow_atlas && shadow_atlas->size) {
+	bool use_shadows = shadow_atlas && shadow_atlas->size;
+
+	state.scene_shader.set_conditional(SceneShaderGLES3::USE_SHADOW, use_shadows);
+
+	if (use_shadows) {
 		glActiveTexture(GL_TEXTURE0 + storage->config.max_texture_image_units - 5);
 		glBindTexture(GL_TEXTURE_2D, shadow_atlas->depth);
 		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE, GL_COMPARE_REF_TO_TEXTURE);
@@ -4521,15 +4525,15 @@ void RasterizerSceneGLES3::render_scene(const Transform &p_cam_transform, const
 
 	if (state.directional_light_count == 0) {
 		directional_light = NULL;
-		_render_list(render_list.elements, render_list.element_count, p_cam_transform, p_cam_projection, sky, false, false, false, false, shadow_atlas != NULL);
+		_render_list(render_list.elements, render_list.element_count, p_cam_transform, p_cam_projection, sky, false, false, false, false, use_shadows);
 	} else {
 		for (int i = 0; i < state.directional_light_count; i++) {
 			directional_light = directional_lights[i];
 			if (i > 0) {
 				glEnable(GL_BLEND);
 			}
-			_setup_directional_light(i, p_cam_transform.affine_inverse(), shadow_atlas != NULL && shadow_atlas->size > 0);
-			_render_list(render_list.elements, render_list.element_count, p_cam_transform, p_cam_projection, sky, false, false, false, i > 0, shadow_atlas != NULL);
+			_setup_directional_light(i, p_cam_transform.affine_inverse(), use_shadows);
+			_render_list(render_list.elements, render_list.element_count, p_cam_transform, p_cam_projection, sky, false, false, false, i > 0, use_shadows);
 		}
 	}
 
@@ -4607,12 +4611,12 @@ void RasterizerSceneGLES3::render_scene(const Transform &p_cam_transform, const
 
 	if (state.directional_light_count == 0) {
 		directional_light = NULL;
-		_render_list(&render_list.elements[render_list.max_elements - render_list.alpha_element_count], render_list.alpha_element_count, p_cam_transform, p_cam_projection, sky, false, true, false, false, shadow_atlas != NULL);
+		_render_list(&render_list.elements[render_list.max_elements - render_list.alpha_element_count], render_list.alpha_element_count, p_cam_transform, p_cam_projection, sky, false, true, false, false, use_shadows);
 	} else {
 		for (int i = 0; i < state.directional_light_count; i++) {
 			directional_light = directional_lights[i];
-			_setup_directional_light(i, p_cam_transform.affine_inverse(), shadow_atlas != NULL && shadow_atlas->size > 0);
-			_render_list(&render_list.elements[render_list.max_elements - render_list.alpha_element_count], render_list.alpha_element_count, p_cam_transform, p_cam_projection, sky, false, true, false, i > 0, shadow_atlas != NULL);
+			_setup_directional_light(i, p_cam_transform.affine_inverse(), use_shadows);
+			_render_list(&render_list.elements[render_list.max_elements - render_list.alpha_element_count], render_list.alpha_element_count, p_cam_transform, p_cam_projection, sky, false, true, false, i > 0, use_shadows);
 		}
 	}
 
diff --git a/drivers/gles3/shaders/scene.glsl b/drivers/gles3/shaders/scene.glsl
index e1b0e9f595..088fa12592 100644
--- a/drivers/gles3/shaders/scene.glsl
+++ b/drivers/gles3/shaders/scene.glsl
@@ -1256,6 +1256,7 @@ void light_process_omni(int idx, vec3 vertex, vec3 eye_vec, vec3 normal, vec3 bi
 	vec3 light_attenuation = vec3(omni_attenuation);
 
 #if !defined(SHADOWS_DISABLED)
+#ifdef USE_SHADOW
 	if (omni_lights[idx].light_params.w > 0.5) {
 		// there is a shadowmap
 
@@ -1300,6 +1301,7 @@ void light_process_omni(int idx, vec3 vertex, vec3 eye_vec, vec3 normal, vec3 bi
 #endif
 		light_attenuation *= mix(omni_lights[idx].shadow_color_contact.rgb, vec3(1.0), shadow);
 	}
+#endif //USE_SHADOW
 #endif //SHADOWS_DISABLED
 	light_compute(normal, normalize(light_rel_vec), eye_vec, binormal, tangent, omni_lights[idx].light_color_energy.rgb, light_attenuation, albedo, transmission, omni_lights[idx].light_params.z * p_blob_intensity, roughness, metallic, specular, rim * omni_attenuation, rim_tint, clearcoat, clearcoat_gloss, anisotropy, diffuse_light, specular_light, alpha);
 }
@@ -1318,6 +1320,7 @@ void light_process_spot(int idx, vec3 vertex, vec3 eye_vec, vec3 normal, vec3 bi
 	vec3 light_attenuation = vec3(spot_attenuation);
 
 #if !defined(SHADOWS_DISABLED)
+#ifdef USE_SHADOW
 	if (spot_lights[idx].light_params.w > 0.5) {
 		//there is a shadowmap
 		highp vec4 splane = (spot_lights[idx].shadow_matrix * vec4(vertex, 1.0));
@@ -1334,6 +1337,7 @@ void light_process_spot(int idx, vec3 vertex, vec3 eye_vec, vec3 normal, vec3 bi
 #endif
 		light_attenuation *= mix(spot_lights[idx].shadow_color_contact.rgb, vec3(1.0), shadow);
 	}
+#endif //USE_SHADOW
 #endif //SHADOWS_DISABLED
 
 	light_compute(normal, normalize(light_rel_vec), eye_vec, binormal, tangent, spot_lights[idx].light_color_energy.rgb, light_attenuation, albedo, transmission, spot_lights[idx].light_params.z * p_blob_intensity, roughness, metallic, specular, rim * spot_attenuation, rim_tint, clearcoat, clearcoat_gloss, anisotropy, diffuse_light, specular_light, alpha);