static void SetupSpotLight(VolumetricLight light, CommandBuffer cb, Vector3 lightPos, bool drawShadows)
        {
            float angleScale = Mathf.Tan((light.spotAngle + 1) * 0.5f * Mathf.Deg2Rad) * light.range;

            Quaternion rotation = light.transform.rotation;
            Matrix4x4  world    = Matrix4x4.TRS(lightPos, rotation, new Vector3(angleScale, angleScale, light.range));
            Matrix4x4  view     = Matrix4x4.TRS(lightPos, rotation, Vector3.one).inverse;

            Vector3 fwd = light.transform.forward;
            // cosAngle, planeD,
            Vector2 extraParams = new Vector2(Mathf.Cos((light.spotAngle + 1) * 0.5f * Mathf.Deg2Rad), -Vector3.Dot((lightPos + fwd * light.lightC.range), fwd));

            cb.SetGlobalVector(_ConeAxis, fwd);

            SetNonDirectionalParams(light, cb, lightPos, ref world, drawShadows, extraParams);

            if (light.cookie != null)
            {
                Matrix4x4 proj = Matrix4x4.Perspective(light.spotAngle, 1, 0, 1);
                cb.SetGlobalMatrix(_MyLightMatrix0, spotClipNeg * proj * view);
            }

            if (drawShadows)
            {
                Matrix4x4 proj = Matrix4x4.Perspective(light.spotAngle, 1, SystemInfo.usesReversedZBuffer ? light.range : light.lightC.shadowNearPlane, SystemInfo.usesReversedZBuffer ? light.lightC.shadowNearPlane : light.range);
                Matrix4x4 m    = spotClip * proj;
                m[0, 2] *= -1; m[1, 2] *= -1; m[2, 2] *= -1; m[3, 2] *= -1;
                cb.SetGlobalMatrix(_MyWorld2Shadow, m * view);
            }

            cb.DrawMesh(VolumetricLightUtils.spotlightMesh, world, VolumetricLightUtils.GetMaterial(LightType.Spot), 0, IsCameraInSpotLightBounds(light, fwd) ? 0 : 1);
        }
        static void SetupDirectionalLight(VolumetricLight light, CommandBuffer cb, bool drawShadows)
        {
            if (drawShadows)
            {
                cb.SetGlobalTexture(_World2ShadowTex, light.world2ShadowCache.world2ShadowTex);
            }

            cb.Blit(null as Texture, _RenderTarget, VolumetricLightUtils.GetMaterial(LightType.Directional), 0);
        }
        static void SetupPointLight(VolumetricLight light, CommandBuffer cb, Vector3 lightPos, bool drawShadows)
        {
            Matrix4x4 world = Matrix4x4.TRS(lightPos, Quaternion.identity, Vector3.one * light.range * 2.0f);

            SetNonDirectionalParams(light, cb, lightPos, ref world, drawShadows, Vector2.zero);

            //view
            if (light.cookie != null)
            {
                cb.SetGlobalMatrix(_MyLightMatrix0, Matrix4x4.TRS(lightPos, light.transform.rotation, Vector3.one).inverse);
            }

            cb.DrawMesh(RenderUtils.GetMesh(PrimitiveType.Sphere), world, VolumetricLightUtils.GetMaterial(LightType.Point), 0, IsCameraInPointLightBounds(light) ? 0 : 1);
        }