Merge pull request #33668 from clayjohn/Fix_environment_mapping_issues

Fix issues with environment mapping

7 files changed, 285 insertions, 63 deletions

diff --git a/drivers/gles2/shaders/scene.glsl b/drivers/gles2/shaders/scene.glsl
index e36e776881..2a220658a1 100644
--- a/drivers/gles2/shaders/scene.glsl
+++ b/drivers/gles2/shaders/scene.glsl
@@ -1547,7 +1547,11 @@ FRAGMENT_SHADER_CODE
 #endif // !USE_SHADOW_TO_OPACITY
 
 #ifdef BASE_PASS
-	//none
+
+	// IBL precalculations
+	float ndotv = clamp(dot(normal, eye_position), 0.0, 1.0);
+	vec3 f0 = F0(metallic, specular, albedo);
+	vec3 F = f0 + (max(vec3(1.0 - roughness), f0) - f0) * pow(1.0 - ndotv, 5.0);
 
 #ifdef AMBIENT_LIGHT_DISABLED
 	ambient_light = vec3(0.0, 0.0, 0.0);
@@ -1561,12 +1565,15 @@ FRAGMENT_SHADER_CODE
 	ref_vec.z *= -1.0;
 
 	specular_light = textureCubeLod(radiance_map, ref_vec, roughness * RADIANCE_MAX_LOD).xyz * bg_energy;
+#ifndef USE_LIGHTMAP
 	{
 		vec3 ambient_dir = normalize((radiance_inverse_xform * vec4(normal, 0.0)).xyz);
-		vec3 env_ambient = textureCubeLod(radiance_map, ambient_dir, RADIANCE_MAX_LOD).xyz * bg_energy;
+		vec3 env_ambient = textureCubeLod(radiance_map, ambient_dir, 4.0).xyz * bg_energy;
+		env_ambient *= 1.0 - F;
 
 		ambient_light = mix(ambient_color.rgb, env_ambient, ambient_sky_contribution);
 	}
+#endif
 
 #else
 
@@ -1574,7 +1581,6 @@ FRAGMENT_SHADER_CODE
 	specular_light = bg_color.rgb * bg_energy;
 
 #endif
-
 #endif // AMBIENT_LIGHT_DISABLED
 	ambient_light *= ambient_energy;
 
@@ -1646,12 +1652,9 @@ FRAGMENT_SHADER_CODE
 		const vec4 c0 = vec4(-1.0, -0.0275, -0.572, 0.022);
 		const vec4 c1 = vec4(1.0, 0.0425, 1.04, -0.04);
 		vec4 r = roughness * c0 + c1;
-		float ndotv = clamp(dot(normal, eye_position), 0.0, 1.0);
 		float a004 = min(r.x * r.x, exp2(-9.28 * ndotv)) * r.x + r.y;
 		vec2 env = vec2(-1.04, 1.04) * a004 + r.zw;
-
-		vec3 f0 = F0(metallic, specular, albedo);
-		specular_light *= env.x * f0 + env.y;
+		specular_light *= env.x * F + env.y;
 
 #endif
 	}
diff --git a/drivers/gles3/rasterizer_scene_gles3.cpp b/drivers/gles3/rasterizer_scene_gles3.cpp
index 0820997529..9815936d1e 100644
--- a/drivers/gles3/rasterizer_scene_gles3.cpp
+++ b/drivers/gles3/rasterizer_scene_gles3.cpp
@@ -2011,7 +2011,7 @@ void RasterizerSceneGLES3::_set_cull(bool p_front, bool p_disabled, bool p_rever
 	}
 }
 
-void RasterizerSceneGLES3::_render_list(RenderList::Element **p_elements, int p_element_count, const Transform &p_view_transform, const CameraMatrix &p_projection, GLuint p_base_env, bool p_reverse_cull, bool p_alpha_pass, bool p_shadow, bool p_directional_add, bool p_directional_shadows) {
+void RasterizerSceneGLES3::_render_list(RenderList::Element **p_elements, int p_element_count, const Transform &p_view_transform, const CameraMatrix &p_projection, RasterizerStorageGLES3::Sky *p_sky, bool p_reverse_cull, bool p_alpha_pass, bool p_shadow, bool p_directional_add, bool p_directional_shadows) {
 
 	glBindBufferBase(GL_UNIFORM_BUFFER, 0, state.scene_ubo); //bind globals ubo
 
@@ -2019,14 +2019,15 @@ void RasterizerSceneGLES3::_render_list(RenderList::Element **p_elements, int p_
 	if (!p_shadow && !p_directional_add) {
 		glBindBufferBase(GL_UNIFORM_BUFFER, 2, state.env_radiance_ubo); //bind environment radiance info
 
-		if (p_base_env) {
+		if (p_sky != NULL) {
 			glActiveTexture(GL_TEXTURE0 + storage->config.max_texture_image_units - 2);
 			if (storage->config.use_texture_array_environment) {
-				glBindTexture(GL_TEXTURE_2D_ARRAY, p_base_env);
+				glBindTexture(GL_TEXTURE_2D_ARRAY, p_sky->radiance);
 			} else {
-				glBindTexture(GL_TEXTURE_2D, p_base_env);
+				glBindTexture(GL_TEXTURE_2D, p_sky->radiance);
 			}
-
+			glActiveTexture(GL_TEXTURE0 + storage->config.max_texture_image_units - 6);
+			glBindTexture(GL_TEXTURE_2D, p_sky->irradiance);
 			state.scene_shader.set_conditional(SceneShaderGLES3::USE_RADIANCE_MAP, true);
 			state.scene_shader.set_conditional(SceneShaderGLES3::USE_RADIANCE_MAP_ARRAY, storage->config.use_texture_array_environment);
 			use_radiance_map = true;
@@ -4231,7 +4232,7 @@ void RasterizerSceneGLES3::render_scene(const Transform &p_cam_transform, const
 		_fill_render_list(p_cull_result, p_cull_count, true, false);
 		render_list.sort_by_key(false);
 		state.scene_shader.set_conditional(SceneShaderGLES3::RENDER_DEPTH, true);
-		_render_list(render_list.elements, render_list.element_count, p_cam_transform, p_cam_projection, 0, false, false, true, false, false);
+		_render_list(render_list.elements, render_list.element_count, p_cam_transform, p_cam_projection, NULL, false, false, true, false, false);
 		state.scene_shader.set_conditional(SceneShaderGLES3::RENDER_DEPTH, false);
 
 		glColorMask(1, 1, 1, 1);
@@ -4355,7 +4356,6 @@ void RasterizerSceneGLES3::render_scene(const Transform &p_cam_transform, const
 
 	RasterizerStorageGLES3::Sky *sky = NULL;
 	Ref<CameraFeed> feed;
-	GLuint env_radiance_tex = 0;
 
 	if (state.debug_draw == VS::VIEWPORT_DEBUG_DRAW_OVERDRAW) {
 		clear_color = Color(0, 0, 0, 0);
@@ -4409,9 +4409,6 @@ void RasterizerSceneGLES3::render_scene(const Transform &p_cam_transform, const
 
 				sky = storage->sky_owner.getornull(env->sky);
 
-				if (sky) {
-					env_radiance_tex = sky->radiance;
-				}
 				break;
 			case VS::ENV_BG_CANVAS:
 				//copy canvas to 3d buffer and convert it to linear
@@ -4505,7 +4502,7 @@ void RasterizerSceneGLES3::render_scene(const Transform &p_cam_transform, const
 	}
 
 	if (probe && probe->probe_ptr->interior) {
-		env_radiance_tex = 0; //for rendering probe interiors, radiance must not be used.
+		sky = NULL; //for rendering probe interiors, radiance must not be used.
 	}
 
 	state.texscreen_copied = false;
@@ -4524,7 +4521,7 @@ 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, env_radiance_tex, 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, shadow_atlas != NULL);
 	} else {
 		for (int i = 0; i < state.directional_light_count; i++) {
 			directional_light = directional_lights[i];
@@ -4532,7 +4529,7 @@ void RasterizerSceneGLES3::render_scene(const Transform &p_cam_transform, const
 				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, env_radiance_tex, false, false, false, i > 0, shadow_atlas != NULL);
+			_render_list(render_list.elements, render_list.element_count, p_cam_transform, p_cam_projection, sky, false, false, false, i > 0, shadow_atlas != NULL);
 		}
 	}
 
@@ -4610,12 +4607,12 @@ 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, env_radiance_tex, 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, shadow_atlas != NULL);
 	} 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, env_radiance_tex, false, true, false, i > 0, 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, i > 0, shadow_atlas != NULL);
 		}
 	}
 
@@ -4898,7 +4895,7 @@ void RasterizerSceneGLES3::render_shadow(RID p_light, RID p_shadow_atlas, int p_
 	if (light->reverse_cull) {
 		flip_facing = !flip_facing;
 	}
-	_render_list(render_list.elements, render_list.element_count, light_transform, light_projection, 0, flip_facing, false, true, false, false);
+	_render_list(render_list.elements, render_list.element_count, light_transform, light_projection, NULL, flip_facing, false, true, false, false);
 
 	state.scene_shader.set_conditional(SceneShaderGLES3::RENDER_DEPTH, false);
 	state.scene_shader.set_conditional(SceneShaderGLES3::RENDER_DEPTH_DUAL_PARABOLOID, false);
diff --git a/drivers/gles3/rasterizer_scene_gles3.h b/drivers/gles3/rasterizer_scene_gles3.h
index e6d2449653..a756ce251e 100644
--- a/drivers/gles3/rasterizer_scene_gles3.h
+++ b/drivers/gles3/rasterizer_scene_gles3.h
@@ -837,7 +837,7 @@ public:
 	_FORCE_INLINE_ void _render_geometry(RenderList::Element *e);
 	_FORCE_INLINE_ void _setup_light(RenderList::Element *e, const Transform &p_view_transform);
 
-	void _render_list(RenderList::Element **p_elements, int p_element_count, const Transform &p_view_transform, const CameraMatrix &p_projection, GLuint p_base_env, bool p_reverse_cull, bool p_alpha_pass, bool p_shadow, bool p_directional_add, bool p_directional_shadows);
+	void _render_list(RenderList::Element **p_elements, int p_element_count, const Transform &p_view_transform, const CameraMatrix &p_projection, RasterizerStorageGLES3::Sky *p_sky, bool p_reverse_cull, bool p_alpha_pass, bool p_shadow, bool p_directional_add, bool p_directional_shadows);
 
 	_FORCE_INLINE_ void _add_geometry(RasterizerStorageGLES3::Geometry *p_geometry, InstanceBase *p_instance, RasterizerStorageGLES3::GeometryOwner *p_owner, int p_material, bool p_depth_pass, bool p_shadow_pass);
 
diff --git a/drivers/gles3/rasterizer_storage_gles3.cpp b/drivers/gles3/rasterizer_storage_gles3.cpp
index 625bfb4554..71a3a79eb3 100644
--- a/drivers/gles3/rasterizer_storage_gles3.cpp
+++ b/drivers/gles3/rasterizer_storage_gles3.cpp
@@ -1757,6 +1757,7 @@ RID RasterizerStorageGLES3::sky_create() {
 
 	Sky *sky = memnew(Sky);
 	sky->radiance = 0;
+	sky->irradiance = 0;
 	return sky_owner.make_rid(sky);
 }
 
@@ -1768,7 +1769,9 @@ void RasterizerStorageGLES3::sky_set_texture(RID p_sky, RID p_panorama, int p_ra
 	if (sky->panorama.is_valid()) {
 		sky->panorama = RID();
 		glDeleteTextures(1, &sky->radiance);
+		glDeleteTextures(1, &sky->irradiance);
 		sky->radiance = 0;
+		sky->irradiance = 0;
 	}
 
 	sky->panorama = p_panorama;
@@ -1791,10 +1794,14 @@ void RasterizerStorageGLES3::sky_set_texture(RID p_sky, RID p_panorama, int p_ra
 
 	glActiveTexture(GL_TEXTURE0);
 	glBindTexture(texture->target, texture->tex_id);
-	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
-	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
-	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
-	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); //need this for proper sampling
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 0);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 10);
+	// Need Mipmaps regardless of whether they are set in import by user
+	glGenerateMipmap(texture->target);
+	glTexParameterf(texture->target, GL_TEXTURE_WRAP_S, GL_REPEAT);
+	glTexParameterf(texture->target, GL_TEXTURE_WRAP_T, GL_REPEAT);
+	glTexParameterf(texture->target, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
+	glTexParameterf(texture->target, GL_TEXTURE_MAG_FILTER, GL_LINEAR_MIPMAP_LINEAR);
 
 	if (config.srgb_decode_supported && texture->srgb && !texture->using_srgb) {
 
@@ -1808,6 +1815,66 @@ void RasterizerStorageGLES3::sky_set_texture(RID p_sky, RID p_panorama, int p_ra
 #endif
 	}
 
+	{
+		//Irradiance map
+		glActiveTexture(GL_TEXTURE1);
+		glGenTextures(1, &sky->irradiance);
+		glBindTexture(GL_TEXTURE_2D, sky->irradiance);
+
+		GLuint tmp_fb;
+
+		glGenFramebuffers(1, &tmp_fb);
+		glBindFramebuffer(GL_FRAMEBUFFER, tmp_fb);
+
+		int size = 64;
+
+		bool use_float = config.framebuffer_half_float_supported;
+
+		GLenum internal_format = use_float ? GL_RGBA16F : GL_RGB10_A2;
+		GLenum format = GL_RGBA;
+		GLenum type = use_float ? GL_HALF_FLOAT : GL_UNSIGNED_INT_2_10_10_10_REV;
+
+		glTexImage2D(GL_TEXTURE_2D, 0, internal_format, size, size * 2, 0, format, type, NULL);
+
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 0);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 0);
+		glTexParameterf(texture->target, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+		glTexParameterf(texture->target, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+
+		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+
+		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, sky->irradiance, 0);
+
+		shaders.cubemap_filter.set_conditional(CubemapFilterShaderGLES3::USE_DUAL_PARABOLOID, true);
+		shaders.cubemap_filter.set_conditional(CubemapFilterShaderGLES3::USE_SOURCE_PANORAMA, true);
+		shaders.cubemap_filter.set_conditional(CubemapFilterShaderGLES3::COMPUTE_IRRADIANCE, true);
+		shaders.cubemap_filter.bind();
+
+		// Very large Panoramas require way too much effort to compute irradiance so use a mipmap
+		// level that corresponds to a panorama of 1024x512
+		shaders.cubemap_filter.set_uniform(CubemapFilterShaderGLES3::SOURCE_MIP_LEVEL, MAX(Math::log(float(texture->width)) / Math::log(2.0f) - 10.0f, 0.0f));
+
+		for (int i = 0; i < 2; i++) {
+			glViewport(0, i * size, size, size);
+			glBindVertexArray(resources.quadie_array);
+
+			shaders.cubemap_filter.set_uniform(CubemapFilterShaderGLES3::Z_FLIP, i > 0);
+
+			glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
+			glBindVertexArray(0);
+		}
+
+		shaders.cubemap_filter.set_conditional(CubemapFilterShaderGLES3::USE_DUAL_PARABOLOID, false);
+		shaders.cubemap_filter.set_conditional(CubemapFilterShaderGLES3::USE_SOURCE_PANORAMA, false);
+		shaders.cubemap_filter.set_conditional(CubemapFilterShaderGLES3::COMPUTE_IRRADIANCE, false);
+
+		glBindFramebuffer(GL_FRAMEBUFFER, RasterizerStorageGLES3::system_fbo);
+		glDeleteFramebuffers(1, &tmp_fb);
+	}
+
+	// Now compute radiance
+
 	glActiveTexture(GL_TEXTURE1);
 	glGenTextures(1, &sky->radiance);
 
@@ -1833,8 +1900,8 @@ void RasterizerStorageGLES3::sky_set_texture(RID p_sky, RID p_panorama, int p_ra
 
 		glTexImage3D(GL_TEXTURE_2D_ARRAY, 0, internal_format, size, size * 2, array_level, 0, format, type, NULL);
 
-		glTexParameterf(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
-		glTexParameterf(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+		glTexParameterf(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+		glTexParameterf(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 
 		GLuint tmp_fb2;
 		GLuint tmp_tex;
@@ -1846,8 +1913,8 @@ void RasterizerStorageGLES3::sky_set_texture(RID p_sky, RID p_panorama, int p_ra
 			glBindTexture(GL_TEXTURE_2D, tmp_tex);
 			glTexImage2D(GL_TEXTURE_2D, 0, internal_format, size, size * 2, 0, format, type, NULL);
 			glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, tmp_tex, 0);
-			glTexParameterf(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
-			glTexParameterf(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+			glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+			glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 #ifdef DEBUG_ENABLED
 			GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
 			ERR_FAIL_COND(status != GL_FRAMEBUFFER_COMPLETE);
@@ -1858,25 +1925,25 @@ void RasterizerStorageGLES3::sky_set_texture(RID p_sky, RID p_panorama, int p_ra
 
 			glBindFramebuffer(GL_FRAMEBUFFER, tmp_fb2);
 
-			if (j == 0) {
+			if (j < 3) {
 
 				shaders.cubemap_filter.set_conditional(CubemapFilterShaderGLES3::USE_DUAL_PARABOLOID, true);
 				shaders.cubemap_filter.set_conditional(CubemapFilterShaderGLES3::USE_SOURCE_PANORAMA, true);
-				shaders.cubemap_filter.set_conditional(CubemapFilterShaderGLES3::USE_DIRECT_WRITE, true);
 				shaders.cubemap_filter.set_conditional(CubemapFilterShaderGLES3::USE_SOURCE_DUAL_PARABOLOID_ARRAY, false);
 				shaders.cubemap_filter.bind();
 				glActiveTexture(GL_TEXTURE0);
 				glBindTexture(texture->target, texture->tex_id);
+				shaders.cubemap_filter.set_uniform(CubemapFilterShaderGLES3::SOURCE_RESOLUTION, float(texture->width / 4));
 			} else {
 
 				shaders.cubemap_filter.set_conditional(CubemapFilterShaderGLES3::USE_DUAL_PARABOLOID, true);
 				shaders.cubemap_filter.set_conditional(CubemapFilterShaderGLES3::USE_SOURCE_PANORAMA, false);
 				shaders.cubemap_filter.set_conditional(CubemapFilterShaderGLES3::USE_SOURCE_DUAL_PARABOLOID_ARRAY, true);
-				shaders.cubemap_filter.set_conditional(CubemapFilterShaderGLES3::USE_DIRECT_WRITE, false);
 				shaders.cubemap_filter.bind();
 				glActiveTexture(GL_TEXTURE0);
 				glBindTexture(GL_TEXTURE_2D_ARRAY, sky->radiance);
 				shaders.cubemap_filter.set_uniform(CubemapFilterShaderGLES3::SOURCE_ARRAY_INDEX, j - 1); //read from previous to ensure better blur
+				shaders.cubemap_filter.set_uniform(CubemapFilterShaderGLES3::SOURCE_RESOLUTION, float(size / 2));
 			}
 
 			for (int i = 0; i < 2; i++) {
@@ -1902,7 +1969,6 @@ void RasterizerStorageGLES3::sky_set_texture(RID p_sky, RID p_panorama, int p_ra
 		shaders.cubemap_filter.set_conditional(CubemapFilterShaderGLES3::USE_SOURCE_PANORAMA, false);
 		shaders.cubemap_filter.set_conditional(CubemapFilterShaderGLES3::USE_DUAL_PARABOLOID, false);
 		shaders.cubemap_filter.set_conditional(CubemapFilterShaderGLES3::USE_SOURCE_DUAL_PARABOLOID_ARRAY, false);
-		shaders.cubemap_filter.set_conditional(CubemapFilterShaderGLES3::USE_DIRECT_WRITE, false);
 
 		//restore ranges
 		glActiveTexture(GL_TEXTURE0);
@@ -1947,23 +2013,64 @@ void RasterizerStorageGLES3::sky_set_texture(RID p_sky, RID p_panorama, int p_ra
 
 		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 0);
 		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, mipmaps - 1);
+		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+
+		GLuint tmp_fb2;
+		GLuint tmp_tex;
+		{
+			// Need a temporary framebuffer for rendering so we can read from previous iterations
+			glGenFramebuffers(1, &tmp_fb2);
+			glBindFramebuffer(GL_FRAMEBUFFER, tmp_fb2);
+			glGenTextures(1, &tmp_tex);
+			glBindTexture(GL_TEXTURE_2D, tmp_tex);
+			glTexImage2D(GL_TEXTURE_2D, 0, internal_format, size, size * 2, 0, format, type, NULL);
+			glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, tmp_tex, 0);
+			glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+			glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+#ifdef DEBUG_ENABLED
+			GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
+			ERR_FAIL_COND(status != GL_FRAMEBUFFER_COMPLETE);
+#endif
+		}
 
 		lod = 0;
 		mm_level = mipmaps;
 
 		size = p_radiance_size;
 
-		shaders.cubemap_filter.set_conditional(CubemapFilterShaderGLES3::USE_DUAL_PARABOLOID, true);
-		shaders.cubemap_filter.set_conditional(CubemapFilterShaderGLES3::USE_SOURCE_PANORAMA, true);
-		shaders.cubemap_filter.bind();
-
 		while (mm_level) {
-
+			glBindFramebuffer(GL_FRAMEBUFFER, tmp_fb);
 			glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, sky->radiance, lod);
+
 #ifdef DEBUG_ENABLED
 			GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
 			ERR_CONTINUE(status != GL_FRAMEBUFFER_COMPLETE);
 #endif
+			glBindTexture(GL_TEXTURE_2D, tmp_tex);
+			glTexImage2D(GL_TEXTURE_2D, 0, internal_format, size, size * 2, 0, format, type, NULL);
+			glBindFramebuffer(GL_FRAMEBUFFER, tmp_fb2);
+			glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, tmp_tex, 0);
+			if (lod < 3) {
+
+				shaders.cubemap_filter.set_conditional(CubemapFilterShaderGLES3::USE_DUAL_PARABOLOID, true);
+				shaders.cubemap_filter.set_conditional(CubemapFilterShaderGLES3::USE_SOURCE_PANORAMA, true);
+				shaders.cubemap_filter.set_conditional(CubemapFilterShaderGLES3::USE_SOURCE_DUAL_PARABOLOID, false);
+				shaders.cubemap_filter.bind();
+				glActiveTexture(GL_TEXTURE0);
+				glBindTexture(texture->target, texture->tex_id);
+				shaders.cubemap_filter.set_uniform(CubemapFilterShaderGLES3::SOURCE_RESOLUTION, float(texture->width / 4));
+			} else {
+
+				shaders.cubemap_filter.set_conditional(CubemapFilterShaderGLES3::USE_DUAL_PARABOLOID, true);
+				shaders.cubemap_filter.set_conditional(CubemapFilterShaderGLES3::USE_SOURCE_PANORAMA, false);
+				shaders.cubemap_filter.set_conditional(CubemapFilterShaderGLES3::USE_SOURCE_DUAL_PARABOLOID, true);
+				shaders.cubemap_filter.bind();
+				glActiveTexture(GL_TEXTURE0);
+				glBindTexture(GL_TEXTURE_2D, sky->radiance);
+				shaders.cubemap_filter.set_uniform(CubemapFilterShaderGLES3::SOURCE_MIP_LEVEL, lod - 1); //read from previous to ensure better blur
+				shaders.cubemap_filter.set_uniform(CubemapFilterShaderGLES3::SOURCE_RESOLUTION, float(size));
+			}
 
 			for (int i = 0; i < 2; i++) {
 				glViewport(0, i * size, size, size);
@@ -1976,6 +2083,14 @@ void RasterizerStorageGLES3::sky_set_texture(RID p_sky, RID p_panorama, int p_ra
 				glBindVertexArray(0);
 			}
 
+			glBindFramebuffer(GL_DRAW_FRAMEBUFFER, tmp_fb);
+			glFramebufferTextureLayer(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, sky->radiance, 0, lod);
+			glBindFramebuffer(GL_READ_FRAMEBUFFER, tmp_fb2);
+			glReadBuffer(GL_COLOR_ATTACHMENT0);
+			glBlitFramebuffer(0, 0, size, size * 2, 0, 0, size, size * 2, GL_COLOR_BUFFER_BIT, GL_NEAREST);
+			glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
+			glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
+
 			if (size > 1)
 				size >>= 1;
 			lod++;
@@ -1995,6 +2110,8 @@ void RasterizerStorageGLES3::sky_set_texture(RID p_sky, RID p_panorama, int p_ra
 
 		glBindFramebuffer(GL_FRAMEBUFFER, RasterizerStorageGLES3::system_fbo);
 		glDeleteFramebuffers(1, &tmp_fb);
+		glDeleteFramebuffers(1, &tmp_fb2);
+		glDeleteTextures(1, &tmp_tex);
 	}
 }
 
diff --git a/drivers/gles3/rasterizer_storage_gles3.h b/drivers/gles3/rasterizer_storage_gles3.h
index 3b1021d0e1..350b259b2b 100644
--- a/drivers/gles3/rasterizer_storage_gles3.h
+++ b/drivers/gles3/rasterizer_storage_gles3.h
@@ -388,6 +388,7 @@ public:
 
 		RID panorama;
 		GLuint radiance;
+		GLuint irradiance;
 		int radiance_size;
 	};
 
diff --git a/drivers/gles3/shaders/cubemap_filter.glsl b/drivers/gles3/shaders/cubemap_filter.glsl
index 619e29b130..d83a109cb9 100644
--- a/drivers/gles3/shaders/cubemap_filter.glsl
+++ b/drivers/gles3/shaders/cubemap_filter.glsl
@@ -30,12 +30,22 @@ uniform sampler2DArray source_dual_paraboloid_array; //texunit:0
 uniform int source_array_index;
 #endif
 
-#if !defined(USE_SOURCE_DUAL_PARABOLOID_ARRAY) && !defined(USE_SOURCE_PANORAMA)
+#ifdef USE_SOURCE_DUAL_PARABOLOID
+uniform sampler2D source_dual_paraboloid; //texunit:0
+#endif
+
+#if defined(USE_SOURCE_DUAL_PARABOLOID) || defined(COMPUTE_IRRADIANCE)
+uniform int source_mip_level;
+#endif
+
+#if !defined(USE_SOURCE_DUAL_PARABOLOID_ARRAY) && !defined(USE_SOURCE_PANORAMA) && !defined(USE_SOURCE_DUAL_PARABOLOID)
 uniform samplerCube source_cube; //texunit:0
 #endif
 
 uniform int face_id;
 uniform float roughness;
+uniform float source_resolution;
+
 in highp vec2 uv_interp;
 
 layout(location = 0) out vec4 frag_color;
@@ -133,6 +143,19 @@ vec3 ImportanceSampleGGX(vec2 Xi, float Roughness, vec3 N) {
 	return TangentX * H.x + TangentY * H.y + N * H.z;
 }
 
+float DistributionGGX(vec3 N, vec3 H, float roughness) {
+	float a = roughness * roughness;
+	float a2 = a * a;
+	float NdotH = max(dot(N, H), 0.0);
+	float NdotH2 = NdotH * NdotH;
+
+	float nom = a2;
+	float denom = (NdotH2 * (a2 - 1.0) + 1.0);
+	denom = M_PI * denom * denom;
+
+	return nom / denom;
+}
+
 // http://graphicrants.blogspot.com.au/2013/08/specular-brdf-reference.html
 float GGX(float NdotV, float a) {
 	float k = a / 2.0;
@@ -160,10 +183,12 @@ vec2 Hammersley(uint i, uint N) {
 #ifdef LOW_QUALITY
 
 #define SAMPLE_COUNT 64u
+#define SAMPLE_DELTA 0.05
 
 #else
 
-#define SAMPLE_COUNT 1024u
+#define SAMPLE_COUNT 512u
+#define SAMPLE_DELTA 0.01
 
 #endif
 
@@ -171,7 +196,7 @@ uniform bool z_flip;
 
 #ifdef USE_SOURCE_PANORAMA
 
-vec4 texturePanorama(vec3 normal, sampler2D pano) {
+vec4 texturePanorama(vec3 normal, sampler2D pano, float mipLevel) {
 
 	vec2 st = vec2(
 			atan(normal.x, normal.z),
@@ -182,7 +207,7 @@ vec4 texturePanorama(vec3 normal, sampler2D pano) {
 
 	st /= vec2(M_PI * 2.0, M_PI);
 
-	return textureLod(pano, st, 0.0);
+	return textureLod(pano, st, mipLevel);
 }
 
 #endif
@@ -202,6 +227,20 @@ vec4 textureDualParaboloidArray(vec3 normal) {
 
 #endif
 
+#ifdef USE_SOURCE_DUAL_PARABOLOID
+vec4 textureDualParaboloid(vec3 normal) {
+
+	vec3 norm = normalize(normal);
+	norm.xy /= 1.0 + abs(norm.z);
+	norm.xy = norm.xy * vec2(0.5, 0.25) + vec2(0.5, 0.25);
+	if (norm.z < 0.0) {
+		norm.y = 0.5 - norm.y + 0.5;
+	}
+	return textureLod(source_dual_paraboloid, norm.xy, float(source_mip_level));
+}
+
+#endif
+
 void main() {
 
 #ifdef USE_DUAL_PARABOLOID
@@ -225,7 +264,7 @@ void main() {
 
 #ifdef USE_SOURCE_PANORAMA
 
-	frag_color = vec4(texturePanorama(N, source_panorama).rgb, 1.0);
+	frag_color = vec4(texturePanorama(N, source_panorama, 0.0).rgb, 1.0);
 #endif
 
 #ifdef USE_SOURCE_DUAL_PARABOLOID_ARRAY
@@ -233,12 +272,51 @@ void main() {
 	frag_color = vec4(textureDualParaboloidArray(N).rgb, 1.0);
 #endif
 
-#if !defined(USE_SOURCE_DUAL_PARABOLOID_ARRAY) && !defined(USE_SOURCE_PANORAMA)
+#ifdef USE_SOURCE_DUAL_PARABOLOID
+
+	frag_color = vec4(textureDualParaboloid(N).rgb, 1.0);
+#endif
+
+#if !defined(USE_SOURCE_DUAL_PARABOLOID_ARRAY) && !defined(USE_SOURCE_PANORAMA) && !defined(USE_SOURCE_DUAL_PARABOLOID)
 
 	N.y = -N.y;
 	frag_color = vec4(texture(N, source_cube).rgb, 1.0);
 #endif
 
+#else // USE_DIRECT_WRITE
+
+#ifdef COMPUTE_IRRADIANCE
+
+	vec3 irradiance = vec3(0.0);
+
+	// tangent space calculation from origin point
+	vec3 UpVector = vec3(0.0, 1.0, 0.0);
+	vec3 TangentX = cross(UpVector, N);
+	vec3 TangentY = cross(N, TangentX);
+
+	float num_samples = 0.0f;
+
+	for (float phi = 0.0; phi < 2.0 * M_PI; phi += SAMPLE_DELTA) {
+		for (float theta = 0.0; theta < 0.5 * M_PI; theta += SAMPLE_DELTA) {
+			// Calculate sample positions
+			vec3 tangentSample = vec3(sin(theta) * cos(phi), sin(theta) * sin(phi), cos(theta));
+			// Find world vector of sample position
+			vec3 H = tangentSample.x * TangentX + tangentSample.y * TangentY + tangentSample.z * N;
+
+			vec2 st = vec2(atan(H.x, H.z), acos(H.y));
+			if (st.x < 0.0) {
+				st.x += M_PI * 2.0;
+			}
+			st /= vec2(M_PI * 2.0, M_PI);
+
+			irradiance += texture(source_panorama, st, source_mip_level).rgb * cos(theta) * sin(theta);
+			num_samples++;
+		}
+	}
+	irradiance = M_PI * irradiance * (1.0 / float(num_samples));
+
+	frag_color = vec4(irradiance, 1.0);
+
 #else
 
 	vec4 sum = vec4(0.0, 0.0, 0.0, 0.0);
@@ -246,15 +324,26 @@ void main() {
 	for (uint sampleNum = 0u; sampleNum < SAMPLE_COUNT; sampleNum++) {
 		vec2 xi = Hammersley(sampleNum, SAMPLE_COUNT);
 
-		vec3 H = ImportanceSampleGGX(xi, roughness, N);
+		vec3 H = normalize(ImportanceSampleGGX(xi, roughness, N));
 		vec3 V = N;
-		vec3 L = (2.0 * dot(V, H) * H - V);
+		vec3 L = normalize(2.0 * dot(V, H) * H - V);
 
-		float ndotl = clamp(dot(N, L), 0.0, 1.0);
+		float ndotl = max(dot(N, L), 0.0);
 
 		if (ndotl > 0.0) {
+
+			float D = DistributionGGX(N, H, roughness);
+			float ndoth = max(dot(N, H), 0.0);
+			float hdotv = max(dot(H, V), 0.0);
+			float pdf = D * ndoth / (4.0 * hdotv) + 0.0001;
+
+			float saTexel = 4.0 * M_PI / (6.0 * source_resolution * source_resolution);
+			float saSample = 1.0 / (float(SAMPLE_COUNT) * pdf + 0.0001);
+
+			float mipLevel = roughness == 0.0 ? 0.0 : 0.5 * log2(saSample / saTexel);
+
 #ifdef USE_SOURCE_PANORAMA
-			sum.rgb += texturePanorama(L, source_panorama).rgb * ndotl;
+			sum.rgb += texturePanorama(L, source_panorama, mipLevel).rgb * ndotl;
 #endif
 
 #ifdef USE_SOURCE_DUAL_PARABOLOID_ARRAY
@@ -262,7 +351,12 @@ void main() {
 			sum.rgb += textureDualParaboloidArray(L).rgb * ndotl;
 #endif
 
-#if !defined(USE_SOURCE_DUAL_PARABOLOID_ARRAY) && !defined(USE_SOURCE_PANORAMA)
+#ifdef USE_SOURCE_DUAL_PARABOLOID
+
+			sum.rgb += textureDualParaboloid(L).rgb * ndotl;
+#endif
+
+#if !defined(USE_SOURCE_DUAL_PARABOLOID_ARRAY) && !defined(USE_SOURCE_PANORAMA) && !defined(USE_SOURCE_DUAL_PARABOLOID)
 			L.y = -L.y;
 			sum.rgb += textureLod(source_cube, L, 0.0).rgb * ndotl;
 #endif
@@ -273,5 +367,6 @@ void main() {
 
 	frag_color = vec4(sum.rgb, 1.0);
 
-#endif
+#endif // COMPUTE_IRRADIANCE
+#endif // USE_DIRECT_WRITE
 }
diff --git a/drivers/gles3/shaders/scene.glsl b/drivers/gles3/shaders/scene.glsl
index 403de25dd0..e1b0e9f595 100644
--- a/drivers/gles3/shaders/scene.glsl
+++ b/drivers/gles3/shaders/scene.glsl
@@ -627,6 +627,8 @@ layout(std140) uniform Radiance { // ubo:2
 
 #define RADIANCE_MAX_LOD 5.0
 
+uniform sampler2D irradiance_map; // texunit:-6
+
 #ifdef USE_RADIANCE_MAP_ARRAY
 
 uniform sampler2DArray radiance_map; // texunit:-2
@@ -1766,6 +1768,11 @@ FRAGMENT_SHADER_CODE
 
 	vec3 eye_vec = view;
 
+	// IBL precalculations
+	float ndotv = clamp(dot(normal, eye_vec), 0.0, 1.0);
+	vec3 f0 = F0(metallic, specular, albedo);
+	vec3 F = f0 + (max(vec3(1.0 - roughness), f0) - f0) * pow(1.0 - ndotv, 5.0);
+
 #ifdef USE_RADIANCE_MAP
 
 #ifdef AMBIENT_LIGHT_DISABLED
@@ -1775,22 +1782,27 @@ FRAGMENT_SHADER_CODE
 
 		{ //read radiance from dual paraboloid
 
-			vec3 ref_vec = reflect(-eye_vec, normal); //2.0 * ndotv * normal - view; // reflect(v, n);
+			vec3 ref_vec = reflect(-eye_vec, normal);
 			ref_vec = normalize((radiance_inverse_xform * vec4(ref_vec, 0.0)).xyz);
 			vec3 radiance = textureDualParaboloid(radiance_map, ref_vec, roughness) * bg_energy;
 			env_reflection_light = radiance;
 		}
-		//no longer a cubemap
-		//vec3 radiance = textureLod(radiance_cube, r, lod).xyz * ( brdf.x + brdf.y);
 	}
 #ifndef USE_LIGHTMAP
 	{
 
-		vec3 ambient_dir = normalize((radiance_inverse_xform * vec4(normal, 0.0)).xyz);
-		vec3 env_ambient = textureDualParaboloid(radiance_map, ambient_dir, 1.0) * bg_energy;
+		vec3 norm = normal;
+		norm = normalize((radiance_inverse_xform * vec4(norm, 0.0)).xyz);
+		norm.xy /= 1.0 + abs(norm.z);
+		norm.xy = norm.xy * vec2(0.5, 0.25) + vec2(0.5, 0.25);
+		if (norm.z > 0.0) {
+			norm.y = 0.5 - norm.y + 0.5;
+		}
+
+		vec3 env_ambient = texture(irradiance_map, norm.xy).rgb * bg_energy;
+		env_ambient *= 1.0 - F;
 
 		ambient_light = mix(ambient_light_color.rgb, env_ambient, radiance_ambient_contribution);
-		//ambient_light=vec3(0.0,0.0,0.0);
 	}
 #endif
 #endif //AMBIENT_LIGHT_DISABLED
@@ -1892,12 +1904,9 @@ FRAGMENT_SHADER_CODE
 		const vec4 c0 = vec4(-1.0, -0.0275, -0.572, 0.022);
 		const vec4 c1 = vec4(1.0, 0.0425, 1.04, -0.04);
 		vec4 r = roughness * c0 + c1;
-		float ndotv = clamp(dot(normal, eye_vec), 0.0, 1.0);
 		float a004 = min(r.x * r.x, exp2(-9.28 * ndotv)) * r.x + r.y;
 		vec2 env = vec2(-1.04, 1.04) * a004 + r.zw;
-
-		vec3 f0 = F0(metallic, specular, albedo);
-		specular_light *= env.x * f0 + env.y;
+		specular_light *= env.x * F + env.y;
 #endif
 	}